S
F
S
F
F
S
11-12
1.8
0
1
3
6
2N
12,5N
23-24
21-22
13-14
13-14
21-22
0
10
35
55
75
6.5Ncm
6Ncm
Common Features of Electromechanical Switches
Switching systems
Switching elements lie at the heart of all
electromechanical switching devices and
must correspond to the respective applica-
tion. Essentially there are two basic types
of switching system that differ in terms of
their mechanical design and consequently
their scope of application:
l Slow-action contacts
l Snap-action contacts
Slow-action contacts
l On actuation, the normally-closed and
normally-open contact functions corres-
pond to the movement of the impact pin
l The approach speed controls the contact
opening (closing) time
l Large distance/actuating travel between
normally-closed and normally-open con-
tact function
l The switching points are identical in
forward and reverse travel
Fig. 1 shows the contact force during the
switching cycle of a slow-action contact.
Overlap
l The switching principle of slap-action
contacts makes overlapping of the NC/
NO contact function possible. The term
overlap refers to the area, in which both
the normally-closed contact as well as
the normally-open contact are closed in
connection with a changeover switch
with delay.
Fig. 2 shows the contact force during the
switching cycle of a slow-action contact
with overlap.
Snap-action contact
l On actuation, the normally-closed con-
tact function is immediately followed by
the normally-open contact function
l In this conguration there is no overlap
of the NC/NO contacts. The switch pro-
vides a distinct OR-function.
l The changeover accuracy is not depen-
dent on the approach speed
l Consistently eective suppression
of DC arc
l Reliable contact-making also for
extremely slow approach speeds
l The snap mechanism triggers the
full opening width of the contact on
reaching the changeover point
l Due to the force reversal in the mecha-
nical system, a dierent switching point
occurs in forward and reverse travel.
The lag is referred to as hysteresis.
Fig. 3 shows the contact force during the
switching cycle of a snap-action contact.
1) Changeover point in forward travel
2) Changeover point in reverse travel
Switching diagram
The switching diagram describes the
function of the switching device in detail.
It combines the mechanical input variables
that act on the contact system via the actu-
ator with the electrical output variables. The
user can deduct the following information
from the switching diagram:
l Mechanical input variables
(force, travel, torque, angle)
l Electrical contact-making in forward
and reverse travel
l Terminal designation
l Point at which positive opening
is achieved
l Type of contact system
Slow-action contact Snap-action contact
■ Contact closed
■ Contact open
Lag between NC and NO
contact function
Lag between NC and NO
contact function
Lag
(hysteresis)
2) 1)
12
Contact designation
In accordance with DIN 50013 and DIN 50005
the terminal designations of the contact ele-
ments are always make up of two digits.
The contact rows are numbered consecuti-
vely with the allocating digit (1st digit) in
actuation direction. Contacts of a switching
element that belong together have the
same allocating digit.
The second digit is the function digit that
denotes the type of contact element.
1–2 Normally-closed contact
3–4 Normally-open contact
5–6 Normally-closed contact with
delayed opening
7–8 Normally-open contact with
delayed closing
Protection class
The protection class of an enclosed device
denotes the degree of protection. The de-
gree of protection includes the protection
of persons against contact with parts under
voltage and the protection of equipment
against the infiltration of foreign bodies
and water. BERNSTEIN standard enclosures
mainly correspond to protection classes
IP65 and IP67. Higher protection ratings are
also available for individual customer solu-
tions. In accordance with DIN EN 60521
(IEC 529), the numerals used in the protec-
tion rating denote the following:
1st digit Degree of protection against con-
tact and infiltration of foreign bodies
2nd digit Degree of protection against
infiltration of water
Example IP65:
6 =
l
Complete protection against contact
with components under voltage or
with internal moving parts
l
Protection against dust infiltration
5 =
l
A water jet directed from all directions
at the device must not have damaging
effects
l
Protection against hose water
Enclosures
Limit switches are supplied either in a moul-
ded enclosure or a metal enclosure. Which
material is to be selected for a specific appli-
cation depends on the ambient conditions,
the location as well as several other factors.
Moulded limit switches provide protective
insulation and are resistant to many aggres-
sive chemicals and liquids. The formation of
condensation water in moist environments
with extreme temperature fluctuations is
significantly reduced on moulded enclosures.
In insulation-enclosed switches the switch-
ing elements are integrated directly in the
moulded enclosure and are therefore not
replaceable (complete switching devices).
Metal-enclosed limit switches are able to
withstand high mechanical loads, they
can also be used wherever hot metal chips
and sparks occur and are resistant to many
solvents and detergents. The switching
elements in metal-enclosed switches are
often integrated in the metal enclosure as
modular built-in switches. The enclosure
has a VDE-compliant connection for the
PE conductor.
