Mitsubishi MELSEC Q Series Programming Manual page 132

(3) PLS instructions using the same device
The PLS instruction turns ON the specified device when the execution command is turned
ON from OFF.
It turns OFF the device at any other time (OFF to OFF, ON to ON, or ON to OFF).
If two or more PLS instructions using the same device are executed in one scan, each
instruction turns ON the device when the corresponding execution command is turned ON
from OFF and turns OFF the device in other cases.
For this reason, if multiple PLS instructions using the same device are executed in a single
scan, a device that has been turned ON by the PLS instruction may not be turned ON during
one scan.
[Ladder]
[Timing Chart]
• The ON/OFF timing of the X0 and X1 is different. (The specified device does not turn ON
X0
X1
M0
3-42
X0
PLS
X1
PLS
throughout the scan.)
END
ON
OFF
OFF
OFF
M0 turns ON because
X0 goes ON (OFF
M0
M0
X0
PLS M0
X1
PLS
END
ON
ON
M0 turns OFF because X1
status is other than OFF
ON).
X0
X1
M0
ON
M0 turns ON because X1
goes ON (OFF
ON.
M0 turns OFF because X0 status
is other than OFF
(M0 remains OFF.)
PLS M0
PLS M0
END
ON).
ON.