www.sensirion.com Version 1.1 – May 2010 1/7
Datasheet Evaluation Kit EK-H4
For SHT7x and SHT2x Humidity and Temperature Sensors
Ready to use Hard and Software
Suitable for data-logging experiments
Programmable Interface
Dew Point and Energy Calculation
Multiple Multiplexer Boxes with Sensors lockable
Set Up
Figure 1 Schematic of Evaluation Kit EK-H4. Multiplexer box
works without connection to computer but using a power plug.
Optionally, the multiplexer box may be connected to computer
with data-logger software for recording and displaying data
readings.
Material Contents
EK-H4 contains the following components, enclosed in a
handy suitcase:
1 EK-H4 multiplexer box: Providing 4 channels for
sensor cables, one port for power supply cable and
one port for optional USB interface with a computer.
Measured values may be read from a display on the
multiplexer.
4 SHT71 sensors: Pin type sensor with version 4B
sensor chip. Please refer to datasheet SHT7x for
more details.
4 SHT21 sensors: SMD type, DFN 3-0 packaged
sensors with version 4C sensor chip mounted to small
PCB with connector. Please refer to datasheet SHT21
for more details.
4 Sensor cables with RJ45 plug for connecting
sensors with multiplexer box of 3m length.
1 USB cable for connection to computer.
1 Power supply unit with US, EU, AU adapter.
1 Memory Stick with multi viewer software for run-
ning EK-H4 as a data-logger.
Device Certification
The Evaluation Kit EK-H4 is RoHS and WEEE compliant.
Product Summary
The evaluation kit EK-H4 is made for running
Sensirion’s humidity and temperature sensors and
display measured values. It is able to communicate
with SHT1x, SHT7x as well as the new generation
SHT2x and display the measurement values on a
display on the multiplexer. The main purpose of the
evaluation kit is demonstrating the unique
performance of Sensirion’s humidity and temperature
sensors without any own hard or software design
work.
In connection with a computer and specific software
supplied with the evaluation kit it may also be used
as a data-
logger for simple experimental
measurements. The multiplexe
r with 4 ports is
connected to the computer via USB interface. The
software may record and display humidity and
temperature values as well as calculated values of
dew point and power consumption. Various
multiplexer boxes with sensors
may be run by same
software across various USB interfaces.
Datasheet EK-H4
www.sensirion.com Version 1.1 – May 2010 2/7
Specification
Electrical specification:
Parameter min typ max
Unit
Input Voltage 8 9 10 V
Input Voltage Ripple
0.5 V
External Supply
Supply Current 170 280 mA
Input Voltage 4.75
5 5.25
V
USB Supply Supply Current 170 280 mA
Range 2.1 3.0 3.6 V
Resolution 0.1 V
Accuracy 2 5 %
Sensor Supply
Voltage Output current 40 110 1
mA
Temperature Resolution 11 14 Bit
Humidity Resolution 8 12 Bit
Measurement interval 1 1440
s
Communication USB (via Virtual Com Port (VCP))
Operating
Temperature 0 – 50°C (multiplexer box)
-20 – 70°C (cables, sensor)
Default Configuration
Initial configuration set for the default mode (values can be
changed by using the measurement software)
Parameter Default value
Sensor Supply Voltage 3.0 V
Temperature Resolution 12 Bit
Humidity Resolution 12 Bit
Measurement interval 1 s
Heater off
SHT7x on
OTP reload SHT2x off
Power Supply
Used Connection EK-H4 supplied from
DC DC (9V)
DC and USB DC (9V)
USB USB (5V)
The EK-H4 may be supplied by DC Power Supply Unit at
9V or USB connection at 5V. Power supply by USB is only
possible if USB driver is installed correctly.
Pin Name Comment
- GND Ground
+ Positive
Voltage 9V Supply
Table 1 DC Power Supply: Pin Diagram
1 short circuit current
EK-H4 Circuit Board
EK-H4 Pin Assignment
RJ45 Pin Sensor Pin Name Description
1 3 VSS Ground
3 1 SCL Serial clock
5 2 VDD Supply voltage
7 4 SDA Serial data
Table 2 Pin Assignments: Female RJ45 pin diagram on the
left – SHT21 and SHT71 sensors on the right of the upper panel.
