Failure And Replacement Of Profibus-Dp Cables - Siemens SIMATIC S7-400H Manual

Failure and Replacement of Components During Operation
9.2.4

Failure and Replacement of PROFIBUS-DP Cables

Initial situation
The S7-400H is in the Redundant system
mode and the PROFIBUS-DP cable is
defective.
Replacement procedure
To replace PROFIBUS-DP cables, perform the following steps:
Step
1 Check the wiring and localize the
interrupted PROFIBUS-DP cable.
2 Replace the defective cable.
3 Switch the failed modules to RUN.
9-16
Failure
What Has To Be Done?
S7-400H Programmable Controller Fault-Tolerant Systems
How Does the System React?
With single-channel, one-sided I/O:
Rack failure OB (OB 86) is started
(incoming event). DP master can no
longer process connected DP slaves
(station failure).
With switched I/O:
I/O redundancy error OB (OB 70) is
started (incoming event). DP slaves are
addressed via the DP master of the
partner.
How Does the System React?
-
-
CPUs process error OBs in synchronism
With one-sided I/O:
Mounting rack failure OB 86 (event
having the state cleared)
DP slaves can be addressed via the
DP master system.
With switched I/O:
I/O redundancy error OB70 (event
having the state cleared).
DP slaves can be addressed via both
DP master systems.
A5E00068197-04