Rockwell Automation 5730 DriveLogix5730 Controller for PowerFlex 700S Drives with Phase II Control - Manual (Page 20)

1-8 What is DriveLogix5730?
The following example shows the task execution order for an application
with two periodic tasks and one 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
to 6. The dedicated I/O task interrupts tasks with priority levels 8 to 15.
This task runs at the selected RPI rate scheduled for the DriveLogix5730
system (2ms 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.
Defining programs
Each program contains program tags, a main executable routine, other
routines, and an optional fault routine. Each task can schedule as many as
32 programs.
The scheduled programs within a task execute to completion from first to
last. Programs that are not attached to any task show up as unscheduled
programs. You must specify (schedule) a program within a task before the
controller can scan the program.
Task: Priority Level: Task Type:
Example
Execution Time: Worst Case
Completion Time:
1 5 periodic task, executes every 20 ms 2 ms 2 ms
2 7 dedicated I/O task (5 ms RPI) 1 ms 3 ms
3 10 periodic task, executes every 10 ms 4 ms 8 ms
4 none (lowest) continuous task 25 ms 60 ms
0 30 25 20 15 10 5 45 40 35 50 65 60 55
Task 1
Task 2
Task 3
Task 4
Time (ms)
task_example.eps