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6.22.1High speed interrupt program execution function
This function executes an interrupt program according to the high speed interrupt pointer (I49).
(1) Setting method
In the PLC system tab of the PLC parameter dialog box, click the
button in the
System interrupt settings area.
Enter a value in the range of 0.2 to 1.0 (ms) for "High speed interrupt I49 fixed scan interval".
(2) Precautions
(a) High speed interrupt while interrupt is disabled
The high speed interrupt program is not executed while interrupt is disabled.
It becomes executable when interrupt is enabled.
For the items that cannot start the high speed interrupt due to disabled interrupt, refer to Section 6.22.4(3).
(b) When a high speed interrupt is ignored
If the interrupt-disabled period continues longer than the set interrupt interval, a high speed interrupt may be
ignored.
High speed interrupt is ignored once when it occurs twice during interrupt-disabled period.
(c) High speed interrupt program execution
This function is executed when all of the following conditions are satisfied.
• The EI instruction is being executed.
• The CPU module is in the RUN status.
• The high speed interrupt pointer (I49) is not masked by the IMASK instruction.
(By default, it is not masked.)
For the IMASK and EI instructions, refer to the following.
MELSEC-Q/L Programming Manual (Common Instruction)
Figure 6.88 High speed interrupt setting
High speed interrupt setting
Set a value within
the range of 0.2 to
1.0ms.
