Pcs7, Step 3: Stopping The Standby Cpu - Siemens SIMATIC S7-400H Manual

10.2.3

PCS7, Step 3: Stopping the Standby CPU

Initial situation
The fault-tolerant system is working in the Redundant system 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 Stop
button.
Result
The standby CPU switches to STOP mode, the master CPU remains in RUN
mode, the fault-tolerant system works in Solo mode. One-way I/O of the standby
CPU are no longer addressed.
Whilst I/O access errors of the one-way I/O will result in OB 85 being called, due to
the superior CPU redundancy loss (OB 72) these will not be reported. OB 70 (I/O
redundancy loss) will not be called.
S7-400H Programmable Controller Fault-Tolerant Systems
A5E00068197-04
Modifications to the System while in Operation
10-9