7.5.2 Sub-Program # 1
If the
The figure below shows the first scan operation.
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2nd scan
Mode
I/O 
Timer Main program
The end of the
7.5.3Timer Interrupt Program
The timer interrupt is the highest priority task. It is executed cyclically with a user specified interval, while suspend- ing other operation. The operations interval is set in the system information. (5 to 1000 ms, 5 ms units).
1 scan
Scan
1 scan
1 scan
1 scan
Timer interrupt
Timer interrupt interval
Time
Timer interrupt interval
The end of the timer interrupt is recognized by the IRET instruction.
7.5.4 I/O Interrupt Program
The I/O interrupt program is also the highest priority task. It is executed immediately when the interrupt factor is generated, while suspending other operations.
The following 2 types I/O interrupt programs are supported in the V200 CPU.
(1)I/O interrupt #1
The I/O interrupt #1 is used with the high speed counter function. When the count value reaches the preset value, etc., the I/O interrupt #1 is activated immediately with suspending other operation. The end of the I/O interrupt #1 is recognized by the IRET instruction.
(2)I/O interrupt #2
The I/O interrupt #2 is also used with the high speed counter function.
If an interrupt factor is generated while other interrupt program is executing (including the timer interrupt), the inter- rupt factor is hold. Then it will be activated after finishing the other interrupt program execution.
If two or more interrupt factors are generated at the same time, the priority is as follows: Timer > I/O #1 > I/O #2
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