CP 341 Point-to-Point Communication,
Installation and Parameter Assignment
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SIMATIC
S7-300
CP 341 Point-to-Point
Communication, Installation and
Parameter Assignment
Manual
04/2011
A5E02191071-03
Preface
Product Description
1
Basic Principles of Serial
Data Transmission
2
Commissioning the CP 341
3
Mounting the CP 341
4
Configuring and Parameter
Assignment the CP 341
5
Communication via Function
Blocks
6
Start-up Characteristics and
Operating Mode Transitions
of the CP 341
7
Diagnostics with the CP 341
8
Programming Example for
Standard Function Blocks
9
Technical Specifications
A
Connecting cables
B
Accessories and order
numbers
C
Literature on SIMATIC S7
D
Legal information
Legal information
Warning notice system
This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent
damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert
symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are
graded according to the degree of danger.
DANGER
indicates that death or severe personal injury will result if proper precautions are not taken.
WARNING
indicates that death or severe personal injury may result if proper precautions are not taken.
CAUTION
with a safety alert symbol, indicates that minor personal injury can result if proper precautions are not taken.
CAUTION
without a safety alert symbol, indicates that property damage can result if proper precautions are not taken.
NOTICE
indicates that an unintended result or situation can occur if the relevant information is not taken into account.
If more than one degree of danger is present, the warning notice representing the highest degree of danger will
be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to
property damage.
Qualified Personnel
The product/system described in this documentation may be operated only by personnel qualified for the specific
task in accordance with the relevant documentation, in particular its warning notices and safety instructions.
Qualified personnel are those who, based on their training and experience, are capable of identifying risks and
avoiding potential hazards when working with these products/systems.
Proper use of Siemens products
Note the following:
WARNING
Siemens products may only be used for the applications described in the catalog and in the relevant technical
documentation. If products and components from other manufacturers are used, these must be recommended
or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and
maintenance are required to ensure that the products operate safely and without any problems. The permissible
ambient conditions must be complied with. The information in the relevant documentation must be observed.
Trademarks
All names identified by ® are registered trademarks of Siemens AG. The remaining trademarks in this publication
may be trademarks whose use by third parties for their own purposes could violate the rights of the owner.
Disclaimer of Liability
We have reviewed the contents of this publication to ensure consistency with the hardware and software
described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the
information in this publication is reviewed regularly and any necessary corrections are included in subsequent
editions.
Siemens AG
Industry Sector
Postfach 48 48
90026 NÜRNBERG
GERMANY
A5E02191071-03
Ⓟ 07/2011
Copyright © Siemens AG 2011.
Technical data subject to change
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 3
Preface
Purpose of this manual
The information in this manual enables you to set up and commission a point-to-point
connection.
Contents of the manual
The manual describes the hardware and software of the CP 341 communication processor
and its integration in an S7-300 programmable controller. It is divided up into instruction-
based chapters and a reference section (appendices).
The following subjects are covered:
● The basics of the point-to-point connection with the CP 341
● Commissioning the CP 341
● Mounting the CP 341
● Communication via the CP 341
● Troubleshooting
● Application example
● Properties and technical specifications
Scope of the manual
The manual is relevant for:
Product Order number as of product version
CP 341-RS 232C 6ES7 341-1AH02-0AE0 01
CP 341-20mA TTY 6ES7 341-1BH02-0AE0 01
CP 341-RS 422/485 6ES7 341-1CH02-0AE0 01
Note
The descriptions of the CP 341 communication processors in this manual were correct at the
time of publication. We reserve the right to describe modifications to the functionality of the
modules in a separate product information.
Preface
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
4 Manual, 04/2011, A5E02191071-03
Conventions
The abbreviation CP 341 is used in this documentation when information applies to all three
module variants: CP 341-RS232C, CP 341-20mA TTY and CP 341-RS 422/485.
Navigation features of this manual
The manual's navigation features outlined below support quick access to specific
information:
● At the beginning of the manual you can find a comprehensive list of contents.
● In the main body of the text, the information in the left-hand column of each page
summarizes the contents of each section.
● Following the appendices, a glossary defines important technical terms used in the
manual.
● Finally, a comprehensive index allows quick access to information on specific subjects.
Electronic manuals
The entire set of SIMATIC S7 documentation is available on the SIMATIC S7 Collection CD-
ROM.
Recycling and disposal
The CP 341 is an environment-friendly product. It's characteristic features include:
● In spite of its excellent resistance to fire, the flame-resistant agent in the plastic used for
the housing does not contain halogens.
● Laser inscriptions (i.e. no labels)
● Plastics identification in accordance with DIN 54840
● Fewer materials used due to size reduction; fewer parts due to integration in ASICs
The CP 341 is suitable for recycling on account of the low level of contaminants in its
components.
Please contact a certified waste disposal company for eco-friendly recycling and to dispose
of your old device.
Preface
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 5
Additional support
If you have any unanswered questions regarding use of the products described in this
manual, please contact your local Siemens representative.
● You can locate your contact partner on this Internet URL:
http://www.siemens.de/automation/partner (http://www.siemens.com/automation/partner)
● The portal to our technical documentation for the various SIMATIC products and systems
is available at:
http://www.siemens.de/simatic-doku (http://www.siemens.com/simatic-doku)
The online catalog and the online ordering system are available at:
http://www.siemens.de/automation/mall (http://www.siemens.com/automation/mall)
Training center
We offer a range of relevant courses to help you to get started with the SIMATIC S7
automation system. Please contact your regional training center or the central training center
in D90327 Nuremberg, Germany.
● Internet: http://www.siemens.com/sitrain (http://www.siemens.com/sitrain)
Preface
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
6 Manual, 04/2011, A5E02191071-03
Technical Support
How to contact Technical Support for all Industry Automation and Drive Technology products
● Use the Web form for the support request
http://www.siemens.com/automation/support-request
(http://www.siemens.com/automation/support-request)
Additional information about our technical support is available on the Internet at
http://www.siemens.de/automation/service&support
(http://www.siemens.com/automation/service&support)
Service & Support on the Internet
In addition to our documentation, we offer a comprehensive knowledge base on the Internet.
http://www.siemens.de/automation/service&support
(http://www.siemens.com/automation/service&support)
There you will find:
● The newsletter, which constantly provides you with up-to-date information on your
products
● Relevant documentation for your application, which you can access via the search
function in Product Support
● the bulletin board, a worldwide knowledge exchange for users and experts.
● Your local Industry Automation and Drive Technology representative in our contact
database
● Information about repairs, spare parts and consulting.
See also
Literature on SIMATIC S7 (Page 237)
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 7
Table of contents
Preface ...................................................................................................................................................... 3
1 Product Description ................................................................................................................................. 11
1.1 Possible applications for the CP 341 ...........................................................................................11
1.2 Design of the CP 341...................................................................................................................14
1.3 Components for a Point-to-Point Connection with the CP 341....................................................16
1.3.1 Required Hardware Components ................................................................................................16
1.3.2 Required Software Components..................................................................................................17
1.4 Properties of the Serial Interface .................................................................................................18
1.4.1 RS 232C Interface of the CP 341-RS 232C ................................................................................18
1.4.2 20mA-TTY interface of the CP 341-20mA TTY ...........................................................................19
1.4.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485..............................................................20
1.5 Cables for Connecting the Communication Processor to a Communication Partner..................21
2 Basic Principles of Serial Data Transmission........................................................................................... 23
2.1 Serial Transmission of a Character .............................................................................................23
2.2 Transmission Procedure with a Point-to-Point Connection .........................................................27
2.3 Transmission integrity ..................................................................................................................29
2.4 Data Transmission with the 3964(R) Procedure..........................................................................32
2.4.1 Principle of the Data Transmission with the 3964(R) Procedure.................................................32
2.4.2 Control characters of the 3964(R) procedure ..............................................................................32
2.4.3 Block Checksum ..........................................................................................................................33
2.4.4 Sending Data with 3964(R)..........................................................................................................34
2.4.5 Receiving Data with 3964(R) .......................................................................................................38
2.4.6 Handling Erroneous Data.............................................................................................................43
2.5 Data Transmission with the RK 512 Computer Connection ........................................................46
2.5.1 Sending Data with RK 512...........................................................................................................49
2.5.2 Fetching Data with RK 512 ..........................................................................................................52
2.5.3 Quasi-Full-Duplex Operation .......................................................................................................55
2.5.4 RK 512 CPU Requests ................................................................................................................56
2.6 Data Transmission with the ASCII Driver ....................................................................................59
2.6.1 Principle of the Data Transmission with the ASCII Driver ...........................................................59
2.6.2 Sending data with the ASCII driver..............................................................................................59
2.6.3 Receiving data with the ASCII driver ...........................................................................................61
2.6.4 RS 485 mode ...............................................................................................................................67
2.6.5 RS 232C operation ......................................................................................................................68
2.6.6 Data flow control/Handshaking ....................................................................................................71
2.7 Data transmission with the printer driver .....................................................................................72
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CP 341 Point-to-Point Communication, Installation and Parameter Assignment
8 Manual, 04/2011, A5E02191071-03
2.8 Configuration data....................................................................................................................... 76
2.8.1 Configuration Data of the 3964(R) Procedure ............................................................................ 76
2.8.2 Configuration Data of the RK 512 Computer Connection........................................................... 82
2.8.3 Configuration data of the ASCII Driver........................................................................................ 84
2.8.4 Parameter assignment data of the printer driver......................................................................... 91
2.8.5 Conversion and control statements for printout .......................................................................... 96
3 Commissioning the CP 341 ................................................................................................................... 105
4 Mounting the CP 341 ............................................................................................................................. 107
4.1 CP 341 slots.............................................................................................................................. 107
4.2 Mounting and Dismounting the CP 341 .................................................................................... 108
4.2.1 Installation steps ....................................................................................................................... 108
4.2.2 Removal steps .......................................................................................................................... 109
4.2.3 Installation guidelines................................................................................................................ 109
5 Configuring and Parameter Assignment the CP 341 ............................................................................. 111
5.1 Parameter Assignment Options ................................................................................................ 111
5.2 Installing the Programming Interface ........................................................................................ 111
5.3 Configuring the CP 341............................................................................................................. 112
5.4 Assigning Parameters to the Communications Protocols......................................................... 113
5.5 Identification data ...................................................................................................................... 114
5.6 Managing the Parameter Data.................................................................................................. 116
5.7 Subsequent Loading of Drivers (Transmission Protocols)........................................................ 117
5.8 Firmware updates ..................................................................................................................... 118
5.8.1 Subsequent Loading of Firmware Updates............................................................................... 118
5.8.2 Viewing the Firmware Version .................................................................................................. 121
6 Communication via Function Blocks ...................................................................................................... 123
6.1 Overview of the Function Blocks............................................................................................... 124
6.2 Using function blocks ................................................................................................................ 126
6.3 Using the Function Blocks with the 3964(R) Procedure ........................................................... 127
6.3.1 S7 Sends Data to a Communication Partner............................................................................ 128
6.3.2 S7 receives data from a communication partner ...................................................................... 132
6.4 Using the Function Blocks with the RK 512 Computer Connection.......................................... 136
6.4.1 Sending Data with FB P_SND_RK (Active Request)................................................................ 138
6.4.2 Receiving Data with FB P_RCV_RK (Passive Request) .......................................................... 143
6.4.3 Readying Data with FB P_RCV_RK (Passive Request) ........................................................... 147
6.4.4 Fetching Data with P_SND_RK FB (Active Request) ............................................................... 151
6.5 Using the System Function Blocks with the ASCII Driver......................................................... 157
6.5.1 Function blocks with ASCII driver ............................................................................................. 157
6.5.2 Interface status of the CP 341, checking .................................................................................. 158
6.5.3 Interface outputs of the CP 341, setting/resetting..................................................................... 160
Table of contents
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 9
6.6 Use of function blocks to output message texts to a printer ......................................................162
6.7 General Information on Program Processing ............................................................................167
6.8 Technical Specifications of the Function Blocks........................................................................168
7 Start-up Characteristics and Operating Mode Transitions of the CP 341............................................... 171
7.1 Operating Modes of the CP 341 ................................................................................................171
7.2 Startup Characteristics of the CP 341 .......................................................................................172
7.3 Behavior of the CP 341 on Operating Mode Transitions of the CPU ........................................173
8 Diagnostics with the CP 341.................................................................................................................. 175
8.1 Diagnostics Functions of the CP 341.........................................................................................175
8.1.1 Diagnostics via the display elements of the CP 341..................................................................177
8.1.2 Diagnostics Messages of the Function Blocks ..........................................................................178
8.1.3 Error Numbers in the Response Message Frame .....................................................................194
8.1.4 Diagnostics via the diagnostic buffer of the CP 341 ..................................................................195
8.1.5 Diagnostic Interrupt....................................................................................................................197
9 Programming Example for Standard Function Blocks............................................................................ 199
9.1 General Information ...................................................................................................................199
9.2 Device Configuration..................................................................................................................200
9.3 Settings ......................................................................................................................................200
9.4 Blocks Used ...............................................................................................................................201
9.5 Installation, Error Messages ......................................................................................................202
9.6 Activation, Start-Up Program and Cyclic Program.....................................................................203
A Technical Specifications ........................................................................................................................ 205
A.1 Technical Data of the CP 341....................................................................................................205
A.2 Transmission Rates ...................................................................................................................212
B Connecting cables ................................................................................................................................. 215
B.1 RS 232C Interface of the CP 341-RS 232C ..............................................................................215
B.2 20 mA TTY interface on the CP 341-20mA-TTY .......................................................................223
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485............................................................230
C Accessories and order numbers ............................................................................................................ 235
D Literature on SIMATIC S7...................................................................................................................... 237
D.1 Literature on SIMATIC S7..........................................................................................................237
Glossary ................................................................................................................................................ 239
Index...................................................................................................................................................... 245
Table of contents
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
10 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 11
Product Description 1
1.1 Possible applications for the CP 341
The CP 341 communication processor enables you to exchange data between automation
devices or computers by means of a point-to-point connection.
Functionality of the CP 341
The CP 341 communication processor provides the following functionality:
● Transmission rate up to 115.2 kbaud, half duplex
● Integration of the most important transmission protocols in the module firmware:
– 3964(R) procedure
– RK 512 computer link
– ASCII driver
– Printer driver
● Subsequent loading of other drivers (transmission protocols) with the CP 341: Point-to-
Point Communication, Parameter Assignment parameter assignment interface.
● Adaptation of the transmission protocols using the CP 341: Point-to-Point
Communication, Parameter Assignment parameter assignment interface
● Integrated serial interface:
Three module variants are available, each having a different interface type that is suitable
for different communication partners (see following table).
Module variants
The following variants of the CP 341 communication processor are available:
Table 1- 1 CP 341 module variants
Module Order number Integrated interface
CP 341-RS 232C 6ES7 341-1AH02-0AE0 RS 232C interface
CP 341-20mA-TTY 6ES7 341-1BH02-0AE0 20mA-TTY interface
CP 341-RS 422/485 6ES7 341-1CH02-0AE0 X27 (RS 422/485) interface
Product Description
1.1 Possible applications for the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
12 Manual, 04/2011, A5E02191071-03
Functions of module variants
Different driver functions can be used depending on the module variant of the CP 341:
Table 1- 2 Functions of CP 341 module variants
Function CP 341-
RS 232C
CP 341-
20mA-TTY
CP 341-RS 422/485
RS 422* RS 485*
ASCII driver: Yes Yes Yes Yes
Control of RS 232C accompanying signals Yes No No No
Controlling/reading of RS 232C
accompanying signals with FBs
Yes No No No
RTS/CTS flow control Yes No No No
XON/XOFF flow control Yes Yes Yes No
3964(R) procedure Yes Yes Yes No
RK 512 computer link Yes Yes Yes No
Printer driver Yes Yes Yes Yes
* The RS 422 and RS 485 are differentiated through parameter assignment.
Uses of the CP 341
The CP 341 communication processor enables a point-to-point connection with various
Siemens modules and with non-Siemens products:
● SIMATIC S5 via the 3964(R) driver or RK 512 with corresponding interface module on S5
side
● Siemens PDA terminals from the ES 2 family via 3964(R) driver
● MOBY I (ASM 420/421, SIM), MOBY L (ASM 520) and ES 030K data acquisition terminal
via 3964R driver
● PCs via the 3964(R) procedure (the following development tools are available for
programming on PCs for MS DOS or for Windows: PRODAVE S5 DOS/Win 64R
(6ES5 897-2VD01))
● Barcode readers via the 3964(R) or ASCII driver
● Non-Siemens PLCs via the 3964(R) driver, ASCII driver, or RK 512
● Other devices with simple protocol structures by means of appropriate protocol
adaptation with the ASCII driver
● Other devices that also have a 3964(R) driver or RK 512
● Printers (HP Deskjet, HP Laserjet, Postscript, Epson, IBM)
Product Description
1.1 Possible applications for the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 13
The CP 341 can also be operated in a distributed configuration using the ET 200M (IM153)
I/O device.
The CP 341 can be operated in a PROFINET IO network if
● the corresponding PROFINET IO controller is integrated in the SIMATIC STEP 7 CPU,
● FB7 (P_RCV_RK) / FB8 (P_SND_RK) - blocks with versions higher than or equal to V3.0
are used.
Note
The CP 341 modules (6ES7 341-1xH0y-0AE0) cannot be operated downstream from the
external communication CPs CP 342-5 (PROFIBUS DP) and CP 343-1 (PROFINET IO).
Product Description
1.2 Design of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
14 Manual, 04/2011, A5E02191071-03
1.2 Design of the CP 341
The CP 341 communication processor is supplied with an integrated serial interface.
Positions of the module elements
The diagram shows the arrangement of the module elements on the front panel of the
CP 341 communication processor.
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Figure 1-1 Positions of the module elements on the CP 341 communication processor
Product Description
1.2 Design of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 15
LED indicators
The following LED indicators are located on the front panel of the communication processor:
SF (red) Error display
TxD (green) Interface sending
RxD (green) Interface receiving
Section "Diagnostics via the display elements of the CP 341 (Page 177)" describes the
operating states and errors that these LEDs indicate. Section "Subsequent Loading of
Firmware Updates (Page 118)" provides information on the LED indicators that occur when
loading a firmware update.
Integrated interface
The CP 341 is available in three variants with different interface types:
● RS 232C
● X27 (RS 422/485)
● 20-mA-TTY
The interface type is indicated on the front of the CP 341. A detailed interface description
can be found in Section "Properties of the Serial Interface (Page 18)".
Bus connector for the S7 backplane bus
A bus connector is supplied with the CP 341. The bus connector is inserted onto the rear
panel connector of the CP 341 during installation. The S7-300 backplane bus is connected
by means of the bus connector.
The S7-300 backplane bus is a serial data bus via which the CP 341 communicates with the
modules of the programmable controller.
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Figure 1-2 Bus connector
Product Description
1.3 Components for a Point-to-Point Connection with the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
16 Manual, 04/2011, A5E02191071-03
1.3 Components for a Point-to-Point Connection with the CP 341
To establish a point-to-point connection between the communication processor and a
communication partner, you require certain hardware and software components.
1.3.1 Required Hardware Components
Hardware components
The following table lists the hardware components for establishing a point-to-point
connection with the CP 341.
Table 1- 3 Hardware components for a point-to-point connection
Component Function Illustration
Rack (mounting rail) ... provides the mechanical and electrical
connections of the S7-300.
Power supply module (PS) ... converts the line voltage (120/230 V AC) into
the operating voltage of 24 V DC required to
supply the S7-300.
Central processing unit (CPU)
Accessories:
Memory card
Backup battery
... executes the user program; communicates with
other CPUs or with a programming device via the
MPI interface.
Communication processor ... communicates with a communication partner
via the interface.
Standard connecting cable ... connects the CP 341 communication processor
to the communication partner.
Product Description
1.3 Components for a Point-to-Point Connection with the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 17
Component Function Illustration
PG cable ... connects a CPU to a programming device/PC.
Programming device (PG) or PC ... communicates with the CPU of the S7-300.
1.3.2 Required Software Components
Software components
The following table lists the software components required for establishing a point-to-point
connection with the CP 341.
Table 1- 4 Software components for a point-to-point connection with the CP 341
Component Function Illustration
STEP 7 software package ... configures, assigns parameters,
programs and tests the S7-300.
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Parameter assignment interface: Point-
to-Point Communication, Parameter
Assignment parameter assignment
interface
... assigns parameters for the interface of
the CP 341.
Function blocks (FB) with programming
example
... controls the communication between
CPU and CP 341.
Loadable drivers ... with transmission protocols that can be
loaded on the CP 341 in addition to the
standard protocols in the module firmware.
'RQJOH
Product Description
1.4 Properties of the Serial Interface
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
18 Manual, 04/2011, A5E02191071-03
1.4 Properties of the Serial Interface
Three module variants of the communication processor are available, each having a different
interface type that is suitable for different communication partners.
The interfaces of the module variants are described in the following sections.
1.4.1 RS 232C Interface of the CP 341-RS 232C
Definition
The RS 232C interface is a voltage interface used for serial data transmission in compliance
with the RS 232C standard.
Properties
The RS 232C interface has the following attributes and is in compliance with the following
requirements:
Type: Voltage interface
Front connector: 9-pin subminiature D male connector with a screw-type fitting (compatible
with the 9-pin COM port (PC/PG))
RS 232C signals: TXD, RXD, RTS, CTS, DTR, DSR, RI, DCD, GND; all isolated against the
S7-internal power supply (S7-300 backplane bus) and the external 24 V DC
supply
Max. baud rate: 115.2 kbaud
Max. cable length: 15 m, cable type LIYCY 7 x 0.14 (6ES7 902-1Ax00-0AA0)
Standard: DIN 66020, DIN 66259, EIA-RS 232C, CCITT V.24/V.28
Product Description
1.4 Properties of the Serial Interface
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 19
RS 232C signals
The following table shows the meanings of the RS232C accompanying signals.
Table 1- 5 RS 232C interface signals
Signal Designation Meaning
TXD Transmitted Data Transmitted data; Transmission line is held by CP 341 on logic "1" in idle state.
RXD Received Data Received data; Receive line must be held on logic "1" by communication partner.
RTS Request To Send RTS "ON": CP 341 ready to send
RTS "OFF": CP 341 is not sending
CTS Clear To Send Communication partner can receive data from the CP 341. The communication
processor expects the signal as response to RTS "ON".
DTR Data Terminal Ready DTR "ON": CP 341 is switched on and ready for operation
DTR "OFF": CP 341 is not switched on and is not ready for operation
DSR Data Set Ready DSR "ON": Communication partner is switched on and ready for operation
DSR "OFF": Communication partner is not switched on and not ready for operation
RI Ring Indicator Incoming call on connection of a modem
DCD Data Carrier Detect Carrier signal on connection of a modem
1.4.2 20mA-TTY interface of the CP 341-20mA TTY
Definition
The 20mA-TTY interface is a current-loop interface used for serial data transmission.
Properties
The 20mA-TTY interface has the following properties and meets the following requirements:
Type: Current-loop interface
Front connector: 9-pin subminiature D female with screw interlock
20mA TTY signals: two isolated 20 mA current sources, receive loop (RX) "-" and "+" transmit
loop (TX) "-" and "+"; all isolated against the S7-internal power supply
(S7-300 backplane bus) and the external 24 V DC supply
Max. baud rate: 19.2 kbaud
Max. cable length: 1000 m active at 9.6 kbaud1) (CP supplies the current loop), 1000 m passive
at 9.6 kbaud 1) (partner supplies the current loop), 500 m active, 500 m
passive at 19.2 kbaud; cable type LIYCY 7 x 0.14 (6ES7 902-2Ax00-0AA0)
Standard: DIN 66258 Part 1
1) The switch from active to passive is made possible through appropriate wiring on the cable
connector.
Product Description
1.4 Properties of the Serial Interface
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
20 Manual, 04/2011, A5E02191071-03
1.4.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
Definition
The X27 (RS 422/485) interface is a differential voltage interface for serial data transmission
in compliance with the X27 standard.
Properties
The X27 (RS 422/485) interface has the following properties and meets following
requirements:
Type: Differential voltage interface
Front connector: 15-pin sub-D female, with screwed interlock
RS 422 signals: TXD (A), RXD (A), TXD (B), RXD (B), GND; all isolated against the
S7-internal power supply
RS 485 signals: R/T (A), R/T (B), GND; all isolated against the S7-internal power supply
(S7-300 backplane bus) and the external 24 V DC supply
Max. baud rate: 115.2 kbaud
Max. cable length: 250 m at 115.2 kbaud 500 m at 38.4 kbaud 1200 m at 19.2 kbaud; cable
type LIYCY 7 x 0.14 (6ES7 902-3Ax00-0AA0)
Standard: DIN 66259 Parts 1 and 3, EIA-RS 422/485, CCITT V.11
Note
With the RK 512 and 3964(R) protocols, the X27 (RS 422/485) interface module can only be
used in four-wire mode.
Product Description
1.5 Cables for Connecting the Communication Processor to a Communication Partner
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 21
1.5 Cables for Connecting the Communication Processor to a
Communication Partner
Standard Cables
Siemens offers standard cables in various lengths for point-to-point connection between the
communication processor and a communication partner.
The order numbers and the length of the standard cables are listed in the appendix
"Accessories and order numbers (Page 235)" of this manual.
Fabricating Your Own Cables
If you are fabricating your own cables, there are a few points to take into consideration:
Refer to section "Connecting cables (Page 215)" of this manual for information about this
and for the pin assignment of the sub D cable and the wiring diagrams.
Product Description
1.5 Cables for Connecting the Communication Processor to a Communication Partner
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
22 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 23
Basic Principles of Serial Data Transmission 2
2.1 Serial Transmission of a Character
The system provides various networking options for the exchange of data between two or
more communication partners. The simplest form of data interchange is via a point-to-point
connection between two communication partners.
Point-to-point connection
With the point-to-point connection, the communication processor forms the interface
between a programmable controller and a communication partner. The data is transmitted
serially in the point-to-point connection with the communication processor.
Serial data transmission
In serial data transmission, the individual bits of each byte of information to be transmitted
are transmitted one after the other in a fixed order.
Drivers for uni/bidirectional data traffic
The CP 341 itself handles data transmission with the communication partner via its serial
interface. The CP 341 is equipped with three different drivers for this purpose.
Unidirectional data traffic:
● Printer driver
Bidirectional data traffic:
● ASCII driver
● 3964(R) procedure
● RK 512 computer link
The CP 341 handles the data transmission via the serial interface in accordance with the
interface type and the selected driver.
Unidirectional data traffic - printer output
In the case of printer output (printer driver), n bytes of user data is output to a printer. No
characters are received. The only exception to this are individual data flow control characters
(e.g., XON/XOFF).
Basic Principles of Serial Data Transmission
2.1 Serial Transmission of a Character
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
24 Manual, 04/2011, A5E02191071-03
Bidirectional data traffic - operating modes
The communication processor has two operating modes for bidirectional data traffic:
● Half-duplex mode (3964(R) procedure, ASCII driver, RK 512)
Data is exchanged between one or more communication partners in both directions
alternately. Half-duplex mode means that data is either being sent or received at any
given moment. The exception to this may be individual data flow control characters
(e.g., XON/XOFF), which can also be sent during a receive operation or received during a
send operation.
● Full-duplex mode (ASCII driver)
Data is exchanged between one or more communication partners in both directions
simultaneously; both sending and receiving can take place at the same time. Every
communication partner must be able to handle send and receive operations
simultaneously.
With an RS 485 (2-wire) setting, the X27 (RS 422/485) interface module can only be run in
half-duplex mode.
Asynchronous data transmission
With the CP 341, serial data transmission occurs asynchronously. The so-called time grid
synchronism (a fixed time grid for transmission of a fixed character string) is only maintained
during transmission of a character. Each character to be sent is preceded by a
synchronization pulse, or start bit. The length of the start-bit transmission determines the
clock pulse. The end of the character transfer is signaled by the stop bit.
Declarations
As well as the start and stop bits, further declarations must be made between the sending
and receiving partners before serial data transmission can take place. These include:
● Transmission speed (baud rate)
● Character and acknowledgment delay times
● Parity
● Number of data bits
● Number of stop bits
Sections "Configuration data (Page 76)" and "Transmission Procedure with a Point-to-Point
Connection (Page 27)" describe the role the declarations play in the various transmission
procedures, and how they are parameterized.
Basic Principles of Serial Data Transmission
2.1 Serial Transmission of a Character
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 25
Character frame
Data is transmitted between the the CP 341 and a communication partner via the serial
interface in a character frame. Three data formats are available for each character frame.
You can assign the desired format for data transmission in the CP 341: Point-to-Point
Communication, Parameter Assignment parameter assignment interface.
The figure below shows an example of the three data formats of the 10-bit character frame.
12 8910
12 109
12 8 109
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6LJQDOVWDWHಯಯ
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GDWDELWVVWDUWELWGDWDELWVVWRSELW
GDWDELWV
SDULW\ELW
VWRSELW
VWRSELW
GDWDELWV
Figure 2-1 10-bit character frame
Basic Principles of Serial Data Transmission
2.1 Serial Transmission of a Character
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
26 Manual, 04/2011, A5E02191071-03
Character delay time
The figure below shows the maximum time permitted between two characters received
within a message frame. This is known as the character delay time.
1
&KDUDFWHUGHOD\WLPH
6LJQDO
QWKFKDUDFWHU
QWKFKDUDFWHU
7LPHW
Figure 2-2 Character delay time
Basic Principles of Serial Data Transmission
2.2 Transmission Procedure with a Point-to-Point Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 27
2.2 Transmission Procedure with a Point-to-Point Connection
When data is transmitted, all communication partners must adhere to a fixed set of rules for
handling and implementing data traffic. ISO has defined a 7-layer model, which is recognized
as the basis for a worldwide standardization of transmission protocols.
Protocol
All communication partners must adhere to a fixed set of rules for handling and implementing
data traffic. Such rules are called protocols.
A protocol defines the following:
● Operating mode
Half-duplex or full-duplex mode
● Initiative
Specifies which communication partner can initiate the transmission and under what
conditions.
● Control characters
Specifies which control characters are to be used for data transmission
● Character frame
Specifies the character frame to be used for data transmission.
● Data backup
Specifies the data backup procedure to be used
● Character delay time
Specifies the time period within which a character to be received must be arrive.
● Transmission speed
Specifies the baud rate in bits/s
Procedure
This is the specific process according to which the data is transmitted.
Basic Principles of Serial Data Transmission
2.2 Transmission Procedure with a Point-to-Point Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
28 Manual, 04/2011, A5E02191071-03
ISO 7-layer reference model
The reference model defines the external behavior of the communication partners. Each
protocol layer, except for the lowest one, is embedded in the next one down.
The individual layers are defined as follows:
1. Physical layer
– Physical requirements for data transmission, e.g., transmission medium, baud rate
2. Data link layer
– Security procedure for the data transmission
– Access method
3. Network layer
– Definition of communication paths
– Specification of the addressing for the data transmission between two communication
partners
4. Transport layer
– Error detection procedure
– Corrective actions
– Handshaking
5. Session layer
– Setup of data transmission
– Execution
– Release of data transmission
6. Presentation layer
– Implementation of the standardized communication system display type in a device-
specific form (data interpretation guidelines)
7. Application layer
– Specification of the communication task and the functions it requires
Processing the protocols
The sending communication partner runs through the protocols from the highest layer (No. 7
- application-oriented) to the lowest layer (No. 1, physical specifications) while the receiving
communication partner processes the protocols in the reverse order, i.e., starting with
layer 1.
Not every protocol has to take all seven layers into account. If the sending and receiving
communication partner speak the same language, layer 6 is omitted.
Basic Principles of Serial Data Transmission
2.3 Transmission integrity
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 29
2.3 Transmission integrity
Transmission integrity plays an important role in the transmission of data and in selection of
the transmission procedure. Generally speaking, the more layers of the reference model are
applied, the greater the transmission integrity.
Classifying the supplied protocols
The CP 341 can use the following protocols:
● 3964(R) procedure
● RK 512 computer link
● ASCII driver
● Printer driver
The figure below illustrates how these protocols of the CP 341 fit into the reference model:
RK 512
3964(R)
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Figure 2-3 Position of the supplied protocols of the CP 341 in the reference model
Basic Principles of Serial Data Transmission
2.3 Transmission integrity
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
30 Manual, 04/2011, A5E02191071-03
Transmission Integrity with the Printer Driver
Data integrity when using the printer driver:
● No data integrity precautions are taken for data transport with the printer driver.
● To prevent data from being lost in the event of the printer receive buffer overflowing, you
can work with data flow control (XON/XOFF, RTS/CTS).
● When data is output to the printer, the printer's BUSY signal is evaluated. The CP 341
receives the BUSY signal as a CTS signal and evaluates it in the same way (see ASCII
driver). Note that, when using CTS/RTS flow control, you must set the polarity of the
BUSY signal to CTS = "OFF" on the printer.
Transmission Integrity with the ASCII driver
Data integrity when using the ASCII driver:
● When data is transmitted via the ASCII driver, there are no data integrity precautions
other than the use of a parity bit (can also be canceled, depending on how the character
frame is set). This means that, although this type of data transport has a very efficient
throughput rate, security is not guaranteed.
● Using the parity bit makes it possible to detect an inverted bit in a character that is to be
transmitted. If two or more bits of a character are inverted, this error can no longer be
detected.
● To increase transmission integrity, a checksum and length specification for a message
frame can be employed. These measures must be implemented by the user.
● A further increase in data integrity can be achieved by means of acknowledgment
message frames in response to send or receive message frames. This is the case with
high-level protocols for data communication (ISO 7-layer reference model).
Transmission Integrity with 3964(R)
Enhanced data integrity through use of the 3964(R) procedure:
● The Hamming distance with the 3964(R) is 3. This measures the integrity of a data
transmission.
● The 3964(R) procedure ensures high transmission integrity on the transmission line. This
high transmission integrity is achieved by means of a specified message-frame setup and
release as well as the use of a block check character (BCC).
Two different procedures for data transmission can be used, either with or without a block
check character:
● Data transmission without a block check character: 3964
● Data transmission with a block check character: 3964R
In this manual, the designation 3964(R) is used when descriptions and notes refer to both
data transmission procedures.
Basic Principles of Serial Data Transmission
2.3 Transmission integrity
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 31
Performance limits with 3964R
● Further processing of the send/receive data by the PLC program in the communication
partner is not guaranteed. You can only ensure this by using a programmable
acknowledgment mechanism.
● The block check of the 3964R procedure (EXOR operation) cannot detect missing zeros
(as a whole character) because a zero in the EXOR operation does not affect the result of
the calculation.
