Interrupts; Overview - Omron CP1E CPU UNIT SOFTWARE User Manual

10 Interrupts

10-1 Interrupts

10-1-1 Overview

CP1E CPU Units normally repeat processes in the following order: overseeing processes, program exe-
cution, I/O refreshing, peripheral servicing. During the program execution stage, cyclic tasks (ladder
programs) are executed.
The interrupt function, on the other hand, allows a specified condition to interrupt a cycle and execute a
specified program.
Interrupts can thus be used to perform high-speed processing that is not restricted by the cycle time.
The CP1E performs the following processing when an interrupt occurs.
(1)When an interrupt occurs, execution of the ladder programs in cyclic tasks is interrupted.
(2)The ladder program in the interrupt task is executed.
(3)When the interrupt task is finished, the ladder program that was being executed is returned to.
Cycle
Interrupt Factors and Types of Interrupts
Interrupts are classified by the interrupt factor. There are the following three types of interrupts.
• Changes in status of built-in inputs on the CPU Unit → Input Interrupts in Page 10-3
• Specified intervals measured by internal timers
• PVs of high-speed counter
10-2
Cyclic tasks
(ladder programs)
(1)Interrupt occurs
END
(3)When the interrupt task is finished,
I/O refreshing the ladder diagram that was being
executed is returned to.
(2)Interrupt task executed
Ladder program
END
→ Scheduled Interrupts in Page 10-10
→ High-speed Counter Interrupts in Page 11-14
CP1E CPU Unit Software User's Manual(W480)