Modifying the System During Operation
11-21
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
Response if monitoring times are exceeded
If one of the monitored times exceeds the maximum value configured the update is
interrupted and no change of master takes place. The fault-tolerant system
remains in single mode with the previous master CPU and in certain conditions
attempts to perform the change of master later. For more details refer to
Section 6.3.
11.3.6 PCS 7, Step VI: Transition to Redundant System Mode
Initial situation
The fault-tolerant system works with the new hardware configuration in single
mode.
Procedure
1. In SIMATIC Manager, select a CPU of the fault-tolerant system, and choose the
PLC > Operating Mode menu command.
2. In the Operating Mode dialog box, select the standby CPU and click the
Restart (warm restart) button.
Result
Standby CPU links up again and is updated. The fault-tolerant system works with
the new hardware configuration in redundant system mode.
Behavior of the I/O
Type of I/O One-way I/O of standby
CPU
One-way I/O of master
CPU
Switched I/O
I/O modules to be
removed
1)
Are no longer addressed by the CPU.
Driver blocks are no longer present.
I/O modules that
continue to be
present
Are re-parameterized
2)
and updated by the CPU.
Continue to work without interruption.
DP stations to be
removed:
as for I/O modules to be removed (see above)
1) No longer contained in the hardware configuration, but still plugged in
2) Central modules are first reset in addition. Output modules briefly output 0 during this time (instead of the
substitute or holding values configured).
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