Technical data

4.4.1
MANUAL and AUTOMATIC
COLD RESTART
When is a COLD RESTART
permitted?
A COLD RESTART is always permitted provided the system is not
requesting an OVERALL RESET.
MANUAL COLD RESTART You carry out a MANUAL COLD RESTART as follows:
•• Hold the mode selector in the RESET position; at the same time,
switch the mode selector from STOP to RUN.
•• Or use the PC START programmer function (COLD RESTART).
AUTOMATIC COLD
RESTART
AUTOMATIC COLD RESTART is triggered in the following case:
After power failure/POWER OFF in RESTART or RUN followed by
power restore/POWER ON, the CPU runs an initialization routing and
then attempts to automatically execute a COLD RESTART as long as
DX 0 is correctly parameterized (see Chapter 7).
Prerequisite: • The switches on all CPUs and on the
coordinator must remain at RUN.
• There must have been no faults in the
initialization run.
• The CPU was not in the STOP mode
when the power was switched off.
In the case of power failure in an expansion unit (PEU signal), the
CPU goes to STOP. It remains in STOP until the PEU signal is
switched inactive and then attempts to execute an AUTOMATIC
COLD RESTART or an AUTOMATIC WARM RESTART.
RESTART Mode
CPU 928B Programming Guide
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