3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
3.1 Sequence Program
3.1.3 Interrupt programs
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2) High Performance model QCPU, Process CPU or Redundant CPU
• Interrupt factors of I0 to 27 and I50 to 255 are stored only once, and then the
interrupt program of each stored interrupt factor is executed after completion
of the current interrupt program execution.
For those of I28 to 31 and in the fixed scan execution type program, all
interrupt factors occurred are stored, and then all the interrupt programs
corresponding to those factors are executed after completion of the current
interrupt program execution.
• Interrupt factors of I32 to I41 and I49 are discarded.
3) Universal model QCPU
Interrupt factors of I0 to 15, I45, and I50 to 255 are stored only once, and then
the interrupt program of each stored interrupt factor is executed after
completion of the current interrupt program execution.
For those of I28 to 31 and in the fixed scan execution type program, all
interrupt factors occurred are stored, and then all the interrupt programs
corresponding to those factors are executed after completion of the current
interrupt program execution.
(e) When instruction is being executed
The interrupt program may be executed during execution of the main routine
program instruction with the instruction execution being suspended.
When the same device is used for the main routine program and interrupt
program, device data may become inconsistent.
In this case, take the following measures to prevent device data inconsistency.
1) Transfer device data to another device
Do not specify the device, which is to be written into the interrupt program,
directly in the main routine program, but use it in another device by
transferring it with the transfer instruction.