Rockwell Automation Logix5000 Controllers Tasks, Programs, and Routines Programming Manual - Manual (Page 54)

Chapter 2 Manage event tasks
Example – axis watch trigger
At the labeling station of a bottling line, you want to check the position of the
label on the bottle.
• When the axis reaches the position that is defined as the watch point, check
the label and perform any required adjustment.
• Due to the speed of the line, you have to arm axis for the watch position
within the event task.
Let the watch position…
…for the axis named Axis_1 trigger the event task..
This event task interrupts all other tasks.
The following logic arms and re-arms the axis for the watch position.
Continuous task
If Arm_Watch = 1 (system is ready to set up a watch position) then
the ONS instruction limits the EVENT instruction to one scan.
the EVENT instruction triggers Task_1 (event task).
Task_1 (event task)
54 Rockwell Automation Publication 1756-PM005-EN-P - October 2014