Although the loss of an entire character (this character has to be a zero!) is highly
unlikely, it could possibly occur under very bad transmission conditions.
You can protect a transmission against such errors by sending the length of the data
message frame along with the data itself, and having the length checked in the
communication partner.
● Such transmission errors are ruled out when the RK 512 computer link is used for data
transmission, because here (unlike the 3964(R) procedure) further processing (e.g.,
storage in the destination data block) is acknowledged via response message frames and
the send data length is recorded in the message frame header. This enables the RK 512
to achieve a higher Hamming distance (of 4) than the 3964R.
Transmission Integrity with RK 512
Very high data integrity through use of RK 512:
● The Hamming distance with the RK 512 and 3964R is 4. This is a measure of the integrity
of a data transmission.
● Using the RK 512 computer link guarantees high transmission integrity on the data line
(because the RK 512 uses the 3964R procedure for data transport).
● Further processing in the communication partner is ensured (because the RK 512
interpreter checks the additional length specification in the header and, after storing the
data in the destination data area of the communication partner, generates a message
frame acknowledging the success or failure of the data transport).
● The RK 512 computer link independently guarantees the correct use of the 3964R
procedure and the analysis/addition of the length specification as well as the generation
of the response message frames. There is no user handling! All you need to do is
evaluate the positive/negative final acknowledgment.
Performance limits with RK 512
● Using the RK 512 computer link provides maximum data integrity! You can improve this
still further by, for example, using other block check mechanisms (such as CRC checks).
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
32 Manual, 04/2011, A5E02191071-03
2.4 Data Transmission with the 3964(R) Procedure
2.4.1 Principle of the Data Transmission with the 3964(R) Procedure
The 3964(R) procedure controls the data transmission in a point-to-point connection
between the communication processor and a communication partner. As well as the physical
layer (layer 1), the 3964(R) procedure also incorporates the data-link layer (layer 2).
2.4.2 Control characters of the 3964(R) procedure
Control characters
During data transmission, the 3964(R) procedure adds control characters to the user data
(data-link layer). These control characters allow the communication partner to check whether
the data has arrived complete and without errors.
The 3964(R) procedure analyzes the following control characters:
● STX Start of text;
Start of character string to be transmitted
● DLE Data Link Escape;
Data transmission switchover
● ETX End of Text;
End of character string to be transmitted
● BCC Block check character (3964R only);
Block check character
● NAK Negative Acknowledge;
negative acknowledgment
Note
If DLE is transmitted as an information character, it is sent twice (DLE duplication) so that
it can be distinguished from the DLE control character on the send line for connection
setup and release. The receiver then reverses the DLE duplication.
Priority
With the 3964(R) procedure, one communication partner must be assigned a higher priority
and the other partner a lower priority. If both communication partners issue a send request at
the same time, the partner with the lower priority will defer its send request.
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 33
2.4.3 Block Checksum
Block Checksum
With the 3964R transmission protocol, data integrity is increased by the additional sending of
a block check character (BCC).
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Figure 2-4 Block Checksum
The block checksum is the even longitudinal parity (EXOR operation on all data bytes) of a
sent or received block. Its calculation begins with the first byte of user data (first byte of the
message frame) after the connection setup, and ends after the DLE ETX code on connection
release.
Note
If DLE duplication occurs, the DLE code is accounted for twice in the BCC calculation.
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
34 Manual, 04/2011, A5E02191071-03
2.4.4 Sending Data with 3964(R)
Sending data with 3964(R)
The figure below illustrates the transmission sequence when data is sent with the 3964(R)
procedure.
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Figure 2-5 Data traffic when sending with the 3964(R) procedure
Connection setup for sending
To set up the connection, the 3964(R) procedure sends the STX control character. If the
communication partner responds with the DLE character before the acknowledgment delay
time expires, the procedure switches to send mode.
If the communication partner answers with NAK or with any other character (except for DLE
or STX) or the acknowledgment delay time expires without a response, the procedure
repeats the connection setup. After the assigned number of unsuccessful connection
attempts, the procedure cancels the connection setup and sends the NAK character to the
communication partner. The CP 341 reports the error to the P_SND_RK function block
(STATUS output parameter).
Sending data
If a connection is successfully set up, the user data contained in the output buffer of the
communication processor is sent to the communication partner with the chosen transmission
parameters. The partner monitors the times between incoming characters. The interval
between two characters must not exceed the character delay time.
If the communication partner sends the NAK character during an active send operation, the
procedure cancels its transmission of the block and tries again as described above,
beginning with connection setup. If a different character is sent, the procedure first waits for
the character delay time to expire and then sends the NAK character to change the state of
the communication partner to idle. Then the procedure starts to send the data again with the
STX connection setup.
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 35
Connection release for sending
Once the contents of the buffer have been sent, the procedure adds the DLE and ETX
characters and, with 3964R only, the block checksum BCC as the end identifier, and waits
for an acknowledgment character. If the communication partner sends the DLE character
within the acknowledgment delay time, it means that the data block has been received
without errors. If the communication partner responds with NAK, any other character (except
DLE), or a damaged character, or if the acknowledgment delay time expires without a
response, the procedure starts to send the data again with the connection setup STX.
After the assigned number of attempts to send the data block, the procedure stops trying and
sends a NAK to the communication partner. The CP 341 reports the error to the P_SND_RK
function block (STATUS output parameter).
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
36 Manual, 04/2011, A5E02191071-03
Sending with the 3964(R) Procedure
The figure below illustrates sending with the 3964(R) procedure.
No
Yes
No
QVZ
expired ?
ja
Character
received ?
Yes
Yes
Yes
Yes
With N A K ?
Yes
Intercom ?
ja
Yes Yes
Yes
No
No
Yes
No
No
Send N A K
No
No
faulty, n ot DLE or
STX
No
A > A max ?
W > W max ?
No
S end request
Sending with pro ced ure 3964(R)
Send S T X
Send N A K
Add Q V Z
Character
received ?
Send character with
DLE doubling
Own priority high
?
Initialization conflict,
own priority low
QVZ
expired ?
More characters
to send ?
Send D LE ETX
Send B C C
Add Q V Z
With B C C
3964(R) ?
Faulty, not D L E
G 1
W = 1
A = 1
DLE
Z
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A + 1
W + 1
G
Z
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G
4
5
6
Figure 2-6 Flow diagram of sending with the 3964(R) procedure
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 37
C: Counter for connection attempts
R: Counter for retries
D: Default state
W: Waiting for character reception
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
38 Manual, 04/2011, A5E02191071-03
2.4.5 Receiving Data with 3964(R)
Receiving data with 3964(R)
The figure below illustrates the transmission sequence when data is received with the
3964(R) procedure.
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Figure 2-7 Data traffic when receiving with the 3964(R) procedure
Note
As soon as it is ready, the 3964(R) procedure sends a single NAK to the communication
partner to set the latter to idle.
Connection setup for receiving
In the idle state, when there is no send request to be processed, the procedure waits for the
communication partner to set up the connection.
If no empty receive buffer is available during a connection setup with STX, a wait time of 400
ms is started. If there is still no empty receive buffer after this time has expired, the CP 341
reports the error (error message at STATUS output of the FB). The procedure sends a NAK
character and returns to the idle state. Otherwise, the procedure sends the DLE character
and receives the data.
If the procedure receives any control character (except for STX or NAK) while in idle state, it
waits for the character delay time to expire and then sends the NAK character. The CP 341
reports the error to the P_RCV_RK function block (STATUS output parameter).
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 39
Receiving data
After a successful connection setup, the receive characters that arrive are stored in the
receive buffer. If two consecutive DLE characters are received, only one of these is stored in
the receive buffer.
After each receive character, the procedure waits out the character delay time for the next
character. If this period expires before another character is received, the NAK character is
sent to the communication partner. The system program reports the error to the P_RCV_RK
function block (STATUS output parameter). The 3964(R) procedure does not initiate a
repetition.
If transmission errors occur during receiving (lost character, frame error, parity error, etc.),
the procedure continues to receive until the connection is released, then a NAK is sent to the
communication partner. A repetition is then expected. If the block still cannot be received
without errors after the number of transmission attempts defined in the static parameter set,
or if the communication partner does not start the repetition within a block wait time of 4
seconds, the procedure cancels the receive operation. The CP 341 reports the first
erroneous transmission and the final cancelation in the P_RCV_RK function block (STATUS
output parameter).
Connection release for receiving
When the 3964 procedure detects a DLE ETX character string, it stops receiving and
confirms that the block has been successfully received by sending a DLE character to the
communication partner. If an error occurs while receiving, the procedure sends a NAK
character to the communication partner. A repetition is then expected.
If the 3964R procedure detects the string DLE ETX BCC, it stops receiving. It compares the
received BCC block check character with the internally calculated longitudinal parity. If the
BCC is correct and no other receive errors have occurred, the 3964R procedure sends the
DLE character and returns to idle mode. If the BCC is faulty or a different receive error
occurs, the NAK character is sent to the communication partner. A repetition is then
expected.
Note
As soon as it is ready, the 3964(R) procedure sends a single NAK to the communication
partner to set the latter to idle.
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
40 Manual, 04/2011, A5E02191071-03
Receiving with the 3964(R) Procedure
The figure below illustrates receiving with the 3964(R) procedure.
Receiving with procedure 3964(R) (part 1)
Character not equal to STX or faulty
character
Send request
NAK or BREAK
Waiting for character
time delay
Send NAK
Initialization conflict, own
priority low
STX received after
expected repeat
Yes
Add waiting time to free
receiving buffer
No
Has waiting time of 400
ms expired ?
No
Send NAK
Send DLE
Is receiving buffer
free ?
Waiting 50 ms
G 1
STX
G
2
3
4
W = 0
W + 1
Figure 2-8 Flow Diagram for Receiving with the 3964(R) Procedure (Part 1)
R: Counter for retries
D: Default state
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 41
Receiving with 3964(R) procedure (Part 2)
The figure below illustrates receiving with the 3964(R) procedure.
Send DLE
CDT
expired ?
Send NAK
No
No
Yes
Yes
DLE doubling
No
Yes
No
Yes
No
Initialization
conflict, own priority low
Yes
Yes
No
No
no errors, not
DLE
Add character delay time
Character
received ?
Note NAK
faulty, DLE combination
not permitted
Yes
No
with BCC
3964(R) ?
Add character delay time
BCC received ?
BCC correct ?
NAK noted ?
Character delay time
expired ?
Send NAK
Send NAK
W > W max. ?
Add repeat time
STX received
Repeat time
expired ?
Receiving with procedure 3964(R) (part 2)
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Figure 2-9 Flow diagram for receiving with the 3964(R) procedure (Part 2)
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
42 Manual, 04/2011, A5E02191071-03
R: Counter for retries
D: Default state
W: Waiting for character reception
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 43
2.4.6 Handling Erroneous Data
Handling erroneous data
The figure below illustrates how erroneous data is handled with the 3964(R) procedure.
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Figure 2-10 Data traffic when erroneous data is received
After receipt of DLE, ETX, BCC, the CP 341 compares the BCC of the communication
partner with its own internally calculated value. If the BCC is correct and no other receive
errors occur, the CP 341 responds with DLE.
Otherwise, the CP 341 responds with an NAK and waits the block wait time (T) of 4 seconds
for a new attempt. If after the assigned number of transmission attempts the block cannot be
received, or if no further attempt is made within the block wait time, the CP 341 cancels the
receive operation.
Extended error display at the receive FB
Activate the parameter "Display receive error at FB" to also display a message frame
received with errors at the status output of the function block P_RCV_RK.
If the parameter is deactivated, an entry is only created in the diagnostic buffer of the
CP 341.
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
44 Manual, 04/2011, A5E02191071-03
Initialization conflict
The figure below illustrates the data transmission sequence during an initialization conflict.
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Figure 2-11 Data traffic in the event of an initialization conflict
If a device responds to the communication partner's send request (STX) within the
acknowledgment delay time by sending the STX character instead of the DLE or NAK
acknowledgment, an initialization conflict occurs. Both devices want to execute a pending
send request. The device with the lower priority withdraws its send request and responds
with the DLE character. The device with the higher priority sends its data in the manner
described above. Once the connection has been released, the lower-priority device can
execute its send request.
In order to resolve initialization conflicts you must assign different priorities for the
communication partners.
Basic Principles of Serial Data Transmission
2.4 Data Transmission with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 45
Procedure errors
The procedure recognizes both errors caused by faulty communication partner behavior and
errors caused by faults on the line.
In both cases, the procedure initially attempts to send/receive the data block correctly. If the
data block cannot be sent or received error-free within the maximum specified number of
transmission attempts (or if a new error status occurs), the procedure cancels the send or
receive operation. It reports the error number of the first error detected and returns to the idle
state. These error messages are displayed in the STATUS output of the FB.
If the system program frequently reports an error number at the STATUS output of the FB for
send and receive repetitions, this implies occasional disturbances in data traffic. The high
number of transmission attempts balances this out, however. In this case, you are advised to
check the transmission link for possible sources of interference, because frequent repetitions
reduce the user-data rate and integrity of the transmission. However, the disturbance could
also be the result of a malfunction on the part of the communication partner.
In the event of a BREAK on the receive line (receive line interrupted), an error message is
indicated at the STATUS output of the FB. No repetition is started. The BREAK status is
automatically reset as soon as the connection is restored on the line.
For every detected transmission error (lost character, frame or parity error), a standard
number is reported, regardless of whether the error was detected during sending or receiving
of a data block. The error is only reported, however, if previous repetition attempts have
failed.
3964(R) procedure startup
The figure below illustrates the start-up of the 3964(R) procedure.
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Figure 2-12 Flow diagram of the start-up of the 3964(R) Procedure
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
46 Manual, 04/2011, A5E02191071-03
2.5 Data Transmission with the RK 512 Computer Connection
The RK 512 computer link controls data transmission in the case of a point-to-point
connection between the CP 341 and a communication partner.
Unlike the 3964(R) procedure, the RK 512 computer link includes not only the physical layer
(layer 1) and the data-link layer (layer 2), but also the transport layer (layer 4). The RK 512
computer link also offers higher data integrity and better addressing options.
Response message frame
The RK 512 computer link answers every command message frame it receives correctly with
a response message frame to the CPU (transport layer). This allows the sender to check
whether its data has arrived error-free at the CPU or whether the the requested data is
available on the CPU.
Command message frame
Command message frames are either SEND or FETCH message frames.
Refer to section "Communication via Function Blocks (Page 123)" for information on how to
initiate a SEND or FETCH message frame.
SEND message frame
In the case of a SEND message frame, the CP 341 sends a command message frame with
user data, and the communication partner replies with a response message frame without
user data.
FETCH message frame
In the case of a FETCH message frame, the CP 341 sends a command message frame
without user data, and the communication partner replies with a response message frame
with user data.
Continuation message frame
If the volume of data exceeds 128 bytes, SEND and FETCH message frames are
automatically accompanied by continuation message frames.
Message frame header
With RK 512, each message frame begins with a message frame header. It can contain
message frame IDs, information on the data destination and source and an error number.
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 47
Structure of the message frame header
The table below indicates the structure of the header of the command message frame.
Table 2- 1 Structure of command message frame header (RK 512)
Byte Meaning
1 Message frame ID in command message frames (00H),
In continuation command message frames (FFH)
2 Message frame ID (00H)
3 'O' (41H)
'O' (4FH)
'I' (45H)
for SEND request with destination DB or
for SEND request with destination DX or
for FETCH request
Data to be transmitted are off (only 'D' is possible when sending): 4
'D' (44H)
'X' (58H)
'I' (45H)
'O' (41H)
'M' (4DH)
T' (54H)
'C' (5AH)
=Data block
=Expanded data block
=Input bytes
=Output bytes
=Memory bytes
=Timer cells
=counter cells
5 Data destination of SEND request or data source of FETCH request, e.g., byte 5 = DB no., byte 6 = DW no.
(RK 512 addressing describes the data source and destination with word limits. Conversion to byte addresses
in SIMATIC S7 is automatic.)
6
7
Length high byte Length of data to be transmitted according to type in bytes or
Length low byte Words
8
9 Byte number of interprocessor communication flag; FFH is displayed if you have not specified an
interprocessor communication flag.
10 Bits 0 to 3: Bit number of the interprocessor communication flag; the protocol enters FH here if you have not
specified an interprocessor communication flag.
Bits 4 to 7: CPU number (number from 1 to 4); if you have not specified a CPU number (number = 0) but you
have specified an interprocessor communication flag, 0H is displayed here; if you specified neither a CPU
number nor an interprocessor communication flag, FH is shown here.
The letters in bytes 3 and 4 are ASCII characters.
The header of the continuation command message frame consists of bytes 1 to 4 only.
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
48 Manual, 04/2011, A5E02191071-03
Response message frame
Once the command message frame has been transmitted, the RK 512 waits for a response
message frame from the communication partner within the monitoring time. The duration of
the monitoring time depends by default on the transmission rate 20 s. This monitoring time
can be reduced by setting parameters for the user in the "RK512" dialog of the parameter
assignment interface. When the option "dependent on transmission rate" is selected, the
following maximum waiting times are used for monitoring:
Table 2- 2 Monitoring time for response message frame
Transmission rate Monitoring time
300 bps 10 s
600 bps 7 s
1200 bps 5 s
as of 38400 bps 3 s
The "grayed" field "maximum waiting time" is only used to display the monitoring time used
and cannot be edited!
Structure and contents of the response message frame
The response message frame consists of 4 bytes and contains information on the progress
of the request.
Table 2- 3 Structure of response message frame header (RK 512)
Byte Meaning
1 Message frame ID in response message frames (00H),
in continuation response message frames (FFH)
2 Message frame ID (00H)
3 Displays 00H
4 Error number of the communication partner in the response message frame:*
00H if transmission was error-free
> 00H error number
* The error number in the response message frame automatically triggers an event number in the
STATUS output of the function blocks (see chapter "Diagnostics Messages of the Function Blocks
(Page 178)").
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 49
2.5.1 Sending Data with RK 512
Sending data with RK 512
The figure below shows the transmission sequence when sending data with a response
message frame using the RK 512 computer link.
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Figure 2-13 Data traffic when sending with a response message frame
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
50 Manual, 04/2011, A5E02191071-03
Sending data
The SEND request is executed in the following sequence:
● Active partner
Sends a SEND message frame. This contains the message frame header and data.
● Passive partner
Receives the message frame, checks the message frame header and the data, transfers
the data to the CPU, and then acknowledges this with a response message frame.
● Active partner
Receives the response message frame.
Sends user data.
If the volume of user data exceeds 128 bytes, the active partner sends a continuation
SEND message frame.
● Passive partner
Receives the continuation SEND message frame, checks the message frame header and
the data, transfers the data to the CPU, and then acknowledges this with a continuation
response message frame.
Note
If the CPU does not receive the SEND message frame error-free or if an error has
occurred in the message frame header, the communication partner enters an error
number in the 4th byte of the response message frame. This does not apply when
protocol errors occur.
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 51
Continuation SEND message frames
A continuation SEND message frame is started if the volume of data exceeds 128 bytes. The
sequence is the same as for the SEND message frame.
If more than 128 bytes are sent, the extra bytes are automatically transmitted in one or more
continuation message frames.
The figure below shows the transmission sequence when sending a continuation SEND
message frame with a continuation response message frame.
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Figure 2-14 Sequence of a continuation SEND message frame with a continuation response
message frame
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
52 Manual, 04/2011, A5E02191071-03
2.5.2 Fetching Data with RK 512
Fetching data with RK 512
The figure below shows the transmission process when fetching data with a response
message frame using the RK 512 computer link.
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Figure 2-15 Data traffic when fetching with a response message frame
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 53
Fetching data
The FETCH request is executed in the following sequence:
● Active partner
Sends a FETCH message frame. This contains the message frame header.
● Passive partner
Receives the message frame, checks the header, fetches the data from the CPU, and
acknowledges this with a response message frame. This contains the data.
● Active partner
Receives the response message frame.
If the volume of user data exceeds 128 Bytes, the active partner sends a continuation
FETCH message frame. This contains byte 1 to 4 of the message frame header.
● Passive partner
Receives the continuation FETCH message frame, checks the header, fetches the data
from the CPU, and acknowledges this with a continuation response message frame
containing further data.
If there is an error number (not equal to 0) in the 4th byte, the response message frame does
not contain any data.
If more than 128 bytes are requested, the extra bytes are automatically fetched in one or
more continuation message frames.
Note
If the CPU does not receive the FETCH message frame error-free or if an error has occurred
in the message frame header, the communication partner enters an error number in the 4th
byte of the response message frame. This does not apply when protocol errors occur.
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
54 Manual, 04/2011, A5E02191071-03
Continuation FETCH message frame
The figure below shows the transmission sequence when fetching data with a continuation
response message frame.
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Figure 2-16 Sequence of a continuation FETCH message frame with a continuation response
message frame
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 55
2.5.3 Quasi-Full-Duplex Operation
Quasi-full-duplex mode
Quasi full-duplex mode means: The partners can send command and response message
frames at any time as long as the other partner is not sending. The maximum nesting depth
for command and response message frames is "1". The next command message frame,
therefore, cannot be processed until the previous one has been answered with a response
message frame.
It is possible under certain circumstances - if both partners want to send - to transmit a
SEND message frame from the partner before the response message frame. For example, if
a SEND message frame from the partner was entered in the output buffer of the CP 341
before the response message frame.
In the following figure the continuation response message frame to the first SEND message
frame is not sent until after the partner's SEND message frame.
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Figure 2-17 Quasi-full-duplex mode
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
56 Manual, 04/2011, A5E02191071-03
2.5.4 RK 512 CPU Requests
Processes involved in the RK 512 when CPU requests are made
The figure below shows the processes involved in the RK 512 computer connection when
CPU requests are made.
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Figure 2-18 Flow diagram of data transmission with the RK 512 when CPU requests are made
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 57
Extended error display at the receive FB
Activate the parameter "Display receive error at FB" to also display a message frame
received with errors at the status output of the function block P_RCV_RK.
If the parameter is deactivated, an entry is only created in the diagnostic buffer of the
CP 341.
RK 512 Partner Requests
The figure below shows the processes involved in the RK 512 computer connection when
partner requests are made.
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Figure 2-19 Flow diagram of data transmission with the RK 512 when partner requests are made
Basic Principles of Serial Data Transmission
2.5 Data Transmission with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
58 Manual, 04/2011, A5E02191071-03
Extended error display at the receive FB
Activate the parameter "Display receive error at FB" to also display a message frame
received with errors at the status output of the function block P_RCV_RK.
If the parameter is deactivated, an entry is only created in the diagnostic buffer of the
CP 341.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 59
2.6 Data Transmission with the ASCII Driver
2.6.1 Principle of the Data Transmission with the ASCII Driver
The ASCII driver controls data transmission via a point-to-point connection between the
communication processor and a communication partner. This driver contains the physical
layer (layer 1).
The structure of the message frames is left open through the S7 user passing on the
complete send message frame to the communication processor. For the receive direction,
the end criterion of a message must be configured. The structure of the send message
frames may differ from that of the receive message frames.
The ASCII driver allows data of any structure (all printable ASCII characters as well as all
other characters from 00 through FFH (with 8 data bit character frames) or from 00 through
7FH (with 7 data bit character frames) to be sent and received.
2.6.2 Sending data with the ASCII driver
Sending data with ASCII driver
For sending, you specify the number of user data bytes to be transferred when the
P_SND_RK function block is called as the "LEN" parameter.
If you are working with the end criterion "Expiration of character delay time", the ASCII driver
pauses between two message frames when sending. You can call the FB P_SND_RK at any
time, but the ASCII driver does not begin its output until a period longer than the assigned
character delay time has elapsed since the last message frame was sent.
If you are working with the "End-of-text character" end criterion, you have a choice of three
options:
● Send up to and including the end-of-text character
The end-of-text character must be included in the data to be sent. Data is sent only up to
and including the end-of-text character, even if the data length specified in the FB is
longer.
● Send up to length assigned in the FB
Data is sent up to the length assigned in the FB. The last character must be the end-of-
text character.
The message frame will be sent without error message even if the data to be sent do not
contain the end-of-text character.
● Send up to the length assigned in the FB and automatically append the end-of-text
character(s)
Data is sent up to the length assigned in the FB. The end-of-text character is
automatically appended, in other words the end-of-text characters must not be included in
the data to be sent. 1 or 2 characters more than the number specified at the FB are sent
to the partner, depending on the number of end-of-text characters.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
60 Manual, 04/2011, A5E02191071-03
If you are working with the "Fixed message frame length" end criterion, the amount of data
transferred in the send direction is as specified in the "LEN" parameter of the
FB P_SND_RK. The amount of data transferred in the receive direction, i.e. in the receive
DB, is as specified for the receiver using the "Fixed message frame length" parameter in the
parameter assignment interface. The two parameter settings must be identical, in order to
ensure correct data traffic. A pause equal to the length of the character delay time is inserted
between two message frames when sending to allow the partner to synchronize (recognize
start of message frame).
If some other method of synchronization is used, the pause in sending can be deactivated in
the parameter assignment interface.
Note
When XON/XOFF flow control is assigned, the user data must not contain any of the
assigned XON or XOFF characters. The default settings are DC1 = 11H for XON and
DC3 = 13H for XOFF.
Sending data
The figure below illustrates a send operation.
6HQGUHTXHVWDUULYHG
5HTXHVWSURFHVVHG
:DLWLQJIRU
VHQGUHTXHVW
6HQGLQJ
XVHUGDWD
7KHDPRXQWRIGDWDWR
EHVHQWLVWDNHQIURP
WKH/(1SDUDPHWHURI
WKHVHQGUHTXHVW
Figure 2-20 Flowchart of a send operation
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 61
2.6.3 Receiving data with the ASCII driver
Receiving data with ASCII driver
For data transmission using the ASCII driver you can choose between three different end
criteria for data receipt. The end criterion defines when a complete message frame is
received. The possible end criteria are as follows:
● Expiration of the character delay time
The message frame has neither a fixed length nor a defined end-of-text character; the
end of a message frame is defined by a pause on the line (expiration of character delay
time).
● Receipt of the end-of-text character(s)
The end of the message frame is marked by one or two defined end-of-text characters.
● Receipt of fixed number of characters
The length of the receive message frames is always identical.
Code transparency
The code transparency of the procedure depends on the choice of the assigned end criterion
and the flow control:
● With one or two end-of-text characters
– Not code-transparent
● When end criterion is character delay time or fixed message frame length
– Code-transparent
● Code-transparent operation is not possible when the flow control XON/XOFF is used.
Code-transparent means that any character combinations can occur in the user data without
the end criterion being recognized.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
62 Manual, 04/2011, A5E02191071-03
End criterion "Expiration of character delay time"
When data is received, the end of the message frame is recognized when the character
delay time expires. The received data is accepted by the CPU.
In this case the character delay time must be set such that it is certain to expire between two
consecutive message frames. But it should be so long that the end of the message frame is
falsely identified in the case of a send pause of the link within a message frame.
The figure below illustrates a receive operation with the end criterion "Expiration of character
delay time".
:DLWLQJIRU
FKDUDFWHU
&KDUDFWHU
DUULYHG
&KDUDFWHUUHFHLYHG
ZLWKFKDUDFWHU
GHOD\WLPH
PRQLWRULQJ
(QWHUPHVVDJHIUDPH
LQUHFHLYHEXIIHU
PD[0)VRU
E\WHV
(QWHUHUURULQ
67$786RXWSXWRI
WKH)%
:DLWLQJIRUFKDUDFWHU
GHOD\WLPH5HFHLYHG
FKDUDFWHUVGLVFDUGHG
(UURUZKHQUHFHLYLQJQRWD
FKDUDFWHUGHOD\WLPHHUURU
0HVVDJHIUDPHEXIIHUHG
(QGFULWHULRQIRUPHVVDJHIUDPHLGHQWLILHGHUURUHQWU\IROORZV
0HVVDJHIUDPH
FRPSOHWHFKDUDFWHU
GHOD\WLPHH[SLUHG
Figure 2-21 Flow diagram for receiving with end criterion "Expiration of character delay time"
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 63
End criterion end-of-text character
When receiving data, the end of the message frame is recognized when the assigned end-
of-text character(s) are received. The received data including the endoftext character(s) are
accepted from the CPU.
If the character delay time expires while data is still being received, the receive operation is
ended. An error message is issued and the message frame fragment is discarded.
If you are working with endoftext characters, transmission is not code transparent. You must
then make sure that the end character(s) are not included in the user data of the user.
Note the following when the last character in the received message frame is not the end-of-
text character.
● End-of-text character elsewhere in the message frame:
All characters, including the end-of-text character, are written to the receive DB. The
characters located after the end-of-text character are
– Discarded if the character delay time expires at the end of the message frame.
– Merged with the next message frame if a new message frame is received before the
character delay time expires.
● End-of-text character not included in message frame:
The message frame is either:
– Discarded if the character delay time expires at the end of the message frame.
– Merged with the next message frame if a new message frame is received before the
character delay time expires.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
64 Manual, 04/2011, A5E02191071-03
The figure below illustrates a receive operation with the end criterion "Endoftext character".
:DLWLQJIRU
FKDUDFWHU
&KDUDFWHUUHFHLYHG
ZLWKHQGFRQWURO
DQGFKDUDFWHUGHOD\
WLPH
(QWHUPHVVDJHIUDPH
LQUHFHLYHEXIIHU
PD[0)VRU
E\WHV
0HVVDJH
IUDPH
FRPSOHWH
&KDUDFWHU
DUULYHG
&KDUDFWHU
GHOD\WLPH
H[SLUHG
:DLWLQJIRUYDOLG
HQGFRGH
(QWHUHUURULQ
67$786RXWSXWRI
WKH)%
0HVVDJHIUDPHEXIIHUHG
(QGFULWHULRQIRUPHVVDJHIUDPHLGHQWLILHGHUURUHQWU\IROORZV
Figure 2-22 Flow diagram for receiving with end criterion "End-of-text character"
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 65
Fixed message frame length end criterion
When receiving data, the end of the message frame is recognized when the assigned
number of characters have been received. The received data is accepted by the CPU.
If the character delay time expires before the assigned number of characters has been
reached, the receive operation is ended. An error message is generated and the message
frame fragment is discarded.
Note the following if the message frame length of the received characters does not conform
with the fixed assigned message frame length:
● Message frame length of the received characters is greater than the fixed assigned
message frame length:
All characters received after reaching the fixed assigned message frame length are
either:
– Discarded if the character delay time expires at the end of the message frame.
– Merged with the next message frame if a new message frame is received before the
character delay time expires.
● Message frame length of the received characters is less than the fixed assigned message
frame length:
The message frame is either:
– Discarded if the character delay time expires at the end of the message frame.
– Merged with the next message frame if a new message frame is received before the
character delay time expires.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
66 Manual, 04/2011, A5E02191071-03
The figure below illustrates a receive operation with the end criterion "Fixed message frame
length".
:DLWLQJIRU
FKDUDFWHU
&KDUDFWHUUHFHLYHG
ZLWKOHQJWKFRQWURO
DQGFKDUDFWHUGHOD\
WLPH
&KDUDFWHU
DUULYHG
0HVVDJH
IUDPH
FRPSOHWH
&KDUDFWHU
GHOD\WLPH
H[SLUHG
(QWHUPHVVDJHIUDPH
LQUHFHLYHEXIIHU
PD[0)VRU
E\WHV
:DLWLQJIRU
SDUDPHWHUL]HG
QXPEHURI
FKDUDFWHUV
(QWHUHUURULQ
67$786RXWSXWRI
WKH)%
0HVVDJHIUDPHEXIIHUHG
(QGFULWHULRQIRUPHVVDJHIUDPHLGHQWLILHGHUURUHQWU\IROORZV
Figure 2-23 Flow diagram for receiving with end criterion "Fixed message frame length"
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 67
Receive buffer on CP 341
The CP 341 receive buffer accommodates 4096 bytes. During parameter assignment, you
can specify whether overwriting of data in the receive buffer is to be prevented. You can also
specify the range of values (1 to 250) for the number of buffered receive message frames.
The receive buffer on the CP 341 is a ring buffer:
● If multiple message frames are written to the CP 341 receive buffer: The CP 341 always
sends the oldest message frame to the CPU.
● If you want to transfer only the latest received frame to the CPU, you must assign the
value "1" for the number of buffered message frames and deactivate overwrite protection.
Note
If continuous reading of the receive data is interrupted for a certain time in the user
program and new receive data is requested, the CP 341 might first receive an old
message frame from the CPU and then the latest message frame. The old message
frames are those that were on the bus between the CP 341 and the CPU at the time of
interruption or that had already been received by the FB.
Extended error display at the receive FB
Activate the parameter "Display receive error at FB" to also display a message frame
received with errors at the status output of the function block P_RCV_RK.
If the parameter is deactivated, an entry is only created in the diagnostic buffer of the
CP 341.
2.6.4 RS 485 mode
RS 485 mode
When you run the ASCII driver in RS 485 mode (half-duplex, two-wire mode), you must take
steps in the user program to ensure that only one station sends data at any one time. If two
stations send data simultaneously, the message frame will be corrupted.
Switchover times for RS485 module in half-duplex mode
The maximum switch-over time between sending and receiving is 1 ms.
This value is applicable to modules as of order number 6ES7 341–1xH01–0AE0.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
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2.6.5 RS 232C operation
RS 232C accompanying signals
The following RS 232C accompanying signals are available on the CP 341 RS 232C:
● DCD (input) Data carrier detect;
Data carrier detected
● DTR (output) Data terminal ready;
CP 341 ready for operation
● DSR (input) Data set ready;
Communication partner ready for operation
● RTS (output) Request to send;
CP 341 ready to send
● CTS (input) Clear to send;
Communication partner can receive data from CP 341
(Response to RTS = ON of the CP 341)
● RI (input) Ring Indicator;
Ring Indicator
When the CP 341-RS 232C is switched on, the output signals are in the OFF state (inactive).
You can control the DTR/DSR and RTS/CTS control signals using the CP 341: Point-to-Point
Communication, Parameter Assignment parameter assignment interface or via functions
(FCs) in the user program.
Controlling RS 232C accompanying signals
The RS 232C accompanying signals can be controlled as follows:
● When automatic control of all RS 232C accompanying signals is assigned
● When data flow control (RTS/CTS) is assigned
● By means of the FC V24_STAT and FC V24_SET functions
Note
When automatic control of the RS 232C accompanying signals is assigned, neither
RTS/CTS data flow control nor RTS and DTR control by means of the FC V24_SET
function are possible. When RTS/CTS data flow control is assigned, RTS control by
means of the FC V24_SET function is not possible. On the other hand, it is always
possible to read all RS 232C accompanying signals by means of the FC V24_STAT
function.
