Execution Status Of The Multiple Task - Mitsubishi Electric Melsec Q Series Programming Manual

9 OPERATION FOR MOTION SFC AND PARAMETER

9.3 Execution Status of the Multiple Task

NMI task-execute program
3.55ms event task-execute program
Normal task-execute program
If too many NMI tasks and event tasks are executed, an operation cycle over occurs, or the
majority normal tasks are not executed and a WDT error may occur.
Execution status of each Motion SFC program when the Motion SFC program is
executed multiple tasks is shown below.
When there are programs which are executed by the NMI task, 3.55ms fixed-cycle
even task with a program to run by the NMI task, and the normal task like a chart,
(1) The 3.55ms fixed-cycle event task is executed at intervals of 3.55ms;
(2) The NMI task is executed with the highest priority when an NMI interrupt is input;
and
(3) The normal task is executed at free time.
as shown above.
[Points]
One Motion SFC program can be executed partially by another task by setting the area
to be executed by another task as a subroutine and setting a subroutine running task
as another task.
<Example>
No. 0 Main Motion SFC program
No. 1 Subroutine
3.55ms NMI interrupt
Normal task
Event task (3.55ms cycle)
CAUTION
9 - 6
NMI interrupt