Starting Timing; Figure 5-5 Interrupt Task Starting Timing - Hitachi IR.LINK User Manual

5.2.4 Starting timing

Starting timing of interrupt task
Figure 5-5 shows the relation between an interrupt I/O input and the task start timing.
Task start
IR.LINK input fetch
Input delay time
DI module input fetch
Interrupt I/O input
signal
For the interrupt I/O input signal, an input delay time is caused by the filter of the DI module.
(For the delay time due to the filter, see the specifications of each DI module.)
After the signal is fetched to the DI module as an input, it is transmitted to the IR.LINK by
cyclic communication. This transmission time is equal to the maximum refresh cycle of the
IR.LINK. Accordingly, the interrupt I/O input should be kept ON longer (1.5 times or more)
than Input delay time + Refresh cycle. If the ON time is shorter than Input delay time +
Refresh cycle, the interrupt input cannot be recognized and the task may not be started.
Likewise, if the OFF time is shorter than Input delay time + Refresh cycle, the interrupt I/O
input is regarded as being kept ON and the task may not be started.
The task starting time starts the task immediately after the I/O input is recognized. However,
it varies with the task priority level and CPU or LPU (CMU) program processing status.
Releasing the interrupt task
At a task start after the interrupt I/O input is recognized, the task is not released.
Accordingly, release the interrupt task by the user program. If the interrupt task is not
released by the user, the task is not started.
Response time
Transmission
time
OFF
This should be kept ON longer than Input delay time + Refresh cycle.

Figure 5-5 Interrupt Task Starting Timing

Task starting time
ON
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OFF