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Interrupt Control Instructions
1,2,3...
Main program
execution
Scheduled interrupt
task execution
Precautions
1. The time to the first scheduled interrupt is set to 20 ms with CLI(691).
2. The scheduled time interval is set to 100 ms and execution of scheduled
interrupt 2 is enabled with MSKS(690).
3. Scheduled interrupt 2 is executed 20 ms after execution of MSKS(690) and
every 100 ms thereafter.
4. After scheduled interrupt processing has begun, the time to the next
scheduled interrupt can be changed with CLI(690), but this setting is effec-
tive only one time.
5. After scheduled interrupt processing has begun, the scheduled time inter-
val can be changed by executing MSKS(690). In this case, the time interval
is changed from 100 ms to 200 ms.
6. Scheduled interrupt processing is disabled by executing MSKS(690) with
a time interval of 0000.
The following timing chart shows the operation of the example listed above.
1, 2
3
3
3
20 ms 100 ms 100 ms
Be sure that the scheduled time interval is longer than the time required to
execute the scheduled interrupt task. If the scheduled time interval is too
short, the interrupt task will be executed continuously and a Cycle Time Too
Long Error will occur. (A long scheduled interrupt task can seriously affect the
main program's overall execution time.)
The scheduled interrupt is executed after the specified time interval plus the
execution time for one instruction. Normally the time required to execute one
instruction is negligible, but it can cause errors when instructions that take a
1-cycle
ON Flag
at startup
4
5
3
3
3
3
50 ms 100 ms100 ms 200 ms
Section 3-20
1
2
4
5
6
6
3
863
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