Rockwell Automation 5720 DriveLogix System - Manual (Page 38)

Publication 20D-UM002C-EN-P - November 2003
2-4 What Is DriveLogix?
The following example shows the task execution order for an application with
periodic tasks and a continuous task.
Notes:
A. The highest priority task interrupts all lower priority tasks.
B. The dedicated I/O task can be interrupted by tasks with priority levels
1-6. The dedicated I/O task interrupts tasks with priority levels 8-15.
This task runs at the fastest RPI rate scheduled for the DriveLogix
system (5ms in this example).
C. The continuous task runs at the lowest priority and is interrupted by all
other tasks.
D. A lower priority task can be interrupted multiple times by a higher
priority task.
E. When the continuous task completes a full scan it restarts immediately,
unless a higher priority task is running.
Task: Priority Level: Task Type: Actual
Execution Time: Worst Case
Execution Time:
1 5 20ms periodic task 2ms 2ms
2 7 dedicated I/O task
5ms fastest RPI
1ms 3ms
3 10 10ms periodic task 4ms 8ms
4 none (lowest) continuous task 25ms 60ms
0 30 25 20 15 10 5 45 40 35 50 65 60 55
Task 1
Task 2
Task 3
Task 4