LED Functions
LED Function
Power LED LED off denotes low supply
voltage (DC < 8V, USB < 4.75V)
or not connected.
Green LED Sensor detected RJ45
Connector Orange LED Measurement is in progress
4 sensor channels
Display
2 buttons for
display modes
User field
connected to MCU
Micro Controller Unit
Debug interface
Reset button
USB interface
Power supply
Power LED
8 1
1 2 3 4
1
2
3
4
+
www.sensirion.com Version 1.1 – May 2010 3/7
EK-H4 Users Guide
1 Evaluation Kit Features
The Evaluation Kit EK-H4 may be used as a stand-alone
device, displaying measured values on the screen on the
multiplexer box or – connected to a computer – as a data-
logger run by multi-viewer software.
The stand-alone device displays temperature and humidity
values of each connected sensor plus dew-point derived
from the two measured values.
Besides the above mentioned values the data-logger
software displays calculated absolute humidity and power
consumption. Furthermore, supply voltage, sensor
resolution and measurement frequency can be chosen in
a certain range and the on-chip heater may be plugged on
and off. Eventually measured data can be exported for
data processing.
2 EK-H4 Suitcase
Figure 2 Contents of EK-H4 suitcase: Respective adapter
plug needs to be mounted to power side of power supply cable.
Make sure protective plastic cap on power supply cable is
removed before doing this. MS = Memory Stick with EK-H4
software and datasheets. SHT = humidity and temperature
sensors, SHT71 and SHT21. Sensors are connected to sensor
cables and those to the multiplexer box. USB cable is needed to
connect the multiplexer box to a computer for data-logging
function. One cavity remains empty.
3 Stand-Alone Evaluation Kit
3.1 Getting Started
Set up and application of the stand-alone device is straight
forward:
1. Select multiplexer box, power supply cable, sensors
with sensor cables as many as needed.
2. Connect sensors via sensor cables to the multiplexer
box.
3. Connect multiplexer box via power supply cable to
power (voltage supply also may occur via USB cable
from a computer). Please note: The specific plug
needs to be connected to the power supply cable –
the plastic protection cap on cable side must be
removed before connecting the plug.
4. As soon as the green LED light is shining, the
measurement starts automatically.
Figure 3 Stand-Alone Evaluation Kit. Voltage supply to be set
in the range of AC 80 … 250V.
3.2 Display Information
After powering the EK-H4 as standalone measurement
tool the screen shows following information:
The first screen shows an overview over the connected
sensors. In the first row the sensor number, which can be
matched with the printed number on the cover, is visible.
In the second column the temperature is displayed in °C.
The third column shows the relative humidity. Not
connected sensor ports are displayed with “--.-- ” .
Multiplexer box
Adapter plugs
for power
supply cable
Power supply
cable
Empty
4 Sensor cables
USB cable
MS
SHT
MS
1 25.45°C 45.32%RH
2 --.--°C --.--%RH
3 24.98°C 46.27%RH
4
25.71°C
45.46%RH
Sensirion
Evaluation Kit
for SHTxx
EKH4 V1.0
Datasheet EK-H4
www.sensirion.com Version 1.1 – May 2010 4/7
By pressing the buttons the displayed information can be
switched from all sensors to the respective single sensors:
Right button: Sensor 1 → 2 → 3 → 4 → all → 1
Left button: Sensor 4 → 3 → 2 → 1 → all → 4
The displayed information by choosing only one sensor is
as following:
If no sensor is connected to the chosen port sensor
designation is replaced with “no sens”.
To execute a self test for testing the sensor ports and
voltage supply both buttons must be pressed for longer
than one second. For a successful self test each port
requires a sensor to be connected. If no sensor is
connected the corresponding port will show an error.
By pressing one of the buttons the display information will
switch back to the measurement.
4 Data-Logger with Software
Using the EK-H4 system as a data-logger requires the
installation of the read-out software on a computer and
connecting multiplexer box and computer via USB cable.
Prior to this a driver installation may be necessary.
