Allen-Bradley MicroLogix 1200 Reference Manual

Publication 1762-RM001C-EN-P
18-2 Using Interrupts
Information About Using
Interrupts
The purpose of this section is to explain some fundamental properties of
the User Interrupts, including:
•
What is an interrupt?
•
When can the controller operation be interrupted?
•
Priority of User Interrupts
•
Interrupt Latency
•
User Fault Routine
What is an Interrupt?
An interrupt is an event that causes the controller to suspend the task it is
currently performing, perform a different task, and then return to the
suspended task at the point where it suspended. The Micrologix 1200 and
MicroLogix 1500 support the following User Interrupts:
•
User Fault Routine
•
Event Interrupts (4)
•
High-Speed Counter Interrupts
(1)
•
Selectable Timed Interrupt
An interrupt must be configured and enabled to execute. When any one
of the interrupts is configured (and enabled) and subsequently occurs, the
user program:
1. suspends its execution
2. performs a defined task based upon which interrupt occurred
3. returns to the suspended operation.
(1) The MicroLogix 1200 has one HSC Interrupt, HSC0. The MicroLogix 1500 has two, HSC0 and HSC1.
Program File 2
Program File 10
rung 0
rung 123
rung 275
Interrupt Operation Example
Program File 2 is the main control program.
Program File 10 is the interrupt routine.
•
An Interrupt Event occurs at rung 123.
•
Program File 10 is executed.
•
Program File 2 execution resumes
immediately after program file 10 is
scanned.

Allen-Bradley MicroLogix 1200 Specifications

General

Brand	Allen-Bradley
Model	MicroLogix 1200
Category	Control Unit
Language	English