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MELSEC-Q
4 SEQUENCE PROGRAM CONFIGURATION AND EXECUTION
CONDITIONS
4.1.3 Interrupt programs
(1) Definition of interrupt program
(a) An interrupt program begins from the interrupt pointer (I
), and ends at the
IRET instruction. 1
(b) Interrupt programs are executed only when an interrupt factor occurs. 1
POINT
The interrupt pointers include a pointer designed for only the high speed interrupt
function (I49).
When you have used I49, do not use interrupt programs, which use the other
interrupt pointers I0 to I48, I50 to I255, and fixed scan execution type programs.
If any fixed scan execution type program or the like is run, the interrupt program
using I49 cannot be executed at the preset interrupt cycle intervals.
See Section 7.20 for details on the high speed interrupt function.
REMARK
1: See Section 10.10 for details on interrupt factors and interrupt pointers.
(2) Interrupt program management
Interrupt programs are created after the main routine program (after the FEND
instruction), and the combination of main and sub-routine programs can be
managed as one program.
(a) When created after the main routine program
• An interrupt program is created between the main routine program's
FEND and END instructions.
• Because there are no restrictions on the order in which interrupt programs
are created, it is not necessary to set the interrupt pointers in ascending
order when creating multiple interrupt programs.
High Performance model QCPU
Program memory/ Standard
ROM / Memory card
File of
program A
Program A
Interrupt
program
Write
Interrupt pointer
Main routine
program
FEND
END
I32
IRET
IRET
Y10
IRET
Y11
Y12
I0
I28
