34 Rockwell Automation Publication 1789-UM002K-EN-P - January 2015
Chapter 2 What is the SoftLogix System?
Developing Programs
The controller’s execution model is a preemptive, multitasking system that is
IEC 1131-3 compliant. This environment provides the following:
• Tasks to configure controller execution
• Programs to group data and logic
• Routines to encapsulate executable code written in a single
programming language
Configuring Tasks
A task provides scheduling and priority information for a set of one or more
programs. You can configure tasks as either continuous or periodic. The
SoftLogix controller supports as many as 32 tasks, only one of which can
be continuous.
A task can have as many as 32 separate programs, each with its own executable
routines and program-scoped tags. Once a task is activated, all of the programs
assigned to the task execute in the order in which they are grouped. Programs can
appear only once in the Controller Organizer and cannot be shared by
multiple tasks.
Figure 2 - Control Application
Controller Fault Handler
Task 32
Task 1
Configuration
Status
Watchdog
Program 32
Program 1
Main Routine
Fault Routine
Program (local)
Tags
Other Routines
Controller (global) Tags I/O Data System-shared Data
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