Create a Task
A task is a scheduling mechanism for executing a program. A program executes a set of instructions in a project. Schedule a maximum of 32 programs to execute when a task is triggered. ControlLogix and SoftLogix allow a maximum of 1,000 programs . Configure a task to run as a continuous task or a periodic task, or when triggered by an event. Create a maximum of 32 tasks to schedule programs.
For large programs, it is possible to schedule different parts of the process at different times.
A task is a scheduling mechanism for executing a program. Schedule a maximum of 32 programs to execute when a task is triggered; for ControlLogix and SoftLogix, the maximum number of programs is 1,000.
A continuous task is a task that runs continuously (that is, in the background), from top to bottom, through all its assigned programs, unless interrupted by another task. All CPU time not allocated to other operations (for example, motion, communications, and periodic or event tasks) is used to execute the programs within the continuous task. Once the task completes a full execution scan, an output update is triggered and the scan immediately starts over at the top.
TIP:
A project does not require a continuous task. However, each project allows only one continuous task.
A task executed at a fixed interval, ranging from .1 msec to 2,000,000 msec, in increments of 1 msec.
Periodic tasks perform a function according to a specific rate. When the end of this specified time period is reached, the task is triggered. When triggered, the task interrupts any lower priority task (either continuous, periodic, or event), and all programs assigned to the task are executed or scanned once, from top to bottom. After this single scan, an output update is triggered and control is returned to the task that was interrupted, at the point at which it was interrupted.
TIP:
Multiple periodic tasks may exist on a controller, where each task is configured to operate at independent rates.
A maximum of 32 tasks can be created to schedule programs. Use a task to schedule the execution of programs. Schedule a task to run continuously, periodically, or when triggered by a specific event. A controller can have up to 32 tasks.
The steps to create a task vary, depending on the type of task. Follow the procedure according to the task type.
Access the New Task dialog
From the
File
menu, choose New Component > Task
.Alternately, right-click the
Task
folder in the Controller Organizer, and choose New Task
.Provide Feedback