Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual page 900

Interrupt Control Instructions
I/O Interrupt Processing (N=0 to 3)
Operation of MSKS(690)
I/O Interrupt Task
Priority Levels
860
The instructions that act on individual interrupts have an operand, N, that
identifies the source of the interrupt. Numbers 0 to 3 indicate Interrupt Input
Units 0 to 3 and numbers 4 and 5 indicate scheduled interrupts 2 and 3.
An I/O interrupt is caused by an input signal from an Interrupt Input Unit. Up to
four Interrupt Input Units can be connected to the PLC. Unit numbers 0 to 3
are assigned to the Units based on their position in the PLC from left to right.
The following program example demonstrates the operation of MSKS(690)
and CLI(691) when they are used to control I/O interrupts.
Both I/O interrupt tasks and scheduled interrupt tasks are masked (disabled)
when the PLC is first turned on. MSKS(690) can be used to unmask or mask
I/O interrupts and set the time intervals for scheduled interrupts.
In this example, MSKS(690) uses the contents of D00100 to unmask interrupt
inputs 0 to 3 and mask interrupt inputs 4 to 7 from Interrupt Input Unit 0.
Interrupt inputs from Unit 0
Interrupt mask settings
When interrupt input 3 goes from OFF to ON, execution of the main program
will be interrupted and I/O interrupt task 3 (interrupt task 103) will be exe-
cuted. Execution of the main program execution is resumed at the point of
interruption after I/O interrupt task 3 has been completed.
When two or more interrupt inputs are received simultaneously, the interrupts
will be executed in order of their interrupt numbers from lowest to highest (100
to 131).
Unit
Interrupt Input Unit 0 Inputs 0 to 7 correspond to I/O interrupt tasks 100 to 107.
Interrupt Input Unit 1 Inputs 0 to 7 correspond to I/O interrupt tasks 108 to 115.
Interrupt Input Unit 2 Inputs 0 to 7 correspond to I/O interrupt tasks 116 to 123.
Interrupt Input Unit 3 Inputs 0 to 7 correspond to I/O interrupt tasks 124 to 131.
When more interrupt inputs are received while an interrupt task is being exe-
cuted, the recorded interrupts will be executed in order of their priority after
the current interrupt task is completed.
If a scheduled interrupt occurs, the scheduled interrupt task will take priority
over the I/O interrupt tasks.
F 0
1=Mask (Disable) 0=Unmask (Enable)
Interrupt tasks
Section 3-20