Siemens SIMATIC S7 Functional Safety Manual page 116

Fail-Safe signal module (SM) diagnostics
6.1 Reactions to faults
Time-out of the PROFIsafe message (F-monitoring time exceeded) passivates all module
channels.
Table 6- 1 Signal module type and passivation result
Signal module type
SM 1226 F-DI 16 x 24 VDC
SM 1226 F-DQ 4 x 24 VDC
SM 1226 F-DQ 2 x Relay
Response to faults in the fail-safe system
You should prepare maintenance procedures for your system to assure that return to
operation after a detected fault is controlled and documented.
The following steps must be performed:
1. Diagnosis and repair of the fault
2. Revalidation of the safety function
3. Recording in the service report
116
Passivation result
Tests are evaluated per channel, in order to allow chan-
•
nel-granular passivation of defective inputs.
If a channel fault occurs for a 1oo1 configuration, only
•
the affected channel is passivated. For a 1oo2, the
channel group of two inputs in the 1oo2 configuration are
passivated.
Tests are evaluated per channel, in order to allow chan-
•
nel-granular passivation of defective outputs.
Diagnostic evaluations are performed separately for
•
each of the two switches of a channel. Failure detection
for one switch leads to passivation of the channel.
Tests are evaluated per channel, in order to allow chan-
•
nel-granular passivation of defective outputs.
Diagnostic evaluations are performed separately for
•
each of the two relays of a channel. Failure detection for
one relay leads to passivation of the channel.
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA