Siemens SIMATIC S7-1200 Safety Programming Manualline page 7

2 Configuring Fail-Safe Controllers
The following figure shows the influence of the safety program's cycle time on the
time that is available for processing the standard user program.
Figure 2-2: Influence of the safety program's cycle time on the standard user program
Note
Please note that higher-priority organization blocks (e.g., cyclic interrupt OBs or
motion control OBs) can interrupt the safety program in the same way as shown
in Figure 2-2.
To make sure that the safety program cannot be interrupted, you can customize
the priorities in the properties of the appropriate OBs.
NOTICE
The cycle time must be longer than the execution duration of the safety program.
Safety Programming Guideline
Entry ID: 109750255, V1.0, 10/2017
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