Mitsubishi MELSEC-F FX-TRN-BEG-E, User Manual

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FX-TRN-BEG-E B: Let’s Study the Basics 2
B-19
2.2.3 Points of training and control specifications
1) Latched output instruction
The latched output instruction is frequently used in PLC programming. The Output contact
latches On when first energized by an Input(s), remaining On until forced Off by another
programming condition.
Example of latched output instruction
• Write the contact of OUT instruction Y000
in parallel to the input condition X020.
Operation
• When X020 is set ON, Y000 is driven
(turned ON) as indicated with the dotted
line 1.
• Even if X020 is set OFF the ON status of
the output Y000 is held as indicated with
the dotted line 2.
Example to shut down the latched output instruction
• Enter another input condition X24 so that
the route 1 and 2 are shut down and the
latched output status is not operated.
* X024 is an NC contact and normally ON.
When an input signal is given, X024 is
set OFF, and the operation is stopped.
2) Holding an output status using other methods
Another instructions provided in the PLC can be used to easily hold the output status.
Example of SET (Set) / RST (Reset) instructions
• When X020 is set ON, the output Y000
turns ON.
Even if the X020 is set OFF, the output
status of Y000 remains On.
• When X024 is set ON, Y000 is Reset
(turned Off).
The operation of this program is the same as the operation described above where the
latched output instruction is shut down by another input condition.
X020
Y000
Y000
(input condition)
X020
Y000
Y000
1
2
X020
Y000
Y000
X024
Attention!
X020
Y000
X024
OFF
ON
X020
Y000
X024
SET
Y000 RST