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7.17
Progr
am co
ntrol instr
uctions
7.17
Program control instructions
(1) Processing when the execution type is converted with the program control instruction is as follows.
Once the fixed scan execution type program is changed to another execution type, it cannot be returned to the fixed scan
execution type.
(2) As program execution type conversions by PSCAN and PSTOP instructions occur at the END processing, such
conversions are impossible during program execution.
When different execution types have been set for the same program in the same scan, the execution type will be that
specified by the execution switching command that was executed last.
*1:
The order of "GHI" and "DEF" program execution is determined by the program settings parameters.
Switching from the fixed scan execution type program to the execution type program is performed in the following timing.
(a) For the Universal model QCPU, LCPU
The execution type is changed when the execution of the fixed scan execution type is stopped at the END
processing after the program control instruction execution.
(b) Basic model QCPU, High Performance model QCPU, Process CPU, and Redundant CPU
The execution of the fixed scan execution type is stopped at the execution of the program control instruction, and
the execution type is changed at the END processing.
(3) When the POFF instruction is executed, the output is turned OFF at the next scan, and the execution type will be the
stand-by type at the second next scan and later.
If executed prior to the output OFF processing, the program control instruction is ignored.
Execution type before change
Executed Instruction
PSCAN
PSTOP
POFF
PLOW
Scan execution type
No change-remains
scan type execution.
Becomes stand-by type.
Output turned OFF in
next scan.
Becomes stand-by
type from the next
scan after that.
Becomes low speed
execution type.
Initial execution type
Becomes scan
execution type.
Stand-by type
No change-remains
stand-by type
Ignored
Low speed execution type
Low speed execution
type execution is
stopped, becomes
scan execution type
from the next scan.
(Execution from step 0)
Low speed execution
type execution is
stopped, becomes
stand-by type from next
scan.
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.
No change -remains low
speed execution type.
Fixed scan execution type
Becomes scan
execution type.
Becomes stand-by type.
Output turned OFF in
next scan.
Becomes stand-by
type from the next
scan after that.
Becomes low speed
execution type.
END processing
"ABC"
GHI
GHI
*1
*1
DEF
GHI
PSTO executes "ABC"
PSCAN executes "DEF"
Execution
program name
GHI
END processing
END processing
Con
v
erts "DEF" into the scan execution
type program and "ABC" to the stand-by
type program