The sections that follow describe the basic principles for controlling and evaluating RS 232C
accompanying signals.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Automatic control of accompanying signals
Automatic control of the RS 232C accompanying signals is implemented on the CP 341 as
follows:
● As soon as the CP 341 is assigned for operation in a mode with automatic control of the
RS 232C accompanying signals, it sets the RTS line to OFF and the DTR line to ON
(CP 341 ready for operation).
This prevents sending and receiving of message frames until the DTR line is set to ON.
No data is received at the RS 232C interface as long as DTR = OFF. Any send requests
will be cancelled with a corresponding error message.
● When a send job is queued, the module sets RTS=ON, and triggers the configured data
output wait time. After the data output time has elapsed and CTS = ON, the data is sent
via the RS 232C interface.
● If during sending the CTS line is not set to ON within the data output wait time or if CTS
changes to OFF during the send operation, the send request is canceled and a
corresponding error message is generated.
● Once the data has been sent and the assigned Clear RTS time has elapsed, the RTS line
is set to OFF. There is no waiting time for the transition from CTS to OFF.
● Data can be received via the RS 232C interface when DSR=ON. If the receive buffer of
the CP 341 is close to overflow, the CP 341 will not respond.
● If DSR changes from ON to OFF, an active send request as well as the receipt of data will
be canceled with an error message. The message "DSR = OFF (automatic use of V24
signals)" is entered in the diagnostic buffer of the CP 341.
Note
Automatic control of the RS 232C accompanying signals is only possible in half-duplex
mode. When automatic control of the RS 232C accompanying signals is assigned,
neither RTS/CTS data flow control nor RTS and DTR control by means of the
FC V24_SET function are possible.
Note
The "Clear RTS time" must be set in the parameter assignment interface so that the
communication partner can receive the last characters of the message frame in their
entirety before RTS, and thus the send request, is canceled. The "data output wait time"
must be set so that the communication partner can be ready to receive before the time
elapses.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
70 Manual, 04/2011, A5E02191071-03
Timing diagram
The figure illustrates the chronological sequence of a send request.
576 2))
21
&76 21
7;'
576 21
&76 21
&76 2))
2))
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3DUWQHUV
'DWDRXWSXWZDLWLQJWLPH
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7LPHWR
5762))
'DWDRXWSXW
ZDLWLQJWLPH
6HQG
FRPSOHWHG
7LPHWR576
2))HODSVHG
Figure 2-24 Timing diagram of automatic control of the RS 232C accompanying signals
Reading/controlling via FC V24_STAT and FC V24_SET
The FC V24_STAT function can be used to determine the status of each RS 232C
accompanying signal. The FC V24_SET function can be used to control the DTR and RTS
output signals.
Basic Principles of Serial Data Transmission
2.6 Data Transmission with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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2.6.6 Data flow control/Handshaking
Data flow control/Handshaking
Handshaking controls the data flow between two communication partners. Handshaking
ensures that data is not lost in transmissions between devices that work at different speeds.
There are essentially two types of handshaking:
● Software handshaking (e.g., XON/XOFF)
● Hardware handshaking (e.g., RTS/CTS)
Data flow control is implemented as follows on the CP 341:
● As soon as the CP 341 is assigned for operation in a mode with flow control, it sends the
XON character or sets the RTS line to ON.
● If the assigned number of message frames or 50 characters are reached before the
receive buffer overflows (size of the receive buffer: 4096 bytes), the CP 341 sends the
XOFF character or sets the RTS line to OFF. If the communication partner ignores this
state and continues transmission, an error message is generated if the receive buffer
overflows. The data received in the last message frame will be discarded.
● As soon as a message frame is fetched by the S7 CPU and the receive buffer is ready to
receive, the CP 341 sends the XON character or sets the RTS line to ON.
● The CP 341 interrupts the send operation when it receives the XOFF character or the
CTS control signal of the communication partner is set to OFF. If an XON character is not
received or the partner does not set CTS to ON within an assigned time period, the send
operation is canceled and a corresponding error message (0708H) is generated at the
STATUS output of the function blocks.
Note
When RTS/CTS data flow control is assigned, you must fully wire the interface signals in
the plug connection. When RTS/CTS data flow control is assigned, RTS control by
means of the FC V24_SET function is not possible.
Basic Principles of Serial Data Transmission
2.7 Data transmission with the printer driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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2.7 Data transmission with the printer driver
Introduction
The printer driver allows you to output date- and time-stamped message texts to a printer.
This enables you to monitor simple processes, print error or fault messages, or issue
instructions to operating personnel, for example.
The printer driver includes the physical layer (layer 1).
Message texts and parameters for printout
With the CP 341: Point-to-Point Communication, Parameter Assignment parameter
assignment interface, you can configure the message texts and assign the parameters (page
layout, character set, control characters) for printout. Message texts and printout parameters
are transmitted to the CP 341 together with the module parameters when it starts up.
Message texts:
You can configure message texts with variables and control statements (e.g., for bold,
condensed, expanded, or italic type and underlining). Each message text is assigned a
number during configuration. A message text is printed if its number is specified in a format
string when the P_PRINT function block is called.
You must have stored the format string and variables in data blocks beforehand.
Page layout:
You can configure the margins, possible line breaks and headers and footers.
Character set:
The ANSI character set is converted from STEP 7 to the printer characters set by means of a
character conversion table. You can change a character conversion table suggested for a
printer type in order to include special characters required for a particular language, for
example.
Control characters:
You can use a control character table to change the control statements in the message text
for the printer emulation for switching on and off bold, condensed, expanded, or italic type
and underlining, and to add other control characters.
Variables
Up to 4 variables (3 + a message text number) can be displayed in a message text. The
values of variables can be transmitted from the CPU to the CP 341. The following can be
displayed as variables: Calculated values of the user program, such as: fill levels), date and
time, strings (string variables), or other message texts.
A conversion statement must be specified in the configured message text or in the format
string for each variable, and the meaning and output format of the variable value must be
encoded in this statement.
Basic Principles of Serial Data Transmission
2.7 Data transmission with the printer driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Format string
The format string allows you to define the display type and composition of a message text.
The format string can consist of:
● Text (all printable characters, for example: The level ... l was reached at ... hours.)
● Conversion statements for variables (e.g., %N = pointer to message text number x, where
x is the value of a variable (see example 2 below))
There must be one (and only one) conversion statement for each variable in the format
string or configured message text. The conversion statements are applied to the variables
in the sequence in which they occur.
● Control statements with control characters for bold, condensed, expanded, italic, and
underlining (e.g., \B = bold type on) or with additional control characters you have defined
You can use other control characters if you enter them in the control character table in the
CP 341: Point-to-Point Communication, Parameter Assignment parameter assignment
interface and reassign the CP 341 parameters.
Additional functions
In addition to outputting message texts, you can use the following functions for printout. To
execute one of these functions, simply specify it in the format string in the same way.
● Set page number (format string = %P)
● Begin new page (format string = \F)
● Print with/without line break (\x at the end of the format string)
Note that a line feed is carried out by default after each output.
Examples
Example 1: The level "200" l was reached at "17:30" hours.
Format string = The level %i l was reached at %Z hours.
Variable 1 = time
Variable 2 = level
Example 2: The pressure in the chamber "is falling"
Format string = %N %S
Variable 1 = 17 (message text no. 17: The pressure in the chamber ...)
Variable 2 = reference to string (string variable: ... is falling)
Example 3: (Setting the page number to 10)
Format string = %P
Variable 1 = 10 (page number: 10)
Basic Principles of Serial Data Transmission
2.7 Data transmission with the printer driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
74 Manual, 04/2011, A5E02191071-03
Printout
To output n bytes of user data to a printer, specify the block number of a pointer DB when
calling the P_PRINT function block. The pointers to the data blocks are stored in the pointer
DB together with the format string and the variables and in a specific order.
During output the data is edited for printing. Print editing is performed as configured in the
CP 341: Point-to-Point Communication, Parameter Assignment parameter assignment
interface (page layout, character set, control characters, etc.).
Characters are not received during printout, with the exception of flow control characters,
provided this has been assigned. Any characters received are not accepted.
Note
When XON/XOFF flow control is assigned, the user data must not contain the assigned XON
or XOFF characters. The default settings are DC1 = 11H for XON and DC3 = 13H for XOFF.
Outputting a message text
The figure below illustrates the sequence of operations for a printout.
:DLWIRUD
SULQWMRE
3ULQWHGLWLQJDQG
RXWSXWRIWKH
PHVVDJHWH[W
7KHPHVVDJHWH[WWR
EHRXWSXWLVVSHFLILHG
E\WKHSRLQWHUVLQWKH
SRLQWHU'%
-RESURFHVVHG
3ULQWMREUHFHLYHG
Figure 2-25 Flow chart of printout
Basic Principles of Serial Data Transmission
2.7 Data transmission with the printer driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 75
Data flow control/Handshaking
Handshaking controls the data flow between two communication partners. Handshaking
ensures that data is not lost in transmissions between devices that work at different speeds.
You can also send message texts with data flow control during printout. There are essentially
two types of handshaking:
● Software handshaking (e.g., XON/XOFF)
● Hardware handshaking (e.g., RTS/CTS)
Data flow control is implemented as follows on the CP 341 during printout:
● As soon as the CP 341 is assigned for operation with flow control, it sends the XON
character or sets the RTS line to ON.
● CP 341 interrupts the output of characters when it receives the XOFF character, or when
control signal CTS = OFF is set. If neither an XON character is received nor CTS is set to
ON once a configured time has elapsed, printout is canceled and an appropriate error
message (0708H) is generated at the STATUS output of the SFB PRINT.
Note
When RTS/CTS flow control is assigned, you must fully wire the interface signals in the
plug connection.
BUSY signal
The CP 341 evaluates the printer's "BUSY" control signal. The printer signals to the CP 341
that it is ready to receive:
● For CP 341-20mA-TTY: With current on RxD line
● For CP 341–RS 232C and CP 341-RS 422/485: CTS signal = "ON".
Note
When RTS/CTS flow control is assigned, you must set the polarity of the BUSY signal on
the printer as follows:
BUSY signal: CTS = "OFF"
Note that some printers use the DTR signal to display the BUSY signal. In such cases
you must wire the cable to the CP 341 appropriately.
See also
RS 232C Interface of the CP 341-RS 232C (Page 215)
Basic Principles of Serial Data Transmission
2.8 Configuration data
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2.8 Configuration data
By selecting different protocols, you can adjust your CP 341 communication processor to suit
the properties of the communication partner.
The sections that follow describe the parameter assignment data for the 3964(R) procedure,
RK 512 computer link, ASCII driver, and printer driver.
2.8.1 Configuration Data of the 3964(R) Procedure
Using the parameter assignment data of the 3964(R) procedure, you can adjust the CP 341
to suit the properties of its communication partner.
Parameter assignment data of the 3964(R) procedure
With the CP 341: Point-to-Point Communication, Parameter Assignment parameter
assignment interface, you can specify the parameters for the physical layer (layer 1) and for
the data-link layer (layer 2) of the 3964(R) procedure. You will find a detailed description of
the parameters below.
Section "Assigning Parameters to the Communications Protocols (Page 113)" describes how
to enter the parameter assignment data using the CP 341: Point-to-Point Communication,
Parameter Assignment parameter assignment interface.
X27 (RS 422/485) interface
Note the following with reference to the X27 (RS 422/485) interface:
Note
For the CP 341-RS 422/485 module variant, the 3964(R) procedure can only be used in four-
wire mode.
Basic Principles of Serial Data Transmission
2.8 Configuration data
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 77
Protocol
The table below describes the protocol.
Table 2- 4 3964(R) protocol
Parameters Description Default value
3964 with default
values and no
block check
Default values are assigned to the protocol parameters.
If the CP 341 recognizes the string DLE ETX, it stops receiving
and sends a DLE to the communication partner if the block was
received error-free, or an NAK if an error occurred.
3964R with default
values and block
check
Default values are assigned to the protocol parameters.
If the CP 341 recognizes the string DLE ETX BCC, it stops
receiving. The CP 341 compares the block check character (BCC)
received with the length parity calculated internally. If the BCC is
correct and no other receive errors have occurred, the CP 341
sends the DLE character to the communication partner (the NAK
character is sent if an error occurred).
3964 assignable
without block
check
The protocol parameters can be freely assigned by the user.
If the CP 341 recognizes the string DLE ETX, it stops receiving
and sends a DLE to the communication partner if the block was
received error-free, or an NAK if an error occurred.
3964R assignable
with block check The protocol parameters can be freely assigned by the user.
If the CP 341 recognizes the string DLE ETX BCC, it stops
receiving. The CP 341 compares the block check character (BCC)
received with the length parity calculated internally. If the BCC is
correct and no other receive errors have occurred, the CP 341
sends the DLE character to the communication partner (the NAK
character is sent if an error occurred).
3964R with default values
and block check:
Character delay time =
220 ms
Acknowledgment delay time
= 2000 ms
Connection attempts = 6
Transmission attempts = 6
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Protocol parameters
You can only assign the protocol parameters if you have not specified the default values for
the protocol.
Table 2- 5 Protocol parameters (3964(R) procedure)
Parameters Description Range of values Default value
20 ms to 65530 ms in 10 ms
increments
The shortest character delay time
depends on the baud rate:
Character delay time The character delay time defines the
maximum permissible time that may
elapse between two received characters
in a frame.
300 bps:
600 bps:
1200 bps:
2400 to 115200 bps:
60 ms
40 ms
30 ms
20 ms
220 ms
20 ms to 65530 ms in 10 ms
increments
The shortest acknowledgment
delay depends on the baud rate:
Acknowledgment delay
time
The acknowledgment delay time defines
the maximum permissible time that may
elapse before the partner's
acknowledgment arrives during
connection setup (time between STX and
partner's DLE acknowledgment) or
release (time between DLE ETX and
partner's DLE acknowledgment).
300 bps:
600 bps:
1200 bps:
2400 to 115200 bps:
60 ms
40 ms
30 ms
20 ms
2000 ms
(550 ms for 3964
without block
check)
Connection attempts This parameter defines the maximum
number of attempts of the CP 341 to set
up a connection.
1 to 255 6
Transmission attempts This parameter defines the maximum
number of attempts to transfer a message
frame (including the first one) in the event
of errors.
1 to 255 6
Basic Principles of Serial Data Transmission
2.8 Configuration data
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Baud rate/Character frame
The table below describes the baud rate/character frame.
Table 2- 6 Baud rate/Character frame (3964(R) procedure)
Parameters Description Range of values Default value
Baud rate Data transmission rate in bps (baud)
Note:
A maximum of 19200 bps is possible for the 20mA-TTY interface.
300
600
1200
2400
4800
9600
19200
38400
57600
76800
115200
9600
Start bit During transmission, a start bit is prefixed to each character to be
sent.
1 (fixed value) 1
Data bits Number of bits to which a character is mapped. 7
8
8
Stop bits During transmission, the stop bits are appended to every
character to be sent; this signals the end of a character. 1
2
1
Parity A sequence of information bits can be extended to include
another bit, the parity bit. The addition of its value ("0" or "1")
brings the value of all the bits up to a defined status. This
improves data integrity.
"No" parity means that no parity bit is sent.
None
Odd
Even
Even
Priority A partner has high priority if its send request takes precedence
over the other partner's send request. A partner has low priority if
its send request has to wait until the other partner's send request
has been dealt with. With the 3964(R) procedure, you must
configure both communication partners with different priorities,
i.e., one partner is assigned high priority, the other low.
Low
High
High
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Extended error display at the receive FB
Table 2- 7 Receive buffer on CP (3964(R) procedure)
Parameters Description Range of
values
Default value
Extended error display at the
receive FB
Activate the parameter "Display receive error at FB" to
also display a message frame received with errors at the
status output of the function block P_RCV_RK.
If the parameter is deactivated, an entry is only created in
the diagnostic buffer of the CP 341.
Yes
No
No
X27 (RS 422) interface
You will find a description of the parameters for the X27 (RS 422) interface in the table
below. RS 485 operation is not possible in conjunction with the 3964(R) procedure.
Table 2- 8 X27 (RS 422) interface (3964(R) procedure)
Parameters Description Range of values Default value
None: This setting only makes sense with bus-
capable special drivers.
None
R(A) 5V / R(B) 0V: Break detection is possible in
this initial state.
R(A) 5V / R(B) 0V
Receive line initial
state
R(A) 0V / R(B) 5V: Break detection is not
possible in this initial state.
(also see the following figure)
R(A) 0V / R(B) 5V
R(A) 5V / R(B) 0V
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Receive line initial state
The figure illustrates the wiring of the receiver at the X27 (RS 422) interface:
9
9
9
9
5$95%9
5$95%9
5$
5%
5$
5%
5$
5%
QRQH
Figure 2-26 Wiring of the receiver at the X27 (RS 422) interface (3964(R) procedure)
Basic Principles of Serial Data Transmission
2.8 Configuration data
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2.8.2 Configuration Data of the RK 512 Computer Connection
You can use the parameter assignment data of the RK 512 computer link to adjust the
CP 341 to suit the properties of the communication partner.
Parameter Assignment Data of the RK 512 Computer Link
The parameters are identical to those of the 3964(R) procedure because the 3964(R)
procedure is a subset of the RK 512 computer link in the ISO 7-layer reference model (see
Section "Configuration data (Page 76)").
Note
Exception: The number of data bits per character is set permanently to 8 with the RK 512
computer link.
The parameters of the transport layer (layer 4) must be specified in the function blocks (FB)
used.
Waiting time for response message frames
Table 2- 9 RK512 computer connection
Parameters Description Range of
values
Default value
Waiting time for response message
frames
Once the command message frame
has been transmitted, the RK 512 waits
for a response message frame from the
communication partner within the
monitoring time. The duration of the
monitoring time depends by default on
the transmission speed 20 s.
This monitoring time can be reduced by
setting parameters for the user in the
"RK512" dialog of the parameter
assignment interface.
Activate the parameter ""dependent on
transmission rate" to monitor response message
frames expected from the partner with the
following waiting times:
300 baud 10 s
600 baud 7 s
1200 baud 5 s
from 38400 baud 3 s
The "grayed" field "maximum waiting time" is
only used to display the monitoring time used
and cannot be edited!
Yes
No
No
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Extended error display at the receive FB
Table 2- 10 Receive Buffer on CP (3964(R) Procedure)
Parameters Description Range of
values
Default value
Extended error display at the receive
FB
Activate the parameter "Display receive error at
FB" to also display a message frame received
with errors at the status output of the function
block P_RCV_RK.
If the parameter is deactivated, an entry is only
created in the diagnostic buffer of the CP 341.
Yes
No
No
Basic Principles of Serial Data Transmission
2.8 Configuration data
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2.8.3 Configuration data of the ASCII Driver
Using the parameter assignment data of the ASCII driver, you can adjust the communication
processor to suit the properties of the communication partner.
Parameter assignment data of the ASCII driver
With the CP 341: Point-to-Point Communication, Parameter Assignment parameter
assignment interface, you specify the parameters for the physical layer (layer 1) of the ASCII
driver. You will find a detailed description of the parameters below.
Section "Assigning Parameters to the Communications Protocols (Page 113)" describes how
to enter the parameter assignment data using the CP 341: Point-to-Point Communication,
Parameter Assignment parameter assignment interface.
X27 (RS 422/485) interface
Note the following with reference to the X27 (RS 422/485) interface:
Note
In the case of the CP 341-RS 422/485 module variant, the ASCII driver can be used in four-
wire mode (RS 422) and two-wire mode (RS 485). During parameter assignment, you must
specify the type of interface (RS 422 or RS 485).
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Protocol parameters
The table below describes the protocol parameters.
Table 2- 11 Protocol Parameters (ASCII Driver)
Parameters Description Range of values Default value
Indicator for end of
receive message frame
Defines which criterion signals the
end of each message frame. After character delay time
expires
On receipt of end-of-text
character(s)
On receipt of a fixed
number of characters
After character delay
time expires
2 ms to 65535 ms
The shortest character delay
time depends on the baud rate
Character delay time The character delay time defines the
maximum permitted time between 2
consecutively received characters.
Baud
300
600
1200
2400
4800
9600
19200
38400
57600
76800
115200
Character
delay time
(ms)
130
65
32
16
8
4
2
2
2
2
2
4 ms
End-of-text character 1 2 Code of first end code. With 7 data bits:
0 to 7FH (hex) 3
With 8 data bits:
0 to FFH (hex) 3
3 (03H = ETX)
End-of-text character 2 2 Code of second end code, if
specified. With 7 data bits:
0 to 7FH (hex) 3
With 8 data bits:
0 to FFH (hex) 3
0
Message frame length
when received 1
When the end criterion is "fixed
message frame length", the number
of bytes making up a message frame
is defined.
1 to 4096 (bytes) 240
1 Can only be set if the end criterion is "Fixed message frame length".
2 Can only be set if the end criterion is "End-of-text character".
3 Depending on whether you assign 7 or 8 data bits for the character frame.
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2.8 Configuration data
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Baud rate/Character frame
The table below contains descriptions of and specifies ranges of values for the relevant
parameters.
Table 2- 12 Baud rate/Character frame (ASCII driver)
Parameters Description Range of values Default value
Baud rate Data transmission rate in bps (baud)
Notes:
A maximum of 19200 bps is possible for the 20mA-TTY interface.
300
600
1200
2400
4800
9600
19200
38400
57600
76800
115200
9600
Start bit During transmission, a start bit is prefixed to each character to be
sent.
1 (fixed value)
Data bits Number of bits to which a character is mapped. 7
8
8
Stop bits During transmission, the stop bits are appended to every character
to be sent; this signals the end of a character. 1
2
1
Parity A sequence of information bits can be extended to include another
bit, the parity bit. The addition of its value ("0" or "1") brings the
value of all the bits up to a defined status. This improves data
integrity.
"No" parity means that no parity bit is sent.
None
Odd
Even
Even
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Data flow control
The table below contains a description of the parameters for data flow control.
Data flow control is not possible with the RS 485 interface. Data flow control with "RTS/CTS"
and "automatic operation of V24 signals" is only supported at the RS 232C interface (see
section " Possible applications for the CP 341 (Page 11) ").
Table 2- 13 Data flow control (ASCII driver)
Parameters Description Range of values Default value
Data flow control Defines which data flow control procedure
is used. None
XON/XOFF
RTS/CTS
Automat. control of V24
signals
None
XON character 1 Code for XON character With 7 data bits:
0 to 7FH (hex) 4
With 8 data bits:
0 to FFH (hex) 4
11 (DC1)
XOFF character 1 Code for XOFF character With 7 data bits:
0 to 7FH (hex) 4
With 8 data bits:
0 to FFH (hex) 4
13 (DC3)
Waiting for XON after
XOFF (wait time for
CTS = ON) 2
Period of time for which the
communication processor should wait for
the XON code or for CTS="ON" of the
communication partner when sending.
20 ms to 65530 ms
in 10 ms increments
20000 ms
Clear RTS time 3 Time allowed to elapse after the
transmission before the communication
processor sets the RTS line to OFF.
0 ms to 65530 ms
in 10 ms increments
10 ms
Data output wait time 3 Time that the communication processor
should wait when transmitting for the
communication partner to set CTS to ON
after setting the RTS line to ON and before
starting the transmission.
0 ms to 65530 ms
in 10 ms increments
10 ms
1 Only for data flow control with XON/XOFF.
2 Only for data flow control with XON/XOFF or CTS/RTS.
3 Only for automatic control of the RS 232C accompanying signals.
4 Depending on whether you set 7 or 8 data bits for the character frame.
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2.8 Configuration data
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Further information
Additional information regarding data flow control with XON/XOFF or RTS/CTS and
automatic control of the RS 232C accompanying signals can be found in Section "Data
Transmission with the ASCII Driver (Page 59) " starting at "RS 232C Accompanying
Signals".
Receive buffer on CP
The table below describes the parameters for the CP receive buffer.
Table 2- 14 Receive buffer on CP (ASCII driver)
Parameters Description Range of values Default value
Delete CP receive
buffer at startup
You can specify whether the CP receive buffer
should be deleted on startup or an existing (old)
frame should be sent to the CPU.
Yes
No
No
Buffered receive
message frames
You can specify the number of receive message
frames to be buffered in the CP receive buffer.
If you specify "1" here and deactivate the
following parameter "prevent overwrite" and
cyclically read the received data from the user
program, a current message frame will always
be sent to the CPU.
1 to 250 250
Prevent overwriting You can deactivate this parameter if the
"buffered receive message frames" parameter is
set to "1". This authorizes the overwriting of the
buffered receive message frame.
Yes
No (only if "Buffered receive
message frames" = "1")
Yes
Extended error display
at the receive FB
Activate the parameter "Display receive error at
FB" to also display a message frame received
with errors at the status output of the function
block P_RCV_RK.
If the parameter is deactivated, an entry is only
created in the diagnostic buffer of the CP 341.
Yes
No
No
Further information
Additional information regarding handling of the receive buffer can be found in Section " Data
Transmission with the ASCII Driver (Page 59) " in "Receive buffer on CP 341".
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Manual, 04/2011, A5E02191071-03 89
X27 (RS 422/485) interface
You will find a description of the parameters for the X27 (RS 422/485) interface in the table
below.
Table 2- 15 X27 (RS 422/485) interface (ASCII driver)
Parameters Description Range of values Default value
Operating mode Specifies whether the X27 (RS 422/485)
interface is to be operated in full-duplex
(RS 422) or half-duplex (RS 485) mode.
(See also Serial Transmission of a
Character (Page 23))
Full-duplex (RS 422)
four-wire mode
Half-duplex (RS 485)
two-wire mode
Full-duplex (RS 422)
four-wire mode
Receive line initial state None: This setting only makes sense with
bus-capable special drivers.
R(A) 5V / R(B) 0V: This default setting
supports break detection in "Full-duplex
(RS 422) four-wire mode".
R(A) 0V / R(B) 5V: This default
corresponds to idle state (no senders
active) in "Half-duplex (RS 485) two-wire
mode". Break detection is not possible in
this initial state.
(also see the following figure)
None
R(A) 5V / R(B) 0V 1
R(A) 0V / R(B) 5V
R(A) 5V / R(B) 0V 1
(In "Half-Duplex (RS
485) Two-Wire Mode",
the default setting is
R(A) 0V / R(B) 5V.)
Delete CP receive
buffer at startup
You can specify whether the CP receive
buffer should be deleted on startup or
existing (old) message frames should be
sent to the CPU.
Yes
No
No
1 Only in the case of "Full-Duplex (RS 422) Four-Wire Mode".
Basic Principles of Serial Data Transmission
2.8 Configuration data
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90 Manual, 04/2011, A5E02191071-03
Receive line initial state
The figure illustrates the wiring of the receiver at the X27 (RS 422/485) interface:
9
9
9
9
5$95%9
5$95%9
5$
5%
5$
5%
5$
5%
QRQH
Figure 2-27 Wiring of the receiver at the X27 (RS 422/485) interface (ASCII driver)
Basic Principles of Serial Data Transmission
2.8 Configuration data
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2.8.4 Parameter assignment data of the printer driver
Introduction
You can use the parameter assignment data of the printer driver to generate the
transmission-specific parameters and the message texts for printout.
Parameter assignment data of the printer driver
With the CP 341: Point-to-Point Communication, Parameter Assignment parameter
assignment interface, you can specify:
● The parameters for the physical layer (layer 1) of the printer driver
● The message texts for printout
● The page layout, character set, and control characters for the message texts
You will find a detailed description of the parameters below.
Baud rate/Character frame
The table below contains descriptions of and specifies ranges of values for the relevant
parameters.
Table 2- 16 Baud rate/Character frame (printer driver)
Parameters Description Range of values Default value
Baud rate Data transmission rate in bps 300
600
1200
2400
4800
9600
19200
38400
57600
76800
115200
9600
Start bit During transmission, a start bit is prefixed to each
character to be sent.
1
(fixed value)
1
Data bits Number of bits to which a character is mapped. 7
8
8
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2.8 Configuration data
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Parameters Description Range of values Default value
Stop bits During transmission, the stop bits are appended
to every character to be sent; this signals the end
of a character.
1
2
1
Parity A sequence of information bits can be extended
to include another bit, the parity bit. The addition
of its value ("0" or "1") brings the value of all the
bits up to a defined status. This improves data
integrity. "No" parity means that no parity bit is
sent. "Any" parity indicates that the CP 341 has
set the send parity to a value of "0".
None
Odd
Even
Any
Even
Data flow control
The table below contains a description of the parameters for data flow control.
Data flow control is not possible with the RS 485 interface. RTS/CTS data flow control is only
supported with the RS 232C interface.
Table 2- 17 Data flow control (printer driver)
Parameters Description Range of values Default value
Data flow control Defines which data flow
control procedure is used.
None
XON/XOFF
RTS/CTS
None
XON character
(Only for data flow control
with XON/XOFF.)
Code for XON character For 7 data bits:
0 to 7FH (hex)
With 8 data bits:
0 to FFH (hex)
(Depending on whether you
set 7 or 8 data bits for the
character frame.)
11 (DC1)
XOFF character
(Only for data flow control
with XON/XOFF.)
Code for XOFF character For 7 data bits:
0 to 7FH (hex)
With 8 data bits:
0 to FFH (hex)
(Depending on whether you
set 7 or 8 data bits for the
character frame.)
13 (DC3)
Wait for XON after XOFF
(wait time for CTS = ON)
(Only for data flow control
with XON/XOFF or
RTS/CTS.)
Period of time for which the
CP 341 should wait for the
XON code or for CTS="ON"
of the communication partner
when sending.
Up to 65530 ms
in 10 ms increments
2000 ms
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Manual, 04/2011, A5E02191071-03 93
X27 (RS 422/485) interface
You will find a description of the parameters for the X27 (RS 422/485) interface in the table
below.
Table 2- 18 X27 (RS 422/485) interface (ASCII driver)
Parameters Description Range of values Default value
Receive line initial state R(A)5V/R(B)0V: This initial
state supports BREAK
detection; it cannot be
deactivated.
R(A)0V/R(B)5V: This initial
state does not support break
detection.
R(A) 5V / R(B) 0V
R(A) 0V / R(B) 5V
R(A) 5V / R(B) 0V
Page layout
The table below contains a description of the parameters for the page layout.
Table 2- 19 Page layout (printer driver)
Parameters Description Range of values Default value
Left margin (number of
characters)
Number of spaces to
precede each line in the
body of the text, header or
footer. It is up to you to
ensure that a line is not too
long for the printer.
0 to 255 3
Lines per page (with header
and footer)
Number of lines to be printed
on each page. The number
of lines printed is calculated
on the basis of the
separators output. In other
words, all headers and
footers must be counted.
1 to 255
0 (continuous printing)
50
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2.8 Configuration data
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Parameters Description Range of values Default value
Separators/
Line end
Characters which end each
line in the body of the text,
header or footer.
The body of the text, header
and footer must contain the
defined separator.
CR (carriage return)
LF (line feed)
CR LF (carriage return
and line feed)
LF CR (line feed and
carriage return)
CR LF (carriage return and
line feed)
Headers/Footers Text for up to two header
and footer lines; a header or
footer line is output when the
entry field in the parameter
assignment software
contains a text or at least a
blank space. If a text is
specified only for the 2nd
header or footer line, the 1st
header or footer line is
automatically padded with a
blank and printed. A blank
line is output before and after
the header/footer.
ASCII characters (text)
%P output conversion
statement for page
numbers)
(max. 60 characters)
Character set
The table below contains a description of the parameters for the character set.
Table 2- 20 Character set (printer driver)
Parameters Description Range of values Default value
Printer character set Set "IBM" to convert the set Windows ANSI character
set into the printer character set. If you set "User-
Defined", you can adapt the character set to include
special characters for a particular language.
IBM
User-defined
IBM
Control characters
The table below contains a description of the parameters for control characters.
Table 2- 21 Control characters (printer driver)
Parameters Description Range of values Default value
Printer emulation Sets the printer emulation (printer commands for the
following control characters: bold, condensed, expanded,
italics, and underlining). Set "User-Defined" to modify the
printer emulation and include additional control characters.
The characters A to Z and a to z are permissible as control
characters.
HP DeskJet
HP LaserJet
IBM Proprinter
User-defined
HP DeskJet
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Performance features
Boundary conditions for configuring message texts:
● Size of the text SDB: 15 kbytes
● Max. length of a message text without variables: 150 characters
● Maximum length of message texts with variables displayed: 250 characters
● Maximum number of variables per message text: 4 (3 + message text number)
Message texts
The table below contains a description of the parameters for configuring message texts
(using the CP 341: Point-to-Point Communication, Parameter Assignment parameter
assignment interface).
Table 2- 22 Message texts (printer driver)
Parameters Description Range of values Default value
Name of text SDB/text file The message texts for a CP 341
(serial interface) must be saved to a
text SDB for parameter assignment.
You can also store configured
message texts in an external text file.
ASCII characters (max. 8
characters)
-
Version number Version number of the text SDB/text
file
1 to 255.9 -
Message texts All the message texts stored in the text
block are displayed here together with
their message text numbers; you can
change a selected message text line
by means of the "Edit Message"
parameter.
ASCII characters (unchangeable) -
Edit message You can transfer message texts edited
here to the "Message Texts" list by
clicking the "Enter" button.
Message number:
0 to 1999
Message text (max. 150
characters):
ASCII characters (text)
Conversion statements (for
variables)
Control characters (all those
defined in the control character
table)
-
Font style You can easily assign control
characters to text selected in the "Edit
Message" entry box by using buttons B
to U.
B (bold)
C (condensed)
E (expanded)
I (italic)
U (underlined)
-
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2.8 Configuration data
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2.8.5 Conversion and control statements for printout
Introduction
The output of a message text with variables and control statements (e.g., for bold,
condensed, expanded, or italic type and underlining) is defined by means of a format string.
In the format string you can also define statements to execute other useful functions for
printout (e.g., to set a page number or start a new page).
All the permissible characters and display types for the format string are described below.
You can also configure all the described control statements (except \F "start new page" and
\x "print without line break") and conversion statements for variables (except for %P "set
page number") in the message texts using the CP 341: Point-to-Point Communication,
Parameter Assignment parameter assignment interface.
Format string
The figure illustrates the structure of the format string schematically.
A format string can contain normal text and/or conversion statements for variables and/or
control statements. Normal text, conversion statements, and control statements can occur in
any sequence in the format string.
There must be one (and only one) conversion statement for each variable in the format string
or message text. The conversion statements are applied to the variables in the sequence in
which they occur.
