Siemens SIMATIC S7-400H System Manual page 53

Operating sequence for restart t/warm restart
1. Set the switch to the STOP position.
2. Set the switch to the RUN position.
Whether the CPU performs a cold start or a hot restart is determined by its configuration.
Operating sequence for cold restart
A cold start is always initiated using the PG command "Cold start". To do so, the CPU must
be in STOP, and the mode selector switch must be set to RUN.
S7-400H
System Manual, 09/2007, A5E00267695-03
Result: The STOP LED lights.
Result: The STOP LED goes out, the RUN LED is lit.
Installation of a CPU 41x–H
5.6 Operating sequence for memory reset
53