Siemens SIMATIC S7-400H System Manual page 279

Replacement procedure
Proceed as follows to replace PROFIBUS DP cables:
Step
1
2
3
S7-400H
System Manual, 03/2012, A5E00267695-11
16.3 Failure and replacement of components of the distributed I/Os
What has to be done?
Check the cabling and localize the
interrupted PROFIBUS DP cable.
Replace the defective cable.
Switch the failed modules to RUN
mode.
Failure and replacement of components during operation
How does the system react?
–
–
The CPUs process the error OBs synchronized
with each other
With one-sided I/O:

Rack failure OB 86 (outgoing event)
The DP slaves can be addressed via the
DP master system.
With switched I/O:

I/O redundancy error OB 70 (outgoing
event).
The DP slaves can be addressed via both
DP master systems.
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