Application 4: Wiring External Contactors: Separate P And M Output Channels For Each Contactor; Application 5: Separate Circuits Of A Relay Channel Controlling External Contactors - Siemens SIMATIC S7 Functional Safety Manual

3.2.5 Application 4: Wiring external contactors: Separate P and M output channels for
each contactor
3.2.6 Application 5: Separate circuits of a relay channel controlling external
contactors
Redundant external relays or contactors are controlled by independent electrical circuits that
are switched as a single process variable channel.
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S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
External fuse
Fail-Safe signal module (SM) applications
3.2 Digital output applications
77