Siemens SIMATIC ET 200S Installation And Operating Manual page 119

Wiring Diagram for Use Case 2.1 - Connecting one channel of one sensor to two inputs
One channel of a sensor is connected to two inputs of the F-module for each process signal
(1oo2 evaluation).
Note
If the voltage is supplied to the sensor by the F-DI module, you must use the internal sensor
supply Vs1. Connection to Vs2 is not possible.
The wiring is carried out on the appropriate terminal module.
Figure 7-22
ET 200S Distributed I/O System - Fail-Safe Modules
Hardware Installation and Operating Manual, 07/2005, A5E00103686-04
7.5 4/8 F-DI VDC24V PROFIsafe Digital Electronic Module
Wiring Diagram for EM 4/8 F-DI 24 VDC - One Sensor Connected to Two Inputs via One
Channel, Internal Sensor Supply
Fail-Safe Modules
7-59