Mitsubishi Electric MELSEC iQ-F Series Training Manual page 75

2.4 Self-holding Ladder
A self-holding ladder holds the operation status of the coil by its contact.
By configuring the sequence, the output status can be held or canceled.
[Example of ladder diagram]
X0
0
Y10
4
[Timing chart]
ON
Contact X0
Contact X1
Coil Y10
Both of the following ladders hold the output.
[Self-holding ladder of output]
X0 X1
Y10
Using the SET instruction can hold the on status of the output even when the contact which
drives the coil turns off.
X1
Y10
Self-holding
END
ON
ON
Y10
END
Operation will be the same.
Step
0
1
2
3
4
[Sequence]
When the input X0 is on and X1 is
off, the output Y10 turns on.
The output Y10 remains on even
when the input X0 is turned off
(self-holding). Turning on the input
X1 turns off the output Y10.
[SET/RST ladder of output]
2-23
[List program]
Instruction
LD X0
OR Y10
ANI X1
OUT Y10
END
X0
SET
Y10
X1
RST Y10
END