Tasks - Mitsubishi Electric MELSEC Q Series Programming Manual

Tasks

A task is an element that contains multiple POUs, and it is registered to a program file. One or more programs of POU need to
be registered in a task. (Functions and function blocks cannot be registered in a task.)
Program file 1
Task Task Task
POU
Program
POU
Program
Task Task Task
POU
Program
POU
Program
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.
■Always (Default executing condition)
Executes registered programs for each scan.
■Event
Executes tasks when values are set to the corresponding devices or labels.
■Interval
Executes tasks in a specified cycle.
Priority
A priority can be set for each task execution.
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 Task Task
POU
Program
POU
Program
POU
Program
Program file n
Task Task Task
POU
Program
POU
Program
Task Task Task
POU
Program
4 PROGRAM CONFIGURATION
4.1 Overview of Program Configuration
4
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