2 Instructions
2-298 CP1E CPU Unit Instructions Reference Manual(W483)
Interrupt Control Instructions
CP1E CPU Units support the following interrupts.

Outline of Interrupt Control Instructions

SET INTERRUPT MASK: MSKS(690)

Both I/O interrupt tasks and scheduled interrupt tasks are masked (disabled) when the PLC enters RUN
mode. MSKS(690) can be used to unmask or mask I/O interrupts and set the time intervals for sched-
uled interrupts.

CLEAR INTERRUPT: CLI(691)

CLI(691) clears or retains recorded interrupt inputs for I/O interrupts or sets the time to the first sched-
uled interrupt for scheduled interrupts. It also clears or retains recorded high-speed counter interrupts.

DISABLE INTERRUPTS: DI(693)

DI(693) disables execution of all interrupt tasks.

ENABLE INTERRUPTS: EI(694)

EI(694) enables execution of all interrupt tasks.

Precautions in Using Interrupt Tasks

Precautions for All Interrupts

•When multiple interrupts occur at once, the order of execution of the interrupts is as follows:
I/O interrupt > scheduled interrupt
Note “A > B” indicates that A is given priority over B. On the same interrupt level, lower numbered tasks are given
priority over higher numbered tasks.

Precautions for I/O Interrupts

•Only built-in inputs from CP1E CPU Units are supported for interrupt tasks.
•Use interrupt inputs on the CPU Rack from 0ch02 bit to 0ch07 bit. I/O interrupt tasks will not be exe-
cuted if using any other input.
•All interrupt inputs that have been detected will be cleared when the interrupt mask is cleared.
•There is no limit on the number of I/O interrupt inputs that can be recorded, but only one interrupt is
recorded for each I/O interrupt number. Furthermore, the recorded interrupt is not cleared until its
interrupt task has been completed, so a new interrupt input will be ignored if it is received while its
interrupt task is being executed.

Precautions for Scheduled Interrupts

•Be sure that the time interval is longer than the time required to execute the scheduled interrupt task.
•To accurately control the time to the first interrupt and the interrupt interval, program CLI(691) to set
the time to the first schedule interrupt just before programming MSKS(690). If MSKS(690) is used to
restart a schedule interrupt, the time to the first scheduled interrupt will be accurate even if CLI(691)
is not used.
•The time unit for the scheduled interrupt is always 0.1ms.
Type Execution condition Setting procedure
I/O Interrupts Interrupt input from the built-in Input on the CPU
Rack turns ON/OFF.
Use the MSKS instruction to assign inputs from Interrupt Input on
the CPU Rack.
Scheduled Interrupts Scheduled (fixed intervals) Use the MSKS instruction to set the interrupt interval.