Siemens SIMATIC Operating Instructions Manual page 99

Use Case 3: Wiring Two Loads in Parallel to Each Digital Output
Avoiding/Managing Cross Circuits:
To protect against cross circuits between P- and M-switches of a fail-safe digital output, we
recommend the following wiring schemes:
2L+
2L+ M
L+ M
Figure 8-20
See also
Block Diagram for the 4/8 F-DI/4 F-DO DC24V/2A PROFIsafe Electronic Module (Page 91)
ET 200pro Distributed I/O System - Fail-Safe Modules
Operating Instructions, 05/2007, A5E00394073-02
8.2 4 /8 F-DI/4 F-DO DC24V/2A PROFIsafe Digital Electronic Module
4/8 F-DI/4 F-DO
DO0 DO0 DO1 DO1
(P0) (M0) (P1) (M1)
K3
K1
K4
K2
Wiring Diagram for Each of Two Relays Parallel at One F-DO of the 4/8 F-DI/4 F-DO
DC24V/2A PROFIsafe Electronic Module
Fail-Safe Electronic Modules
DO2 DO2 DO3
(P2) (M2) (P3)
K1 K3
K2 K4
M
M
DO3
(M3)
99