System modifications during operation
17.6 Removing components in STEP 7
S7-400H
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System Manual, 03/2012, A5E00267695-11
17.6.6
STEP 7, step 6: Transition to redundant system mode
Starting situation
The fault-tolerant system is operating with the new (restricted) hardware configuration in
single mode.
Procedure
1.
In SIMATIC Manager, select a CPU of the fault-tolerant system, then choose "PLC >
Operating Mode" from the menu.
2.
From the "Operating Mode" dialog box, select the reserve CPU, then click "Warm
Restart".
Result
The reserve CPU links up and is updated. The fault-tolerant system is operating in redundant
system mode.
Reaction of the I/O
Type of I/O
One-sided I/O of reserve CPU One-sided I/O of master CPU
Switched I/O
I/O modules to be
removed
1)
are no longer addressed by the CPU.
I/O modules still
present
are given new parameter
settings
2)
and updated by the
CPU.
continue operation without interruption.
DP stations to be
removed
as for I/O modules to be removed (see above)
1) No longer included in the hardware configuration, but still plugged in
2) Central modules are first reset. Output modules briefly output 0 during this time (instead of the configured substitute or
hold values).
Reaction to monitoring timeout
If one of the monitored times exceeds the configured maximum, the update is canceled. The
fault-tolerant system remains in single mode with the previous master CPU and, assuming
certain conditions are met, attempts the link-up and update later. For additional information,
refer to section Time monitoring (Page 155).