4.1 EK-H4 Driver Installation
Connect the EK-H4 multiplexer box to the computer via
USB cable. EK-H4 uses a Silicon Laboratories CP210x
USB to UART bridge controller. If a driver for this controller
is not installed yet, a dialog pops up which helps you to
search for a driver on the internet. Alternatively, the driver
software may be installed from the EK-H4 memory stick.
4.2 Read-Out Software Installation
EK-H4 read-out software requires the .NET framework 2.0
or later. If it is not already installed on the computer, it may
be downloaded from
http://www.microsoft.com/downloads/.
To install the EK-H4 software, simply copy the EK-H4
folder from the memory stick to the hard drive of the
computer.
Figure 4 EK-H4 configuration with connection to read-out
software on computer. No additional power supply is needed.
4.3 Starting a Measurement
Connect the EK-H4 multiplexer box with a USB cable to
the computer and then start the software by double-
clicking on EKH4Viewer.exe. The connect dialog displays
the COM ports to which EK-H4 multiplexer boxes are
connected – see Figure 5.
After clicking OK, a connection to the multiplexer box is
established and the sensors are listed in the Sensor
Select and Measurement Data sections – see Figure 6.
Figure 5 Connect dialog of read-out software. Window in the
center displays COM ports with multiplexer boxes connected.
4.4 Multiple EK-H4 Devices
EK-H4 read-out software is able to read sensors from
various EK-H4 multiplexers. The different systems are
selected via connect dialog at start-up or using the menu
item File/Connect. To disconnect EK-H4 systems use the
menu item File/Disconnect.
Sens 1: OK 3: OK
Sens 2: OK 4: OK
Sensor Supply : OK
EKH4 Supply
: OK
Sensor 1: SHT7x
Temperature: 25.45°C
Humidity RH: 45.32%
Dew Point:
16.76°C
Datasheet EK-H4
www.sensirion.com Version 1.1 – May 2010 5/7
Figure 6 EK-H4 software window before measurement starts.
Sensors are displayed in different colors.
4.5 Temperature and Humidity Measurement
Measurements are started and stopped by the Start/Stop
button. The measured data are displayed in the
Measurement Data table. The measurements which are
displayed in this table can be selected in the context menu
which appears when the right mouse button is clicked on
the table.
Two plots are available, which display the progress of a
measurement over time. The measurement can be
selected in the list below the plot. The scale of the axes
can be altered by pressing the left mouse button on the
axis and moving the mouse. The plot can be dragged
using the left mouse button. The right mouse button can
be used to display a context menu, which offers functions
to print or copy the plot, or to set auto-scale options for the
axes.
Figure 7 Software surface during measurement. Displayed
values may be selected via menus at the bottom of the window.
4.6 Calculated Values
Relative humidity and temperature data are measured by
the sensors. From this data dew point and absolute
humidity values are derived.
Power consumption values are calculated based on
sensor type and setting parameters. All these entities may
be displayed in the graphs – to be selected by the menus
at the bottom of the window. Please note: These data are
not measured but simulated.
4.7 Settings
The Data Handling section contains controls for settings
which affect all connected sensors. If SHT7x and SHT2x
sensors are connected simultaneously only features from
SHT7x sensors apply. By using only SHT2x sensors the
full range of settings can be used. After disconnection
default configuration is put in place.
SHT2x SHT7x
Sensor Voltage 2.1…3.6 V 2.1…3.6 V
Temp. resolution 11, 12, 13, 14 Bit 12, 14 Bit
Humidity resolution 8, 10, 11, 12 Bit 8, 12 Bit
Heater On, Off On, Off
Measurement interval 1 … 1440 s 1 … 1440 s
Table 3 Parameter ranges for the different sensor types.
4.8 Data Logging and Data Export
The data displayed in the measurement plots is kept in
memory. The measured values can be exported to a CSV
file using the menu item File/Export Data. The
measurement data can be cleared with the Clear Data
button. Because the data memory is limited, long-running
measurements should be logged directly to disk. Logging
can be started and stopped using the menu item File/Log
to File.
4.9 Sensor and EK-H4 Properties
Information about the sensors and evaluation kits can be
displayed with the Properties command in the context
menu of the cells in the Sensor Select table.
