Installation In Cyclic Interrupt Obs; Safety Program Can Be Installed In Ob 3X Only - Siemens SIMATIC S7 F Manual

Fail-Safe Blocks
8.1.5

Installation in Cyclic Interrupt OBs

Safety Note – Safety Program can be installed in OB 3x ONLY
!
Fail-safe blocks can only be installed in a cyclic interrupt OB 3x. Installation in the
OB 1 is not permissible.
The cycle time of the cyclic interrupt OB is assigned parameters in HWCONFIG
(CPU parameters "Cyclic Interrupts, Execution". See "Monitoring the F Cycle
Time").
8-8
Fail-Safe Systems
A5E00085588-03