Siemens SIMATIC ET 200S Installation And Operating Manual page 131

Wiring Diagram for Application 3.2 - Connecting a Non-equivalent Sensor to Two Non-equivalent
Channels
Four process signals can be connected to an EM 4/8 F-DI 24 VDC PROFIsafe. Two
channels of a sensor are connected nonequivalently to two inputs of the F-module for each
process signal (1oo2 evaluation).
The left-hand channels on the F-module (DI0 through DI3) supply the useful 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 on the appropriate terminal module.
Figure 7-31
Warning
To achieve AK6/SIL3/Category 4 using this wiring, you must use a sensor qualified for this
class.
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 DC24V - One Nonequivalent Sensor Connected
Nonequivalently via Two Channels, Internal Sensor Supply
Fail-Safe Modules
7-71