Siemens SIMATIC S7 F Manual page 18

Product Overview
The safety functions are primarily incorporated in the following components:
•
In the safety-related user program on the central processing unit
•
In the fail-safe input/output modules
Safety and Availability
To increase the availability of the automation system and consequently avoid
process downtimes as a result of failures in the F-System, fail-safe systems can be
optionally configured for high availability (fault tolerance). This increased
availability can be achieved by means of redundant components (power supply,
central processing unit and communication and I/O systems).
The fail-safe and fault-tolerant S7 F/FH Systems allow production to continue
without causing any harm to people or the environment.
Use in Process Engineering
The figure below shows integration options for the S7 F/FH Systems in process
automation systems with PCS 7.
1-2
Fail-Safe Systems
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