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3.
INTERRUPT PROCESSING
MELSEC-A
3.6
lnterrupt Processing Timing
,
.
The time to actually execute an Interrupt program is delayed even+when an
interrupt signal is input. In addition, execution of a program will be delayed if
an interrupt is input while executing other interrupts as explained below.
lnterrupt input
(external switch)
lnterrupt detection and
pre-processing
Sequence program
0.2ms
Y
lnterrupt program
-
The t ~ m e untll executing an interrupt pro-
gram after turnlng ON an lnterrupt
,
If a CPU
IS
executing the following processing, execution of an interrupt
program is delayed. Therefore, the *time changes.
The values are as follows. (The following shows maximum values.)
The time of
*
when the above processing overlaps is the total time of the
individual value.
[Sample calculation]
If an interrupt is executed from an A1S161 while processing general data
*
Value
= 0.2
+
1.5 msec
A Program from
129 to 131 is
being Executed.
1 msec
t
execu-
t ~ o n time of the
~nterrupt pro-
gram of 129 to
131
Item
Value
of
*
General Data
Monitor lnterrupt
is being
rupt is being
Processed.
Peripheral
Device lnterrupt
A D 5 1 ,
etc.
POINT
~ v e l i f a basic instruction and an application instruction are being ex-
ecuted, they are Interrupted and an interrupt program is executed according
to t h i timing Indicated above.
A
Sequence is
being Executed
Normally.
o
2 msec
I 5 msec
0.65 msec
0 5 msec
.
mon~toring it
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