PROFINET
8.8 System redundancy
S7-400H
System Manual, 03/2012, A5E00267695-11
107
This topology has the following advantage: The entire system can continue to operate in
case of an interrupted connection, no matter where it occurs. One of the two communication
connections of the IO devices will always remain intact. The IO devices that were redundant
until now will continue operating as one-sided IO devices.
The figure below shows the view in STEP7, the logical view and the physical view of the
configuration with two integrated IO devices in system redundancy. Note that the view in
STEP7 does not exactly match the physical view.
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Figure 8-3
System redundancy in different views