Digital modules
8.3 SM 326; DI 24 x DC 24V
Fail-safe signal modules
88
Installation and Operating Manual, 01/2010, A5E00085586-10
8.3.6
Application 4: Safety mode SIL2/Cat.3/PLd with high availability (in S7 F/FH
Systems only)
Introduction
Below are the wiring scheme and the parameter assignment of the SM 326; DI 24 x DC 24V
digital module for application 4: Safety Mode SIL2/Cat.3/PLd with high availability.
Diagnostic messages, possible causes of the problem and their corrective measures are
found in tables in the chapter "Diagnostic messages of SM 326; DI 24 x DC 24V (Page 99)".
Wiring scheme for application 4 with single-channel connection of one sensor
One sensor is connected via one channel to the two digital modules for each process signal
(1oo1 evaluation). The sensors must be connected to an external sensor supply.
/
0
',
/
0
',
0
/
9V
9V
60
',['&9
60
',['&9
Figure 8-11 Wiring scheme of the SM 326; DI 24 x DC 24V for application 4 – one sensor single-
channel connection
WARNING
To achieve SIL2/Cat.3/PLd using this wiring, you must use a suitably qualified sensor.