Siemens SIMATIC S7 - 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

Fail-Safe signal module (SM) applications
3.2 Digital output applications
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
77
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.
①
External fuse