1RUPDOWH[WDOOSULQWDEOHFKDUDFWHUV
&RQYHUVLRQVWDWHPHQW
&RQWUROVWDWHPHQW
Figure 2-28 Schematic structure of the format string
Permissible characters for text
The following can be specified as text:
● All printable characters
● All characters preceded by $ at the language interface (ICE 1131-3). The language
compilers convert these characters into the corresponding hex code. Exception: The
character $N is not permitted.
Example: Carriage return ODH = $R in the format string
Basic Principles of Serial Data Transmission
2.8 Configuration data
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Conversion statement
The figure illustrates the structure of a conversion statement schematically.
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W\SH
3UHFLVLRQ:LGWK)ODJ
Figure 2-29 Schematic structure of a conversion statement
Flag
None = Right-justified output
– = Left-justified output
Width
None = Output in the default display
N = Exactly n characters are output (up to 255 characters are possible); blanks may be
added before (right-justified output) or after (left-justified output)
Precision
Precision is only relevant to display types A, D, F, and R. It is ignored otherwise.
None = Output in the default display
.0 = No output of decimal point or decimal places in
real (R) and floating point (F) display types.
.n = Output of decimal point and n (1 to 99) significant decimal places in real (R) and
floating point (F) display types. In the case of dates (= display types A and D),
precision relates to the number of digits used for the year. Only 2 and 4 are
permitted for dates.
Note that the precision is always preceded by a period. The period serves to identify it and
separate it from the width.
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Display type
The table below describes the possible display types for the values of the variables. Display
types N and P are exceptions and are explained below the table.
The display type supports both uppercase and lowercase letters.
Table 2- 23 Display types in the conversion statement
Display type Associated data type Default display Width of the default
display
Description
A DATE, WORD 10.06.1992 (German) 10 German
Date format
C CHAR, BYTE
WORD
DWORD
ARRAY OF CHAR
ARRAY OF BYTE
A, B
AB
ABCD
ABCDE ...
ABCDE ...
1
2
4
–
–
Alphanumeric characters
D DATE, WORD 1996-06-10 (US English) 10 Date format compliant
with ICE 1131-3
F REAL, DWORD 0.123456 8 Floating point, without
exponent
H All data types incl.
ARRAY OF BYTE
In accordance with the
data type
In accordance with
the data type
Hexadecimal format
I INT, WORD
DINT, DWORD
–32767
–2147483647
Max. 6
Max. 11
Integer range
N(1) WORD (text number) Message text output – Integer 0 to 1999
P(2) INT, WORD Set page number 5 –
R REAL, DWORD 0.12E-04 8 Floating point, with
exponent
S STRING Text output – Text strings
T(1) TIME, DWORD 2d_3h_10m_5s_250ms Max. 22 Duration (negative
duration is identified by a
leading (-) minus sign)
U BYTE
WORD
DWORD
255
65535
4294967295
Max. 3
Max. 5
Max. 10
Integer range, unsigned
X BOOL
BYTE
WORD
DWORD
1
11101100
11001... (16)
11001... (32)
1
8
16
32
Binary format
Basic Principles of Serial Data Transmission
2.8 Configuration data
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Display type Associated data type Default display Width of the default
display
Description
Y(3) DATE_AND_TIME_
OF_DAY, DT
10.06.1992
–15:42:59.723
25 Date and time of day
Z TIME_OF_DAY
DWORD
15:42:59.723 12 Time
(1) If there is no message text number or system time in these display types, 6 "*" characters appear in the printout instead
(the CP 341 does not keep the time). %N is the only conversion statement which cannot be used in the message text.
(2) The P display type is only permitted in the format string. P is not permitted in configurable message texts.
(3) The current time and date must be read first by means of the SFC 1 "READ_CLOCK" system function and stored in the
user memory (bit memory, data).
Output by means of message text number (%N)
Use the N display type to start printing message texts stored on the CP 341. The conversion
statement variable contains the number of the message text.
Example: The pressure in the chamber "is falling"
Format string = %N %S
Variable 1 = 17 (message text no. 17: The pressure in the chamber ...)
Variable 2 = reference to string (string variable: ... is falling)
Note
Within a message text, all conversion statements except for %N and all control statements
except for "\F" and "\x" are allowed! An explicit width setting of %N limits the printed length of
the referenced message text to the width indicated.
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Setting the page number (%P)
Use the P display type to change the page number in the printout.
The CP 341 always begins a printout at page 1. This conversion statement allows you to set
the page number to a specific value. The conversion statement variable contains the page
number to be set.
Example: (Setting the page number to 10)
Format string = %P
Variable 1 = 10 (page number: 10)
Note
In the case of the P display type, there must be no further text, conversion statements, or
control statements in the format string. The P display type is not permitted in configured
message texts.
Notes about conversion statements
Please note the following in relation to conversion statements:
● Whenever a maximum length is specified for the default display, the actual output can
also be shorter. Example: The output of the integer 10 consists of only 2 characters.
● The length of the data to be printed depends on the length of the variables. For example,
in the case of the I display type a maximum of 6 places can be output for the INT data
type and a maximum of 11 places for the DINT data type.
● A width of "0" is not permissible in conversion statements. This is printed out as "******"
with the valid conversion statement.
● If the specified width is too small, in the case of text-based output (display types A, C, D,
S, T, Y, and Z), only the number of characters corresponding to the specified width are
output (the remainder are truncated). In all other cases, "*" characters are output
corresponding to the width.
● Undefined or invalid conversion statements are not executed. This is printed out as
"******" (e.g. display type missing: %2.2).
The rest of the conversion statement (i.e., everything after the character identified as
incorrect) is output. This allows the exact cause of the error to be determined.
● Conversion statements without associated variables will be ignored. Variables for which
there is no conversion statement are not output.
● Conversion statements in a header or footer that are not supported are not executed.
Instead, they are forwarded to the printer transparently.
Basic Principles of Serial Data Transmission
2.8 Configuration data
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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● You must use control statements to specify formatting (line feed, tabs, etc.) in a message
text or in the printout of a longer conversion statement.
● If both the format string and the message text contain conversion statements, the format
string is expanded first, followed by the message text.
Example: Voltage 3 V – Current 2 A
Message text 1 = Voltage %I V
Format string = '%N – Current: %I A’
Variable 1 = 1
Variable 2 = 2
Variable 3 = 3
Examples of invalid conversion statements
Below are several examples of invalid conversion statements.
Example 1: ******.2R
Format string = %303.2R
Variable 1 = 1.2345E6
Error: Invalid width in the R display type. The maximum permissible value for all display
types is 255.
Example 2: ****
Format string = %4.1I
Variable 1 = 12345 DEC
Error: The selected width was too small for the variable value to be output. The precision is
not relevant to display type I.
Example 3: 96–10–3
Format string = %7.2D
Variable 1 = D#1996–10–31
Error: The format string is formally correct, but the selected width was too small to print the
date in full.
Example 4: **********
Format string = %.3A
Variable 1 = D#1996–10–31
Error: The default width of display type A was selected but with invalid precision. The
possible values here are 2 and 4.
Example 5: ******
Format string = %3.3
Variable 1 = 12345 HEX
Error: A display type was not specified.
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Examples of correct conversion statements
Below are some examples of correct conversion statements.
Example 1: .....31.10.1996
Format string = %15.4A
Variable 1 = D#1996–10–31
A width of 15 with a precision of 4 (width of the year) and right-justified formatting were
selected.
Example 2: 12345.
Format string = %–6I
Variable 1 = 12345 DEC
The selected width was one character greater than the variable value to be output; left-
justified formatting.
Example 3: 12d_0h_0m_23s_348ms
Format string = %T
Variable 1 = T#12D23S348MS
The IEC time is in the standard format; unspecified time units are inserted with zeros.
Example 4: 1.234560E+02
Format string = %12.6R
Variable 1 = 123.456
A width of 12 is available to display the whole variable, with the precision (number of decimal
places) taking up 6 places.
Example 5: TEST..
Format string = %–6C
Variable 1 = TEST
Left-justified formatting of the text variables
Basic Principles of Serial Data Transmission
2.8 Configuration data
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Control statements
Control statements are used to achieve specific results in the printout (e.g., underlining).
In addition to the standard control statements (for bold, condensed, expanded, or italic type
and underlining), you can also use other control characters if you enter them in the control
character table on the CP 341: Point-to-Point Communication, Parameter Assignment
parameter assignment interface prior to assigning parameters to CP 341.
The figure illustrates the structure of the control statement schematically.
?
?
%
&
(
,
.
8
2XWSXWRIWKHFKDUDFWHU
VWDQGDUGFRQWUROVWDWHPHQW
2XWSXWRIWKHFKDUDFWHU?
6ZLWFKRQ %ROGW\SH
&RQGHQVHGW\SH
([SDQGHGW\SH
,WDOLFW\SH
6PDOOFDSLWDOV
8QGHUOLQLQJ
6ZLWFKRII
Figure 2-30 Schematic structure of control statements
Examples
Below are some examples with control statements.
Example 1:
To print the text "Bold type and underlining are ways of highlighting a text", you have to enter
the following:
\BBold type\-B and \UUnderlining\-U are ways of highlighting a text
Example 2:
To output the format string with the conversion statement "Message text no. %i of %8.2A"
transparently on the printer, you have to enter the following:
'Message text no. \%i of \%8.2A'
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2.8 Configuration data
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104 Manual, 04/2011, A5E02191071-03
Starting a new page (\F)
Taking into account the assigned page layout, i.e. the configured headers and footers and
the number of lines per page, the \F control statement can be used to begin a new page.
This differs from a pure form feed on the printer.
Example: (Starting a new page)
Format string = \F
Note
In the case of the \F control statement, there must be no further text, conversion statements,
or control statements in the format string. The variables remain unassigned.
Printing without a line break (\x)
The CP 341 normally appends the assigned end-of-line character (CR, LF, CR LF, LF CR)
when it sends a message text. The \x control statement cancels the line break after a
message text. This means that you can print several message texts in a single line in order,
for example, to display more variables in a line. The \x control statement is appended at the
end of the format string.
Example: The level "200" l was reached at "17:30" hours. ...
Format string = The level %i l was reached at %Z hours.\x
Variable 1 = time
Variable 2 = level
Note
Note that when you use the \x control statement, the new line always begins without a left
margin.
Notes about control statements
Note the following in relation to control statements:
● If the deactivation of an effect is requested without it previously having been activated, or
if the output device is incapable of producing the effect, the control statement is ignored.
● The % and \ characters required to define the format string can be printed by means of
the control statement.
● Undefined or invalid control statements are not executed.
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Manual, 04/2011, A5E02191071-03 105
Commissioning the CP 341 3
To commission the communication processor, you will need to perform the following
operations in the order given:
1. Mounting the CP 341
2. Configuring the CP 341
3. Assigning Parameters to the CP 341
4. Saving the parameter data
5. Create a user program for the CP 341
Mounting the CP 341
Mounting of the CP 341 involves its integration into the mounting rail (rack) of your
programmable controller.
You can find a detailed description in Section "Configuring the CP 341 (Page 112)" of this
manual.
Configuring the CP 341
Configuration of the CP 341 involves its layout in the configuration table. You configure the
CP 341 using the STEP 7 software.
You can find a detailed description in Section "Configuring the CP 341 (Page 112)" of this
manual.
Assigning Parameters to the CP 341
Parameter assignment of the CP 341 involves the creation of specific parameters of the
protocols and the configuration of message texts for printout. You carry out the parameter
assignment of the CP 341 using the CP 341:Point-to-Point Communication, Parameter
Assignment parameter assignment interface.
You can find a detailed description in Section "Assigning Parameters to the Communications
Protocols (Page 113)" of this manual.
Saving the parameter data
Storage of the parameter assignment data of the CP 341 involves saving the parameters,
loading the parameters to the CPU, and transferring the parameters to the communication
processor. You store the parameter assignment data using STEP 7 software.
You can find a detailed description in Section "Managing the Parameter Data (Page 116)" of
this manual.
Commissioning the CP 341
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106 Manual, 04/2011, A5E02191071-03
Creating a User Program for the CP 341
Programming of the CP 341 involves the program interface of the CP 341 to the associated
CPU using the STEP 7 user program. You program the CP 341 using the language editors
of the STEP 7 software.
A comprehensive programming example is available in Section "Programming Example for
Standard Function Blocks (Page 199)". A detailed description of programming with STEP 7
is contained in the
Programming with STEP 7
manual.
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Mounting the CP 341 4
4.1 CP 341 slots
The following section describes the rules you must observe when positioning the CP 341 in
the rack (mounting rail).
Position of the CP 341 in the rack (mounting rail)
The following rules apply when positioning the CP 341 in the rack (mounting rail):
● A maximum of 8 communication modules can be inserted to the right of the CPU.
● The number of communication modules that can be inserted is limited by the
expandability of the CPU (e. g., CPU 312 IFM in first row) or the ET 200M (IM 153) in
distributed applications (single-row configuration only).
Note
Prior to removing or inserting the CP 341, you must switch the CPU to STOP mode and
switch off the power supply. There are no restrictions for removing or inserting the cable
for the integrated interface on the CP 341. However, you must make sure that there is no
data being transmitted via the integrated interface when you do this. Otherwise, data may
be lost.
Further information
Further information about slots is available in the Manual
S7–300 Programmable Controller,
CPU Data, Installation
.
Mounting the CP 341
4.2 Mounting and Dismounting the CP 341
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4.2 Mounting and Dismounting the CP 341
When installing and removing the CP 341, you must observe certain rules.
Tool
For installing and removing the CP 341, you require a 4.5 mm cylindrical screwdriver.
24 V DC load power supply
The CP 341 has an external 24 V DC load power supply. The 24 V DC load power supply
must satisfy the following requirements:
Only a safe, isolated extra-low voltage of ≤ 60 V DC may be used as the load current supply.
The reliable electrical insulation can be implemented in compliance with the requirements of
● VDE 0100 Part 410 / HD 60364.4.41:2007 / IEC 60364–4–41:2005
(as functional extra-low voltage with safe electrical isolation) or
● VDE 0805 / EN 60950 / IEC 950
(as safety extra-low voltage SELV) or VDE 0106 Part 101.
4.2.1 Installation steps
Inserting the rack (mounting rail)
To insert the CP 341 in a rack (mounting rail), proceed as follows:
1. Switch the CPU to STOP mode.
2. Switch off the power supply.
3. The CP 341 is accompanied by an expansion bus. Plug this onto the backplane
connector of the module to the left of the CP 341.
4. If more modules are to be mounted to the right of the CP 341, plug the expansion bus of
the next module onto the right backplane connector of the CP 341.
5. Hook the FM 341 onto the mounting rail and swivel it downwards.
6. Screw the CP 341 tight.
7. Connect the DC 24 V of the load power supply to the CP 341.
Mounting the CP 341
4.2 Mounting and Dismounting the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 109
Connection terminals
0'&9
/'&9
0'&9
-XPSHUVIRU
JURXQGHG
FRQILJXUDWLRQ
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Figure 4-1 Connection terminal
● Connect the positive cable of the 24 V supply to terminal L+.
● Connect the negative cable of the 24 V supply to terminal M.
● The two M terminals are interconnected internally. The 24-V connection has polarity
reversal protection.
● If you do not want to ground the 24 V ground cable, remove the jumper between the
functional ground and M terminals.
4.2.2 Removal steps
Dismounting the rack (mounting rail)
To dismount the CP 341 from the rack (mounting rail), proceed as follows:
1. Switch the CPU to STOP mode.
2. Shut down the power supply.
3. Open the front doors.
4. Disconnect the connection to the DC 24V supply.
5. Disconnect the sub-D connector from the integral interface.
6. Release the securing screw on the module.
7. Tilt the module and remove it from the rail, and then remove it from the PLC.
4.2.3 Installation guidelines
To be Observed
The general installation guidelines for the S7-300 must be observed (see the S7-300
Programmable Controller, CPU Data, Installation manual).
To comply with EMC (electromagnetic compatibility) values, the shield of the cables must be
connected to a shielding bus.
Mounting the CP 341
4.2 Mounting and Dismounting the CP 341
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Configuring and Parameter Assignment the CP 341 5
5.1 Parameter Assignment Options
Configuration options
You configure and assign the module variants of the CP 341 using STEP 7 or the CP 341:
Point-to-Point Communication, Parameter Assignment parameter assignment interface.
Table 5- 1 Configuration options for the CP 341
Product Order number Assignable using the parameter
assignment interface
Under STEP 7
CP 341-RS 232C 6ES7 341-1AH02-0AE0
CP 341-20mA-TTY 6ES7 341-1BH02-0AE0
CP 341-RS 422/485 6ES7 341-1CH02-0AE0
as of version V5.1.7 as of version V5.3
5.2 Installing the Programming Interface
Installation
The CP 341: Point-to-Point Communication, Parameter Assignment parameter assignment
interface is located on the CD along with the function blocks and programming example. To
install the parameter assignment interface:
1. Insert the CD into the CD drive of your programming device or PC.
2. In Microsoft Windows, start the dialog for installing software by double-clicking the
"Add and Remove Programs" icon in the "Control Panel".
3. In the dialog, select the CD drive and the "Setup.exe" file and start installation.
4. Follow the on-screen instructions provided by the setup program.
Configuring and Parameter Assignment the CP 341
5.3 Configuring the CP 341
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5.3 Configuring the CP 341
Once you have mounted the CP 341 you must inform the programmable controller that it is
there. This process is known as "configuring".
Requirements
The CP 341:Point-to-Point Communication, Parameter Assignment: parameter assignment
interface is installed in the STEP 7 software on your programming device or PC (see section
"Parameter Assignment Options (Page 111)").
Before you can enter the communication processor in the configuration table of the STEP 7
software, you must have created a project and a station with STEP 7.
Configuring
In the following, "configuring" refers to the placement of the CP 341 in the configuration table
of the STEP 7 software. You enter the rack, the slot, and the order number of the CP 341 in
the configuration table. STEP 7 then automatically assigns an address to the CP 341.
The CPU is now able to find the CP 341 in its slot in the rack by way of its address.
NOTICE
Prior to starting up a configured CP 341, you have to assign parameters to the module with
a communication protocol - as described in the following section Assigning Parameters to
the Communications Protocols (Page 113). A (non explicitly assigned CP 341) which is only
connected is not automatically assigned specific default parameters!
Requirement
Before you can enter the CP 341 in the configuration table of the STEP 7 software, you must
have created a project and a station with STEP 7.
Further information?
How to configure S7-300 modules is described in detail in the
Configuring Hardware and
Communication Connections STEP 7
manual.
In addition, the STEP 7 online help offers you comprehensive support when configuring an
S7-300 module.
Configuring and Parameter Assignment the CP 341
5.4 Assigning Parameters to the Communications Protocols
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5.4 Assigning Parameters to the Communications Protocols
You must parameterize the CP 341 and its serial interface after having entered the CP 341
in the configuration table. In the case of the printer driver, you can also configure message
texts for printer output.
Parameter assignment
The term "parameter assignment" is used in the following to describe the setting of protocol-
specific parameters. The parameter assignment is carried out with the CP 341: Point-to-
Point Communication, Parameter Assignment parameter assignment interface.
You start the parameter assignment interface by double-clicking the order number (CP 341)
in the configuration table or by selecting the CP 341 and then the Edit > Object Properties
menu command. The "Properties – CP 341" dialog will appear.
Click the "Parameters" button to go to protocol selection. Set the protocol and double-click
the icon for the transmission protocol (an envelope). This takes you to the dialog for setting
the protocol-specific parameters.
Further information?
The basic operation of the CP 341: Point-to-Point Communication, Parameter Assignment
parameter assignment interface is the same for all communication processors and is self-
explanatory. For this reason, the parameter assignment interface is not described in detail
here.
Also, the online help will support you when working with the parameter assignment interface.
Configuring and Parameter Assignment the CP 341
5.5 Identification data
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5.5 Identification data
Definition
Identification data represent information stored on the module and support you in:
● Troubleshooting a plant
● Verifying your plant configuration
● Locating hardware modifications in a plant
This ID data allows the unambiguous identification of modules in online mode. Starting with
order no. 6ES7 341–1xH02–0AE0, this data is available on the CP 341.
To view the identification data, select PLC > Module Information, or Read Data Record (see
below).
Reading the identification data
Users can access specific ID data by selecting Read Data Record.
The element of the ID data which is assigned to the corresponding index is found under the
associated data record number.
All data records which contain ID data have a length of 64 bytes.
The table below shows the structure of those data records.
Table 5- 2 Data record structure
Content Length (bytes) Coding (hex)
Header information
SZL ID 2 F1 11
Index 2 00 0x
Length of identification data 2 00 38
Number of blocks which contain ID data 2 00 01
Table 5- 3 Identification data
Identification data
Index 2 00 0x
Identification data associated with the relevant
index
54
Configuring and Parameter Assignment the CP 341
5.5 Identification data
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Identification data of the CP 341 module
Table 5- 4 Identification data of the CP 341 module
Identification data Access Default setting Description
Index 1 (data record 231/read only)
Manufacturer Read
(2 bytes)
00 2A hex (= 42 dec) The name of the manufacturer is saved to
this parameter
(42 dec = Siemens AG).
Device name Read
(20 bytes)
6ES7 341–1xH02–0AE0 Order number of the module
x = A(RS232), B(TTY), C(RS422/485)
Device serial number Read
(16 bytes)
The serial number of the module is saved to this parameter. This
structure allows the unique identification of the module.
Hardware revision Read
(2 bytes)
Provides information about the product version of the module.
Software revision Read
(4 bytes)
Provides information about the firmware version of the module.
Statistical
revision no.
Read
(2 bytes)
- Not supported
Profile_ID Read
(2 bytes)
F6 00 hex Internal parameter
(to PROFIBUS DP)
Profile–specific type Read
(2 bytes)
00 04 hex (= 4 dec) Internal parameter (communication module,
to PROFIBUS DP)
I&M version Read
(2 bytes)
00 00 hex (= 0 dec) Internal parameter
(to PROFIBUS DP)
I&M supported Read
(2 bytes)
00 01 hex (= 1 dec) Internal parameter (I&M0 and I&M1, to
PROFIBUS DP)
Index 2 (data record 232/read and write)
HID Read/write
(max.
32 characters)
- Plant (higher-level) designation of the
module.
LD Read/write
(max.
22 characters)
- Location designation of the module.
Index 3 (data record 233/read and write)
Device installation date Read/write
(max.16
characters)
- Installation date
Index 4 (data record 234/read and write)
Descriptor Read/write (max.
54 characters)
- Additional information
Configuring and Parameter Assignment the CP 341
5.6 Managing the Parameter Data
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5.6 Managing the Parameter Data
The configuration and parameter assignment data of the communication processor is saved
in the current project (on the hard disk of the programming device/PC).
Data management
When you exit the configuration table by selecting the Station > Save or Station > Save As
menu command, the configuration data and parameter assignment data (including the
module parameters) are automatically stored in the project/user file you have created.
Loading the configuration and parameters
You can now download the configuration data and parameter assignment data online from
the programming device to the CPU (menu command PLC > Download). The CPU accepts
the parameters immediately after the download.
The module parameters are automatically transmitted to the communication processor,
● when they are loaded onto the CPU and as soon as the communication processor can be
reached via the S7-300 backplane bus,
or
● when the CPU changes from STOP to RUN mode (CPU start-up).
Default settings apply if parameters are not changed.
Further information
The
Configuring Hardware and Communication Connections with STEP 7
manual describes
in detail how you
● Save the configuration and the parameters
● Download the configuration and the parameters to the CPU
● Read, modify, copy, and print the configuration and the parameters
Configuring and Parameter Assignment the CP 341
5.7 Subsequent Loading of Drivers (Transmission Protocols)
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 117
5.7 Subsequent Loading of Drivers (Transmission Protocols)
To extend the functionality of the CP 341 and adapt it to the communication partner, you can
load other transmission protocols onto the CP 341 (loadable drivers) in addition to the
standard protocols in the module firmware (ASCII, 3964(R), RK 512).
The loadable drivers are not shipped with the CP 341 or the parameter assignment interface.
You have to order them separately. (see Catalog ST 70, section "Loadable drivers")
To find out how to install and assign parameters to a loadable driver and load it onto the
CP 341, consult the separate documentation for the loadable driver. Only the requirements
and the fundamentals are described below.
Requirements
The prerequisites for subsequently loading the drivers are:
● STEP 7 V5.3 and higher
● CP 341: Point-to-Point Communication, Parameter Assignment parameter assignment
interface, V5.0 or higher
● The driver dongle must be connected to the port at the rear of CP 341.
● The valid parameter assignment was saved in HW Config beforehand and has been
downloaded to the CPU.
Introduction to the parameter assignment interface
You select the loadable driver for parameter assignment in the CP 341: Point-to-Point
Communication, Parameter Assignment parameter assignment interface.
After you have successfully installed the parameter assignment interface and loadable
drivers, you select the driver you want and assign the protocol-specific parameters in the
same way as you do for the standard protocols. Installation of the parameter assignment
interface and selection of a transmission protocol: see section: "Assigning Parameters to the
Communications Protocols (Page 113)".
To find out what parameters are assigned and how to download the drivers to the CP 341,
consult the separate documentation for the loadable driver.
Configuring and Parameter Assignment the CP 341
5.8 Firmware updates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
118 Manual, 04/2011, A5E02191071-03
5.8 Firmware updates
5.8.1 Subsequent Loading of Firmware Updates
You can download the firmware update to the operating system memory of the CP 341 in
order to expand its functionality and for error handling.
Requirements
The requirements for loading firmware updates are as follows:
● STEP 7 V5.3 and higher
● You must first create a valid project in HW Config and load it onto the CPU before you
can update the firmware of the CP.
● The CP 341 must be available online on the PG/PC.
● Refer to the instructions for the firmware update package for the storage location of the
firmware update files.
The "..\CP341.nnn" path always identifies the firmware version.
Load firmware in HW Config
(valid as of order number 6ES7 341-1xH02-0AE0)
Carry out a firmware update as follows:
1. Switch the CPU to STOP mode.
2. Open HW Config, then select the relevant CP 341 module.
3. Select the menu command PLC > Update Firmware.
For additional information on procedures, refer to the
STEP 7
online help.
The system outputs a message to indicate successful completion of the update and
immediately activates the new firmware.
Configuring and Parameter Assignment the CP 341
5.8 Firmware updates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 119
Loading firmware with the CP 341 parameter assignment interface
(valid for order numbers 6ES7 341-1xH00-0AE0 and 6ES7 341-1xH01-0AE0)
The firmware is transferred to the CP 341 using the CP 341:Point-to-Point Communication,
Parameter Assignment parameter assignment interface (as of V5.0).
Proceed as follows:
1. Switch the CPU to STOP mode.
2. Start the parameter assignment interface:
In SIMATIC Manager: File > Open > Project > Open Hardware Config > double-click on
CP 341 > select the "Parameters" button.
3. Select the Options > Firmware Update menu command.
Result:
If a connection can be established to the CP 341, the current module firmware status is
displayed.
If no firmware is found on CP 341, the string " - - - - " will be returned. This can happen,
for example, if you cancelled the firmware update. In this case, the old firmware will be
deleted. You have to reload a firmware prior to commissioning.
4. Click the "Find File ..." button to select the firmware to be loaded (*.UPD).
Note: The basic firmware consists of three files each with a *.UPD extension. Select only
the file called HEADER.UPD for the basic firmware.
Result:
The version of the selected firmware is displayed under "Selected FW version".
5. Click the "Load Firmware" button to start loading the firmware to the CP 341. You are
prompted for confirmation. The load operation will be canceled immediately if you click
the "Cancel" button.
Note: Before the basic firmware is deleted from the module, the CP 341 checks the order
no. of the firmware to be downloaded in order to ensure that the firmware is approved for
the CP 341.
Result:
The new firmware is loaded into the operating system memory of the CP 341. "Done"
shows the progress on a status bar and as a percentage. The module is immediately
ready for operation once the firmware update is successfully completed.
Update successful
After you have completed the CP 341 firmware update, attach a new label showing the new
firmware version.
Configuring and Parameter Assignment the CP 341
5.8 Firmware updates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
120 Manual, 04/2011, A5E02191071-03
LED indicators
LED indicators when loading a firmware update:
Table 5- 5 LED indicators for firmware update
Status SF TXD RXD Comment Remedy
Firmware update in progress On On On - -
Firmware update completed On Off Off - -
CP 341 without module
firmware
Flashing
(2 Hz)
Off Off Module firmware
deleted, firmware update
canceled, firmware
update still possible
Reload the firmware
Hardware fault during firmware
update
Flashing
(2 Hz)
Flashing
(2 Hz)
Flashing
(2 Hz)
Delete/write operation
failed
Switch power supply to
module off and then on
again and reload the
firmware.
Check whether the
module is defective.
Configuring and Parameter Assignment the CP 341
5.8 Firmware updates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 121
5.8.2 Viewing the Firmware Version
Viewing the hardware and firmware version
You can view the current hardware and firmware version on the CP 341 in STEP 7 in the
"Module Information" dialog. Access this dialog box as follows:
● In SIMATIC Manager: File > Open > Project > Open HW Config > Station > Open Online
and double-click the CP 341 module.
Configuring and Parameter Assignment the CP 341
5.8 Firmware updates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
122 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 123
Communication via Function Blocks 6
Communication between the CPU, the CP 341 and a communication partner takes place via
the function blocks and the protocols of the CP 341.
Communication between CPU and CP 341
The function blocks form the software interface between the CPU and the CP 341. They
must be called in cycles from the user program.
Communication between CP 341 and a communication partner
The transmission protocol conversion takes place on the CP 341. The protocol is used to
adapt the interface of the CP 341 to the interface of the communication partner.
This enables you to link an S7 programmable controller with any communication partner that
can handle today's standard protocols available in SIMATIC S5 (ASCII driver, 3964(R)
procedure, RK 512 computer link, or printer driver).
Interrupt response
Calling the CP 341 function blocks in process (OB 40) or diagnostic (OB 82) interrupts is not
permitted.
The function blocks P_SND_RK and P_RCV_RK of the CP 341 may only be called in one
and the same execution level.
Communication via Function Blocks
6.1 Overview of the Function Blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
124 Manual, 04/2011, A5E02191071-03
6.1 Overview of the Function Blocks
The S7-300 programmable controller provides you with a number of function blocks which
initiate and control communication between the CPU and the CP 341 in the user program.
Function blocks/functions
The table below lists the function blocks/functions of the CP 341 and describes their
purpose.
Table 6- 1 Function blocks / functions of the CP 341
FB/FC Meaning Protocol
FC 5 V24_STAT
(Version 2.0)
The V24_STAT function allows you to read the signal states at the RS
232C interface of the CP 341-RS 232C.
ASCII driver
FC 6 V24_SET
(Version 2.0)
The V24_SET function allows you to set/reset the outputs at the
RS 232C interface of the CP 341-RS 232C.
ASCII driver
FB 7 P_RCV_RK The P_RCV_RK function block allows you to receive data from a
communication partner and place it in a data block or to provide data to
the communication partner.
3964(R) procedure,
ASCII driver, RK 512
computer link
FB 8 P_SND_RK The P_SND_RK function block allows you to send an entire area or
subarea of a data block to a communication partner or fetch data from
the communication partner.
3964(R) procedure,
ASCII driver, RK 512
computer link
FB 13 P_PRINT_RK The P_PRINT_RK function block enables you to output a message text
with up to 4 variables to a printer.
Printer driver
Scope of supply and installation
The function blocks of the CP 341, together with the parameter assignment interface and the
programming example, are supplied on CD which comes with this manual.
The function blocks are installed together with the parameter assignment interface. After
installation, the function blocks can be found in the library:
● CP 341: FC 5 V24_STAT (Version 2.0), FC 6 V24_SET (Version 2.0), FB 7 P_RCV_RK,
FB 8 P_SND_RK and FB 13 P_PRINT_RK
You open the library under "CP PTP\CP 341\Blocks" in the STEP 7 SIMATIC Manager by
selecting the File > Open > Library menu command.
When working with the function blocks, you only have to copy each function block to your
project.
Communication via Function Blocks
6.1 Overview of the Function Blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 125
Permissible versions of the FBs and FCs
Note the following regarding permissible function blocks and functions:
WARNING
For the CP 341, you can use only the FC 5 V24_STAT and FC 6 V24_SET functions with
version ≥ 2.0. Use of Version 1.0 can result in data corruption. For data transmission with
the CP 341, only the FB 7 P_RCV_RK and FB 8 P_SND_RK function blocks can be used.
The FB 2 P_RCV and FB 3 P_SEND function blocks of the CP 340 must not be used
because this can result in data corruption.
Communication via Function Blocks
6.2 Using function blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
126 Manual, 04/2011, A5E02191071-03
6.2 Using function blocks
The following sections describe the factors to be considered when assigning parameters for
the function blocks.
STATUS Indicator on the FB
Note the following regarding the STATUS indicator on the function blocks:
Note
The DONE, NDR, ERROR, and STATUS parameters are valid for only one block cycle. To
display the STATUS, you should therefore copy it to a free data area.
DONE = '1' means that the request was completed without error.
In other words:
● When using the ASCII driver: Request was sent to the communication partner. It is not
ensured that all data were received by the communication partner.
● When using the 3964(R) procedure: Request was sent to the communication partner and
positive acknowledgement was returned. It is not ensured that the data were also passed
onto the partner CPU.
● With RK 512 computer link: Request was sent to the communication partner, which
forwarded it without error to the partner CPU.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 127
6.3 Using the Function Blocks with the 3964(R) Procedure
The function blocks available for connection to a communication partner with the 3964(R)
procedure are as follows:
● FB 8 P_SND_RK for transmitting data
● FB 7 P_RCV_RK for receiving data
Requests that can be processed simultaneously
Only one FB P_SND_RK and one FB P_RCV_RK can be programmed for each CP 341 in
the user program.
Bear in mind, too, that you can use only:
● 1 instance data block for FB P_SND_RK and
● 1 instance data block for FB P_RCV_RK
This is because the statuses needed for the FB's internal routines are stored in the instance
data block.
Data consistency
The block size limits the data consistency for data transmission between the CPU and
CP 341 to 32 bytes.
If you want consistent data transmission exceeding 32 bytes, you must take the following
into account:
● Sender: Only access the send DB when all data have been completely transferred
(DONE = 1).
● Receiver: Only access the receive DB when all data are received (NDR = 1). Then you
must disable the receive DB (EN_R = 0) until you have processed the data.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
128 Manual, 04/2011, A5E02191071-03
6.3.1 S7 Sends Data to a Communication Partner
The FB P_SND_RK transmits data from a data block, specified by the DB_NO, DBB_NO and
LEN parameters, to the CP 341. For purposes of data transmission, the FB P_SND_RK is
called cyclically or, alternatively, statically in a time-driven program (without conditions).
