Safety-Related Communication With As-Interface; Operating Principle Of Code Sequences Of Safe As-I Slaves - Siemens SIMATIC ET 200SP Manual

5.2

Safety-related communication with AS-Interface

5.2.1

Operating principle of code sequences of safe AS-i slaves

For realization of safety-related communication, each safe AS-i input slave sends a code
sequence over the AS-i bus. To prevent a mix-up of the AS-i input slaves on an AS-i bus,
each AS-i input slave sends a different code sequence. The code sequences are
permanently stored in the AS-i input slave.
The F-CM AS-i Safety ST module checks every code sequence for correct data content.
Depending on the result of the evaluation, the module sets the the safe input image.
During initial commissioning, the F-CM AS-i Safety ST module must teach the code
sequences of all safe AS-i input slaves present on the AS-i bus and transfer them to non-
volatile memory. In so doing, the module detects both the slaves for which input monitoring
is activated as well as the other safe input slaves.
After replacement of a safe AS-i input slave, the new code sequence must be taught and
saved.
If the code sequence is not saved for a safe AS-i input slave, or if the code sequence does
not correspond to the saved code sequence, the input channel will be passivated and
assigned the substitute value "0".
As soon as the F-CM AS-i Safety ST module detects a new code sequence, the code
sequences are automatically taught. Confirm the transfer of the code sequences into the
memory to prevent unauthorized changes to the AS-i component.
You will find more information about teaching code sequences, and the LED behavior, in
Section "Code sequences (Page 75)".
You can find a description of the individual parameters in the Section "Process signal errors
(Page 20)".
Fail-safe Module F‑CM AS‑i Safety ST (3RK7136‑6SC00‑0BC1)
Manual, 03/2017, A5E03957059020A/RS-AB/002
5.2 Safety-related communication with AS-Interface
Configuring
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