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3.9 Operation when the OUT, SET/RST, or PLS/PLF Instructions Use the Same Device
3.9 Operation when the OUT, SET/RST, or PLS/PLF
Instructions Use the Same Device
The following describes the operation for executing multiple instructions of the OUT, SET/RST, or
PLS/PLF that use the same device in one scan.
(1) OUT instructions using the same device
Do not program more than one OUT instruction using the same device in one scan. If the
OUT instructions using the same device are programmed in one scan, the specified device
will turn ON or OFF every time the OUT instruction is executed, depending on the operation
result of the program up to the relevant OUT instruction. Since turning ON or OFF of the
device is determined when each OUT instruction is executed, the device may turn ON and
OFF repeatedly during one scan. The following diagram shows an example of a ladder that
turns the same internal relay (M0) with inputs X0 and X1 ON and OFF.
[Ladder]
[Timing Chart]
With the refresh type CPU module, when the output (Y) is specified by the OUT instruction,
the ON/OFF status of the last OUT instruction of the scan will be output.
M0
X0
M0
X1
M0
M0
M0
M0
OFF
ON
ON
OFF
ON
END
END END
X0
X1
M0
X0
X0
X1 X1
OFF
M0 turns ON because X0 is ON.
M0 turns OFF because X1 is OFF.
M0 remains OFF because X0 is OFF.
M0 turns ON because X1 is ON.