The data transmission is initiated by a positive edge at the REQ input. A data transmission
operation can run over several calls (program cycles), depending on the amount of data
involved.
The FB P_SND_RK function block can be called cyclically when the signal state at the R
parameter input is "1". This cancels the transmission to the CP 341 and places the
FB P_SND_RK in its initial state. Data that has already been received by the CP 341 is still
sent to the communication partner. If the signal state at the R input remains static at "1", this
means that sending is deactivated.
The LADDR parameter specifies the address of the CP 341 to be addressed.
Error display at the FB P_SND_RK
The DONE output shows "request completed without errors". ERROR indicates whether an
error has occurred. If an error has occurred, the corresponding event number is displayed in
STATUS (see section "Diagnostics Messages of the Function Blocks (Page 178)"). If no
error has occurred, STATUS has the value 0. DONE and ERROR/STATUS are also output
at RESET of the FB P_SEND RK (see figure in section "Receiving Data with FB P_RCV_RK
(Passive Request) (Page 143)"). In the event of an error, the binary result BR is reset. If the
block has been completed without errors, the binary result has the status "1".
Note
The P_SND_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode. Before the CP 341 can process an
activated request after the CPU has changed from STOP to RUN mode, the CP-CPU startup
mechanism of the FB P_SND_RK must have been completed (see section "Diagnostics
Messages of the Function Blocks (Page 178)"). Any requests initiated in the meantime are
not lost. They are transmitted once the start-up coordination with the CP 341 is finished.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 129
Block call
STL representation LAD representation
CALL P_SND_RK, I_P_SND_RK
SF: =
REQ: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
LEN: =
R_CPU_NO: =
R_TYP: =
R_NO: =
R_OFFSET: =
R_CF_BYT =
R_CF_BIT =
DONE: =
ERROR: =
STATUS: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Assignment in the data area
The FB P_SND_RK works together with an I_SND_RK instance DB. The DB number is
passed on with the call. The instance DB requires 414 bytes load memory and 156 bytes
RAM. Access to the data in the instance DB is not permitted.
Note
Exception: If the error STATUS == W#16#1E0F occurred, you can consult the SFCERR
variable for additional details. This error variable can only be loaded via symbolic access to
the instance DB.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
130 Manual, 04/2011, A5E02191071-03
FB P_SND_RK parameters
The table below lists the parameters of the FB P_SND_RK.
Note
The R_CPU_NO, R_TYP, R_NO, R_OFFSET, R_CF_BYT, and R_CF_BIT parameters are
irrelevant for the 3964(R) procedure and do not have to be assigned. The SF parameter also
does not have to be assigned since 'S' for sending is entered by default.
Table 6- 2 FB P_SND_RK parameters
Name Sort Data type Comment Permitted values, remark
REQ INPUT BOOL Initiates request on positive
edge
R INPUT BOOL Cancels request Cancels the request in progress.
Transmission is disabled.
LADDR INPUT INT CP 341 start address The start address is taken from STEP 7.
DB_NO INPUT INT Data block number Send DB no.: CPU-specific,
zero is not permitted
DBB_NO INPUT INT Data byte number 0 ≤ DBB_NO ≤ 8190 Send data starting from
data byte
LEN INPUT INT Data length 1 ≤ LEN ≤ 4096, specified in number of bytes
DONE 1 OUTPUT BOOL Request completed without
errors
STATUS parameter == 16#00;
ERROR 1 OUTPUT BOOL Request completed with
errors
Error information is written to the STATUS
parameter.
STATUS 1 OUTPUT WORD Specification of error If ERROR == 1, the STATUS parameter will
contain error information.
1 The parameter is available until the next time the FB is called.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 131
Time sequence chart of FB P_SND_RK
The figure below illustrates the behavior of the DONE and ERROR parameters depending
on the input circuit of REQ and R.
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Note
The REQ input is edge-triggered. A positive edge at the REQ input is sufficient. The result of
the logic operation must not be at "1" at any point during transfer.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
132 Manual, 04/2011, A5E02191071-03
6.3.2 S7 receives data from a communication partner
The FB P_RCV_RK transmits data from the CP 341 to an S7 data area, specified by the
DB_NO, DBB_NO, and LEN parameters. For purposes of data transmission, the
FB P_RCV_RK is called cyclically or, alternatively, statically in a time-driven program
(without conditions).
A (static) signal state "1" at the EN_R, parameter enables a check to determine whether data
can be read from the CP 341. An active transmission can be canceled with signal state "0" at
the EN_R parameter. The canceled receive request is terminated with an error message
(STATUS output). Receiving is disabled as long as the signal state at the EN_R parameter is
"0". A data transmission operation can run over several calls (program cycles), depending on
the amount of data involved.
If the function block recognizes signal state "1" at the R parameter, the current transmission
request is canceled and the FB P_RCV_RK is placed in its initial state. Receiving is disabled
as long as the signal state at the R parameter is "1".
The LADDR parameter defines the CP 341 to be addressed.
Error display at the FB P_RCV_RK
The NDR output shows "request completed without errors/data accepted" (all data read).
ERROR indicates whether an error has occurred. If an event has occurred, the
corresponding event number is displayed in STATUS. If no error has occurred, STATUS has
the value 0. NDR and ERROR/STATUS are also output in response to a RESET of the
FB P_RCV_RK (LEN parameter == 16#00). In the event of an error, the binary result BR is
reset. If the block has been completed without errors, the binary result has the status "1".
Note
The P_RCV_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode. Before the CP 341 can receive a
request after the CPU has changed from STOP to RUN mode, the CP-CPU start-up
mechanism of the FB P_RCV_RK must have been completed.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 133
Block call
STL representation LAD representation
CALL P_RCV_RK, I_RCV_RK
EN_R: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
L_TYP: =
L_NO: =
L_OFFSET: =
L_CF_BYT =
L_CF_BIT =
NDR: =
ERROR: =
LEN: =
STATUS: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Assignment in the data area
The FB P_RCV_RK works together with an I_RCV_RK instance DB. The DB number is
passed on with the call. The instance DB requires 414 bytes load memory and 152 bytes
RAM. Access to the data in the instance DB is not permitted.
Note
Exception: If the error STATUS == W#16#1E0E occurred, you can consult the SFCERR
variable for additional details. This error variable can only be loaded via symbolic access to
the instance DB.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
134 Manual, 04/2011, A5E02191071-03
FB P_RCV_RK parameters
The table below lists the parameters of the FB P_RCV_RK.
Note
The L_TYP, L_NO, L_OFFSET, L_CF_BYT, and L_CF_BIT parameters are irrelevant for the
3964(R) procedure and do not have to be assigned.
Table 6- 3 FB P_RCV_RK parameters
Name Sort Data type Comment Permitted values, remark
EN_R INPUT BOOL Enables data reading
R INPUT BOOL Cancels request Cancels the request in progress. Receiving is
disabled.
LADDR INPUT INT CP 341 start address The start address is taken from STEP 7.
DB_NO INPUT INT Data block number Receive DB No.:
CPU-specific, zero is not permitted
DBB_NO INPUT INT Data byte number 0 ≤ DBB_NO ≤ 8190 Receive data starting
from data byte
NDR OUTPUT BOOL Request completed without
errors, data accepted
STATUS parameter == 16#00;
ERROR 1 OUTPUT BOOL Request completed with
errors
Error information is written to the STATUS
parameter.
LEN 1 OUTPUT INT Length of the message
frame received
1 ≤ LEN ≤ 4096, specified in number of bytes
STATUS 1 OUTPUT WORD Specification of error If ERROR == 1, the STATUS parameter will
contain error information.
1 The parameter is available until the next time the FB is called.
Communication via Function Blocks
6.3 Using the Function Blocks with the 3964(R) Procedure
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 135
Time sequence chart of FB P_RCV_RK
The figure below illustrates the behavior of the NDR, LEN, and ERROR parameters
depending on the input circuit of EN_R and R.
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Note
Input EN_R must be set to static "1" state. The EN_R parameter must be supplied with result
of logic operation "1" during the entire receive request.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
136 Manual, 04/2011, A5E02191071-03
6.4 Using the Function Blocks with the RK 512 Computer Connection
The function blocks available for connection to a communication partner with the RK 512
procedure are as follows:
● FB 8 P_SND_RK for sending or fetching data
● FB 7 P_RCV_RK for receiving or providing data
Data transmission options
Active requests:
The FB 8 P_SND_RK function block enables you to issue active requests to the CP 341 in
the user program of the CPU. You can
● Send data from your automation system to a remote communication partner.
● Fetch data from a remote communication partner and store it in an S7 data area of your
automation system
Note: If you fetch data from a CP 341, you must always program an FB P_RCV_RK on
the CP 341.
Passive requests:
The FB 7 P_RCV_RK function block enables you to use passive requests to coordinate the
reading and providing of data on the CP 341. The communication partner is active. You can
● Read in data sent from the communication partner in an S7 data area of your automation
system.
● Provide data in your automation system to a remote communication partner.
Requests that can be processed simultaneously
Only one active and one passive request can be programmed for each CP 341 in the user
program. While the CP 341 is transacting an active request, it can simultaneously process a
passive request.
Bear in mind, too, that you can use only:
● 1 instance data block for FB P_SND_RK and
● 1 instance data block for FB P_RCV_RK
This is because the statuses needed for the FB's internal routines are stored in the instance
data block.
Interprocessor communication flag
The interprocessor communication flag functionality familiar from SIMATIC S5 is supported
as a means of coordinating asynchronous overwriting on receipt or provision of data (FB 7
P_RCV_RK) by the CP 341 and the processing of data on the CPU. The interprocessor
communication flags can only be used with the RK 512 computer link.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 137
Data consistency
The block size limits the data consistency for data transmission between the CPU and
CP 341 to 32 bytes.
If you want consistent data transmission exceeding 32 bytes, you must take the following
into account:
● Sender: Only access the send DB when all data have been completely transferred
(DONE = 1).
● Fetching data: Only access the send DB when all data have been completely transferred
(DONE = 1).
● Receiver: Use the interprocessor communication flag. Do not access the receive DB until
all data has been received (evaluation of the interprocessor communication flag specified
for this job; the interprocessor communication flag is available in the FB for one cycle, if
NDR = 1). After you have processed the received data, reset the interprocessor
communication flag to "0".
● Providing data: Use the interprocessor communication flag. Do not access the provided
data until all of the data have been fetched (evaluation of the interprocessor
communication flag specified for this job). The interprocessor communication flag is
available for one cycle in the FB, if NDR = 1). After you have processed the data to be
fetched, reset the interprocessor communication flag to "0".
If your partner fetches data from the I (inputs), Q (outputs), M (bit memory), T (timers), or C
(counters) areas, the data consistency is limited to 32 bytes, provided you cannot use the
interprocessor communication flag to prevent other locations in the user program from
accessing these areas during the transmission.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
138 Manual, 04/2011, A5E02191071-03
6.4.1 Sending Data with FB P_SND_RK (Active Request)
The FB P_SND_RK function block can be used with parameter setting SF = 'S' to transmit
data from an S7 data area to a CP 341.
The data transmission is initiated by a positive edge at the REQ input. A data transmission
operation can run over several calls (program cycles), depending on the amount of data
involved (LEN).
The LADDR parameter specifies the address of the CP 341 to be addressed.
The area of the data blocks is the only permissible source for data to be sent. The source is
fully specified by the data block number (DB_NO) and the offset (DBB_NO) of the first data
byte to be sent in this data block.
Permissible destination areas are data types (R_TYP) data blocks (DB), and extended data
blocks (DX). The destination is fully specified by the CPU number (R_CPU_NO, relevant only
for multiprocessor communication), the data type (R_TYP: DB or DX), the data block number
(R_NO) and the offset (R_OFFSET) at which the first byte is to be written.
The interprocessor communication flag byte and bit on the partner CPU are specified in
R_CF_BYT and R_CF_BIT.
The FB P_SND_RK function block can be called cyclically when the signal state at the R
parameter input is "1". This cancels the transmission to the CP 341 and places the
FB P_SND_RK in its initial state. Data that has already been received by the CP 341 is still
sent to the communication partner. If the signal state at the R input remains static at "1", this
means that sending is deactivated.
Error display at the FB P_SND_RK
The DONE output shows "request completed without errors". ERROR indicates whether an
error has occurred. In STATUS the event number is displayed in the event of an error. If no
error has occurred, the value of STATUS is 0. DONE and ERROR/STATUS are also output
in response to a RESET of FB P_SND_RK. In the event of an error, the binary result BR is
reset. If the block has been completed without errors, the binary result has the status "1".
Note
The FB P_SND_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 139
Special features for sending data
Note the following special features with regard to sending data:
● RK 512 allows only an even-numbered amount of data to be sent. If you specify an odd-
numbered amount of data for the length (LEN), an additional filler byte with a value of "0"
is sent at the end of the data.
● RK 512 allows only an even-numbered offset. If you specify an odd-numbered offset, the
data is stored in the partner starting from the next lower even-numbered offset.
Example: Offset is 7, data is stored from byte 6.
Block call
STL representation LAD representation
CALL P_SND_RK, I_SND_RK
SF: =
REQ: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
LEN: =
R_CPU_NO: =
R_TYP: =
R_NO: =
R_OFFSET: =
R_CF_BYT =
R_CF_BIT =
DONE: =
ERROR: =
STATUS: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
140 Manual, 04/2011, A5E02191071-03
Assignment in the data area
The FB P_SND_RK works together with an I_SND_RK instance DB. The DB number is
passed on with the call. The instance data block is 62 bytes long. Access to the data in the
instance DB is not permitted.
FB P_SND_RK parameters
The table below lists the parameters of the FB 8 P_SND_RK for the "Send data" request.
Table 6- 4 FB 8 P_SND_RK parameters for "Send data" request
Name Sort Data type Comment Permitted values, remark
SF INPUT CHAR Selection for Send data or Fetch
data
SF = 'S' (Send)
Default: 'S'
REQ INPUT BOOL Initiates request on positive edge
R INPUT BOOL Cancels request Cancels the request in progress.
Transmission is disabled. Default: 0
LADDR INPUT INT CP 341 start address The start address is taken from
STEP 7.
DB_NO INPUT INT Data block number of source Send DB no.: CPU-specific, zero is not
permitted
DBB_NO INPUT INT Data byte number of source 0 ≤ DBB_NO ≤ 8190 Send data
starting from data byte
LEN INPUT INT Data length of the message frame
to be sent
1 ≤ LEN ≤ 4096, specified in number
of bytes; only even-numbered values
are appropriate
R_CPU_NO INPUT INT CPU number of the partner CPU 0 ≤ R_CPU_NO ≤ 4,
only with multiprocessor mode; default
value: 1
R_TYP INPUT CHAR Address type on the partner CPU 'D': Data block
‘X’: Expanded data block
R_NO INPUT INT Data block number on the partner
CPU
0 ≤ R_NO ≤ 255
R_OFFSET INPUT INT Data byte number on the partner
CPU
0 ≤ R_OFFSET ≤ 510, even-numbered
values only
R_CF_BYT INPUT INT Interprocessor communication flag
byte on partner CPU
0 ≤ R_CF_BYTE ≤ 255
Default: 255 (means: without
interprocessor communication flag)
R_CF_BIT INPUT INT Interprocessor communication flag
bit on the partner CPU
0 ≤ R_CF_BIT ≤ 7
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 141
Name Sort Data type Comment Permitted values, remark
DONE 1 OUTPUT BOOL Request completed without errors STATUS parameter == 16#00;
ERROR 1 OUTPUT BOOL Request completed with errors Error information is written to the
STATUS parameter.
STATUS 1 OUTPUT WORD Specification of error If ERROR == 1, the STATUS
parameter contains the error
information.
1 The parameter is available until the next time the FB is called.
Information in the message frame header
The table below shows the information in the message frame header of the RK 512 message
frame.
Table 6- 5 Information in the RK 512 message frame header for "Send data" request
Source on your S7 automation system
(local CPU)
To the destination,
partner CPU
Message frame header, bytes
3/4 command
type
5/6 D-DBNO/D
offset
7/8 number in
Data block Data block AD DB/DW Words
Data block Expanded data
block
AD DB/DW Words
Explanation of the abbreviations used:
D-DBNO: Destination data block number
D-Offset: Destination start address
DW: Offset in words
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
142 Manual, 04/2011, A5E02191071-03
Time sequence chart of FB P_SND_RK
The figure below illustrates the behavior of the DONE and ERROR parameters depending
on the input circuit of REQ and R.
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Note
The REQ input is edge-triggered. A positive edge at the REQ input is sufficient. The result of
the logic operation must not be at "1" at any point during transfer.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 143
6.4.2 Receiving Data with FB P_RCV_RK (Passive Request)
The FB P_RCV_RK transmits data from the CP 341 to an S7 data area. For purposes of
data transmission, the FB P_RCV_RK is called cyclically or, alternatively, statically in a time-
driven program (without conditions).
A (static) signal state "1" at the EN_R parameter enables a check to determine whether data
can be read from the CP 341. An active transmission can be canceled with signal state "0" at
the EN_R parameter. The canceled receive request is terminated with an error message
(STATUS output). Receiving is disabled as long as the signal state at the EN_R parameter is
"0". A data transmission operation can run over several calls (program cycles), depending on
the amount of data involved.
The LADDR parameter specifies the address of the CP 341 to be addressed.
If the communication partner specifies the destination "DB", the data is placed in the data
area specified in the RK 512 message frame header. The parameters (L_...) show the user
the destination area type (L_TYP), the destination data block number (L_NO, only relevant
for L_TYP = DB), the offset in the destination area (L_OFFSET), and the length (LEN) of the
transmitted data. If the partner specifies the destination "DX", the data is placed in the data
block (DB) specified by the DB_NO and DBB_NO parameters.
If the function block recognizes signal state "1" at the R parameter, the current transmission
request is canceled and the FB P_RCV_RK is placed in its initial state. Receiving is disabled
as long as the signal state at the R parameter is "1".
The NDR output shows "request completed without errors/data accepted" (all data read).
The L_TYP, L_NO, and L_OFFSET parameters indicate for the duration of one cycle where
the data are stored. In addition, the L_CF_BYT and L_CF_BIT parameters and length LEN of
the respective request are indicated for one cycle.
Note
The P_RCV_RK function block does not detect if the partner sends a SEND or FETCH
request.
Error display at the FB P_RCV_RK
ERROR indicates whether an error has occurred. In STATUS the event number is displayed
in the event of an error. If no error has occurred, STATUS has the value 0. NDR and
ERROR/STATUS are also output in response to a RESET of the FB P_RCV_RK (LEN
parameter == 16#00). In the event of an error, the binary result BR is reset. If the block has
been completed without errors, the binary result has the status "1".
Note
The P_RCV_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
144 Manual, 04/2011, A5E02191071-03
Use of interprocessor communication flags
Prior to data receipt, the interprocessor communication flags specified in the RK 512
message frame header are checked. The data is not transmitted unless the value of the
interprocessor communication flag is "0". When transmission is complete, the function block
sets the interprocessor communication flag to "1" and the interprocessor communication flag
(NDR) is output for one cycle at the function block.
The user program can evaluate the interprocessor communication flag in order to find out if
the transmitted data can be processed. As soon as the data have been processed, the user
must reset the interprocessor communication flag to "0". The communication partner can
now issue a SEND request again.
Block call
STL representation LAD representation
CALL P_RCV_RK, I_RCV_RK
EN_R: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
L_TYP: =
L_NO: =
L_OFFSET: =
L_CF_BYT =
L_CF_BIT =
NDR: =
ERROR: =
LEN: =
STATUS: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 145
Assignment in the data area
The FB P_RCV_RK works together with an I_RCV_RK instance DB. The DB number is
passed on with the call. The instance data block is 60 bytes long. Access to the data in the
instance DB is not permitted.
Note
Exception: If the error STATUS == W#16#1E0E occurred, you can consult the SFCERR
variable for additional details. This error variable can only be loaded via symbolic access to
the instance DB.
FB P_RCV_RK parameters
The table below lists the parameters of the FB 7 P_RCV_RK for the "Receive data" request.
Table 6- 6 FB 7 P_RCV_RK parameters for "Receive data" request
Name Sort Data type Comment Permitted values, remark
EN_R INPUT BOOL Enables data receipt
R INPUT BOOL Cancels request Cancels the request in progress. Receiving is
disabled. Default: 0
LADDR INPUT INT CP 341 start address The start address is taken from STEP 7.
DB_NO INPUT INT Data block number of the
receive data (destination)
Receive DB no.: CPU-specific, zero is not
permitted
(Relevant only for DX data destination)
DBB_NO INPUT INT Data byte number of the
receive data (destination)
0 ≤ DBB_NO ≤ 8190 Receive data starting from
data byte
(Relevant only for DX data destination)
L_TYP 1 OUTPUT CHAR Type of area on local CPU
(destination)
'D': Data block
L_NO 1 OUTPUT INT Data block number on local
CPU (destination)
0 ≤ L_NO ≤ 255
L_OFFSET 1 OUTPUT INT Data byte number on local
CPU (destination)
0 ≤ L_OFFSET ≤ 510
L_CF_BYT 1 OUTPUT INT Interprocessor
communication flag byte on
local CPU
0 ≤ L_CF_BYTE ≤ 255255 means: without
interprocessor communication flag
L_CF_BIT 1 OUTPUT INT Interprocessor
communication flag bit on
local CPU
0 ≤ L_CF_BIT ≤ 7
NDR 1 OUTPUT BOOL Request completed without
errors, data accepted
STATUS parameter == 16#00;
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
146 Manual, 04/2011, A5E02191071-03
Name Sort Data type Comment Permitted values, remark
ERROR 1 OUTPUT BOOL Request completed with
errors
Error information is written to the STATUS
parameter.
LEN 1 OUTPUT INT Length of the message
frame received
0 ≤ LEN ≤ 4096, specified in number of bytes
STATUS 1 OUTPUT WORD Specification of error If ERROR == 1, the STATUS parameter contains
the error information.
1 The parameter is available until the next time the FB is called.
Time sequence chart of FB P_RCV_RK
The figure below illustrates the behavior of the NDR, LEN, and ERROR parameters
depending on the input circuit of EN_R and R.
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Figure 6-4 Time sequence chart of FB 7 P_RCV_RK for "Receive data" request
Note
Input EN_R must be set to static "1" state. The EN_R parameter must be supplied with result
of logic operation "1" during the entire receive request.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 147
6.4.3 Readying Data with FB P_RCV_RK (Passive Request)
The FB P_RCV_RK function block must be called if the communication partner executes a
"Fetch data" request (FETCH request)..
The FB P_RCV_RK provides data from an S7 data area for the CP 341. For purposes of
data transmission, the FB P_RCV_RK is called cyclically or, alternatively, statically in a time-
driven program (without conditions).
A (static) signal state "1" at the EN_R, parameter enables a check to determine whether data
can be provided to the CP 341. An active transmission can be canceled with signal state "0"
at the EN_R parameter. The canceled request is terminated with an error message
(STATUS output). The request is disabled as long as the signal state at the EN_R parameter
is "0". A data transmission operation can run over several calls (program cycles), depending
on the amount of data involved.
The type of source area (L_TYP), the source data block number (L_NO, relevant only when
L_TYP = DB), the offset in the source area (L_OFFSET), and the length (LEN) of the data to
be provided are determined from the first RK 512 message frame. The function block
evaluates the information from this message frame and transfers the requested data to the
CP 341. The DB_NO and DBB_NO parameters are irrelevant for the FB P_RCV_RK function
block.
The LADDR parameter specifies the address of the CP 341 to be addressed.
If the function block recognizes signal state "1" at the R parameter, the current transmission
request is canceled and the FB P_RCV_RK is placed in its initial state. The request is
disabled as long as the signal state at the R parameter is "1".
The NDR output shows "request completed without errors/data accepted" (all data read).
The L_TYP, L_NO, and L_OFFSET parameters indicate for the duration of one cycle the
location from which the data were fetched (possible data types: data blocks, input bytes,
output bytes, timers and counters). In addition, the L_CF_BYT and L_CF_BIT parameters
and length LEN of the respective request are indicated for one cycle.
Note
When the communication partner fetches timers or counters from the CP 341, the length is
limited to a maximum of 32 bytes (16 timers or counters, each consisting of 2 bytes).
Error display at the FB P_RCV_RK
ERROR indicates whether an error has occurred. In STATUS the event number is displayed
in the event of an error. If no error has occurred, STATUS has the value 0. NDR and
ERROR/STATUS are also output in response to a RESET of the FB P_RCV_RK (LEN
parameter == 16#00). In the event of an error, the binary result BR is reset. If the block has
been completed without errors, the binary result has the status "1".
Note
The P_RCV_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
148 Manual, 04/2011, A5E02191071-03
Use of interprocessor communication flags
Following receipt of the message frame, the interprocessor communication flags specified in
the RK 512 message frame header are checked. The data is not provided unless the value
of the interprocessor communication flag is "0". When transmission is complete, the function
block sets the interprocessor communication flag to "1" and the interprocessor
communication flag (NDR) is output for one cycle at the function block.
The user program can evaluate the interprocessor communication flag in order to find out if
the provided data can be accessed again. As soon as the data have been processed, the
user must reset the interprocessor communication flag to "0". The communication partner
can now issue a FETCH request again.
Block call
STL representation LAD representation
CALL P_RCV_RK, I_RCV_RK
EN_R: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
L_NO: =
L_OFFSET: =
L_CF_BYT =
L_CF_BIT =
NDR: =
ERROR: =
LEN: =
STATUS: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 149
Assignment in the data area
The FB P_RCV_RK works together with an I_RCV_RK instance DB. The DB number is
passed on with the call. The instance data block is 60 bytes long. Access to the data in the
instance DB is not permitted.
Note
Exception: If the error STATUS == W#16#1E0E occurred, you can consult the SFCERR
variable for additional details. This error variable can only be loaded via symbolic access to
the instance DB.
FB P_RCV_RK parameters
The table below lists the parameters of the FB 7 P_RCV_RK for the "Provide data" request.
Table 6- 7 FB 7 P_RCV_RK parameters for "Provide data" request
Name Sort Data type Comment Permitted values, remark
EN_R INPUT BOOL Enables data provision
R INPUT BOOL Cancels request Cancels the request in progress. Disables
providing. Default: 0
LADDR INPUT INT CP 341 start address The start address is taken from STEP 7.
DB_NO INPUT INT irrelevant
DBB_NO INPUT INT irrelevant
L_TYP 1 OUTPUT CHAR Type of area on local CPU
(source)
'D': Data block
'M' Memory bit
'I': Inputs
'O': Outputs
'C': Counters
'T': Timers
L_NO 1 OUTPUT INT Data block number on local CPU
(source)
0 ≤ L_NO ≤ 255 (only relevant, if L_TYP =
D)
L_OFFSET 1 OUTPUT INT Data byte number on local CPU
(source)
0 ≤ L_OFFSET ≤ 510 (dependent on the
area type)
L_CF_BYT 1 OUTPUT INT Interprocessor communication
flag byte on local CPU
0 ≤ CF_BYTE ≤ 255
255 means: without interprocessor
communication flag
L_CF_BIT 1 OUTPUT INT Interprocessor communication
flag bit on local CPU
0 ≤ CF_BIT ≤ 7
NDR 1 OUTPUT BOOL Request completed without
errors, data accepted
STATUS parameter == 16#00;
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
150 Manual, 04/2011, A5E02191071-03
Name Sort Data type Comment Permitted values, remark
ERROR 1 OUTPUT BOOL Request completed with errors Error information is written to the STATUS
parameter.
LEN 1 OUTPUT INT Length of the message frame
received
0 ≤ LEN ≤ 4096,
specified in number of bytes
STATUS 1 OUTPUT WORD Specification of error If ERROR == 1, the STATUS parameter
contains the error information.
1 The parameter is available until the next time the FB is called.
Time sequence chart of FB P_RCV_RK
The figure below illustrates the behavior of the NDR, LEN, and ERROR parameters
depending on the input circuit of EN_R and R.
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Figure 6-5 Time sequence chart of FB 7 P_RCV_RK for "Provide data" request
Note
Input EN_R must be set to static "1" state. The EN_R parameter must be supplied with result
of logic operation "1" during the entire receive request.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 151
6.4.4 Fetching Data with P_SND_RK FB (Active Request)
Principle of operation of the FB P_SND_RK function block The FB P_SND_RK function block
can be used with parameter setting SF = F to fetch data from a remote communication
partner and place it in an S7 data area of your programmable controller.
Note
If you fetch data from a CP 341, you must always program a P_RCV_RK function block on
the CP 341.
The data transmission is initiated by a positive edge at the REQ input. A data transmission
operation can run over several calls (program cycles), depending on the amount of data
involved (LEN).
The LADDR parameter specifies the address of the CP 341 to be addressed.
The communication partner from which you want to fetch data is specified by the CPU
number (R_CPU_NO, relevant only for multiprocessor communication). The following data
types (R_TYP) are permissible sources for the data to be fetched: data blocks, extended
data blocks, bit memory, inputs, outputs, counters and timers. The source is fully specified
by the data type (R_TYP), the data block number (R_NO, relevant only for data blocks and
expanded data blocks) and the offset (R_OFFSET) of the first data byte to be sent in this
area.
The interprocessor communication flag byte and bit on the partner CPU are specified in
R_CF_BYT and R_CF_BIT.
The only permissible destination areas are data blocks (DB). The destination is fully
specified by the data block number (DB_NO) and the offset (DBB_NO) of the first data byte
to be written.
The FB P_SND_RK function block can be called cyclically when the signal state at the R
parameter input is "1". This cancels the transmission from the CP 341 and places the
FB P_SND_RK in its initial state. If the signal state at the R input remains static at "1", this
means that fetching is deactivated.
Error display at the FB P_SND_RK
The DONE output shows "request completed without errors". ERROR indicates whether an
error has occurred. In STATUS the event number is displayed in the event of an error. If no
error has occurred, the value of STATUS is 0. DONE and ERROR/STATUS are also output
in response to a RESET of FB P_SND_RK. In the event of an error, the binary result BR is
reset. If the block has been completed without errors, the binary result has the status "1".
Note
The FB P_SND_RK function block does not have a parameter check. If the parameter
assignment is incorrect, the CPU can go to STOP mode.
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
152 Manual, 04/2011, A5E02191071-03
Special features for (expanded) data blocks
Note the following special features with regard to fetching data from data blocks and
expanded data blocks:
● RK 512 allows only an even-numbered amount of data to be fetched. If you specify an
odd-numbered amount for the length (LEN), an extra byte is always transmitted. In the
destination DB, however, the correct amount of data is entered.
● RK 512 allows only an even-numbered offset. If you specify an odd-numbered offset, the
data is fetched from the partner starting from the next lower even-numbered offset.
Example: Offset is 7, data is fetched as of byte 6.
Special features for timers and counters
If you fetch timers or counters from the communication partner, remember that 2 bytes are
fetched for each timer or counter. For example, if you want to fetch 10 counters, you must
enter 20 as the length.
Block call
STL representation LAD representation
CALL P_SND_RK, I_SND_RK
SF: =
REQ: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
LEN: =
R_CPU_NO: =
R_TYP: =
R_NO: =
R_OFFSET: =
R_CF_BYT =
R_CF_BIT =
DONE: =
ERROR: =
STATUS: =
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Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 153
Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Assignment in the data area
The FB P_SND_RK works together with an I_SND_RK instance DB. The DB number is
passed on with the call. The instance data block is 62 bytes long. Access to the data in the
instance DB is not permitted.
FB P_SND_RK parameters
The table below lists the parameters of the FB 8 P_SND_RK for the "Fetch data" request.
Table 6- 8 FB 8 P_SND_RK parameters for "Fetch data" request
Name Sort Data type Comment Permitted values, remark
SF INPUT CHAR Selection for Send data or Fetch
data
SF = 'F' (Fetch)default value: 'S' (Send)
REQ INPUT BOOL Initiates request on positive edge
R INPUT BOOL Cancels request Cancels the request in progress. Fetching is
disabled. Default: 0
LADDR INPUT INT CP 341 start address The start address is taken from STEP 7.
DB_NO INPUT INT Data block number of destination Send DB no.: CPU-specific, zero is not
permitted
DBB_NO INPUT INT Data byte number of destination 0 ≤ DBB_NO ≤ 8190 Send data starting from
data byte
LEN INPUT INT Data length of the message frame
to be fetched
1 ≤ LEN ≤ 4096, specified in number of
bytes1
R_CPU_NO INPUT INT CPU number of the partner CPU 0 ≤ R_CPU_NO ≤ 4, only with multiprocessor
mode; default value: 1
R_TYP INPUT CHAR Address type on the partner CPU 'D': Data block
'X': Expanded data block
'M': Memory bit
'I': Inputs
'O': Outputs
'C': Counters
'T': Timers
R_NO INPUT INT Data block number on the partner
CPU
0 ≤ R_NO ≤ 255
R_OFFSET INPUT INT Data byte number on the partner
CPU
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
154 Manual, 04/2011, A5E02191071-03
Name Sort Data type Comment Permitted values, remark
R_CF_BYT INPUT INT Interprocessor communication flag
byte on partner CPU
0 ≤ CF_BYTE ≤ 255
Default value: 255 (means: without
interprocessor communication flag)
R_CF_BIT INPUT INT Interprocessor communication flag
bit on the partner CPU
0 ≤ CF_BIT ≤ 7
DONE 1 OUTPUT BOOL Request completed without errors STATUS parameter == 16#00;
ERROR 1 OUTPUT BOOL Request completed with errors Error information is written to the STATUS
parameter.
STATUS 1 OUTPUT WORD Specification of error If ERROR == 1, the STATUS parameter
contains the error information.
1 The parameter is available until the next time the FB is called.
Parameters in the FB for data source (Partner CPU)
The following table lists the data types that can be transmitted.
Table 6- 9 Transmittable data types for "Fetch data" request
Source on the partner
CPU
R_TYP R_NO R_OFFSET (in bytes)
(This value is specified by the partner CPU.)
Data block 'D' 0 - 255 0 - 510
(only even-numbered values are appropriate!)
Expanded data block 'X' 0 - 255 0 - 510
(only even-numbered values are appropriate!)
Bit memory 'M' irrelevant 0 - 255
Inputs 'I' irrelevant 0 - 255
Outputs 'O' irrelevant 0 - 255
Counters 'C' irrelevant 0 - 255
Timers 'T' irrelevant 0 - 255
Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 155
Information in the message frame header
The table below shows the information in the message frame header of the RK 512 message
frame.
