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7.4 Precautions at System Switching Occurrence
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PROGRAMMING CAUTIONS
(b) Output is returned corresponding to external input
[Program example]
(Before measures)
(After measures)
POINT
Set [Do tracking] of [Signal flow memory tracking setting] at [Tracking settings] of
[Redundant parameter].
(2) Precautions regarding timer
Pay attention to the following points regarding timer at the time of system switching
occurrence.
1) The present value of timer at the first scan of the new control system CPU
module at the time of system switching occurrence.
2) Depending on timing of system switching occurrence such as turning power
supply OFF, tracking transfer processing may be discontinued, and the device
data may not be reflected to the new control system CPU module after
switching systems.
In this case, the timer whose time is up before switching systems may not be
recognized even after the first scan after system switching.
Diagram 7.18 Program Example when there is Response (Output) to External Input
Response (input) (X10)
Output (Y10)
M0
SET
Y10
X10
Y10
M10
RST
Y10
X10
Y10
Delays SET Y10 by one
scan from PLS M1.
Delays RST Y10 by one
scan from PLS M11.
M1
SET
Y10
M0
PLS
M1
X10
Y10
M11
RST
Y10
M10
PLS
M11
X10
Y10