Siemens CPU 948 User Manual

4.3.1
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.
When is a COLD RESTART
necessary?
A COLD RESTART is necessary after the following:
- OVERALL RESET,
- loading the user memory with the user program while the CPU
is in the stop mode
- ISTACK/BSTACK overflow,
- COLD RESTART aborted (by POWER OFF or changing the
mode selector to "STOP"),
- stop after PG function "program test end"
MANUAL COLD RESTART You can trigger a MANUAL COLD RESTART as follows:
•• Using the operating elements of the CPU:
Hold the reset switch in the RESET position; at the same time change
the mode selector from STOP to RUN (refer to Fig. 4-1).
•• From the PG:
Select the PG function PLC START/COLD RESTART.
AUTOMATIC COLD
RESTART
An AUTOMATIC COLD RESTART is triggered as follows:
At POWER UP, when
- the default "AUTOMATIC WARM RESTART after POWER UP"
in DX 0 has been changed to "AUTOMATIC COLD RESTART
after POWER UP",
- the mode selector on all CPUs and on the coordinator must remain
set to RUN
and
the CPU was not in the STOP mode when the power was switched off.
Note
If the CPU was in the STOP mode when the power was switched
off (for example, following an addressing error), an
AUTOMATIC COLD RESTART is not permitted. The STOP
mode can only be exited in this case with a MANUAL COLD
RESTART.
START-UP Mode
CPU 948 Programming Guide
C79000-G8576-C848-04
4 - 17

Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English