Table 6- 10 Information in the RK 512 message frame header for "Fetch data" request
Message frame header, bytes
Source on the partner CPU To the destination, your S7
automation system (local
CPU) 3/4 command type 5/6 S-DBNR/S-offset 7/8 number in
Data block Data block ED DB/DW Words
Expanded data block Data block EX DB/DW Words
Bit memory Data block EM Byte address Bytes
Inputs Data block EI Byte address Bytes
Outputs Data block EO Byte address Bytes
Counters Data block EC Counter no. Words
Timers Data block ET Timer number Words
Explanation of the abbreviations used:
S-DBNO: Source data block number
S-Offset: Source start address
Time sequence chart of FB P_SND_RK
The figure below illustrates the behavior of the DONE and ERROR parameters depending
on the input circuit of REQ and R.
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Communication via Function Blocks
6.4 Using the Function Blocks with the RK 512 Computer Connection
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
156 Manual, 04/2011, A5E02191071-03
Note
The REQ input is edge-triggered. A positive edge at the REQ input is sufficient. The result of
the logic operation must not be at "1" at any point during transfer.
Communication via Function Blocks
6.5 Using the System Function Blocks with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 157
6.5 Using the System Function Blocks with the ASCII Driver
6.5.1 Function blocks with ASCII driver
The same functions can be used for data transmission with the ASCII driver as with the
3964(R) procedure. In other words, all information for the FB P_SND_RK and
FB P_RCV_RK function blocks for the 3964(R) procedure also applies to the ASCII driver.
In addition, when the ASCII driver is used with the RS 232C interface submodule, you can
read and control the RS 232C secondary signals. The following describes only what you
have to do to use these additional functions.
The following function blocks are available for "reading and controlling" the RS 232C
accompanying signals:
● FC 5 V24_STAT for checking the interface status
● FC 6 V24_SET for setting/resetting the interface outputs
Note
For the CP 341, you can use only the FC 5 V24_STAT and FC 6 V24_SET functions with
version ≥ 2.0. Use of Version 1.0 can result in data corruption.
Communication via Function Blocks
6.5 Using the System Function Blocks with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
158 Manual, 04/2011, A5E02191071-03
6.5.2 Interface status of the CP 341, checking
The FC V24_STAT reads the RS 232C accompanying signals from the CP 341 and makes
them available to the user in the block parameters. The FC V24_STAT is called cyclically or,
alternatively, statically (without conditions) in a time-controlled program.
The RS 232C accompanying signals are updated each time the function is called (cyclic
polling). The CP 341 updates the status of the inputs/outputs in a time grid of 20 ms. The
inputs/outputs are constantly updated independently of this.
The binary result BR is not affected. The function does not issue error messages.
The LADDR parameter defines the CP 341 to be addressed.
Block call
STL representation LAD representation
CALL
V24_STAT
LADDR: =
DTR_OUT: =
DSR_IN: =
RTS_OUT: =
CTS_IN: =
DCD_IN: =
RI_IN: =
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The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR.
Assignment in the data area
The FC V24_STAT function does not occupy any data areas.
Note
A minimum pulse duration is necessary to detect a signal change. Determining factors are
the CPU cycle time, the update time on the CP 341, and the response time of the
communication partner.
Communication via Function Blocks
6.5 Using the System Function Blocks with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 159
FC 5 V24_STAT parameters
The following table lists the parameters of the FC 5 V24_STAT.
Table 6- 11 FC 5 V24_STAT parameters
Name Sort Data type Comment Permitted values, remark
LADDR INPUT INT CP 341 start address The start address is taken from
STEP 7.
DTR_OUT OUTPUT BOOL Data terminal ready,
CP 341 ready for operation
(CP 341 output)
DSR_IN OUTPUT BOOL Data set ready,
Communication partner ready for
operation
(CP 341 input)
RTS_OUT OUTPUT BOOL Request to send,
CP 341 ready to send
(CP 341 output)
CTS_IN OUTPUT BOOL Clear to send,
Communication partner can receive
data from the CP 341 (response to RTS
= ON of the CP 341)
(CP 341 input)
DCD_IN OUTPUT BOOL Data Carrier detect,
receive signal level
(CP 341 input)
RI_IN OUTPUT BOOL Ring Indicator,
Indication of incoming call
(CP 341 input)
Communication via Function Blocks
6.5 Using the System Function Blocks with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
160 Manual, 04/2011, A5E02191071-03
6.5.3 Interface outputs of the CP 341, setting/resetting
FC V24_SET
The user can use the parameter inputs of the FC V24_SET function to set or reset the
corresponding interface outputs. The FC V24_SET function is called cyclically or,
alternatively, statically (without conditions) in a time-controlled program.
The binary result BR is not affected. The function does not issue error messages.
The LADDR parameter defines the CP 341 to be addressed.
Block call
STL representation LAD representation
CALL
V24_SET
LADDR: =
RTS: =
DTR: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR.
Assignment in the data area
The V24_SET function does not occupy any data areas.
Communication via Function Blocks
6.5 Using the System Function Blocks with the ASCII Driver
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 161
FC 6 V24_SET parameters
The following table lists the parameters of the FC 6 V24_SET.
Table 6- 12 FC 6 V24_SET parameters
Name Sort Data type Comment Permitted values, remark
LADDR INPUT INT CP 341 start address The start address is taken from
STEP 7.
RTS INPUT BOOL Request to send,
CP 341 ready to send
(Control CP 341 output)
DTR INPUT BOOL Data terminal ready,
CP 341 ready for operation
(Control CP 341 output)
See also
Principle of the Data Transmission with the ASCII Driver (Page 59)
Communication via Function Blocks
6.6 Use of function blocks to output message texts to a printer
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
162 Manual, 04/2011, A5E02191071-03
6.6 Use of function blocks to output message texts to a printer
Introduction
The FB 13 P_PRINT_RK function block is available for printing message texts. The FB 13
P_PRINT_RK transmits a process message to the CP 341, for example. The CP 341 logs
the process message on the connected printer.
Outputting message texts
The FB P_PRINT_RK transmits a message text with up to four variables to the CP 341.
Configure the message texts with the CP 341: Point-to-Point Communication, Parameter
Assignment parameter assignment interface. For the purpose of data transmission, the
FB P_PRINT_RK is called cyclically, or alternatively, statically (without conditions) in a
time-controlled program.
The DB_NO and DBB_NO parameters enable the pointers (pointers to data blocks) for the
format string and the four variables to be accessed. The pointers must be stored in a certain
order without gaps in the assigned data block (pointer DB) (see Figure "Pointer DB").
The transmission of the message text is initiated by a positive edge at the REQ input. The
format string of the message text is transmitted first, followed by variables 1 to 4.
A data transmission operation can run over several calls (program cycles), depending on the
amount of data involved.
The FB P_PRINT_RK function block can be called cyclically when the signal state at the R
parameter input is "1". This cancels the transmission to the CP 341 and places the
FB P_PRINT_RK in its initial state. Data that has already been received by the CP 341 is still
sent to the communication partner. If the signal state at the R input remains static at "1", this
means that sending of print requests is deactivated.
The LADDR parameter specifies the address of the CP 341 to be addressed.
The DONE output shows "request completed without errors". ERROR indicates whether an
error has occurred. If an event has occurred, the corresponding event number is displayed in
STATUS. If no error has occurred, STATUS has the value 0. DONE and ERROR/STATUS
are also output at RESET of the FB P_PRINT_RK. The binary result BR is reset after an
error has occurred. If the block has been completed without errors, the binary result has the
status "1".
Note
The P_PRINT function block does not have a parameter check. If the parameter assignment
is incorrect, the CPU can go to STOP mode. Before the CP 341 can process an activated
request after the CPU has changed from STOP to RUN mode, the CP-CPU startup
mechanism of the FB P_PRINT_RK must have been completed. Any requests initiated in the
meantime are not lost. They are transmitted once the start-up coordination with the CP 341
is finished.
Communication via Function Blocks
6.6 Use of function blocks to output message texts to a printer
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 163
Block call
STL representation LAD representation
CALL P_PRINT_RK, I_PRINT
REQ: =
R: =
LADDR: =
DB_NO: =
DBB_NO: =
DONE: =
ERROR: =
STATUS: =
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Note
The parameters EN and ENO are only present in the graphical representation (LAD or FBD).
To process these parameters, the compiler uses the binary result BR. The binary result is set
to signal state "1" if the block was terminated without errors. If there was an error, the BR is
set to "0".
Assignment in the data area, instance DB
The FB P_PRINT_RK works together with an I_PRINT instance DB. The DB number is
passed on with the call. The instance data block is 40 bytes long. Access to the data in the
instance DB is not allowed.
Note
Exception: If the error STATUS == W#16#1E0F occurred, you can consult the SFCERR or
SFCSTATUS variable for additional details. See "Calling the SFCERR or SFCSTATUS
variable" for more information.
Communication via Function Blocks
6.6 Use of function blocks to output message texts to a printer
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
164 Manual, 04/2011, A5E02191071-03
Assignment in the data area, pointer DB
The FB P_PRINT_RK uses the DB_NO and DBB_NO parameters to access a pointer DB in
which the pointers to the data blocks containing the message texts and variables are stored
in a fixed sequence. You have to create the pointer DB.
The figure shows the structure of the pointer DB that is addressed by the DB_NO and
DBB_NO parameters of the FB P_PRINT_RK.
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Permissible DB numbers
The permissible DB numbers are CPU-specific. If the value 16#00 is specified as the DB
number for "Pointer to variable", this variable is interpreted as not present and the pointer is
set to the next variable or the format string.
If the DB number is equal to the value 16#00 in "Pointer to format string", the print request is
canceled and event number 16#1E43 is indicated in the STATUS parameter output of the
FB P_PRINT_RK.
Communication via Function Blocks
6.6 Use of function blocks to output message texts to a printer
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 165
Permissible DBB numbers
The variable or format string is located starting at the assigned DBB number. The maximum
length of the variables is 32 bytes and the maximum length of the format string is 150 bytes.
If the maximum length is exceeded, the print request is canceled and event number
16#1E41 is indicated in the STATUS parameter output of the FB P_PRINT_RK.
Permissible length
The length information in the pointer DB must be adapted for the particular display type
(data types) and according to the precision used.
FB 13 P_PRINT_RK parameters
The following table lists the parameters of the FB 13 P_PRINT_RK.
Table 6- 13 FB 13 P_PRINT_RK parameters
Name Sort Data type Comment Permitted values, remark
REQ INPUT BOOL Initiates request on positive
edge
R INPUT BOOL Cancels request Cancels the request in progress.
Printer output is disabled.
LADDR INPUT INT CP 341 start address The start address is taken from
STEP 7.
DB_NO INPUT INT Data block number Pointer to pointer DB:
CPU-specific, zero is not allowed
(The pointers to variables and format
string are stored in the pointer DB in a
fixed order.)
DBB_NO INPUT INT Data byte number 0 ≤ DBB_NO ≤ 8162 Pointer starting
from data byte
DONE 1 OUTPUT BOOL Request completed without
errors
STATUS parameter == 16#00;
ERROR OUTPUT BOOL Request completed with
errors
Error information is written to the
STATUS parameter.
STATUS OUTPUT WORD Specification of error If ERROR == 1, the STATUS
parameter will contain error
information.
1 The DONE parameter is available for one CPU cycle following a successful send request.
Communication via Function Blocks
6.6 Use of function blocks to output message texts to a printer
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
166 Manual, 04/2011, A5E02191071-03
Time sequence chart for FB 13 P_PRINT_RK
The figure below illustrates the behavior of the DONE and ERROR parameters depending
on the input circuit of REQ and R.
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Note
The REQ input is edge-triggered. A positive edge at the REQ input is sufficient. It does not
have to have a signal state of "1" during the entire transmission operation.
Communication via Function Blocks
6.7 General Information on Program Processing
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 167
6.7 General Information on Program Processing
Start-up Characteristics of the CP 341 Programmable Controller
The configuration data is created with the aid of the CP 341: Point-to-Point Communication,
Parameter Assignment parameter assignment and transferred to the CPU with the STEP 7
software. Each time the CPU is started up, the current parameters are transferred to the
CP 341 by the system service of the CPU.
Start-up Characteristics, FB-CP 341
Once the connection between the CPU and the CP 341 has been established, the CP 341
must be initialized.
For each P_SND_RK, P_RCV_RK function block, there is a separate start-up coordination.
Before requests can be actively processed, the accompanying start-up procedure must be
completed.
Disabling alarms
In the function blocks the interrupts are not disabled.
Addressing the module
The logical basic address is defined via STEP 7 and must be specified by the user under the
block parameter LADDR.
Communication via Function Blocks
6.8 Technical Specifications of the Function Blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
168 Manual, 04/2011, A5E02191071-03
6.8 Technical Specifications of the Function Blocks
Memory requirements
The table below shows the memory requirements of the CP 341 function blocks/functions.
Table 6- 14 Memory requirements of the function blocks/functions in bytes
Block Name Version Load memory Working memory Local data
FC 5 V24_STAT 2.0 182 108 2
FC 6 V24_SET 2.0 150 84 2
FB 7 P_RCV_RK 3.2 3756 3144 114
FB 8 P_SND_RK 3.2 3490 2900 40
Minimum number of CPU cycles
The table below describes the minimum number of CPU cycles (FB/FC calls) required to
transact a "minimum request" (32 bytes SEND/RECEIVE for the quantity of user data
transported per program cycle). This only applies in centralized operation.
Table 6- 15 Minimum number of CPU cycles
Number of CPU cycles for processing ...
Completion without
errors
Termination with errors RESET/RESTART
P_RCV_RK ≥ 3 ≥ 3 ≥ 4
P_SND_RK ≥ 3 ≥ 3 ≥ 4
V24_STAT 1 - -
V24_SET 2 >> 2 -
Before the CP 341 can process an activated request after the CPU has changed from STOP
to RUN mode, the CP-CPU startup mechanism P_SND_RK must have been completed. Any
requests initiated in the meantime are not lost. They are transmitted once the start-up
coordination with the CP 341 is finished.
Before the CP 341 can receive a message frame in the user program after the CPU has
changed from STOP to RUN mode, the CP-CPU startup mechanism P_RCV_RK must have
been completed.
Communication via Function Blocks
6.8 Technical Specifications of the Function Blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 169
System functions used
The following system functions are used in the blocks:
● SFB 52 (RDREC), Read data set
● SFB 53 (WRREC), Write data set
NOTICE
The new standard function blocks of the CP341
FB7 ≥ V3.0 (P_RCV_RK)
FB8 ≥ V3.0 (P_SND_RK)
and
and FB13 ≥ V1.0 (P_PRT341)
operate with the new system function blocks SFB52 (RDREC) or SFB53 (WRREC) that
are supported by the latest CPU versions (*) only. This conversion was necessary
because the old system calls SFC58 (WR_REC) and SFC59 (RD_REC) are not suitable
for operation following an IE/PB link or a PROFINET header.
Users with older CPU versions that do not support SFB52 (RDREC) or SFB53
(WRREC) yet will find the older versions of FB7 and FB8 with the designations FB107
(P_RCV_RK_OLD) and FB108 (P_SND_RK_OLD) in their regular location. (*) All
S7-300 CPUs with MMC and S7-400-CPUs as of firmware status V3.0.0 support the
new system function blocks SFB52 and SFB53. CPU318 will permit the use of
SFB52/SFB53 with decentralized periphery only.
Communication via Function Blocks
6.8 Technical Specifications of the Function Blocks
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
170 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 171
Start-up Characteristics and Operating Mode
Transitions of the CP 341 7
7.1 Operating Modes of the CP 341
The CP 341 has the operating modes STOP, parameter reassignment, and RUN.
STOP
When the CP 341 is in STOP mode, no protocol driver is active and all send and receive
requests from the CPU are given a negative acknowledgment.
The CP 341 remains in STOP mode until the cause of the stop is removed (e.g. break,
invalid parameter).
Parameter reassignment
For parameter reassignment, the protocol driver is initialized. The SF LED is on during
parameter reassignment.
Sending and receiving are not possible, and send and receive message frames stored in the
CP 341 are lost when the driver is restarted. Communication between the CP and the CPU
is started afresh (active message frames are aborted).
At the end of the parameter reassignment, the CP 341 is ready to send and receive.
RUN
The CP 341 processes the requests from the CPU. It provides the message frames received
by the communications partner to be fetched by the CPU.
Start-up Characteristics and Operating Mode Transitions of the CP 341
7.2 Startup Characteristics of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
172 Manual, 04/2011, A5E02191071-03
7.2 Startup Characteristics of the CP 341
CP 341 start-up
The CP 341 start-up is divided into two phases:
● Initialization (CP 341 in POWER ON mode)
● Parameter assignment
Initialization
As soon as the CP 341 is energized, all module components are initialized.
Parameter assignment
Parameter assignment means that the CP 341 receives the module parameters assigned to
the current slot as created with the CP 341: Point-to-Point Communication, Parameter
Assignment parameter assignment interface.
A parameter reassignment check is executed. The CP 341 is now ready to operate.
Startup behavior when power supply for the module is turned on
If the CP 341 has its own 24 V DC power supply independent of the CPU, communication
between the CPU and the CP 341 is interrupted if the 24 V DC power supply of the CP 341
fails.
To reestablish communication between CPU and CP 341, set the CPU to STOP and then to
RUN.
Start-up Characteristics and Operating Mode Transitions of the CP 341
7.3 Behavior of the CP 341 on Operating Mode Transitions of the CPU
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 173
7.3 Behavior of the CP 341 on Operating Mode Transitions of the CPU
Once the CP 341 has been started up, all data is exchanged between the CPU and the
CP 341 by means of the function blocks.
General procedure
CPU-STOP
In CPU-STOP mode, communication via the S7 backplane bus is not possible. Any active
CP-CPU data transmission, including both send and receive message frames, is aborted
and the connection is reestablished.
Data traffic at the interface of the CP 341 is continued with the ASCII driver and the printer
driver in the case of parameter assignment without flow control. In other words, the current
send request will still be completed. In the case of the ASCII driver, receive message frames
continue to be received until the receive buffer is full.
CPU START-UP
On start-up, the CP sends the parameters created with the CP 341: Point-to-Point
Communication, Parameter Assignment parameter assignment interface. The CP 341
carries out a parameter reassignment only if parameters have changed.
CPU RUN
When the CPU is in RUN mode, send and receive operations are unrestricted. In the first FB
cycles following the CPU restart, the CP 341 and the corresponding FBs are synchronized.
No new FBs or FCs can be executed until this process has been completed.
Special features for sending message frames and for printout
Message frames can only be sent when the CPU is in RUN mode.
If the CPU changes to STOP mode during the CPU > CP data transmission, the
FB P_SND_RK or the FB P_PRINT_RK reports the error "current program interrupted,
request aborted due to BREAK/restart/reset" following the restart.
Note
The CP 341 sends data to the communication partner only after it has received all the data
from the CPU.
Start-up Characteristics and Operating Mode Transitions of the CP 341
7.3 Behavior of the CP 341 on Operating Mode Transitions of the CPU
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Diagnostics with the CP 341 8
8.1 Diagnostics Functions of the CP 341
The diagnostics functions of the CP 341 enable you to quickly localize any errors which
occur. The following diagnostics options are available:
● Diagnostics via Display Elements of the CP 341
● Diagnosis via the STATUS output of the function blocks
● Diagnostics via the diagnostic buffer of the CP 341
● Diagnosis via the diagnostic alarm
Display elements (LEDs)
The display elements show the operating mode or possible error states of the CP 341. The
display elements give you an initial overview of any internal or external errors as well as
interface-specific errors (see chapter "Diagnostics via the display elements of the CP 341
(Page 177)").
In section "Subsequent Loading of Drivers (Transmission Protocols) (Page 117)" provides
information on other LED indicators that occur when loading a firmware update.
STATUS outputs of the FBs
The P_SND_RK and P_RCV_RK function blocks have a STATUS output for error
diagnostics. Reading the STATUS output of the function blocks gives you information on
errors which have occurred during communication. You can interpret the STATUS output in
the user program.
The CP 341 also enters the diagnostic events at the STATUS output in its diagnostic buffer.
Error numbers in the response message frame
If you are working with the RK 512 computer link and an error occurs at the communication
partner in a SEND or FETCH message frame, the communication partner sends a response
message frame with an error number in the 4th byte (see section "Error Numbers in the
Response Message Frame (Page 194)").
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
176 Manual, 04/2011, A5E02191071-03
Diagnostic buffer of the CP 341
All the CP 341 errors are entered in its diagnostic buffer.
In the same way as with the diagnostic buffer of the CPU, you can also use the STEP 7
information functions on the programming device to display the user-relevant information of
the CP diagnostic buffer (see section "Diagnostics via the diagnostic buffer of the CP 341
(Page 195)").
Diagnostic interrupt
The CP 341 can trigger a diagnostic interrupt on the CPU assigned to it. CP 341 provides
4 bytes of diagnostics information at the S7–300 backplane bus. This information is analyzed
via the user program (OB 82) or using a programming device to read from the CPU
diagnostic buffer.
The CP 341 also writes diagnostic events which have triggered a diagnostic interrupt to its
diagnostic buffer.
When a diagnostics alarm event occurs, the SF LED (red) lights up.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 177
8.1.1 Diagnostics via the display elements of the CP 341
The display elements of the CP 341 provide information on the CP 341. The following
display functions can be distinguished:
● Group error displays
– SF (red) Error has occurred or parameter reassignment is in progress.
● Special displays
– TXD (green) Sending active; lights up when the CP 341 is sending user data via the
interface
– RXD (green) Receiving active; lights up when the CP 341 is receiving user data via
the interface
Note
Section "Subsequent Loading of Firmware Updates (Page 118)" provides information
on other LED indicators that occur when loading a firmware update.
Group error display SF
The group error display SF always lights up after POWER ON and goes out after
initialization. If configuration data has been generated for the CP 341, the SF LED again
lights up briefly during parameter reassignment.
The group error display SF lights up whenever the following occur:
● Hardware fault
● Firmware error
● Parameter assignment error or no parameter assignment exists
● BREAKs (receive cable between CP 341 and communications partner becomes
disconnected)
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
178 Manual, 04/2011, A5E02191071-03
8.1.2 Diagnostics Messages of the Function Blocks
Each function block has a STATUS parameter for error diagnostics. The STATUS message
numbers always have the same meaning, irrespective of which function block is used.
Numbering scheme for event class/event number
The figure below illustrates the structure of the STATUS parameter.
67$786
%LWQR
(YHQWQXPEHU
HUURUQXPEHU
(YHQWFODVV6SDUH
Figure 8-1 Structure of the STATUS parameter
Example
The figure below illustrates the content of the STATUS parameter for the "Request canceled
due to complete restart, restart or reset" event (event class: 1EH, event number 0DH).
[[ [
67$786
(YHQW5HTXHVWFDQFHOHGGXHWRFRPSOHWHUHVWDUWUHVWDUWRUUHVHW
(YHQWFODVV(+6SDUH
(YHQWQXPEHU
HUURUQXPEHU'+
Figure 8-2 Example: Structure of the STATUS parameter for the the "Request canceled due to
complete restart, restart or reset" event
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 179
Event classes
The table below describes the various event classes and numbers.
Table 8- 1 Event classes and event numbers
Event class 0 (00H):
"CP start-up"
Event no. Event text Remedy
(00)03H PtP parameters received -
(00)04H Parameters already on CP (time versions match) -
(00)07H Status transition CPU to STOP -
(00)08H Status transition CPU to RUN/STARTUP -
Event Class 1 (01H):
"Hardware fault on CP"
Event no. Event text Remedy
(01)01H Fault while testing operating system EPROM of CP
(01)02H RAM test of CP errored
(01)03H Request interface of CP defective
CP defective; replace CP.
(01)10H Fault in CP firmware Switch module off and on again. If necessary,
replace module.
Event Class 2 (02H):
"Initialization error"
Event no. Event text Remedy
(02)0FH Invalid parameter assignment detected at start of
assigned communication. Interface parameters
could not be assigned.
Correct invalid parameters and restart.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 3(03H):
"Error during parameter assignment of FBs" (not displayed in the diagnostic buffer)
Event no. Event text Remedy
(03)01H Illegal or missing source/destination data type Area
(start address, length) not permitted
The DB is not permitted or does not exist (e.g.,
DB 0) or
Other data type invalid or missing
Interprocessor communication byte number invalid
or
Interprocessor communication bit number invalid or
neither 'S' nor 'F' selected (for FB P_SND_RK)
Check parameter assignment on CPU and CP, and
correct if necessary.
RK 512 only: Partner returns invalid parameters in
message frame header.
Check parameter assignment on CPU and CP;
create block, if necessary.
See request tables for valid data types.
RK 512 only: Partner returns incorrect parameters in
message frame header.
Event Class 4 (04H):
"CP detected error in data traffic CP - CPU"
Event no. Event text Remedy
(04)03H Incorrect, unknown or illegal data type Check program, e.g. for incorrect parameter
assignment of FB.
(04)07H An error has occurred during data transmission
between the CPU and CP
If the error is signaled continuously, you must check
whether the parameters of the FBs called in the user
program are correctly assigned.
If the error is signaled immediately after POWER ON, a
connection to the CPU is not set up at this time. With
the 3964(R) procedure and the ASCII driver, the data
transmission of the receiving CP 341 is repeated until
the data are transferred to the CPU. With RK 512, the
request is acknowledged negatively and must be
repeated in the user program.
If the message occurs sporadically during active data
transmission, the CPU can not accept the data at
times. With the 3964(R) procedure and the ASCII
driver, the data transmission of the receiving CP 341 is
repeated until the data are transferred to the CPU.
With RK 512, the request is acknowledged negatively
and must be repeated in the user program. As a
remedy, you should call the FB P_RCV_RK more
frequently in your user program.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 181
Event Class 4 (04H):
"CP detected error in data traffic CP - CPU"
Event no. Event text Remedy
(04)08H Error during data transmission between the CPU
and the CP (receipt)
CPU is temporarily overloaded, request is
repeated
The data area of the CPU cannot be
accessed for the time being, e.g., because
the receive block is not called often enough.
The data area of the CPU cannot be
accessed for the time being, e.g., because
the receive block is disabled in the interim
(EN=false).
Reduce the number of communication calls
Call the receive block more often
Check whether the receive block has been disabled
too long
(04)09H Data cannot be received. Error during data
transmission between the CPU and the CP
(receipt). Data cannot be received. After multiple
attempts, the request was cancelled after 10 s,
because
Receive block is not called
Receive block is disabled
Data area of the CPU cannot be accessed
Data area of the CPU is too small
Check your user program to determine whether the
receive block is being executed.
Check whether the receive block is disabled.
Check whether the data area to which the data is to
be transferred is available.
Check the length of the data area
(04)0AH An error has occurred during data transmission
between the CPU and CP. The data
transmission was canceled due to a RESET,
because:
Destination DB is not available
Destination DB is too short
RESET bit set at FB
Create destination DB in the user program or increase
the length of the existing destination DB.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 5 (05H):
"Error while processing CPU request"
Event no. Event Remedy
(05)01H Current request canceled as a result of CP restart. No remedy is possible in the case of a POWER ON.
In the case of parameter reassignment of the CP by
the programming device, before writing an interface
you should ensure there are no more requests
running from the CPU.
(05)02H Request is not permitted in this CP operating mode
(e.g., device interface parameters not assigned).
Assign parameters for the device interface.
(05)05H Printer driver only:
System data block with message texts not
available on the CP
Use the parameter assignment software to configure
the message texts, and then carry out a complete
restart.
(05)06H Printer driver only:
Message text not available
Use the parameter assignment software to configure
the message texts, and then carry out a complete
restart.
(05)07H Printer driver only:
Message text too long
Edit the message text to reduce it to a length of
fewer than 150 characters (or no more than 250
characters if it contains variables)
(05)08H Printer driver only:
Too many conversion statements
You have configured more conversion statements
than variables. Conversion statements without
associated variables will be ignored.
(05)09H Printer driver only:
Too many variables
You have configured more variables than conversion
statements. Variables without associated conversion
statements will not be output.
(05)0AH Printer driver only:
Unknown conversion statement
Check the conversion statement. Undefined or
unsupported conversion statements are replaced in
the printout with ******.
(05)0BH Printer driver only:
Unknown control statement
Check the control statement. Undefined or
unsupported control statements will be ignored. The
control statement will not be output as text either.
(05)0CH Printer driver only:
Conversion statement not executable
Check the conversion statement. Conversion
statements that cannot be executed are output in the
printout in accordance with the defined width and the
valid remainder of the conversion statement or the
default display is output with "*" characters.
(05)0DH Printer driver only:
Width in conversion statement too small or too
great
Correct the specified width of the variable in the
conversion statement on the basis of the variable's
maximum possible number of characters in text-
based display types (A, C, D, S, T, Y, Z). Only as
many characters as will fit in the specified width
appear in the printout; the text is truncated to this
width. In all other cases, "*" characters are output
corresponding to the width.
(05)0EH Only for ASCII drivers:
An error occurred while sending. The defined end-
of-text characters did not occur within the
maximum allowed length or in the case of
automatic appending, the maximum allowed
transmission length was exceeded.
Extend the end-of-text characters in the transmission
buffer at the desired point or select a shorter
message frame length for automatic appending.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 183
Event class 5 (05H):
"Error while processing CPU request"
Event no. Event Remedy
(05)14H Specified start addresses too high for desired data
type, or start address or DB/DX number too low.
Refer to the request tables for the permissible start
addresses and DB/DX numbers that can be
specified in the program.
(05)15H RK 512 only:
Incorrect bit number specified in the interprocessor
communication flag.
Permissible bit numbers: 0 to 7
(05)16H RK 512 only:
Specified CPU number too high.
Permissible CPU no.: none, 0, 1, 2, 3, or 4
(05)17H Transmission length > 1 kbyte is too long for CP, or
length is too short for interface parameter.
Split the request up into several shorter requests.
(05)1AH RK 512 only:
Error sending a command message frame
An associated procedure number has just been
entered in STATUS.
See the remedies for the previous error number.
(05)1BH Printer driver only:
Precision invalid
Correct the specified precision in the conversion
statement. The precision is always preceded by a
period to identify and limit the width (for example,
".2" to output the decimal point and two decimals.)
Precision is only relevant to display types A, D, F,
and R. It is ignored otherwise.
(05)1CH Printer driver only:
Variable invalid
(variable length incorrect/incorrect type)
Correct the specified variable. The corresponding
table indicates the possible data types for each
display type.
(05)1EH Printer driver only:
The "line end sequences" sent with this request
(i.e.: $R / $L / $N) do not fit (any longer) on the
(initial) page
Increase the length of your page, reduce the number
of lines (or line feeds) or spread your printout over a
number of pages
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 6 (06H):
"Error when processing a partner job" only for RK 512
Event no. Event text Remedy
(06)01H Error in 1st command byte (not 00 or FFH) Basic header structure error on partner. Check for
malfunction on partner device, possibly by using an
interface test device interconnected in the data link.
(06)02H Error in 3rd command byte (not A, 0 or E) Basic header structure error on partner. Check for
malfunction on partner device, possibly by using an
interface test device interconnected in the data link.
(06)03H Error in 3rd command byte in the case of
continuation message frames (command not as
for 1st message frame)
Basic header structure error on partner. Check for
malfunction on partner device, possibly by using an
interface test device interconnected in the data link.
(06)04H Error in 4th command byte (command letter
incorrect)
Header layout error at partner or a command
combination has been requested that is not permitted
at the CP. Check the permissible commands. Check
for malfunction on partner device, possibly by using an
interface test device interconnected in the data link.
(06)05H Error in 4th command byte in the case of
continuation message frames (command not as
for 1st message frame)
Basic header structure error on partner. Check for
malfunction on partner device, possibly by using an
interface test device interconnected in the data link.
(06)06H Error in 5th command byte (DB number not
permissible)
Refer to the request tables for the permissible DB
numbers, start addresses, or lengths.
(06)07H Error in the 5th or 6th command byte (start
address too high)
Refer to the request tables for the permissible DB
numbers, start addresses, or lengths.
(06)08H Error in 7th or 8th command byte (impermissible
length)
Obtain from the request tables the permissible DB/DX
numbers, start addresses or lengths.
(06)09H Error in 9th and 10th command byte
(coordination flag for this data type impermissible
or bit number too high)
Basic header structure error on partner. Refer to the
request tables for when a coordination flag is
permitted.
(06)0AH Error in the 10th command byte (illegal CPU
number)
Header layout error at partner
(06)0BH SEND message frame was longer/shorter than
expected (more/less data received than
announced in message frame header).
Correction required at the partner
(06)0CH FETCH command message frame with user data
received.
Correction required at the partner
(06)0DH The CP received a message frame during an
invalid operating mode:
Receive connection between the CPU and
CP is not set up or not yet correctly set up
CP startup is not fully completed
The receiving CPU is in STOP mode
Parameters of the addressed interface are
currently being reassigned
Check whether the addressed connection has been
assigned the correct parameters
This error message can only occur only during CP
startup. Repeat the request.
Place the CPU back in RUN mode and repeat the
request.
This is a temporary error. Repeat the request.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 185
Event class 6 (06H):
"Error when processing a partner job" only for RK 512
Event no. Event text Remedy
(06)0EH Synchronous fault of partner
New (continuation) command message
frame received before response message
frame was sent.
1. command message frame expected and
continuation message frame came.
Continuation command message frame
expected and 1st message frame came.
This error may be reported after your own automation
system is restarted in the case of long message frames
or when the partner is restarted. These cases
represent normal system start-up behavior.
The error can also occur during operation as a
consequence of error statuses only recognized by the
partner.
Otherwise, you have to assume an error on the part of
the partner device. The error may not occur in the case
of requests < 128 bytes.
(06)0FH DB locked by coordination function In local program: Reset the interprocessor
communication flag after the last transmission data
was processed.
In the partner program: Repeat the request
(06)10H Message frame received too short (length < 4
bytes in the case of continuation or response
message frames or <10 bytes in the case of
command message frames)
Check for malfunction on partner device, possibly by
using an interface test device interconnected in the
data link.
(06)11H Message frame length and length specified in
message frame header are not the same.
Check for malfunction on partner device, possibly by
using an interface test device interconnected in the
data link.
(06)12H Error while sending the (continuation) response
message frame. An associated procedure error
number has been entered in STATUS
immediately beforehand.
See remedies for the error number entered
immediately beforehand in STATUS.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 7 (07H):
"Send error"
Event no. Event Remedy
(07)01H Sending of the first repetition:
An error was detected when transmitting the
message frame, or
The partner requested a repetition by means of
a negative acknowledgment character (NAK).
A repetition is not an error, but it can indicate that
there is interference on the data link or the partner
device has malfunctioned. If the message frame still
has not been transmitted after the maximum number
of repetitions, an error number describing the first
error that occurred is output.
