Mitsubishi MELSEC-A series, Programming Manual

Page: 63 / 508

3. INSTRUCTION STRUCTURE
3
−
23
MELSEC-A
(3) If the PLS instruction is used from the same device.
The PLS instruction turns the specified device On when the PLS command goes
from Off to On, and when the PLS command is not going from Onto Off (Off
→
Off, On
→
On, On
→
Off) the specified device goes Off.
If the PLS instruction from the same device is executed multiple times in 1 scan,
the specified device goes On when the PLS command in each PLS instruction
goes from Off to Off, and the specified device goes Off when the PLS command
is other than Off
→
On.
For this reason, if the PLS command from the same device is executed multiple
times in 1 scan, the device turned On by the PLS command may not go On in 1
scan.
[Circuit]
M0
X0
X1
PLS
M0 PLS
[Timing Chart]
•
When the On/Off timing of X0 and X1 differ (the specified device does not go
On in 1 scan)
M0
M0 goes On because X1
goes from Off to On.
OFF
ON
END END END
X0
X1
M0
OFF
OFF
ON
PLS
X0
X1
M0
PLS
M0
PLS
M0 PLS
X0
X1
ON
M0 goes Off because X0 is not Off On.
(M0 remains in the Off state.)
M0 goes Off because X1
is not Off On.
M0 goes On because X0 is Off On.