Siemens SIMATIC ET 200AL System Manual page 950

Applications of the F-I/O module
5.1 Digital input applications
5.1.2 Applications 3 and 4: 1oo2 evaluation of equivalent sensors
F-DI application mode 3
This application mode uses a two-channel sensor or two single-channel sensors in a 1oo2
voting with discrepancy evaluation. When you use an internal sensor supply, you can
successfully perform short-circuit detection.
Note
To incorporate F-DI application mode 3 into a SIL 3-rated application, ensure the sensors are
appropriately qualified devices.
Figure 5-4 F-DI application mode 3: Internal sensor supply (1oo2 evaluation of two-channel sensor shown)
Use Y cable (6ES7194-6KB00-0XA0) for F-DI application mode 3 as follows:
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Digital I/O module F-DI 4+F-DQ 2x24VDC/2A, 4xM12 (6ES7146-5FF00-0BA0)
Equipment Manual, V1.0, 05/2021, A5E51082342-AA