Safety switches
The scope of application for limit switches
has changed over time. Whereas limit swit-
ches were previously used for the purpose
of detecting end positions, today they are
increasingly assuming functions designed
to protect persons and products in machine,
equipment and plant construction.
The BERNSTEIN range of safety switches
offers the right solution for the most diverse
applications in many branches of industry.
Particularly when it comes to safety, users
appreciate the fact that they are able to
procure all required safety switches and
receive professional advice from one source.
The decisive factors governing the selection
of safety equipment include the ambient
conditions, installation situation and risk
analysis.
A switching device that can be used for
safety functions is identified by the standard-
ised symbol conforming to EN 65000-41
and EN 65000-42. The switches can, of course,
also be used for pure position monitoring
purposes.
Safety switches are divided into two cate-
gories, Type 1 and Type 2. The difference is
in the actuating elements which are com-
pletely integrated in the enclosure in Type 1
and separated from the switching element
in Type 2.
Type 1 Type 2
13
Common Features of Electromechanical Switches
1) The letter Z suffix to the designation
of the switching function denotes the
mechanical positive opening action of
the normally-closed contacts. In technical
data sheets, the positive opening point is
identified by the international symbol p.
A2Z1)
Switching system2)
l U1
l SU1
l A2
l SA2
l E2
l SE2
AH
Actuator
See Pages 72-73
I88
Switch group
l C2
l Ti2
l IF
l I88
l Bi2
l ENK
l GC
l SN2
l ENM2
l D
M12
Special features
l M12 connection
l Actuator turned
90°, 180°, 270°
l Special switching
forces
l Special temperature
ranges
l Other special
features on request
2) Please refer to the following pages in the
catalogue to establish which switching
system can be used in the switch groups.
Designation
The designation of BERNSTEIN
switching devices comprises:
l The enclosure designation of the
switching device
l The switching function
l The type of actuator
Type code of position and
safety switches
14
11 12
23 24
23 24
15 16
13 14
21 22
11 1
2
21 2
2
23 24
13 14
11 12
21 22
23 24
13 14
11 12
33 34
21 22
11 12
33 34
23 24
Function Tolerance
Switching travel ± 0.25 mm
Switching angle ± 3.5°
Switching force in N ± 10%
Actuating torque in ± 10%
Table 1
Switching function example
NC = Normally-closed contact
NO = Normally-open contact
U1Z
Slow-action contact, 1 NC, 1 NO
SA2Z
Snap-action contact, 2 NC
UV1Z
Slow-action contact,
with overlapping contacts,
1 NC, 1 NO
U16Z
Slow-action contact, 1 NC, 2 NO
SU1Z
Snap-action contact, 1 NC, 1 NO
E2
Slow-action contact, 2 NO
U15Z
Slow-action contact, 2 NC, 1 NO
UV16Z
Slow-action contact,
with overlapping contacts,
1 NC, 2 NO
A2Z
Slow-action contact, 2 NC
SE2
Slow-action contact, 2 NO
UV15Z
Slow-action contact,
with overlapping contacts,
2 NC, 1 NO
The actuating forces and travel distances are subject to tolerances. These tolerances are listed in Table 1.
In Type 1 and Type 2 position switches, the tolerances are independent of the switching system and switching function.
15
Common Features of Electromechanical Switches
p = Mechanical positive opening action
The term positive opening action refers to
contact separation as the direct result of
defined movement of the switch actuator
by means of non-sprung parts. All parts
involved in contact separation must be
form-fit connected. The positive opening
distance describes the minimum travel
distance from the start of actuation of the
operating element up to the point where
positive opening action of the opening
contacts is completed.
DIN EN 60947-5-1 defines two types of po-
sitive opening action contacts with 4 con-
nections and double break.
Type Za
l Positively opening contacts
not galvanically isolated
Type Zb
l Positively opening contacts
galvanically isolated
Galvanic isolation describes the isolation
of electrically conducted parts by insulating
material or by air gaps.
In switching devices with several contact
elements, galvanically isolated contact
elements make it possible to switch volta-
ges with different potential (e.g. normally-
closed contact in safety circuit, normally-
open contact for indicator).
In accordance with applicable health and
safety requirements, protective devices
(guards) must be mounted on machines,
devices and systems that perform hazar-
dous movements. Safety switches in the
form of electromechanical switching devices
are predominantly used for this purpose as
they offer the following advantages:
l High degree of safety
l Non-susceptibility to interference
l Safety status easily checked on site
l Rational solutions
Form-fit, mechanical drives or coupling
elements in the form of levers, rods,
gearwheels etc. are necessary to ensure
optimum operation of these safety
components.
Switching devices that are used for safety
functions must be identified with the
symbol p internationally standardised in
accordance with DIN EN 60947-5-1.
In defining the class of switching devices,
this symbol denotes two important proper-
ties that must be met for personal protection
applications:
l Mechanical positive opening action
l Disruptive breakdown voltage > 2.5 kV
Disruptive breakdown voltage
In accordance with DIN EN 60947-5-1, the
open contacts must be able to maintain a
minimum surge voltage of 2.5 kV without
disruptive breakdown.
16
Technical data
Electrical data
Rated insulation voltage Ui max. 250 V AC
Conventional thermal current
(up to) 1
Ithe 10 A
Rated operating voltage Ue max. 240 V
Utilization category
(up to) 1
AC-15, Ue/Ie 240 V/3 A
Short-circuit protection
(up to) 1
Fuse 10 A gL/gG
Protection class II, Insulated
Mechanical data
Enclosure material
Thermoplastic, glass bre-reinforced (UL 94-V0)
Ambient temperature -30 °C to +80 °C
Mechanical service life
(up to) 1
10 x 106 switching cycles
B10d
(up to) 1
20 Mio.
Switching frequency ≤ 100/min.
Type of connection Screw connections
Conductor cross sections Single-wire 0.5 - 1.5 mm2 or
Stranded wire with ferrule 0.5 – 1.5 mm2
Cable entry 1 x M20 x 1,5
Standards
VDE 0660 T100, DIN EN 60947-1, IEC 60947-1
VDE 0660 T200, DIN EN 60947-5-1, IEC 60947-5-1
Insulation-Enclosed Limit Switches
I88
Product advantages
lStandard switch conforming to DIN EN 50047
lStandard actuator conforming to DIN EN 50047, Type A, B, C, E
lProtection class IP65 to VDE 0470 T1
lEnclosure and cover PA 6, self-extinguishing (UL-94-V0)
lActuator can be repositioned by 4 x 90°
lCable entry M20 x 1.5
lConnection designation conforming to DIN EN 50013
Options
lAvailable with M12 connector
lAS interface variants available
lCable entry M16 x 1.5
Design layout
lSlow-action and snap-action contacts
lVersions: 1 NC/1NO, 2 NC, 2 NO, overlapping contacts
lAll NC contacts with p in the circuit diagram are positively
opening contacts
lType: Zb (galvanically isolated changeover contact)
lLatching function on request
Mounting
lTwo M4 screws (distance between centres 22 mm),
adjustment with slots
lTwo M5 screws for safety applications without
additional xing element (Fig. 1)
lAdditionally secured by guide plate for lateral
approach forces (Fig. 2)
lFront mounting (depending on type, Fig. 3)
Installation advantages
lSnap-on cover can be released with screwdriver
lCover opening range 135° (cover can also be
detached from hinge)
lCover protects switching element during installation
lScrew connections with self-lifting clamping plates
lEasy-action cover lock (close and press)
lCover additionally secured with screw Fig. 2
Fig. 1
Fig. 3
Recommended use
Thanks to its standard dimensions as well as its wide range of contacts and actuators, this switch
can be used on safety facilities and for position monitoring in virtually any industrial application.
1 Depending on switching system. See Table on Pages 76-79.
32
Switching operation
2 NC contacts
2 NO contacts
1 NC / 1 NO contact
Approvals
1 NC / 1 NO contact
Overlapping
6086167018
I88-SU1Z
RIWK
Snap-action
Replacement actuator: 3918161672
Special features/variants
(on request)
lAvailable with black enclosure
lWith latching function
lWith steel roller and following
contacts:
2 NC /1 NO contact
1 NC /2 NO contact
lBoth with overlap
U
6086817071
I88-E2 RIWK
6086817087
I88-A2Z RIWK
6086117017
I88-U1Z RIWK
Slow-action
(1.04")
26.5
(3.37")
85.5
(0.13")
3
(0.39")
Ø10
(0.39")
10
RIWK (Form C)
6086153012
I88-SU1Z W
Snap-action
Replacement actuator: -
Special features/variants
(on request)
lAvailable with black enclosure
lWith latching function and following
contacts:
2 NC /1 NO contact
1 NC /2 NO contact
