Operating Instructions
Safety Switch STP-TW...AS1 (Twin)
Scope
These operating instructions are valid for all
STP-TW...AS1. These operating instructions, the
document Safety information and any available
data sheet form the complete user information for
your device.
Important!
Make sure to use the operating instructions
valid for your product version. Please contact the
EUCHNER service team if you have any questions.
Supplementary documents
The overall documentation for this device consists
of the following documents:
Document title
Contents
(document number)
Safety information
Basic safety information
(2525460)
Operating instructions
(this document)
(2102352)
Declaration of con-
Declaration of conformity
formity
Any additions to the
Take any associated additions to
operating instructions
the operating instructions or data
sheets into account.
Important!
Always read all documents to gain a complete
overview of safe installation, setup and use of
the device. The documents can be downloaded
from www.euchner.com. For this purpose, enter
the doc. no. or the order number for the device
in the search box.
Correct use
Safety switches series STP-TW...AS1 are operated
as slaves on the safety bus AS-Interface Safety
at Work and function as interlocking devices with
guard locking solenoid (type 2). The actuator has
a low coding level. In combination with a movable
guard and the machine control, this safety compo-
nent prevents the guard from being opened while
a dangerous machine function is being performed.
This means:
Starting commands that cause a dangerous ma-
f
chine function must become active only when the
guard is closed and locked.
The guard locking must not be released until the
f
dangerous machine function has ended.
Closing and locking a guard must not cause auto-
f
matic starting of a dangerous machine function.
A separate start command must be issued. For
exceptions, refer to EN ISO 12100 or relevant
C-standards.
Devices from this series are also suitable for process
protection.
Before the device is used, a risk assessment must
be performed on the machine, e.g. in accordance
with the following standards:
EN ISO 13849-1
f
EN ISO 12100
f
EN IEC 62061
f
Correct use includes observing the relevant require-
ments for installation and operation, particularly
based on the following standards:
EN ISO 13849-1
f
EN ISO 14119
f
EN IEC 60204-1
f
Important!
The user is responsible for the proper integration
f
of the device into a safe overall system. For this
purpose, the overall system must be validated,
e.g. in accordance with EN ISO 13849-1.
If the simplified method according to section
f
6.2.3 of EN ISO 13849-1:2023 is used for
determining the Performance Level (PL), the
PL might be reduced if several devices are
connected in series.
If a data sheet is included with the product, the
f
information on the data sheet applies in case of
discrepancies with the operating instructions.
Safety precautions
WARNING
Danger to life due to improper installation or due
to bypassing (tampering). Safety components
perform a personnel protection function.
www
Safety components must not be bypassed,
f
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turned away, removed or otherwise rendered
ineffective. On this topic pay attention in partic-
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ular to the measures for reducing the possibility
of bypassing according to EN ISO 14119:2013,
section 7.
The switching operation must be triggered only
f
by actuators designated for this purpose.
Prevent bypassing by means of replacement
f
actuators. For this purpose, restrict access to
actuators and to keys for releases, for example.
A complete safety-oriented system generally
f
consists of several signaling devices, sensors,
evaluation units and concepts for safe shutdown.
The manufacturer of a machine or installation is
responsible for correct and safe overall function.
All safety precautions and requirements stated
f
in the operating instructions of the AS-Interface
safety monitor used must be observed.
Mounting, electrical connection and setup only
f
by authorized personnel possessing special
knowledge about handling safety components.
CAUTION
Danger due to high housing temperature at ambi-
ent temperatures above 40 °C.
Protect switch against touching by personnel or
f
contact with flammable material.
Function
Safety switches series STP-TW...AS1 (Twin) have
two actuator heads. They permit the simultaneous
locking or release of two movable guards.
Both actuators must be inserted in order to activate
guard locking.
In the switch head, there is a rotating cam that is
blocked/released by the guard locking pin.
The guard locking pin is moved on the insertion/
removal of the actuators and on the activation/
release of the guard locking. During this process,
the switching contacts are actuated.
If the cam is blocked (guard locking active), the ac-
tuators cannot be pulled out of the switch head. For
design reasons, guard locking can be activated only
when the guard is closed (prevention of inadvertent
locking position (faulty closure protection)).
Position monitoring of the guard and monitoring
of interlocking are performed via two separate
switching elements (door monitoring contact SK
and solenoid monitoring contact ÜK).
6
When the guard is closed and guard locking effec-
tive, each STP-TW...AS1 transmits a switch-specific,
unique safety code sequence with 8 x 4 bits via the
AS-Interface bus. This code sequence is evaluated
by an AS-Interface safety monitor. The positively
driven contact SK for door monitoring is represent-
ed by the AS-Interface input bits D0 and D1. The
solenoid monitoring contact ÜK is represented by
the AS-Interface input bits D2 and D3.
The safety switch must be correspondingly config-
ured in the AS-Interface safety monitor (refer to the
operating instructions of the AS-Interface safety
monitor used and the status table).
The safety switch is designed so that fault exclusions
for internal faults in accordance with EN ISO 13849
2:2013, Table A4, can be assumed.
Version STP-TW3...AS1
(guard locking actuated by spring force and released
by power-ON)
Important!
For the purpose of personnel protection against
dangerous overtraveling movements, the black
AS-Interface cable (auxiliary power) leading to the
AS-Interface distribution box to which the switch is
connected can additionally be switched via a stand-
still monitor or via the safe switch-on delay feature
of a dual-channel AS-Interface safety monitor (e.g.
door locking for duration of the time delay).
Activating guard locking: close guard; no voltage
f
at the solenoid and/or clear AS-Interface output
bit D0
Releasing guard locking: apply voltage to the
f
solenoid and set AS-Interface output bit D0
The spring-operated guard locking functions in ac-
cordance with the closed-circuit current principle. If
the voltage is interrupted at the solenoid, the guard
locking remains active and the guard cannot be
opened directly.
If the guard is open when the power supply is
interrupted and is then closed, guard locking is
activated. This can lead to persons being locked
in unintentionally.
Version STP-TW4...AS1
(guard locking actuated by power-ON and released
by spring force)
Important!
Guard locking devices according to the open-cir-
f
cuit current principle are not intended for pro-
tecting personnel.
Use as guard locking for personnel protec-
f
tion is possible only in special cases, after
strict assessment of the accident risk (see
EN ISO 14119:2013, section 5.7.1)!
Activating guard locking: apply voltage to the
f
solenoid and set AS-Interface output bit D0
Releasing guard locking: disconnect voltage from
f
the solenoid or clear AS-Interface output bit D0
The magnetically actuated guard locking operates in
accordance with the open-circuit current principle. If
the voltage is interrupted at the solenoid, the guard
locking is released and the guard can be opened
directly.
Switching states
The detailed switching states and code sequences
for your switch can be found in the status table.