Siemens SIMATIC Operating Instructions Manual page 127

Wiring Diagram for Use Case 3.2 – Connecting One Nonequivalent Sensor Via Two Channels
Nonequivalently
You can connect two process signals to an F-Switch PROFIsafe. One sensor is connected
nonequivalently via two channels to two inputs of the F-module for each process signal
(1oo2 evaluation).
The left channels of the F-module (DI 0 through DI 1) return the wanted signals. If no faults
are detected, these signals will be available in the I/O area for inputs on the F-CPU.
Note
You must use the internal sensor supply Vs1 to supply voltage to the sensor. Connection to
Vs2 is not possible.
The wiring is carried out at the appropriate connection module.
Figure 8-32
Alternatively, two one-channel sensors can be connected nonequivalently via two channels
(see Figure
Nonequivalently Via Two Channels, Internal Sensor Supply"
variable is measured with mechanically separated sensors.
In order to achieve SIL3/Category 4 with this wiring, you must install a suitably qualified
sensor, for example, in accordance with IEC 60947.
Assignable Parameters for Use Case 3.2
Set the "Type of sensor interconnection" parameter to "2-channel nonequivalent" for the
corresponding input. Enable the "short-circuit test" parameter and set "internal" at the
"sensor supply" parameter.
ET 200pro Distributed I/O System - Fail-Safe Modules
Operating Instructions, 05/2007, A5E00394073-02
Wiring Diagram for F-Switch - One Nonequivalent Sensor Connected Via Two Channels
Nonequivalently, Internal Sensor Supply
"Wiring Diagram for F-DI Modules - Two One-Channel Sensors Connected
WARNING
Fail-Safe Electronic Modules
8.3 F -Switch PROFIsafe Digital Electronic Module
). In this case, the same process
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