Siemens SIMATIC S7 F Manual page 234

Fail-Safe Blocks
Timing Diagram
I/Os
Name
Input: IN
Outputs: OUT
Q
Error Handling
In the event of an error that is critical to safety, the system function SFC F_CTRL
is called. This records the event in the Diagnostic Buffer and requests a switch to
the reserve CPU if the error occurred only on the master CPU. For non-redundant
systems or a common-cause error occurring in both CPUs, the shutdown logic can
be configured to either disable the erred F-run-time group or the entire Safety
Program.
Error Information in Diagnostic Buffer
Error Code (W#16#...)
75DAH
Operation and Monitoring
Parameters IN and Q have the system attribute S7_m_c. They can therefore be
directly operated and monitored from an operator interface system (OS).
8-46
Min. 1s
Max. 1min
9
6
IN
Max. 1min
Q
OUT
: Possible time for a signal change
Data Type
INT
F_BOOL
BOOL
Description
Error in the safety data format (error due to online modification
of the Safety Program or internal CPU fault)
One cycle
t
Explanation
Input variable from the ES
Output for acknowledgment
Status of the time evaluation
Default
0
0
0
Fail-Safe Systems
A5E00085588-03