Use The Event Task - Allen-Bradley 1769-L16ER-BB1B User Manual

Chapter 7 Use I/O Modules with CompactLogix 5370 L1 Controllers

Use the Event Task

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The CompactLogix 5370 L1 controllers support the use of an Event task with
their embedded input points. You can configure embedded input point terminals
to trigger an Event task if a change of state (COS) occurs.
When using the Event task with the CompactLogix 5370 L1 controllers,
IMPORTANT
consider these points:
• You can use the Event task only with Logix Designer application, version
21.00.00 and later.
• You can use the Event task only with the embedded input points of the
controller. You cannot use the Event task with input points in the local
expansion modules, for example, a 1734-IB4 module.
• You can use the Event task only if the input point has an input data
state change.
• An event is recognized only when it maintains the same state for at least
the duration of the input filter time specified.
• Configure the Event task at a rate that stops task overlap conditions.
• Configure the Event task at a rate that is likely to succeed.
A 2 ms signal width is the minimum pulse width that can be used at which
the Event task succeeds.
You can configure multiple embedded input points to trigger an Event task.
However, we recommend that you enable COS for only one point. If you enable
COS for multiple points, a task overlap of the Event task can occur.
You can configure an Event task to trigger if one of these events occurs:
• An event occurs on one point on an input module.
• A trigger event does not occur in a time interval.
You configure whether the task updates output modules at the end of the task.
After the task executes, it does not execute again until the event occurs again.
Each Event task requires a trigger.
Rockwell Automation Publication 1769-UM021G-EN-P - October 2015