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

Modifications to the System while in Operation
10.6.5

Step E: Transition to the Redundant System Mode

Initial situation
The fault-tolerant system works with the modified CPU parameters in Solo mode.
Procedure
1. In SIMATIC Manager select a CPU of the fault-tolerant system and select the
menu command PLC > Operating Mode.
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 is working in
the Redundant system mode.
Reaction of the I/O
Type of I/O One-way I/O of standby
I/O modules Are re-parameterized
and updated by the CPU.
1) Central modules are reset first in addition. Output modules briefly output 0 during this time (instead of the
configured substitute or holding values).
Reaction if monitoring times are exceeded
If one of the monitored times exceeds the maximum value configured the update is
interrupted. The fault-tolerant system remains in Solo mode with the previous
master CPU and in certain conditions attempts to perform the link-up and update
later. For more details refer to Section 5.3.
If the values for the monitoring times in the CPUs are different then the higher
value always applies.
10-46
One-way I/O of master
CPU
1)
Continue to work without interruption.
S7-400H Programmable Controller Fault-Tolerant Systems
Switched I/O
CPU
A5E00068197-04