Tasks - Mitsubishi MELSEC-Q Series Programming Manual

4.1.3

Tasks

A task is an element that contains multiple POUs, and it is registered to a program file.
One or more program blocks of POU need to be registered in a task. (Functions and function
blocks cannot be registered in a task.)
Program file 1
Program block
Program block
Program block
Program block
(1) Task executing condition
The executing conditions in a programmable controller CPU are set for each task that is
registered to program files. Executing processes are determined for each task by setting the
executing condition.
The following are the types of task executing condition.
(a) Scan execution (Default executing condition)
(b) Event execution
(c) Fixed scan execution
A priority can be set for each task execution.
● Priority
4.1 Overview of Program Configuration
4-4
4.1.3 Tasks
Task
POU
POU
Task
POU
POU
Executes registered program blocks for each scan.
Executes tasks when values are set to the corresponding devices or labels.
Executes tasks in a specified cycle.
When executing conditions of multiple tasks are met simultaneously, the tasks are
executed according to the set priority.
Tasks are executed in the order from the smallest priority level number.
Tasks set with a same priority level number are executed in the order of task data name.
Project
Program file 2
Task
POU
Program block
POU
Program block
POU
Program block
Program file
n
Task
POU
Program block
POU
Program block
Task
POU
Program block