Siemens SIMATIC S7 - Applications 1 and 2: 1 Oo1 Evaluation of a Single Sensor

Fail-Safe signal module (SM) applications
3.1 Digital input applications
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
69
3.1.2
Applications 1 and 2: 1oo1 evaluation of a single sensor
If short circuit detection is used, VS1 must be used with a.x inputs and VS2 must be used with b.x inputs.
Figure 3-1 F-DI Application mode 1: Internal sensor supply
Figure 3-2 F-DI Application mode 2: External sensor supply