Siemens SIMATIC ET200SP Function Manual page 26

Circuit diagram example
4.2 Operating principle
There are basically three different combinations for forwarding the contacts of the AS-i
position switch with tumbler as ASIsafe channel 1 and 2 to the controller for evaluation:
3SF13 version
3SF13 ... 1BA1
3SF13 ... 1BA3
3SF13 ... 1BA4
Version 3SF13 ... 1BA3
In the 1BA3 version, both ASIsafe channels are supplied with a normally closed actuator
contact. The signaling contact of the solenoid for the tumbler is not taken into account. This
means that the user program cannot be used to evaluate whether the door is actually locked
(diagnostics not possible). The 1BA3 version must be parameterized in the TIA Portal as 1oo2
(equivalent). The discrepancy time must be adapted to the conditions where the position
switch is installed. The default setting of the discrepancy time (500 ms) is normally suitable
for this position switch.
Version 3SF13 ... 1BA1
In contrast to the 1BA3 version, the signaling contact (normally closed contact) of the
solenoid is evaluated as the second ASIsafe channel in the 1BA1 version. This means that the
user program can be used to evaluate whether the door is actually locked (diagnostics
possible). However this means that the two ASIsafe channels run asynchronously, resulting in
the following requirement on the machine operator:
Each time unlocking the door is requested, the door also has to be opened. In the parameter
assignment of the position switch, a 1oo2 evaluation (equivalent) must be set with the
"Discrepancy time unlimited" option, whereby the F-CM AS-i Safety module expects a zero
crossing of both ASIsafe channels before reclosing becomes possible. Therefore, in the case
of a door release request without subsequent door opening, the F-CPU would prevent a hot
restart of the machine.
Version 3SF13 ... 1BA4
In the 1BA4 version, for the first ASIsafe channel both normally closed contacts of the
actuator are already linked in the switch and automatically evaluated for discrepancy.
Therefore, for this version it must be ensured that the discrepancy analysis is deactivated
(1oo1 evaluation) in the configuration of the AS-i slave in the TIA Portal. The signaling
contact (normally closed contact) of the solenoid is evaluated as the second ASIsafe channel.
This means that the user program can be used to evaluate whether the door is actually locked
(diagnostics possible). The 1BA4 version of the 3SF1 position switch thus offers the
advantage that with a door release request the door does not then have to be opened
immediately. Nevertheless, malfunctioning of the tumbler solenoid can still be diagnosed by
evaluating the signaling contact.
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ASIsafe channel 1
1st normally closed contact of actuator
1st normally closed contact of actuator
1st and 2nd normally closed contacts of actuator
Safety engineering with AS‑Interface in the SIMATIC ET 200SP, including typical circuit diagram
ASIsafe channel 2
Normally closed contact of solenoid
2nd normally closed contact of actuator
Normally closed contact of solenoid
Function Manual, 08/2020, A5E44991382002A/RS-AB/002