Program Control Instructions - Mitsubishi MELSEC Q Series Programming Manual

7.17

Program control instructions

(1) Processing when the execution type is converted with the program control instruction is as
follows.
Execution type before change
Scan execution type
Initial execution type
Stand-by type
Low speed execution type
Fixed scan execution type
7-374
PSCAN
No change-remains
scan type execution.
Becomes stand-by type.
Becomes scan
execution type.
No change-remains
stand-by type
Low speed execution
Low speed execution
type execution is
type execution is
stopped, becomes scan
stopped, becomes
execution type from the
stand-by type from next
next scan.
scan.
(Execution from step 0)
Becomes scan
Becomes stand-by type.
execution type.
Once the fixed scan execution type program is changed to another execution
type, it cannot be returned to the fixed scan execution type.
Executed Instruction
PSTOP POFF
Output turned OFF in
next scan.
Becomes stand-by type
from the next scan after
that.
Ignored
Low speed execution
type execution is
stopped, and output is
turned OFF in the next
scan. Becomes
stand-by type from the
next scan after that.
Output turned OFF in
next scan.
Becomes stand-by type
from the next scan after
that.
PLOW
Becomes low speed
execution type.
No change -remains low
speed execution type.
Becomes low speed
execution type.