Datasheet EK-H4
www.sensirion.com Version 1.1 – May 2010 6/7
4.10 License Information
The EK-H4 viewer software uses the NPlot charting
library, to which the following license applies:
*************************************************************************
NPlot - A charting library for .NET
Copyright (C) 2003-2006 Matt Howlett and others.
All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, are permitted provided that the following
conditions are met:
1. Redistributions of source code must retain the above
copyright notice, this list of conditions and the following
disclaimer.
2. Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials
provided with the distribution.
3. Neither the name of NPlot nor the names of its contributors
may be used to endorse or promote products derived from this
software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT
HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
Datasheet EK-H4
www.sensirion.com Version 1.1 – May 2010 7/7
Revision History
Date Version Page(s) Changes
August 2009 1.0 1 – 7 Initial release
May 2010 1.1 2 Operating temperature ranges are defined – replacement for storage conditions
Important Notices
Warning, Personal Injury
Do not use this product as safety or emergency stop devices or in
any other application where failure of the product could result in
personal injury. Do not use this product for applications other
than its intended and authorized use. Before installing, handling,
using or servicing this product, please consult the data sheet and
application notes. Failure to comply with these instructions could
result in death or serious injury.
If the Buyer shall purchase or use SENSIRION products for any
unintended or unauthorized application, Buyer shall defend, indemnify
and hold harmless SENSIRION and its officers, employees,
subsidiaries, affiliates and distributors against all claims, costs,
damages and expenses, and reasonable attorney fees arising out of,
directly or indirectly, any claim of personal injury or death associated
with such unintended or unauthorized use, even if SENSIRION shall be
allegedly negligent with respect to the design or the manufacture of the
product.
ESD Precautions
The inherent design of this component causes it to be sensitive to
electrostatic discharge (ESD). To prevent ESD-induced damage and/or
degradation, take customary and statutory ESD precautions when
handling this product.
See application note “ESD, Latchup and EMC” for more information.
Warranty
SENSIRION warrants solely to the original purchaser of this product for
a period of 12 months (one year) from the date of delivery that this
product shall be of the quality, material and workmanship defined in
SENSIRION’s published specifications of the product. Within such
period, if proven to be defective, SENSIRION shall repair and/or
replace this product, in SENSIRION’s discretion, free of charge to the
Buyer, provided that:
notice in writing describing the defects shall be given to
SENSIRION within fourteen (14) days after their appearance;
such defects shall be found, to SENSIRION’s reasonable
satisfaction, to have arisen from SENSIRION’s faulty design,
material, or workmanship;
the defective product shall be returned to SENSIRION’s factory at
the Buyer’s expense; and
the warranty period for any repaired or replaced product shall be
limited to the unexpired portion of the original period.
This warranty does not apply to any equipment which has not been
installed and used within the specifications recommended by
SENSIRION for the intended and proper use of the equipment.
EXCEPT FOR THE WARRANTIES EXPRESSLY SET FORTH
HEREIN, SENSIRION MAKES NO WARRANTIES, EITHER EXPRESS
OR IMPLIED, WITH RESPECT TO THE PRODUCT. ANY AND ALL
WARRANTIES, INCLUDING WITHOUT LIMITATION, WARRANTIES
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE, ARE EXPRESSLY EXCLUDED AND DECLINED.
SENSIRION is only liable for defects of this product arising under the
conditions of operation provided for in the data sheet and proper use of
the goods. SENSIRION explicitly disclaims all warranties, express or
implied, for any period during which the goods are operated or stored
not in accordance with the technical specifications.
SENSIRION does not assume any liability arising out of any application
or use of any product or circuit and specifically disclaims any and all
liability, including without limitation consequential or incidental
damages. All operating parameters, including without limitation
recommended parameters, must be validated for each customer’s
applications by customer’s technical experts. Recommended
parameters can and do vary in different applications.
SENSIRION reserves the right, without further notice, (i) to change the
product specifications and/or the information in this document and (ii) to
improve reliability, functions and design of this product.
Copyright© 2009, SENSIRION.
CMOSens® is a trademark of Sensirion
All rights reserved
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