Siemens SIMATIC S7 Functional Safety Manual page 146

Technical specifications
A.2 Fail-Safe CPU technical specifications
Each F-I/O shows you the following information on the "Module information" page in the
"Safety" tab:
● F_Par_CRC (w addresses) (F-parameter signature)
● Safety mode
● F-monitoring time
● F-source address
● F-destination address
You do not have write access to F-blocks.
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S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA