Operation Processing In The Run, Stop, Pause Status - Mitsubishi A1SJH User Manual

4. AnSHCPU MODULE
4.1.2

Operation processing in the RUN, STOP, PAUSE status

PLC CPU operation
processing
RUN/STOP
key switch operation
RUN → STOP
STOP → RUN
The PLC CPU can be operated in the RUN, STOP and PAUSE status as described
below.
(1) RUN operation
RUN indicates repeated operations of the sequence program from step 0 to
the END (FEND) instruction.
When a CPU changes its status to the RUN mode, the CPU restores all
output data which was saved when the CPU was stopped, in accordance with
the STOP → RUN mode set in the parameters.
The PLC CPU needs initialization time before starting a sequence program
operation. It requires two to three seconds after a power ON or reset, and
one to three seconds after the mode is changed from STOP to RUN.
(2) STOP operation
STOP indicates stopping of sequence program operation by executing a
STOP instruction or by using the remote STOP function (see Section 4.2.3).
When the CPU is set to STOP, the output status is saved and all outputs are
switched OFF. Data other than the outputs (Y) is retained.
(3) PAUSE operation
PAUSE indicates stopping of sequence program operation with the output and
data memory status retained.
(4) PLC CPU operation processing upon the RUN/STOP key switch operation
Operation processing
of sequence program
Executes up to an END OS saves the output status
instruction and then and turns all output points
stops. OFF.
Depends on the parameter
output mode when the key
Starts operation.
switch is changed from STOP
to RUN.
POINT
AnSHCPU executes the following operations at any time in the RUN, STOP or
PAUSE mode :
• Refresh processing of the I/O module when the refresh mode is set.
• Data communications with computer link modules.
• Link refresh processing.
Therefore, the following operations are possible even when the AnSHCPU is in
the STOP or PAUSE status :
• Monitoring I/O status and testing using a peripheral device.
• Read/write with computer link modules.
• Communications with other stations in the MELSECNET data link system.
External output
Holds the status just before
the STOP status.
Executes operation from
the status just before the
STOP status.
4 - 5
MELSEC-A
Data memory
Remarks
(Y,M,L,S,T,C,D)