Siemens SIMATIC S7-400H - Configuring with STEP 7

Using I/Os in S7–400H
13.4 Connecting redundant I/O to the PROFIBUS DP interface
S7-400H
System Manual, 03/2012, A5E00267695-11
197
Redundant digital output modules
Fault-tolerant control of a final controlling element can be achieved by connecting two
outputs of two digital output modules or fail-safe digital output modules in parallel (1-out-of-2
configuration).
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Figure 13-9 Fault-tolerant digital output modules in 1-out-of-2 configuration
The digital output modules must be connected to a common load voltage supply.
You will find connection examples in Appendix Connection examples for redundant I/Os
(Page 461).
Interconnection using external diodes <-> without external diodes
The table below lists the redundant digital output modules which in redundant mode you
should interconnect using external diodes:
Table 13- 4 Interconnecting digital output modules with/without diodes
Module with diodes without diodes
6ES7 422–7BL00–0AB0 X -
6ES7 422–1FH00–0AA0 - X
6ES7 326–2BF01–0AB0 X X
6ES7 322–1BL00–0AA0 X -
6ES7 322–1BF01–0AA0 X -
6ES7 322–8BF00–0AB0 X X
6ES7 322–1FF01–0AA0 - X
6ES7 322–8BH01–0AB0 - X
6ES7 322–8BH10–0AB0 - X
6ES7 322–5RD00–0AB0 X -
6ES7 322–5SD00–0AB0 X -