Allen-Bradley 1756-L63XT, User Manual

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154 Rockwell Automation Publication 1756-UM001O-EN-P - October 2014
Chapter 10 Develop Applications
Routines A routine is a set of logic instructions in one programming language, such as
Ladder Diagram (ladder logic). Routines provide the executable code for the
project in a controller. A routine is similar to a program file or subroutine in a
PLC or SLC processor.
Each program has a main routine. The main is the first routine to execute when
the controller triggers the associated task and calls the associated program. Use
logic, such as the Jump to Subroutine ( JSR) instruction, to call other routines.
You can also specify an optional program fault routine. The controller executes
this routine if it encounters an instruction-execution fault within any of the
routines in the associated program.
Figure 35 - Routines in a Control Application
Figure 36 - Routines
Controller Fault Handler
Task 32
Task 1
Configuration
Status
Watchdog
Program 1000
Program 1
Main Routine
Fault Routine
Other Routines
Controller (global) Tags
I/O Data System-shared Data
Program (Local
Tags and
Parameters)
Routine
Routine
Routine
Routine
Controller Designer
Logical Designer