(07)02H 3964(R) only:
Error establishing connection:
After STX was sent, NAK or any other character
(except for DLE or STX) was received.
Check for malfunction of the partner device, possibly
by using interface test device interconnected in the
data link.
(07)03H 3964(R) only:
Acknowledgment delay time (QVZ) exceeded:
After STX was sent, partner did not respond within
the acknowledgment delay time.
The partner device is too slow or not ready to
receive, or there is a break in the transmission line,
for example. Check for malfunction on partner
device, possibly by using an interface test device
interconnected in the data link.
(07)04H 3964(R) only:
Cancellation by partner:
One or more characters were received from the
partner during sending.
Check whether the partner also indicates an error;
possibly it has not received all of the transmitted
data (for example, due to an interrupted data link), or
because fatal errors are pending, or the behavior of
the partner device is faulty. If necessary, use an
interface test device switched into the transmission
line to check.
(07)06H 3964(R) only:
End-of-connection error:
Partner rejected message frame at end of
connection with NAK or a random string
(except for DLE), or
Acknowledgment characters (DLE) received
too early.
Check whether the partner also indicates an error;
possibly it has not received all of the transmitted
data (for example, due to an interrupted data link), or
because fatal errors are pending, or the behavior of
the partner device is faulty. If necessary, use an
interface test device switched into the transmission
line to check.
(07)07H 3964(R) only:
Acknowledgment delay time exceeded at end of
connection or response monitoring time exceeded
after a send message frame:
After connection termination with DLE ETX, no
response received from partner within
acknowledgment delay time.
Partner device too slow or faulty. If necessary, use
an interface test device switched into the
transmission line to check.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 187
Event class 7 (07H):
"Send error"
Event no. Event Remedy
(07)08H ASCII driver and printer driver only:
The waiting time for XON or CTS = ON has
expired.
The communication partner is faulty, too slow, or has
been taken offline. Check the communication
partner; you may need to change the parameter
assignment.
(07)09H Not possible to connect. Number of permitted
setup attempts exceeded.
Check the interface cable or the transmission
parameters.
Also check whether the receive function between the
CPU and CP is assigned correctly in the partner
device.
(07)0AH Data could not be transmitted. The permitted
number of transmission attempts was exceeded.
Check the interface cable or the transmission
parameters.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 8 (08H):
"Receive error"
Event no. Event Remedy
(08)01H Expectation of the first repetition:
An error was detected on receiving a message
frame and the CP requested repetition from the
partner via a negative acknowledgment (NAK).
A repetition is not an error, but it can indicate that
there is interference on the data link or the partner
device has malfunctioned. If the message frame still
has not been transmitted after the maximum number
of repetitions, an error number describing the first
error that occurred is output.
(08)02H 3964(R) only:
Error establishing connection:
In idle mode, one or more random characters
(other than NAK or STX) were received, or
After an STX was received, the partner sent
more characters without waiting for the
response DLE.
After partner power ON:
While partner is being switched on, the CP
receives an undefined character.
Check for malfunction of the partner device, possibly
by using interface test device interconnected in the
data link.
(08)05H 3964(R) only:
Logical error while receiving:
After DLE was received, a further random
character (other than DLE or ETX) was received.
Check whether the partner always duplicates the
DLE in the message frame header and data string or
the connection is released with DLE ETX. Check for
malfunction at partner device, possibly by using
interface test device switched into the transmission
line.
(08)06H Character delay time (ZVZ) exceeded:
Two successive characters were not received
within the character delay time, or
3964(R) only:
1. character after sending of DLE while setting
up connection was not received within the
character delay time.
Partner device too slow or faulty. Prove this using an
interface test device interconnected in the data link.
(08)08H 3964(R) only:
Error in block check character (BCC):
The value of the BCC calculated internally does
not match the BCC received by the partner when
the connection was terminated.
Check whether the connection is seriously disrupted;
in this case you may also occasionally see error
codes. Check for malfunction of the partner device,
possibly by using interface test device
interconnected in the data link.
(08)0AH There is no free receive buffer available:
No receive buffer space available for receiving
data.
The FB P_RCV_RK must be called more frequently.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 189
Event class 8 (08H):
"Receive error"
Event no. Event Remedy
(08)0CH Transmission error:
A transmission error (parity error, stop bit error,
overflow error) was detected.
3964(R) only:
If a corrupted character is received in idle
mode, the error is reported immediately so that
disturbances on the transmission line can be
detected early.
RK 512 and 3964(R) only:
If this happens during send or receive
operations, repetition is started.
Disturbances on the data link cause message frame
repetitions, thus lowering user data throughput. The
risk of an undetected error increases. Change your
system setup or cable wiring.
Check the connecting cable of the communication
partners or check whether both devices have the
same setting for baud rate, parity and number of
stop bits.
(08)0DH BREAK:
Break in receive line to partner.
Reconnect or switch on partner.
(08)15H Discrepancy between settings for transmission
attempts of the CP and the communication partner.
Set the same number of transmission attempts for
the communication partner as for the CP. Check for
malfunction on partner device, possibly by using an
interface test device interconnected in the data link.
(08)16H The length of a received message frame
exceeded the maximum specified length.
Correction at the partner is necessary.
(08)18H ASCII driver only:
DSR = OFF or CTS = OFF
The partner has switched the DSR or CTS signal to
"OFF" before or during a transmission.
Check the partner's control of the RS 232C
accompanying signals.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 9 (09H):
"Response message frame received from interconnection partner with errors or error message frame"
Event no. Event text Remedy
(09)02H Only for RK 512:
Memory access error in partner (memory does not
exist)
With SIMATIC S5 as partner:
Incorrect area for indicator word, or
Data area does not exist (except DB/DX), or
Data area too short (except DB/DX)
Check that the partner has the desired data area and
that it is big enough, or check the parameters of the
called system function block.
Check the length specified in the system function
block.
(09)03H Only for RK 512:
DB/DX access error in the partner (DB/DX does
not exist or is too short)
With SIMATIC S5 as partner:
DB/DX does not exist, or
DB/DX too short, or
DB/DX number impermissible
Permissible source area exceeded with FETCH
request
Check that the partner has the desired data area and
that it is big enough, or check the parameters of the
called system function block.
Check the length specified in the system function
block.
(09)04H Only for RK 512:
Partner reports "Illegal request type".
Partner malfunction, because the CP never outputs
a system command.
(09)05H RK 512 only:Partner error or SIMATIC S5 partner
error:
Source/destination type not permissible, or
Memory error in partner programmable
controller, or
Error notifying CP/CPU at the partner, or
Partner programmable controller is in STOP
mode
Check if the partner can transmit the desired data
type.
Check the configuration of the partner hardware.
Set the mode selector switch of the partner
programmable controller to RUN.
(09)08H Only for RK 512:
Partner detects synchronous error:
Message frame sequence error.
This error occurs at the restart of your own
programmable controller or of the partner. This
represents normal system startup behavior. You do
not need to correct anything. The error is also
conceivable during operation as a consequence of
previous errors. Otherwise, you can assume a
malfunction of the partner device.
(09)09H Only for RK 512:
DB/DX locked at the partner by coordination flag
In the partner program: Reset the coordination
memory after the last transmission data was
processed!
In the program: Repeat the request!
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 9 (09H):
"Response message frame received from interconnection partner with errors or error message frame"
Event no. Event text Remedy
(09)0AH Only for RK 512:
Errors in message frame header that are detected
by the partner: 3rd command byte in header is
incorrect
Check whether the error was caused by faults or by
malfunction of the partner station. Prove this using
an interface test device interconnected in the data
link.
(09)0BH Only for RK 512:
Error in message frame header: 1. or 4th
command byte in header is incorrect
Check whether the error was caused by faults or by
malfunction of the partner station. Prove this using
an interface test device interconnected in the data
link.
(09)0CH Only for RK 512:
Partner detects incorrect message frame length
(total length).
Check whether the error was caused by faults or by
malfunction of the partner station. Prove this using
an interface test device interconnected in the data
link.
(09)0DH Only for RK 512:
Partner was not yet restarted.
Restart the partner programmable controller or set
the mode selector switch on the CP to RUN.
(09)0EH Only for RK 512:
Unknown error number received in the response
message frame.
Check whether the error was caused by faults or by
malfunction of the partner station. Prove this using
an interface test device interconnected in the data
link.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Event class 10 (0AH):
"Errors in response message frame of the partner detected by the CP"
(0A)01H Only for RK 512:
Synchronization error of partner, because:
Response message frame without request
Response message frame received before
continuation message frame sent
Continuation response message frame
received after an initial message frame was
sent
A first response message frame was received
after a continuation message frame was sent
This error is reported after your own programming
device is restarted in the case of long message
frames or when the partner is restarted. This
represents normal system start-up behavior. You do
not have to correct anything.
The error can also occur during operation as a
consequence of error statuses only recognized by
the partner.
Otherwise, you can assume an error on the part of
the partner device. The error may not occur in the
case of requests < 128 bytes.
(0A)02H RK 512 only: Error in the structure of the received
response message frame (1st byte not 00 or FF)
Check for malfunction of the partner device, possibly
by using interface test device interconnected in the
data link.
(0A)03H RK 512 only: Received response message frame
has too many or too few data.
Check for malfunction of the partner device, possibly
by using interface test device interconnected in the
data link.
(0A)04H RK 512 only: Response message frame for SEND
request arrived with data.
Check for malfunction of the partner device, possibly
by using interface test device interconnected in the
data link.
(0A)05H RK 512 only: No response message frame
received from partner within monitoring time.
Is the partner a slow device? This error is also often
displayed as a consequence of a previous error. For
example, procedure receive errors (event class 8)
can be displayed after a FETCH message frame
was sent. Reason: The response message frame
could not be received because of disturbances. The
monitoring time expires. This error also possibly
occurs if the partner is restarted before it could
respond to the last received FETCH message frame.
Displaying and evaluating the STATUS output
You can display and evaluate the actual addresses in the STATUS output of the function
block.
Note
An error message is only output if the ERROR bit (request completed with error) is set at the
same time. In all other cases the STATUS word is zero.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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Event class 30
Event class 30 contains error messages that can be output during communication via the S7
backplane bus between the CP 341 and the CPU.
The table below contains a description of event class 30.
Table 8- 2 Event class 30
Event class 30 (1EH):
"Communication error between CP and CPU"
Event no. Event Additional information/Remedy
(1E)0DH Request canceled due to complete restart, restart, or
reset
(1E)0EH Static error when the RD_REC SFC was called.
Return value RET_VAL of SFC is available for
evaluation in SFCERR variable in instance DB.
Load the SFCERR variable from the instance DB.
(1E)0FH Static error when the WR_REC SFC was called.
Return value RET_VAL of SFC is available for
evaluation in SFCERR variable in instance DB.
Load the SFCERR variable from the instance DB.
(1E)41H The number of bytes specified in the LEN parameter
of the FBs is not permissible
You must stay within a range of values of 1 to 4096
bytes.
(1E)42H FB P_PRINT_RK:
The number of bytes specified for the variable or
format string in the pointer DB under length is not
permissible.
You must specify a permissible length:
32 bytes for variables, 150 bytes for format string
(1E)43H FB P_PRINT_RK:
No pointer available for format string.
Enter the data block no. and data word no. for the
format string in the pointer DB.
Calling the SFCERR variable
You can obtain more information on errors 14 (1E0EH) and 15 (1E0FH) in event class 30 by
means of the SFCERR variable.
You can load the SFCERR variable from the instance DB of the corresponding function
block. The program example in section "Programming Example for Standard Function Blocks
(Page 199)" demonstrates how to load the SFCERR variable.
The error messages written to the SFCERR variable are listed in the System Software for
S7 300/400, System and Standard Functions Reference Manual under the SFC 58
"WR_REC" and SFC 59 "RD_REC" system functions.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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8.1.3 Error Numbers in the Response Message Frame
If you are working with the RK 512 computer link and an error occurs at the communication
partner in a SEND or FETCH message frame, the communication partner sends a response
message frame with an error number in the 4th byte.
Error numbers in the response message frame
The table below shows how the error numbers in the response message frame (REATEL)
are assigned to the event classes/numbers in the STATUS output of the communication
partner. The error numbers in the response message frame are output as hexadecimal
values.
Table 8- 3 Error messages in the response message frame with RK 512
Error Messages
REATEL
Event Class/Event Number
0AH 0905H
0CH 0301H
0607H
0609H
060AH
0902H
10H 0301H
0601H
0604H
0605H
090BH
12H 0904H
14H 0606H
0903H
16H 0602H
0603H
090AH
2AH 060DH
090DH
32H 060FH
0909H
34H 0608H
060BH
060CH
0611H
090CH
36H 060EH
0908H
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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8.1.4 Diagnostics via the diagnostic buffer of the CP 341
Diagnostic buffer of the CP 341
The CP 341 has its own diagnostic buffer in which all the diagnostic events of the CP 341
are entered in the order in which they occur.
The following are displayed in the diagnostic buffer of the CP 341:
● Hardware/firmware errors on the CP 341
● Initialization and parameter assignment errors
● Errors during execution of a CPU request
● Data transmission errors (send and receive errors)
The diagnostic buffer allows the causes of errors in the point-to-point connection to be
evaluated subsequently in order, for example, to determine the causes of a STOP of the
CP 341 or to trace the occurrence of individual diagnostic events.
Note
The diagnostic buffer is a ring buffer designed for a maximum of 9 diagnostic entries. When
the diagnostic buffer is full, the oldest entry is deleted when a new entry is made in it. As a
result, the latest entry is always at the top. In the event of a POWER OFF or parameter
reassignment of the CP 341, the contents of the diagnostic buffer are lost!
Note
To view the time of day of the individual diagnostic entries, you must select the CPU in
"HW Config" and perform the time-of-day synchronization in the "Diagnostics/Clock" folder
("master" synchronization type, time interval of, for example, 10 seconds). When the CP 341
is used in distributed operation (ET 200M), the time of day cannot be displayed.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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Outputting the diagnostic buffer on the programming device
The content of the diagnostic buffer of the CP 341 can be read by means of the STEP 7
information functions.
All the user-relevant information in the CP diagnostic buffer is displayed in the "Diagnostic
Buffer" tab in the "Module Information" dialog box. You can open SIMATIC Manager in
STEP 7 to call the "Module Information" dialog box.
Requirements: In order to obtain module information, there must be an online connection
from the programming device to the programmable controller (online view in the project
window).
Use the following procedure:
1. Open the relevant SIMATIC 300 station (double-click or select menu command Edit >
Open).
2. Then open the "Hardware" object (double-click or select menu command Edit > Open).
Result: The window containing the configuration table appears.
3. Select the CP 341 in the configuration table.
4. Select PLC > Module Information.
Result: The "Module Information" dialog box for the CP 341 appears. The first time the
dialog is called, the "General" tab appears (default setting).
5. Go to the "Diagnostic Buffer" tab.
Result: The latest diagnostic events of the CP 341 are displayed in plain text on the
"Diagnostic Buffer" tab. Additional information about error causes may appear in the
"Event details" output field.
The "Event ID" field displays the number code for the the event. The first part is fixed. The
second part corresponds to the event class and event numbers of the event.
Select the "Help on Event" button to display the remedy for the particular event text.
Click "Update" to read the latest data from the CP 341. Click "Help on Event" to show a help
text for the selected diagnostic event containing information about troubleshooting.
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
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8.1.5 Diagnostic Interrupt
The CP 341 can trigger a diagnostics alarm on the assigned CPU, thus indicating a
malfunction of the CP 341. You can specify at parameterization whether the CP 341 is to
trigger a diagnostics alarm or not in the event of serious errors.
"Diagnostics alarm = NO" is the default.
Diagnostic interrupt
In the event of a fault the CP 341 provides diagnostic information on the S7–300 backplane
bus. In response to a diagnostic interrupt, the CPU reads the system-specific diagnostic data
and enters it in its diagnostic buffer. You can read the contents of the diagnostic buffer on
the CPU using a programming device.
When a diagnostics event occurs, the SF LED (red) lights up. In addition, the OB 82 is called
with this diagnostic data as start information.
Organization block OB 82
You have the option of programming error responses in the user program in the OB 82.
If no OB 82 is programmed, the CPU automatically enters STOP mode in the event of a
diagnostic interrupt.
Diagnostic information (as bit pattern)
The CP 341 provides 4 bytes of diagnostics information. To display the error that has
occurred, these 4 bytes are occupied as follows:
2nd byte:
The 2nd byte of diagnostic data contains the class ID of the CP 341 in bits 0 to 3.
2. Byte
7 6 5 4 3 2 1 0
0 0 0 0 1 1 0 0
Diagnostics with the CP 341
8.1 Diagnostics Functions of the CP 341
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1st, 3rd and 4th bytes:
The 1st, 3rd, and 4th bytes of the diagnostic data represent the error that has occurred.
Bit 0 in the 1st byte is the group error display (SF). Bit 0 is always set to "1" if at least one bit
from bits 1 to 7 is set to "1", i.e. if at least one error is entered in the diagnostic data.
Event 1st byte 3rd byte 4th byte
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
Wire break 0 0 1 0 0 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0
Incorrect parameter 1 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Diagnostic information (hexadecimal)
The table below shows the 4 bytes of diagnostic data of the CP 341 in hexadecimal notation.
Event 1st byte 2nd byte 3rd byte 4th Byte
Wire break 25H 0CH 02H 00H
Incorrect
parameter
83H 0CH 00H 00H
Relationship of the diagnostic interrupt and the CPU operating mode
A diagnostic interrupt is generated via the I/O bus on an incoming event (rising edge) and
outgoing event (falling edge).
When the CPU switches from STOP to RUN mode, the following applies:
● Events (either incoming or outgoing) that occurred when the CPU was in STOP mode are
not stored
● Events that are still present when the CPU switches back to RUN mode are signaled via
a diagnostic interrupt.
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Programming Example for Standard Function Blocks 9
9.1 General Information
The programming example given here and included in the zXX21_01_PtP_Com_CP34x
project describes standard functions for operating the CP 341 communications processor.
Objective
The programming example
● aims to show examples of the most important functions
● enables the correct functioning of the connected hardware to be checked (and is
therefore simple and easy to follow)
● can easily be extended for your own purposes.
The example shows how an 3964(R)/ASCII connection or an RK 512 computer link to a
communications partner can be configured using the standard function blocks P_SND_RK
and P_RCV_RK (to send and receive data respectively).
The example also shows how the inputs and outputs of the CP 341 can be controlled and
monitored using the V24_STAT and V24_SET standard functions.
There are three SIMATIC stations in the example because the CP 341 has to be assigned
parameters differently for data transfer:
● CP341 protocol 3964: Coupling with FB P_SND_RK and FB P_RCV_RK
● CP341 protocol RK512: Coupling with FB P_SND_RK and FB P_RCV_RK
● CP341 V24: Read and control RS 232C secondary signals with FC V24_STAT and
FC V24_SET
Note that the "CP340 PTP Connection" (point-to-point) and "CP340 Printing and V24"
stations contain the examples for the CP 340.
The CP 341 is assigned parameters by the CPU when the latter is started up (system
service).
Requirement
The example can be executed with the minimum hardware equipment. The STEP 7 function
monitor/modify variables is also used (e.g. to modify transmitted data).
Program example
The programming example of the CP 341, together with the programming interface and the
function blocks, is supplied on the installation CD which come with this manual.
It is available both compiled and as an ASCII source file. A list of all the symbols used in the
example is also included.
Programming Example for Standard Function Blocks
9.2 Device Configuration
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9.2 Device Configuration
Application
To try out the program example, you could use the following devices:
● An S7-300 automation system (rack, power supply, CPU)
● A CP 341 module with a communications partner (e.g., a second CP), or insertion of a
"short-circuit connector", i.e. the send line is bridged to the receive line
The use of the "short-circuit connector" is only supported by the ASCII protocols.
● A programming device.
9.3 Settings
Settings in the CPU by means of STEP 7
Use STEP 7 to configure your controller as follows.
● Slot 1: Power supply
● Slot 2: CPU
● Slot 4: CP 341, start address 256
● Slot 5: CP 341, start address 272
Settings on the CP 341
You cannot make any hardware settings on the CP 341.
Use STEP 7 to configure all relevant data, including the parameters for the CP 341 with the
CP 341: Point-to-Point Communication, Parameter Assignment parameter assignment and
upload them to the CPU.
You can run the "CP341 protocol 3964" program example without making changes in the
application program with:
● 3964(R) Procedure
● ASCII driver with "on expiry of character delay time" end criterion
● ASCII driver with "on receipt of fixed message frame length" end criterion.
For the ASCII driver with the "on receipt of the end character(s)" end criterion, you must also
program the end codes.
The functions for reading and controlling RS 232C secondary signals can only be executed
with the ASCII driver. Controlling is only possible if in the "Transmission" tab the "Automatic
use of V24 Signals" parameter is not selected.
Programming Example for Standard Function Blocks
9.4 Blocks Used
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9.4 Blocks Used
Blocks used
The table below shows the blocks used for the sample program.
Block Symbol Description
OB 1 CYCLE Cyclic program processing
OB 100 RESTART Cold restart processing
DB 21 SEND IDB Instance DB for P_SND_RK FB
DB 22 RECV IDB Instance DB for P_RCV_RK FB
DB 40 SEND WORK DB Work DB for the standard FB 8
DB 41 RECV WORK DB Work DB for the standard FB 7
DB 42 SEND SRC DB Send data block
DB 43 RECV DST DB Receive data block
FB 7 P_RCV_RK Standard FB for receiving data (RK 512)
FB 8 P_SND_RK Standard FB for sending data (RK 512)
FC 5 V24_STAT Standard FC for reading CP outputs
FC 6 V24_SET Standard FC for writing to CP outputs
FC 14 V24_CYC Control RS 232C secondary signals
FC 21 SEND Sending Data
FC 22 RECEIVE receiving data
Programming Example for Standard Function Blocks
9.5 Installation, Error Messages
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9.5 Installation, Error Messages
Scope of supply and installation
The programming example of the CP 341, together with the CP 341: Point-to-Point
Communication, Parameter Assignment parameter assignment interface and the function
blocks is located on the CD supplied with the module.
The program example is installed together with the parameter assignment interface.
Following installation, you will find the program example in the project:
"zXX21_01_PtP_Com_CP34x"
Open the project in the STEP 7 SIMATIC Manager by selecting File > Open > Project.
The sample program is available as a compiled program and as an ASCII source file. A list
of all the symbols used in the example is also included.
If there is no second CP 341 available to serve as a communication partner, you have to
delete the CP 341 in HW Config by selecting Edit > Delete. In addition, in OB 1 the FC 22
call (FC for receive) must be commented out.
Loading to the CPU
The hardware for the example is completely set up and the programming device is
connected.
After resetting the CPU memory (STOP operating mode), transfer the entire example to the
user memory. Then switch the mode selector from STOP to RUN.
Error behavior
If an error occurs during startup, the cyclically processed block call commands will not be
executed and the error LED will be set.
In the event of an error message, the ERROR parameter output of the blocks is set. A more
detailed description of the error is then stored in the STATUS parameter of the blocks. If the
STATUS parameter contains either the 16#1E0E or the 16#1E0F error message, the more
detailed description will be stored in the SFCERR variable in the instance DB.
Programming Example for Standard Function Blocks
9.6 Activation, Start-Up Program and Cyclic Program
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9.6 Activation, Start-Up Program and Cyclic Program
Activation, start-up program
The start-up program is located in OB 100.
The control bits and the counters are reset in the start-up procedure
Cyclic program
The cyclic program is in OB 1.
In the example, the function blocks 7 P_RCV_RK FB and 8 P_SND_RK FB work with the
functions FC 21 and FC 22 and with data blocks DB 21 and DB 22 as instance DBs and
DB 42 and DB 43 as send and receive DBs.
The functions FC 5 V24_STAT and FC 6 V24_SET work with the function FC 14.
In the example the function blocks are assigned parameters partly via constants and partly
via symbolically addressed actual operands.
Description, "CP341 Protocol 3964", "CP341 Protocol RK512"
Data is transferred from the CP 341 in slot 4 to the CP 341 in slot 5. If you are using some
other communication partner, the FC 22 call (RECEIVE) is omitted.
Description of FC 21 (SEND)
Program section "Generate edge P_SND_REQ":
The P_SND_RK is initially executed once with P_SND_RK REQ=0. P_SND_RK REQ is then
set to 1. If a signal state change from 0 to 1 is detected at the P_SND_RK REQ control
parameter, the P_SND_RK request is started.
If P_SND_RK DONE=1 or P_SND_RK ERROR=1, P_SND_RK REQ is reset to 0.
Program section "P_SND_RK DONE=1":
If a transfer has been successful, the P_SND_RK DONE parameter is set to 1 at the
parameter output of P_SND_RK. To distinguish between consecutive transfers, a send
counter (P_SND_RK COUNTER_OK) is included in data word 0 of source data block DB 42.
Program section "P_SND_RK ERROR=1":
If P_SND_RK is executed with P_SND_RK ERROR=1, the error counter P_SND_RK
COUNTER_ERR is incremented in data word 2. In addition, P_SND_RK STATUS is copied,
since it will be overwritten with 0 during the next cycle, making it impossible to read it out.
Programming Example for Standard Function Blocks
9.6 Activation, Start-Up Program and Cyclic Program
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Description of FC 22 (RECEIVE)
Program section "Enable receive data":
In order to receive data, the P_RCV_RK EN_R receive enable at the P_RCV_RK block must
be set to 1.
Program section "P_RCV_RK NDR=1":
If P_RCV_RK NDR is set, it means that new data has been received and the receive counter
P_RCV_RK COUNTER_OK is incremented.
Program section "P_RCV_RK ERROR=1":
If an error occurs, i.e., the error bit at the parameter output of P_RCV_RK is set, the
P_RCV_RK COUNTER_ERR error counter is incremented. In addition, P_RCV_RK STATUS
is copied, since it will be overwritten with 0 during the next cycle, making it impossible to
read it out.
All relevant values can be monitored in the VAT for testing purposes.
Description "CP341 V24"
● The "read and control RS 232C accompanying signals" functions can only be carried out
with the ASCII driver. Control is only possible if you have not set the “Automat. control of
V24 signals" parameter on the "Transfer" tab.
● The V24 signals can be read and written using the variable table. The signal states
SET_DTR and SET_RTS can be preselected by means of memory bits M 1.6 and M 1.7.
When the signal at memory bit I 0.7 changes from "0" to "1", this state is transferred to
the CP by the FC V24_SET function.
● The FC V24_STAT function is called cyclically. The status of the CP 341 V24 signals can
be read out via memory bits 3.0 to 3.5.
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Technical Specifications A
A.1 Technical Data of the CP 341
General technical specifications
The following table contains the general technical specifications of the CP 341.
You will find more general technical specifications for the SIMATIC S7-300 in the reference
manual entitled
S7-300 Programmable Controllers, Module Specifications
.
Table A- 1 General technical specifications
Technical specifications
Dimensions W x H x D 40 x 125 x 120 mm
Weight 0.3 kg
Current consumption from 24 V
(24 V DC infeed via front panel connector)
CP 341-RS 232C: Typ. 100 mA
CP 341-20mA-TTY typ. 100 mA
CP 341-RS 422/485: Typ. 100 mA
Area, static
Area, dynamic
Polarity reversal protection
Electrical isolation
20.4 to 28.8 V
18.5 to 30.2 V
Yes
Yes, relative to all other voltages
Current consumption from backplane bus Approx. 70 mA
Power loss CP 341-RS 232C: Typ. 2.4 W
CP 341-20mA-TTY: Typ. 2.4 W
CP 341-RS 422/485: Typ. 2.4 W
Indicators LEDs for transmitting (TXD), receiving (RXD) and
group faults (SF)
Interrupts
Diagnostic interrupt
Programmable
Diagnostic functions
Diagnostic information can be read out
Yes
Supplied protocol drivers ASCII driver
3964(R) procedure
RK 512 computer link
Printer driver
Transmission rate with 3964(R) protocol 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
(half-duplex)
Technical Specifications
A.1 Technical Data of the CP 341
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Technical specifications
Transmission rate with RK 512 computer link 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
(half-duplex)
Transmission rate with ASCII driver 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
Transmission rate with printer driver 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
Character frame No. of bits per character (7 or 8)
No. of start/stop bits (1 or 2)
Parity (none, even, odd)
Quantity of user data transported per program
cycle
Send/receive: 32 bytes
Memory requirement of FB P_SND_RK and FB
P_RCV_RK (RAM)
Approx. 5500 bytes
Technical specifications RS232C interface
The table below shows the technical specifications for the RS 232C interface of the
CP 341–RS 232C:
Table A- 2 Technical specifications of the RS 232C interface
Technical specifications
Interface RS232C, 9-pin sub D male connector
RS232C signals TXD, RXD, RTS, CTS, DTR, DSR, RI, DCD, GND
All electrically isolated relative to the S7-internal supply
(backplane bus) and the external 24 V DC supply
Max. transmission distance 15 m
Max. baud rate 115200 bps
Technical Specifications
A.1 Technical Data of the CP 341
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Technical specifications of the 20mA-TTY interface
The table below shows the technical specifications for the 20-mA-TTY interface of the
CP 341-20mA-TTY:
Table A- 3 Technical specifications of the 20mA-TTY interface
Technical specifications
Interface 20 mA current loop TTY, 9-pin sub D female connector
TTY signals Two isolated 20 mA current sources,
receive loop (RX) "–" and "+" send loop (TX) "–" and "+"
All electrically isolated relative to the S7-internal supply (backplane
bus) and the external 24 V DC supply
Max. transmission distance 1000 m active, 1000 m passive
Max. baud rate 19200 bps
Technical specifications of the X27 (RS 422/485) interface
The table below shows the technical specifications for the X27 (RS 422/485) interface of the
CP 341–RS 422/485.
Table A- 4 Technical specifications of the X27 (RS 422/485) interface
Technical specifications
Interface RS 422 or RS 485, 15-pin sub D female connector
RS 422 signals
RS 485 signals
TXD (A), RXD (A), TXD (B), RXD (B), GND
R/T (A), R/T (B), GND
All electrically isolated relative to the S7-internal supply (backplane
bus) and the external 24 V DC supply
Max. transmission distance 1200 m
Max. baud rate 115200 bps
Technical Specifications
A.1 Technical Data of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
208 Manual, 04/2011, A5E02191071-03
Technical specifications of the 3964(R) procedure
The table below shows the technical specifications for the 3964(R) procedure.
Table A- 5 Technical specifications of the 3964(R) procedure
3964(R) procedure with default values
Max. message frame
length
4096 bytes
Parameter The following can be assigned:
With/without block check character
Priority: low/high
Transmission rate: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
Character frame: 9, 10, 11 or 12 bits
Receive line initial state: none, R(A)5V/R(B)0V, R(A)0V/R(B)5V
3964(R) procedure with parameter assignment
Max. message frame
length
4096 bytes
Parameter The following can be assigned:
With/without block check character
Priority: low/high
Transmission rate:
300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 76800,
115200 bps
Character frame: 9, 10, 11 or 12 bits
Character delay time: 20 ms to 65530 ms in 10 ms increments
Acknowledgment delay time: 20 ms to 65530 ms in 10 ms increments
Number of connection attempts: 1 to 255
Number of transmission attempts: 1 to 255
Receive line initial state: none, R(A)5V/R(B)0V, R(A)0V/R(B)5V
Technical Specifications
A.1 Technical Data of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 209
Technical specifications RK512 computer link
The table below shows the technical specifications for the RK512 computer link.
Table A- 6 Technical specifications of the RK512 computer link
RK 512 computer link
Max. message frame
length
4096 bytes
Parameter The following can be assigned:
Transmission rate: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
Character frame: 10, 11, or 12 bits
Character delay time: 20 ms to 65530 ms in 10 ms increments
Acknowledgment delay time: 20 ms to 65530 ms in 10 ms increments
Number of connection attempts: 1 to 255
Number of transmission attempts: 1 to 255
Initial state of receive line: none, R(A)5V/R(B)0V, R(A)0V/R(B)5V
Technical Specifications
A.1 Technical Data of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
210 Manual, 04/2011, A5E02191071-03
Technical specifications of the ASCII driver
The table below shows the technical specifications for the ASCII driver.
Table A- 7 Technical specifications of the ASCII driver
ASCII driver
Max. message frame
length
4096 bytes
Parameter The following can be assigned:
Transmission rate: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
Character frame: 9, 10, 11 or 12 bits
Character delay time: 2 ms to 65535 ms in 1 ms increments
Flow control: none, XON/XOFF, RTS/CTS; automat. control of V.24
signals
XON/XOFF character (only when "flow control" = "XON/XOFF")
Wait for XON after XOFF (wait time for CTS = ON): 20 ms to 65530
ms in 10-ms increments
Time to RTS OFF: 0 ms to 65530 ms in 10 ms increments (only for
"automat. control of V.24 signals")
Data output waiting time: 0 ms to 65530 ms in 10 ms increments (only
for "automat. control of V.24 signals")
Number of message frames to be buffered: 1 to 250
Prevent overwriting: yes/no (only when "buffered received frames"
= "1")
Indicator for end of received message frame:
– After character delay time expires
– On receipt of end-of-text character(s)
– On receipt of fixed number of characters
Technical Specifications
A.1 Technical Data of the CP 341
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 211
Table A- 8 Additional parameters of end-of-frame detection
ASCII driver with end-of-frame detection after expiration of character delay time
Parameter No other parameter assignments need to be made. The end of a frame is
detected when the programmed character delay time elapses.
ASCII driver with end-of-frame detection using assignable end-of-text characters
Parameter The following can be assigned:
Number of end-of-text characters: 1 or 2
Hex code for first/second end-of-text character
ASCII driver with end-of-frame detection using configured frame length
Parameter The following can be assigned:
Message frame length: 1 to 4096 bytes
Technical specifications of the printer driver
The table below shows the technical specifications of the printer driver.
Table A- 9 Technical specifications of the printer driver
Printer driver
Length of the text SDB 15 kbytes
Parameter The following can be assigned:
Transmission rate: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400,
57600, 76800, 115200 bps
Character frame: 10 or 11 bits
Flow control: None, XON/XOFF, RTS/CTS
XON/XOFF characters (with "flow control" = "XON/XOFF" only)
Wait for XON after XOFF (wait time for CTS = ON): 20 ms to
65530 ms in 10 ms increments
Message text: max. 150 characters (max. 250 characters when
variables are displayed)
Left margin (number of blanks): 0 to 255
Lines per page (with header and footer): 1 to 255 or 0 (continuous
printing)
Separators/line end: CR, LF, CR LF, LF CR
Character set: IBM Proprinter or user-defined
Printer emulation for bold, condensed, expanded, and italic type and
underlining: HP Deskjet, HP Laserjet, IBM Proprinter or user-defined
1/2 header and/or footer
See also
Technical Specifications of the Function Blocks (Page 168)
Technical Specifications
A.2 Transmission Rates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
212 Manual, 04/2011, A5E02191071-03
A.2 Transmission Rates
Transmission Rates
The tables below indicate the transmission times required depending on the transmission
protocol selected.
