Chapter 5. Power Supply / CPU
5-23
5.5 Operation Modes
The CPU module operates in one of the four modes - the RUN, STOP, PAUSE and DEBUG mode. The following describes the PLC
operation processing in each operation mode.
5.5.1 RUN mode
In this mode, programs are normally operated.
1) Processing when the operation mode changes.
Initialization of data area is executed when the first scan starts.
(1) If the PLC is in the RUN mode when applying the power:
(2) If the operation mode has been changed into from the STOP mode into the RUN mode: the initialization is
executed complying with the restart mode set. (cold I warm I hot)
(3) The possibility of execution of the program is decided with check on its effectiveness.
2) Operation processing contents
I/O refreshes and program operation are executed.
(1) Task programs are executed with the detection of their start-up conditions.
(2) Normal or abnormal operation and mounting conditions of the loaded module are checked.
(3) Communications service or other internal operations are processed.
The first scan start in the RUN mode
Check operation mode
Initialize data area according to the preset
restart mode.
Check the program and determine it can be
executed or not.
Execute input refresh
Execute programs and tasks
Check the availability of expansion units
Execute communication and internal service
Execute output refresh
Operation mode is changed?
Change to RUN mode from
STOP mode
Initialize data area according to the
preset restart mode.
Keep RUN mode
Change to other mode
Operate with new mode
If the operation mode is in the RUN
mode when the power is applied.
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