Mitsubishi Electric MELSEC-Q/L - Page 125

3 CONFIGURATION OF INSTRUCTIONS
3.9 Operation When the OUT, SET/RST, or PLS/PLF Instructions Use the Same Device
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3
SET/RST instructions using the same device
• The SET instruction turns ON the specified device when the execution command is ON and performs nothing when the
execution command is OFF. For this reason, when the SET instructions using the same device are executed two or more
times in one scan, the specified device will be ON if any one of the execution commands is ON.
• The RST instruction turns OFF the specified device when the execution command is ON and performs nothing when the
execution command is OFF. For this reason, when the RST instructions using the same device are executed two or more
times in one scan, the specified device will be OFF if any one of the execution commands is ON.
• When the SET instruction and RST instruction using the same device are programmed in one scan, the SET instruction
turns ON the specified device when the SET execution command is ON and the RST instruction turns OFF the specified
device when the RST execution command is ON. When both the SET and RST execution commands are OFF, the ON/
OFF status of the specified device will not be changed.
When using a refresh type CPU module and specifying output (Y) in the SET/RST instruction, the ON/OFF status of the
device at the execution of the last instruction in the scan is returned as the output (Y).
[Ladder]
[Timing Chart]
M0
X0
X1
SET
M0
RST
M0
OFF
ON
END
END END
X0
X1
M0
OFF
OFF
ON
SET
X0
X1
M0RST
M0SET
M0RST
X0
X1
ON
M0 turns ON because X0 is ON.
RST M0 is not executed
because X0 is OFF.
(M0 remains ON.)
M0 turns OFF because X1 is ON.
SET M0 is not executed
because X0 is OFF.
(M0 remains ON.)