Panasonic FP-E Programming Manual page 137

Description
The DF instruction executes and turns on output for only one scan duration when the trigger changes from an
off to an on state.
The DF/ instruction executes and turns on output for only one scan duration when the trigger changes from an
on to an off state.
There is no limit on the number of times the DF and DF/ instructions can be used.
With the DF and DF/ differential instructions, only a change in the on and off status of the contact is detected.
Thus, if the execution condition is initially on such as when the mode is changed to RUN or the power turned
on in RUN mode, output will not be obtained.
Example: Leading edge differential (DF) instruction
X0
Y10
Precautions during programming
With a program such as the one in the figure below, operation will be as follows.
X0 X1
Y10
(DF)
When X1 is off, even if X0 rises, Y10 remains off.
1
Even if X1 rises when X0 is on, Y10 remains off.
2
If X0 rises when X1 is on, then Y10 will go on for one scan.
3
In the following program the execution condition is initially on, therefore output is not obtained.
R9013
DF
R9010
DF
With the following program, output is obtained.
R9014
DF
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on
off
on
off
DF instruction
not executed.
RUN
X0
X1
Y10
3
1 2
Y10
R9013 only turns on during the first scan after
RUN begins.
Y10
R9010 is always on.
Y10
R9014 turns on from the second scan after
RUN begins.
Leading
edge
Basic Instructions
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