lBoth with and without overlap
U
6086303011
I88-UV1Z W
6086803014
I88-E2 W
6086803013
I88-A2Z W
6086103008
I88-U1Z W
Slow-action
(2.91")
74
(0.39")
10
(0.78")
20
(0.31")
Ø8
W (Form B)
33
Switching operation
2 NC contacts
2 NO contacts
1 NC / 1 NO contact
Approvals
1 NC / 1 NO contact
Overlapping
(1.22")
31
(3.62")
92
(0.13")
3
(0.55")
Ø14
(0.39")
10
KNW RO22RIWL
U
U
Replacement actuator: -
Special features/variants
(on request)
Replacement actuator: 3918161673
Special features/variants
(on request)
lAvailable with black enclosure
lWith latching function
lAvailable with dierent actuating
directions
lWith steel roller
6086117050
I88-U1Z RIWL
6086167051
I88-SU1Z RIWL
6186127112
I88-U1Z KNW
RO22
6086177053
I88-SU1Z KNW
RO22
6086817072
I88-A2Z RIWL
6186827246
I88-A2Z KNW
RO22
6086817069
I88-E2 RIWL
Slow-action Snap-action Slow-action Snap-action
21 – 22
13 – 14
13 – 14
21 – 22
4 N
7 N0 mm
5,5
7,8
2,5
I88
34
(3.54")
90
(0.22")
5.5
(1.20")
30.5
(0.43")
Ø11
(0.39")
10
HW RO11 (Form E)
U
Replacement actuator: 3918191547
Special features/variants
(on request)
lAvailable with black enclosure
lWith steel roller
lVarious roller diameters
6086121021
I88-U1Z HW
RO11
6086171022
I88-SU1Z HW
RO11
6086821099
I88-A2Z HW
RO11
6086821068
I88-E2 HW
RO11
6086321100
I88-UV1Z HW
RO11
Slow-action Snap-action
(4.17"-5.61")
106-142.5
(0.98")
Ø25
(0.77"-2.16")
19.5-55
(0.83")
21
(1.86")
47
(0.31")
8
(0.71")
Ø18
(0.94")
24
(0.83")
21
(1.92")
49
(0.31")
8
(4.25")
108
AVAH (Form A)
Slow-action Snap-action
6086135033
I88-U1Z AH
U
U
Replacement actuator: 3918351166
Special features/variants
(on request)
lAvailable with black enclosure
lAvailable with different actuating
directions
lWith steel roller
lVarious roller diameters
lCranked or straight lever
lVarious lever lengths
Replacement actuator: 3918360984
Special features/variants
(on request)
lAvailable with black enclosure
lVarious actuating directions
lVarious roller diameters
lCranked or straight lever
lVarious lever lengths
lWith roller over switch
6086185034
I88-SU1Z AH
6086136037
I88-U1 AV
6086186038
I88-SU1 AV
6086835059
I88-A2Z AH
8Ncm
11 – 12
21 – 22
0°
35°
80°
20°
45°
6086836131
I88-A2 AV
45°
6086835116
I88-E2 AH
6186335628
I88-UV1Z AH
Slow-action Snap-action
35
Switching operation
2 NC contacts
2 NO contacts
1 NC / 1 NO contact
Approvals
1 NC / 1 NO contact
Overlapping
(0.71"-0.94")
18-24
(0.83")
21
(0.87")
Ø22
(1.59")
40.5
(4.15")
105.5
(0.20")
5
(0.39")
10
(0.24"-0.47")
6-12
(0.35")
9
(0.87")
Ø22
(1.59")
40.5
(4.15")
105.5
(0.20")
5
(0.39")
10
DGKW RO22DGHW RO22
U
U
Replacement actuator: 3918271528
Special features/variants
(on request)
lWith latching function
lVarious roller diameters and with
following contacts:
2 NC /1 NO contact
1 NC /2 NO contact
Both with overlap
Replacement actuator: 3918211529
Special features/variants
(on request)
lAvailable with black enclosure
lAvailable with dierent actuating
directions
lVarious roller diameters
6086121029
I88-U1Z DGHW
RO22
6086171030
I88-SU1Z
DGHW RO22
6086127025
I88-U1Z DGKW
RO22
6086177026
I88-SU1Z
DGKW RO22
6086821120
I88-A2Z DGHW
RO22
6186321244
I88-UV1Z
DGHW RO22
Darg
for
Slow-action Snap-action Slow-action Snap-action
I88
36
FF
Replacement actuator: 3918401031
Special features/variants
(on request)
lAvailable with black enclosure
lVarious spring lengths
lDierent spring versions or spring rod
6186140217
I88-U1 FF
6086190078
I88-SU1 FF
Slow-action Snap-action
Withdraw
actuatorn
Inser t
actuator
W RASTKS
Slow-action Snap-action
6116819140
I88-U1Z KS
U
U
Replacement actuator: -
Special features/variants
(on request)
Replacement actuator: -
Special features/variants
(on request)
Withdraw
actuator
Insert
actuator
6186103005
I88-U1Z W
RAST Latch
6186803155
I88-A2Z W
RAST
Latch
Slow-action
37