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MANUAL WARM RESTART
AUTOMATIC WARM
RESTART
CPU 948 Programming Guide
C79000-G8576-C848-04
You trigger a MANUAL WARM RESTART as follows:
• • using the control elements of the CPU:
initial state: the reset switch is in the mid setting
change the mode selector from STOP to RUN (refer to Fig. 4-1)
• • from the PG:
select the PG function PLC START/WARM RESTART.
An AUTOMATIC WARM RESTART is triggered as follows:
With POWER UP, when
-
the default "AUTOMATIC WARM RESTART after POWER UP"
is set in data block DX 0 or DX 0 does not exist,
-
the mode selector on all CPUs and on the coordinator remain
unchanged and set to RUN
and
the CPU was not in the STOP mode when the power was switched
off,
-
no further errors have occurred during the initialization nor before
the power was switched off,
-
no COLD RESTART is required due to the reasons listed above.
Following power failure or switching the power off in the RUN mode
followed by the return of power/POWER UP, the CPU runs through
an initialization routine and then automatically performs a WARM
RESTART.
If there is a power failure on an expansion unit, (PEU signal), the CPU
changes to the STOP mode. It remains in this mode until the PEU
signal is switched inactive and then performs an AUTOMATIC
WARM RESTART or an AUTOMATIC COLD RESTART.
START-UP Mode
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