Step E: Transition To Redundant State - Siemens SIMATIC S7-400H System Manual

System modifications in operation
14.7 Editing CPU parameters
14.7.6

Step E: Transition to redundant state

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 choose "PLC >
2. From the "Operating Mode" dialog box, select the standby CPU, then click "Warm
Result
The standby CPU links up and is updated. The fault-tolerant system is operating in
redundant mode.
Reaction of the I/O
Type of I/O
I/O modules
Central modules are first reset. Output modules briefly output 0 during this time (instead of the configured substitute or
1)
hold values).
Reaction to monitoring timeout
If one of the monitored times exceeds the configured maximum the update is aborted. The
fault-tolerant system remains in single mode with the previous master CPU and, assuming
certain conditions are met, attempts to the link-up and update later. For further information,
refer to section Time monitoring (Page 106).
Where the values for the monitoring times in the CPUs differ, the higher values always apply.
238
Operating Mode" from the menu.
Restart".
One-sided I/O of standby CPU One-sided I/O of master CPU
are given new parameter
settings and updated by the
1)
CPU.
continue operation without interruption.
Switched I/O
System Manual, 09/2007, A5E00267695-03
S7-400H