Two S7-300s, each with a CPU 319-3 PN/DP (6ES7 318-3EL00-0AB0) and a CP 341-V2
(6ES7 341-1AH02-0AE0), were used to measure the time. An P_SND_RK (V3.2) function
block was programmed in the user program of the active CPU, and an P_RCV_RK (V3.2)
function block was programmed in the user program of the passive CPU. The time that
elapsed between the initiation and completion of the request was measured.
ASCII driver
Table A- 10 Transmission rates (in s) for ASCII driver (at minimum character delay time)
Baud rate (bd)
User data
115200 76800 57600 38400 19200 9600 4800 2400 1200 600 300
1 byte 0.003 0.003 0.003 0.003 0.003 0.006 0.011 0.021 0.040 0.081 0.160
10 bytes 0.004 0.004 0.005 0.005 0.008 0.015 0.029 0.058 0.115 0.231 0.455
20 bytes 0.005 0.005 0.006 0.008 0.014 0.027 0.052 0.104 0.207 0.416 0.822
50 bytes 0.007 0.010 0.012 0.017 0.031 0.061 0.121 0.242 0.483 0.966 1.935
100 bytes 0.012 0.017 0.022 0.031 0.059 0.118 0.227 0.472 0.942 1.884 3.727
200 bytes 0.022 0.031 0.041 0.060 0.117 0.234 0.415 0.931 1.861 3.722 7.353
500 bytes 0.051 0.076 0.099 0.148 0.291 0.577 1.076 2.309 4.616 9.233 18.458
1000 bytes 0.101 0.151 0.198 0.294 0.581 1.154 2.146 4.134 9.212 18.424 36.817
4000 bytes 0.331 0.596 0.784 1.170 2.317 4.613 9.205 18.393 36.776 73.553 147.080
Technical Specifications
A.2 Transmission Rates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 213
3964(R) procedure
Table A- 11 Transmission times (in s) with the 3964(R) procedure
Baud rate (bd)
User data
115200 76800 57600 38400 19200 9600 4800 2400 1200 600 300
1 byte 0.003 0.003 0.003 0.004 0.006 0.010 0.018 0.034 0.066 0.130 0.258
10 bytes 0.004 0.004 0.005 0.006 0.011 0.020 0.039 0.075 0.149 0.296 0.590
20 bytes 0.005 0.006 0.007 0.009 0.017 0.032 0.062 0.121 0.241 0.480 0.957
50 bytes 0.007 0.010 0.013 0.018 0.034 0.066 0.131 0.259 0.517 1.031 2.057
100 bytes 0.012 0.018 0.023 0.033 0.063 0.124 0.246 0.489 0.976 1.948 3.896
200 bytes 0.022 0.033 0.042 0.062 0.121 0.240 0.475 0.949 1.895 3.786 7.570
500 bytes 0.053 0.078 0.102 0.150 0.295 0.586 1.167 2.329 4.653 9.301 18.599
1000 bytes 0.103 0.152 0.200 0.297 0.585 1.163 2.317 4.629 9.249 18.491 36.976
4000 bytes 0.332 0.597 0.786 1.172 2.321 4.621 9.216 18.424 36.824 73.635 147.276
RK 512 computer link
Table A- 12 Transmission times (in s) with the RK 512 computer link
Baud rate (bd)
User data
115200 76800 57600 38400 19200 9600 4800 2400 1200 600 300
1 byte 0.007 0.009 0.010 0.012 0.020 0.035 0.066 0.130 0.258 0.514 1.029
10 bytes 0.008 0.010 0.012 0.015 0.025 0.044 0.084 0.167 0.332 0.663 1.323
20 bytes 0.009 0.012 0.014 0.018 0.030 0.056 0.107 0.213 0.424 0.844 1.694
50 bytes 0.013 0.016 0.020 0.027 0.048 0.091 0.176 0.350 0.699 1.396 2.790
100 bytes 0.018 0.024 0.030 0.042 0.077 0.149 0.291 0.580 1.159 2.315 4.627
200 bytes 0.032 0.043 0.055 0.079 0.149 0.289 0.569 1.133 2.262 4.520 9.034
500 bytes 0.071 0.100 0.128 0.184 0.351 0.687 1.357 2.699 5.389 10.776 21.537
1000 bytes 0.139 0.196 0.250 0.363 0.697 1.364 2.700 5.375 10.723 21.438 42.853
4000 bytes 0.540 0.769 0.983 1.431 2.765 5.427 10.758 21.430 42.770 85.443 170.795
Technical Specifications
A.2 Transmission Rates
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
214 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 215
Connecting cables B
B.1 RS 232C Interface of the CP 341-RS 232C
Pin assignment
The table below shows the pin assignment for the 9-pin sub D male connector in the front
panel of the CP 341-RS 232C (compatible with the 9-pin COM port (PC/programming
device).
Table B- 1 Pin assignment for the sub D male connector of the integrated interface of the CP 341-RS 232C
Male Connector
on CP 341-RS
232C*
Pin Designation Input/output Meaning
1 DCD1 Received Detector Input Received signal level
2 RXD Received Data Input Receive data
3 TXD Transmitted Data Output Transmit data
4 DTR Data Terminal Ready Output Data terminal ready
5 GND Ground - Functional ground (GNDint)
6 DSR Data Set Ready Input Data set ready
7 RTS Request To Send Output Request to send
8 CTS Clear To Send Input Clear to send
1
2
3
4
5
9
8
7
6
9 RI Ring Indicator Input Incoming call
* View from the front
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
216 Manual, 04/2011, A5E02191071-03
Connecting cables
If you make your own connecting cables you must remember that unconnected inputs at the
communication partner may have to be connected to open-circuit potential.
Please note that you must only use shielded connector casings. A large surface area of both
sides of the cable shield must be in contact with the connector casing. You are advised to
use Siemens V42 254 shielded connector casings.
CAUTION
Never connect the cable shield with the GND, as this could destroy the interfaces. GND
must always be connected on both sides (pin 5), otherwise the interface modules could be
destroyed.
On the following pages you will find examples of connecting cables for a point-to-point
connection between the CP 341-RS 232C and S7 modules or SIMATIC S5.
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 217
RS 232C connecting cables (S7 (CP 341) - S7 (CP 340/ CP 341/CP 441))
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 340/CP 341/CP 441.
For the connecting cables you will require the following female connectors:
● On the CP 341 side: 9-pin sub D female connector with screw-locking
● On the communication partner: 9-pin sub D female connector with screw-locking
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Figure B-1 RS 232C connecting cable CP 341 - CP 340/CP 341/CP 441
The cable (max. 15 m) is available under the order number (6ES7 902-1...) specified in
appendix Accessories and order numbers (Page 235).
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
218 Manual, 04/2011, A5E02191071-03
RS 232C connecting cables (S7 (CP 341) - CP 544, CP 524, CPU 928B, CPU 945, CPU 948)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 544, CP 524, CPU 928B, CPU 945 or CPU 948.
For the connecting cables you will require the following female/male connectors:
● On the CP 341 side: 9-pin sub D female connector with screw-locking
● On the communication partner: 25-pin sub D male connector with screw-locking
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Figure B-2 RS 232C connecting cable (CP 341 - CP 544, CP 524, CPU 928B, CPU 945,
CPU 948
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 219
RS 232C connecting cables (S7 (CP 341) - CP 521 SI/CP 521 BASIC)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 521 SI/CP 521 BASIC.
For the connecting cables you will require the following female/male connectors:
● On the CP 341 side: 9-pin sub D female connector with screw-locking
● On the communication partner: 25-pin sub D male connector with screw-locking
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Figure B-3 RS 232C connecting cable CP 341 - CP 521 SI/CP 521 BASIC
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
220 Manual, 04/2011, A5E02191071-03
RS 232C connecting cables (S7 (CP 341) - CP 523)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 523.
For the connecting cables you will require the following female/male connectors:
● On the CP 341 side: 9-pin sub D female connector with screw-locking
● On the communication partner: 25-pin sub D male connector with screw-locking
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Figure B-4 RS 232C connecting cable CP 341 - CP 523
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 221
RS 232C connecting cable (S7 (CP 341) - IBM-Proprinter (PT 88), DR 230)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and an IBM Proprinter with serial interface (PT 88 or IBM-compatible printer).
For the connecting cable you will require the following female/male connectors:
● On the CP 341 side: 9-pin sub D female
● For the IBM Proprinter: 25-pin sub D male
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Figure B-5 RS 232C connecting cable CP 341 - IBM Proprinter
Connecting cables
B.1 RS 232C Interface of the CP 341-RS 232C
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
222 Manual, 04/2011, A5E02191071-03
RS 232C connecting cable (S7 (CP 341) - laser printer)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a laser printer with serial interface (PT 10 or Laserjet series II).
For the connecting cable you will require the following female/male connectors:
● On the CP 341 side: 9-pin sub D female
● For the IBM Proprinter: 25-pin sub D male
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Figure B-6 RS 232C connecting cable CP 341 - laser printer
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 223
B.2 20 mA TTY interface on the CP 341-20mA-TTY
Pin assignment
The table below shows the pin assignment for the 9-pin sub D female connector in the front
panel of the CP 341-20mA-TTY.
Table B- 2 Pin assignment for the 9-pin sub D female connector of the integrated interface of the CP 341-20mA-TTY
Female connector on
CP 341-20mA-TTY*
Pin Designation Input/output Meaning
1 TxD- Output Transmit data
2 20 mA - Input 24 V ground
3 20 mA + (I1) Output 20mA current generator 1
4 20 mA + (I2) Output 20mA current generator 2
5 RxD + Input Receive data +
6 -
7 -
8 RxD - Output Receive data -
5
4
3
2
1
6
7
8
9
9 TxD + Input Transmit data +
* View from the front
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
224 Manual, 04/2011, A5E02191071-03
Block diagram
The figure below shows the block diagram for a 20mA-TTY interface.
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Connecting cables
If you make your own connecting cables you must remember that unconnected inputs at the
communication partner may have to be connected to open-circuit potential.
Please note that you must only use shielded connector casings. A large surface area of both
sides of the cable shield must be in contact with the connector casing. You are advised to
use Siemens V42 254 shielded connector casings.
CAUTION
Never connect the cable shield with the GND, as this could destroy the interface modules.
In the following
On the following pages you will find examples of connecting cables for a point-to-point
connection between the CP 341-20mA-TTY and S7 modules or SIMATIC S5.
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 225
20mA-TTY connecting cable (S7 (CP 341) - S7 (CP 340/ CP 341/CP 441))
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 340/CP 341/CP 441.
For the connecting cables you will require the following male connectors:
● On the CP 341 side: 9-pin sub D male connector with screw-locking
● On the communication partner: 9-pin sub D male connector with screw-locking
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Figure B-8 20mA-TTY connecting cable CP 341 - CP 340/CP 341/CP 441
The cable is available under the order number (6ES7 902-2...) specified in appendix
Accessories and order numbers (Page 235).
Note
This cable type (LIYCY 4 x 0.14) can be used in the following lengths for the CP 341 as
communication partner: max. 1000 m at 9600 baud, max. 500 m at 19.2 kbaud.
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
226 Manual, 04/2011, A5E02191071-03
20mA-TTY connecting cable (S7 (CP 341) - CP 544, CP 524, CPU 928B, CPU 945, CPU 948)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 544, CP 524, CPU 928B, CPU 945 or CPU 948.
For the connecting cables you will require the following male connectors:
● On the CP 341 side: 9-pin sub D male connector with screw-locking
● On the communication partner: 25-pin sub D male connector with screw-locking
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Figure B-9 20mA-TTY connecting cable CP 341 - CP 544, CP 524, CPU 928B, CPU 945,
CPU 948
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 227
20mA-TTY connecting cable (S7 (CP 341) - CP 523)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 523.
For the connecting cables you will require the following male connectors:
● On the CP 341 side: 9-pin sub D male connector with screw-locking
● On the communication partner: 25-pin sub D male connector with screw-locking
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Figure B-10 20mA-TTY connecting cable CP 341 - CP 523
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
228 Manual, 04/2011, A5E02191071-03
20mA-TTY connecting cable (S7 (CP 341) - CP 521 SI/CP 521 BASIC/ IBM-compatible printer)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 521 SI/CP 521 BASIC.
For the connecting cables you will require the following male connectors:
● On the CP 341 side: 9-pin sub D male connector with screw-locking
● On the communication partner: 25-pin sub D male connector with screw-locking
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Figure B-11 20mA-TTY connecting cable CP 341 - CP 521 SI/CP 521 BASIC
Connecting cables
B.2 20 mA TTY interface on the CP 341-20mA-TTY
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 229
20mA-TTY connecting cable (S7 (CP 341) - CPU 944/AG 95)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CPU 944/AG 95.
For the connecting cables you will require the following male connectors:
● On the CP 341 side: 9-pin sub D male connector with screw-locking
● On the communication partner: 15-pin sub D male connector with screw-locking
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See also
Mounting the CP 341 (Page 107)
Connecting cables
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
230 Manual, 04/2011, A5E02191071-03
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
Pin assignment
The table below shows the pin assignment for the 15-pin sub D females connector in the
front panel of the CP 341-RS 422/485.
Table B- 3 Pin assignment for the 15-pin sub D female connector of the integrated interface of the CP 341-RS 422/485
Female connector on
CP 341-RS 422/485*
Pin Designation Input/output Meaning
1 - - -
2 T (A) - Output Send data (four-wire mode)
3 - - -
4 R (A)/T (A) - Input
Input/output
Receive data (four-wire mode)
Receive/send data (two-wire mode)
5 - - -
6 - - -
7 - - -
8 GND - Functional ground (isolated)
9 T (B) + Output Send data (four-wire mode)
10 - - -
11 R (B)/T (B) + Input
Input/output
Receive data (four-wire mode)
Receive/send data (two-wire mode)
12 - - -
13 - - -
14 - - -
15 - - -
* View from the front
Connecting cables
If you make your own connecting cables you must remember that unconnected inputs at the
communication partner may have to be connected to open-circuit potential.
Please note that you must only use shielded connector casings. A large surface area of both
sides of the cable shield must be in contact with the connector casing. You are advised to
use Siemens V42 254 shielded connector casings.
CAUTION
Never connect the cable shield with the GND, as this could destroy the interface modules.
GND must always be connected on both sides (pin 8), otherwise the interface modules
again be destroyed.
Connecting cables
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 231
In the following
On the following pages you will find examples of connecting cables for a point-to-point
connection between the CP 341-RS 422/485 and S7 modules or SIMATIC S5.
X 27 connecting cable (S7 (CP 341) - CP 340/CP 341/CP 441)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 340/CP 341/CP 441 for RS 422 mode.
For the connecting cables you will require the following male connectors:
● At the CP 341 end: 15-pin sub D male connector with screw-locking
● On the communication partner: 15-pin sub D male connector with screw-locking
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Figure B-13 X27 connecting cable CP 341 - CP 340/CP 341/CP 441 for RS 422 mode (four-wire)
The cable is available under the order number (6ES7 902-3...) specified in appendix
Accessories and order numbers (Page 235).
Note
This cable type can be used in the following lengths for the CP 341 as communication
partner: max. 1200 m at 19200 bps, max. 500 m at 38400 bps. 250 m at 115200 bps.
Connecting cables
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
232 Manual, 04/2011, A5E02191071-03
X 27 connecting cable (S7 (CP 341) - CP 340/CP 341/CP 441)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 340/CP 341/CP 441 for RS 485 mode.
For the connecting cables you will require the following male connectors:
● At the CP 341 end: 15-pin sub D male connector with screw-locking
● On the communication partner: 15-pin sub D male connector with screw-locking
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Figure B-14 X27 connecting cable CP 341 - CP 340/CP 341/CP 441 for RS 485 mode (two-wire)
Note
The previous figure shows the wiring if you want to make the connecting cable yourself.
In both RS 485 mode (two wire) and RS 422 mode (four wire) you can also use Siemens
connecting cables. The figure below illustrates the internal wiring in the connecting cable.
The jumpers 2-4 and 9-11 are "installed" by parameter assignment of the CP.
Connecting cables
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 233
Connecting cable X 27 (S7 (CP 341) - CP 544, CP 524, CPU 928B, CPU 945, CPU 948)
The figure below illustrates the connecting cable for a point-to-point connection between a
CP 341 and a CP 544, CP 524, CPU 928B, CPU 945, CPU 948 for RS 422 mode.
For the connecting cables you will require the following male connectors:
● At the CP 341 end: 15-pin sub D male connector with screw-locking
● On the communication partner: 15-pin sub D male connector with clip fixing
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Figure B-15 X27 connecting cable CP 341 - CP 544, CP 524, CPU 928B, CPU 945, CPU 948 for
RS 422 mode (four-wire)
Connecting cables
B.3 X27 (RS 422/485) Interface of the CP 341-RS 422/485
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
234 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 235
Accessories and order numbers C
Module variants
The table below contains the different variants of the CP 341.
Table C- 1 Order numbers of the module variants of the CP 341
Product Order number
CP 341–RS 232C 6ES7 341–1AH02–0AE0
CP 341–20mA–TTY 6ES7 341–1BH02–0AE0
CP 341–RS 422/485 6ES7 341–1CH02–0AE0
Connecting cables
Connecting cables are available in the commonly preferred lengths: 5 m, 10 m and 50 m.
Table C- 2 Order numbers of the connecting cables
Connecting cables for
CP 341 - CP 340; CP 341 –
CP 341; CP 341 - CP 441
Version Order number
RS 232C, 5 m 6ES7 902–1AB00–0AA0
RS 232C, 10 m 6ES7 902–1AC00–0AA0
RS 232C interface
RS 232C, 15 m 6ES7 902–1AD00–0AA0
20mA-TTY, 5 m 6ES7 902–2AB00–0AA0
20mA-TTY, 10 m 6ES7 902–2AC00–0AA0
20mA-TTY interface
20mA-TTY, 50 m 6ES7 902–2AG00–0AA0
X27 (RS 422), 5 m 6ES7 902–3AB00–0AA0
X27 (RS 422), 10 m 6ES7 902–3AC00–0AA0
X27 (RS 422) interface
X27 (RS 422), 50 m 6ES7 902–3AG00–0AA0
Accessories and order numbers
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
236 Manual, 04/2011, A5E02191071-03
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 237
Literature on SIMATIC S7 D
D.1 Literature on SIMATIC S7
Literature on SIMATIC S7
On the following pages, you will find a comprehensive overview of:
● Manuals that you require for configuring and programming the S7–300,
● Manuals which describe the components of a PROFIBUS DP network,
● Technical overviews with which you can find out about the S7–300.
Manuals for configuring and commissioning
An extensive user documentation is available to assist you in configuring and programming
the S7–300. You can select and use this documentation as required. The following table also
provides you with an overview of the documentation to STEP 7.
Table D- 1 Manuals for configuring and programming the S7–300
Title Contents
Manual
Programming with STEP 7
(http://support.automation.siemens.com/
WW/view/en/18652056)
The programming manual offers basic information on the design of the
operating system and a user program of an S7 CPU. It is intended to give first-
time users of an S7-300/400 an overview of the programming methodology,
thereby providing a basis on which they can build their user programs.
Manual
Configuring Hardware and
Communication Connections with
STEP 7
(http://support.automation.siemens.com/
WW/view/en/18652631)
This STEP 7 manual explains the principles behind the use and functions of the
STEP 7 automation software. It will provide both first-time users of STEP 7 and
those with knowledge of STEP 5 with an overview of the procedures for
configuring, programming and starting up an S7-300/400. When working in the
software, users can access the relevant sections of the online help where they
will find specific support for its application.
Reference Manual
Instruction list (IL) for S7-300/400
(http://support.automation.siemens.com/
WW/view/en/18653496)
Reference Manual
Ladder Diagram (LAD) for S7-300/400
(http://support.automation.siemens.com/
WW/view/en/18654395)
Reference Manual
Function block diagram (FBD) for
S7-300/400
(http://support.automation.siemens.com/
WW/view/en/18652644)
The manuals for the STL, LAD, FBD, and SCL language packages feature both
instructions for users and language descriptions. You only need one of the
languages to program an S7-300/400, however, you can change the language
as required within a project. If you are using the languages for the first time, we
recommend that you refer to the manual in order to familiarize yourself with the
programming methodology.
When working with the software you can use the online help to access detailed
information about using the associated editors and compilers.
Literature on SIMATIC S7
D.1 Literature on SIMATIC S7
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
238 Manual, 04/2011, A5E02191071-03
Title Contents
Reference Manual
S7-SCL for S7-300/400
(http://support.automation.siemens.com/
WW/view/en/5581793) 1)
Manual
S7–GRAPH for S7-300/400
Programming Sequential Control
Systems
(http://support.automation.siemens.com/
WW/view/en/1137630) 1)
Manual
Programming S7–HiGraph State Graphs
(http://support.automation.siemens.com/
WW/view/en/1137299) 1)
Manuals
CFC for SIMATIC S7
(http://support.automation.siemens.com/
WW/view/en/15236182) 1)
The GRAPH, HiGraph and CFC languages support additional options for
implementing sequential controls, state controls, or graphic interconnections of
blocks. The manuals feature both instructions for users and language
descriptions. If you are using the language for the first time, we recommend that
you refer to the manual in order to familiarize yourself with the programming
methodology. When working with the software you can also use the online help
(with the exception of HiGraph) to access detailed information about using
editors and compilers.
Reference Manual
System and Standard Functions for
S7-300/400
(http://support.automation.siemens.com/
WW/view/en/1214574)
The S7 CPU operating systems feature integrated system and standard
functions, which you can use during programming in any of the supported
languages (STL, LAD and SCL). The manual provides an overview of the basic
functions supported by S7 and, for reference purposes, detailed interface
descriptions for use in your user program.
1) Option packages for S7–300/400 system software
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 239
Glossary
Address
The address indicates the physical storage space and enables direct access to the operand
that is stored under this address.
Block
Blocks are parts of the user program that are separated by their function, structure or
purpose. STEP 7 has the following blocks
• Code blocks (FB, FC, OB SFB, SFC)
• Data blocks (DB, SDB) and
• user-defined data types (UDT)
Block call
A block call is the branching of the program processing into the called block.
Block parameter
Block parameters are place holders within multiple use blocks, which are supplied with
updated valves during the calling up of the corresponding block.
Communication processor
Communication processors are modules for point-to-point connections and bus connections
Configuring
Configuring refers to the configuration of separate modules of a programmable controller in
the configuration table.
CP 341 programming interface: Point-to-Point Communication, parameter assignment
Using the CP 341 programming interface: Point-to-Point Communication, Parameter
Assignment - assign parameters to the interface of the communication processor.
Glossary
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
240 Manual, 04/2011, A5E02191071-03
CPU
Central Processing Unit = Central module of the S7 Programmable Controller with control
and computing unit, memory, system program and interfaces to the I/O modules.
Cycle time
The cycle time is the time that the CPU requires to process the user program once.
Cyclic program processing
In cyclic program processing the user program runs in program loop, or cycle, that is
constantly repeated.
Data block (DB)
Data blocks are blocks that contain data and parameters with which the user program works.
Unlike all other blocks, they do not contain any instructions. There are global data blocks and
instance data blocks. The data contained in the data blocks can be accessed absolutely or
symbolically. Complex data can be stored in structured form.
Data type
With the help of the data types you can specify how the value of a variable or constant in the
user program is to be used. The data types are divided into elementary and structured data
types
Default setting
The default setting is a reasonable basic setting that can be used whenever no other value is
specified.
Diagnostic buffer
Each CPU has its own diagnostic buffer, in which detailed information on all the diagnostic
events are entered in the sequence in which they occur.
The CP 341 has its own diagnostic buffer in which all the diagnostic events of the CP 341
are entered (hardware / firmware errors, initialization / parameterization errors, sending and
receiving errors).
Diagnostic events
Diagnostic events are such as module errors, system errors in the CPU which may be
caused by a program error or transitions from one operating mode to another.
Glossary
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 241
Diagnostic functions
The diagnostic functions cover the entire system diagnostics and include the recognition,
interpretation and reporting of errors within the Programmable Controller.
Downloading from the programming device
Downloading of load objects (e.g. code blocks) from the programming device into the load
memory of the central processing unit (CPU).
Downloading to the programming device
Uploading of load objects (e.g. code blocks) from the load memory of the central processing
unit into the programming device.
Function blocks (FBs)
Function blocks are components of the user program and are, according to IEC standard,
"blocks with memory". The memory for the function blocks is an allocated data block, the
"instance data block". Function blocks can be configured, i.e. you can use them with and
without parameters.
Hardware
Hardware is the entire physical and technical equipment of a programmable controller.
Instance data block
The instance data block is a block allocated to a function block, which contains data for this
special function block.
Interrupt
Interrupt is a term that designates the interruption of the processing of a program in the
processor of a programmable controller by an external alarm
Module
Modules are pluggable PCBs for programmable controllers.
Module parameters
Module parameters are values with which the behavior of the module can be set. There are
two different types of module parameters: static and dynamic.
Glossary
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
242 Manual, 04/2011, A5E02191071-03
Online Help
STEP 7 provides you with the option of having context-dependant help texts displayed on
the screen while you are working with the programming software.
Online/Offline
When you are online there is a data connection between the programmable controller and
programming device, when you are offline there is no data connection between them.
Operand
An operand is part of a STEP-7 instruction and states with which unit the process should
execute something. It can be addressed both absolutely and symbolically.
Operating mode
The SIMATIC S7 programmable controllers have three different
operating modes: STOP, START-UP and RUN. The functionality of the CPU is different in
the various operating modes.
Operating system of the CPU
The operating system of the CPU organizes all the functions and process of the CPU that
are not connected to a special control task.
Parameter assignment
Parameter assignment refers to the setting of a module's behavior.
Parameters
Parameters are values that can be allocated. There are two different types of parameters:
block parameters and module parameters.
Point-to-point communication
In point-to-point communication the communication processor forms the interface between a
programmable controller and a communication partner.
Procedure
Procedure refers to the process of a data transmission according to a specific protocol.
Glossary
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 243
Process image
The process image is a special memory area in the programmable controller. At the start of
the cyclic program the signal states of the input modules are transmitted to the process
image of the inputs. At the end of the cyclic program the process image of the outputs is
transmitted as signal state to the output modules.
Programmable controller
A programmable controller is a stored-program control consisting of at least one CPU,
various input and output modules, and operating and monitoring devices.
Protocol
All communication partners involved in data transmission must follow fixed rules for handling
and implementing the data traffic. Such rules are called protocols.
Rack
The rack is the module rail containing the slots for the modules.
S7–300 backplane bus
The S7 300 backplane bus for module intercommunication, and power distribution to the
modules.
Software
Software refers to the entirety of all programs that are used on a computing system. The
operating system and user programs belong to this.
Startup
The START-UP operating mode forms the transition from STOP mode to RUN mode.
STEP 7
STEP 7 is the programming software of SIMATIC S7.
System blocks
System blocks are different from other blocks in that they are already integrated into the S7–
300 system and are available for already defined system functions. There are system data
blocks, system functions and system function blocks.
Glossary
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
244 Manual, 04/2011, A5E02191071-03
System function blocks (SFBs)
System functions are blocks without memory that are already integrated into the operating
system of the CPU and can be called up by the user whenever necessary.
System functions (SFCs)
System functions are blocks without memory that are already integrated into the operating
system of the CPU and can be called up by the user whenever necessary.
User program
The user program contains all instructions and declarations for processing the signals used
for controlling a system or a process. In SIMATIC S7 the user program is structured and
divided into small units, the blocks.
Variable
A variable is an operand (e.g. I 1.0) which can have a symbolic name and therefore also be
addressed symbolically.
Working memory
The working memory is a RAM storage unit in the CPU which the processor draws on when
running the user program.
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 245
Index
2
20mA-TTY interface, 19
Properties, 19
20-mA-TTY interface, 223
3
3964 (R)
Protocol, 77
3964(R) procedure
Handling erroneous data, 43
Initialization conflict, 44
Procedure errors, 45
Receiving data, 38
Sending data, 34
3964R procedure
Block Checksum, 33
A
Acknowledgment delay time, 78
Addressing the module, 167
ASCII driver, 59
Data flow control, 87
Receive buffer, 67
Receiving data, 61
Sending data, 59
B
Baud rate, 79, 86
Bidirectional data traffic
Drivers, 23
Modes of operation, 24
Block call
P_RCV_RK, 133, 144, 148
P_SND_RK, 129, 139, 152
V24_SET, 160
V24_STAT, 158
Block Checksum, 33
Bus connector for the S7 backplane bus, 15
BUSY signal, 75
C
Calling the SFCERR variable, 193
Character delay time, 26, 78, 85
Character frame, 25, 79, 86
Code transparency, 61
Command message frame, 46
Communication via function blocks, 123
Connecting cables, 216
Connection attempts, 78
Continuation message frame, 46
Continuation SEND message frames, 51
CP 341 communications processor, 11
CPU RUN, 173
CPU START-UP, 173
CPU-STOP, 173
D
Data bits, 79, 86
Data flow control, 71, 75
ASCII driver, 87
Diagnostics
Diagnostic buffer, 195
Error numbers in the response message frame, 194
Disabling alarms, 167
Display elements (LEDs), 175
E
End criterion, 62
End-of-text character, 63
Expiration of the character delay time, 62
Fixed message frame length, 65
End-of-text character, 85
Event class, 178
Event number, 178
Index
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
246 Manual, 04/2011, A5E02191071-03
F
FB 13 P_PRINT_RK
Parameters, 165
Time sequence chart, 166
FB 7 P_RCV_RK, 124
FB 8 P_SND_RK, 124
FB P_PRINT_RK
Assignment in the data area, pointer DB, 164
instance DB, 163
Message texts, 162
FB P_RCV_RK
Time sequence chart, 146
Time sequence chart, 146
FB P_SND_RK
Assignment in the data area, 129
Time sequence chart, 131
FC 5 V24_STAT, 124
FC 6 V24_SET, 124
FETCH frame, 46
Fetching data
RK 512, 52
Full-duplex mode, 24
Function block
FB 13 P_PRINT_RK, 162
FB P_PRINT_RK, 162
Function blocks, 17, 124
FB 7 P_RCV_RK, 134, 145, 149
FB 8 P_SND_RK, 130, 140, 153
Functions, 124
Installation, 124
Functionality of the CP 341, 11
Functions
FC 5 V24_STAT, 159
FC 6 V24_SET, 161
G
Group error display SF, 177
Group error displays, 177
H
Half-duplex mode, 24
Handshaking, 71
Hardware components, 16
I
Indicator for end of receive message frame, 85
Initialization, 172
Initialization conflict, 44
Interface
20-mA-TTY, 223
Possible applications, 12
RS 232C, 18, 215
Technical specifications, 206
X27 (RS 422/485), 230
Interprocessor communication flag, 47, 136, 144, 148
ISO 7-layer reference model, 28
Processing the protocols, 28
L
LED indicators, 15
M
Memory requirements, 168
Message frame header
Structure of the RK 512 command message
frame, 47
Message frame length when received, 85
Message texts
Formatting, 96
Variables, 96
Minimum number of CPU cycles, 168
Module elements, 14
Module variants, 11
O
Operating mode transitions, 173
Operating modes, 171
Parameter reassignment, 171
RUN, 171
STOP, 171
Order numbers, 235
Index
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
Manual, 04/2011, A5E02191071-03 247
P
P_RCV_RK
Block call, 133, 144, 148
P_SND_RK
Block call, 129, 139, 152
Parameter
FB 7 P_RCV_RK, 145, 149
FB 8 P_SND_RK, 140, 153
FC 5 V24_STAT, 159
Parameter assignment, 172
Parameter assignment data, 76
Parameter assignment interface, 17
Parameters
FB 7 P_RCV_RK, 134
FB 8 P_SND_RK, 130
FC 6 V24_SET, 161
Parity, 79, 86
PG cable, 17
Printer driver
Baud rate, 91
BUSY signal, 75
Character frame, 91
Character set, 94
Control characters, 94
Data flow control, 75, 92
Examples, 73
Format string, 73
Handshaking, 75
Message texts, 72, 95
Variables, 72
X27 (RS 422/485) interface, 93
Priority, 79
Programming device (PG), 17
Protocol
Integrated in module, 11
Protocol parameters, 78, 85
Q
Quasi-full-duplex, 55
R
Receive buffer, 67, 88
Receive line initial state, 80, 89
Receiving data
3964(R) procedure, 38
ASCII driver, 61
Receiving with the 3964(R) Procedure, 40
Response message frame, 46, 48
Error numbers, 175
Structure and content, 48
RK 512
FB 7 P_RCV_RK,
FB 8 P_SND_RK,
Interprocessor communication flag,
Partner requests, 57
Transmission process, 56
RK 512 computer connection
Command message frame, 46, 47
Response message frame, 46, 48
RK 512 computer link
Fetching data, 52
Sending data, 49
RS 232C
Accompanying signals, 68
Accompanying signals automatic control, 69
Controlling accompanying signals,
RS 232C accompanying signals
Controlling, 160
RS 232C interface, 215
RS 232C interface signals, 19
S
Scope of the manual, 3
SEND frame, 46
Sending data
3964(R) procedure, 34
ASCII driver, 59
RK 512, 49
Sending with the 3964(R) procedure, 36
Setting/resetting Interface outputs of the CP 341, 160
Software components, 17
Special features
For sending message frames, 173
Standard connecting cable, 16
Start bit, 79, 86
Start-up behavior, 167, 172
STATUS outputs of the FBs, 175
Stop bits, 79, 86
System functions used, 169
Index
CP 341 Point-to-Point Communication, Installation and Parameter Assignment
248 Manual, 04/2011, A5E02191071-03
T
Technical specifications
20-mA-TTY interface, 207
3964(R) procedure, 208
ASCII driver, 210
Printer driver, 211
RK512 computer link, 209
RS232 interface, 206
X27 (RS 422/485) interface, 207
Technical specifications of the CP 341, 205
Transmission attempts, 78
Transmission integrity, 29
with ASCII driver, 30
with the RK 512, 31
Transmission Rates
3964(R) procedure, 213
ASCII driver, 212
RK 512 computer link, 213
U
Uses of the CP 341, 12
X
X27 (RS 422/485) interface, 230
Properties, 20
