Omron SYSMAC CP Series, User Manual

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10 Interrupts
10-2
CP2E CPU Unit Software User’s Manual(W614)
10-1 Interrupts
CP2E 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 CP2E 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.
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 Interrupt s in Page 10- 3
• Specified intervals measured by internal timers
→
Scheduled Interrupt s in Page 10-10
• PVs of high-speed counter
→
High- s peed Counter Interrupt s in Page 11-14
10-1-1 Overview
Interrupt Factors and Types of Interrupts
E N D
E N D
Cycle
Cyclic tasks
(ladder programs)
I/O refreshing
(1)Interr u pt occ u rs
(2)Interr u pt task exec u ted
(3) W hen the interr u pt task is finished,
the ladder diagram that w as b eing
exec u ted is ret u rned to.
Ladder program