Operations Arising When The Out, Set/Rst, And Pls/Plf Instructions Of The Same Device Are Used - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

Operations arising when the OUT, SET/RST, and PLS/PLF
instructions of the same device are used
This section describes the operation when two or more OUT, SET/RST, and PLS/PLF instructions that use the same device
are executed within one scan.
In safety programs executed by the Safety CPU, replace some words as follows:
• "Scan"  "Safety cycle processing"
• "X0"  "SA\X0", "X1"  "SA\X1", "M0"  "SA\M0"
• "END" on the rising edge of X0 (in Figures)  "Safety cycle processing start"
• "END" on the falling edge of X0 (in Figures)  "Safety cycle processing end"
*1 For the PLF instruction, replace "END" with "safety cycle processing start" regardless of the X0 status (rising edge or falling edge).
For OUT instructions of the same device
More than one OUT instruction of the same device must not be issued during one scan.
Otherwise, the specified device turns on or off, depending on the operation result up to each OUT instruction while it is in
execution.
In this case, the device may turn on/off during one scan because the on/off state of the specified device is determined during
execution of each OUT instruction.
The following figure shows the behavior arising when a circuit turning on/off the same internal relay (M0) is created with input
X0 and X1.
X0
X1
END
ON
OFF
X0
ON
X1
OFF
ON
OFF
M0
(1) Since X0 is on, M0 turns on.
(2) Since X1 is off, M0 turns off.
(3) Since X1 is off, M0 remains off.
(4) Since X1 is on, M0 turns on.
If output (Y) is specified using an OUT instruction, the on/off state of the last OUT instruction executed during the one scan will
be output.
M0
M0
X0 M0
X1 M0
END
OFF
ON
OFF
(2)
(1)
X0 M0
X1 M0
END
ON
OFF
ON
(4)
(3)
1.5 Precautions on Programming
*1
*1
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