Mitsubishi Electric MELSEC iQ-R Series User Manual page 125

• For I44
If an interrupt factor which is the same as that for the running interrupt program occurs, the factor is not memorized.
Therefore, the corresponding interrupt program will not be executed after the running interrupt program finishes. Also, if the
I44 interrupt program for this cause cannot be executed, SM480 (Cycle overrun flag for inter-module synchronization program
(I44)) is turned on, and SD480 (Number of cycle overrun events for inter-module synchronization cycle program (I44))
reaches its upper limit.
I44
Main routine program
I44 interrupt program
Sc: Inter-module synchronization cycle
(1) The interrupt factor is discarded because the same interrupt (I44) is being executed.
(2) The interrupt is not executed.
(3) The interrupt is executed.
I44 I44
Sc Sc
(1)
(2)
(3)
t
8 RUNNING A PROGRAM
123
8.7 Interrupt Program
8