Step 5: Transition To Redundant System Mode - Siemens CPU 410-5H Process Automation System Manual

Result
The reserve CPU links up, is updated and becomes the master. The previous master CPU
switches to STOP mode, the fault-tolerant system continues operating in single mode.
Reaction of the I/O
Type of I/O
I/O modules
1) 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
The update is canceled and no change of master takes place if one of the monitored times
exceeds the configured maximum. The fault-tolerant system remains in single mode with the
previous master CPU and, assuming certain conditions are met, attempts the master
changeover later. For additional information, refer to section Time monitoring (Page 110).
Where the values for the monitoring times in the CPUs differ, the higher values always apply.
10.5.6

Step 5: Transition to redundant system mode

Starting situation
The fault-tolerant system operates with the modified CPU parameters in single mode.
Procedure
1. In SIMATIC Manager, select a CPU of the fault-tolerant system, then select "PLC >
2. From the "Operating Mode" dialog box, select the reserve CPU, then click "Warm
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA
One-sided I/O of previous
master CPU
are no longer addressed by the
CPU.
Output modules output the
configured substitute or holding
values.
Operating Mode" from the menu.
Restart".
System modifications during redundant operation
One-sided I/O of new master
CPU
are given new parameter
settings and updated by the
1)
CPU.
10.5 Editing CPU parameters
Switched I/O
continue operation without
interruption.
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