Siemens SIMATIC S7-400H Manual page 123

9.2.1 Failure and Replacement of a PROFIBUS-DP Master
Initial situation
The S7-400H is in the Redundant system
mode and one DP master module fails.
Procedure
To replace a PROFIBUS-DP master, perform the following steps:
Step
1 Turn off the power supply of the central
rack.
2 Unplug the DP Profibus cable for the
affected DP master module.
3 Replace the affected module.
4 Plug in the DP Profibus cable again.
5 Turn on the power supply of the
central rack.
S7-400H Programmable Controller Fault-Tolerant Systems
A5E00068197-04
Failure and Replacement of Components During Operation
Failure
What Has To Be Done?
How Does the System React?
With single-channel, one-sided I/O:
DP master can no longer process
connected DP slaves.
With switched I/O:
DP slaves are addressed via the DP
master of the partner.
How Does the System React?
The fault-tolerant system goes to Solo
mode.
-
-
-
CPU performs automatic LINK-UP
and UPDATE.
CPU changes to RUN and
operates as the standby CPU.
9-13