Mitsubishi MELSEC-A series, Programming Manual

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3. INSTRUCTION STRUCTURE
3
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22
MELSEC-A
(2) If the SET/RST instruction is used from the same device.
(a) The SET instruction turns On the specified device when the SET command
goes On and when the SET command goes Off, there is no processing.
For this reason, when the SET instruction is executed multiple times in 1
scan from the same device, if even one SET command goes On, the
specified device goes On.
(b) The RST instruction turns off the specified device when the RST command
goes On and when the RST instruction goes Off, there is no processing.
For this reason, when a RST instruction is executed multiple times in 1 scan
from the same device, if even one RST command goes On, the specified
device goes Off.
(c) If there is a SET instruction and a RST instruction from the same device in 1
scan, the SET instruction turns the specified device On when the SET
command goes On and the RST instruction turns the specified device Off
when the RST command goes On.
If the SET command and RST command go Off, the On/Off state of the
specified device does not change.
[Circuit]
M0
X0
X1
SET
M0 RST
[Timing Chart]
M0
M0 goes On because X0 is On.
RST and M0 are not processed
because X1 is Off.
(M0 remains in the On state.)
SET and M0 are not processed
becaus e X0 is Off.
(M0 remains in the On state.)
M0 goes Off because
X1 is On.
OFF
ON
END END END
X0
X1
M0
OFF
OFF
ON
SET
X0
X1
M0
RST
M0 SET
M0 RST
X0
X1