Step 7, Step 7: Transition To Redundant System Mode - Siemens SIMATIC S7-400H Manual

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.
11.4.7

STEP 7, Step 7: 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
Added I/O modules Are configured and
updated by the CPU.
Output modules briefly
output the substitute
values configured.
I/O modules that Are re-parameterized
continue to be and updated by the CPU.
present
Added DP stations as for added I/O modules
(see above)
1) Central modules are additionally first reset. Output modules briefly output 0 during this time (instead of the
configured substitute or holding values).
Automation System S7-400H Fault-tolerant Systems
A5E00068197-07
One-way I/O of master
CPU
Are updated by the CPU.
1)
Continue to work without interruption.
Are updated by the CPU.
Modifying the System During Operation
Switched I/O
CPU
Are updated by the CPU.
Generate plug in interrupt;
must be ignored in OB 83.
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