Motion Control Principles; Cpu Unit Tasks - Omron NJ501-1400 User Manual

2 Motion Control Configuration and Principles
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Motion Control Principles

This section provides information on the CPU Unit tasks and how they relate to motion control.
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CPU Unit Tasks

Tasks are attributes of programs that determine the execution conditions and sequence of the pro-
grams. The NJ-series CPU Units support the following tasks.
Tasks that execute programs at a fixed period
Refer to the NJ-series CPU Unit Software User's Manual (Cat. No. W501) for details on programs,
tasks, and setting methods.
Types of Tasks and Task Priority
The NJ-series CPU Unit can execute the user program with a single task or multiple tasks. Tasks have
an execution priority. Tasks with the highest execution priority are executed first. If the execution condi-
tions are met for another task with a higher execution priority while a task is under execution, the task
with the higher execution priority is given priority in execution. The following table lists the tasks in which
you can use motion control instructions and the task priorities for the NJ-series CPU Unit.
Type of task
Primary 1
periodic task
Periodic tasks 0 or 1
* The CPU Unit has some periodic tasks with an execution priority of 17 or 18. However, you cannot use motion
control instructions in these tasks. These tasks also do not perform I/O refreshing.
Precautions for Correct Use Precautions for Correct Use
• Motion control instructions can be used in the primary periodic task and in a priority-16 peri-
odic task.
• If motion control instructions are used in any other tasks, an error will occur when the user pro-
gram is built on the Sysmac Studio.
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Type of task
Number of
Priority
tasks
4 (fixed)
*
16
Primary periodic task
Periodic tasks (execution priority: 16, 17, and 18)
Operation
This task executes I/O refreshing, programs, and motion con-
trol in the specified task period. This task has the highest exe-
cution priority of all tasks and can be executed quickly and
precisely. Therefore, this task is best suited for situations when
synchronized control or highly responsive control is required.
Use the primary periodic task to execute all control with a sin-
gle task.
These tasks execute programs and I/O refreshing in the speci-
fied task period. The execution period for this task is longer
than the execution period of the primary periodic task. There-
fore, periodic tasks are used to execute programs. For exam-
ple, synchronized control and control requiring a fast response
time are placed in the primary periodic task. Overall device
control is placed in a periodic task.
NJ-series CPU Unit Motion Control User's Manual (W507)
Task name