Omron NJ Series

5-1
NJ-series CPU Unit Software User’s Manual (W501)
5
This section describes the task system and types of tasks.
5-1 Overview of Task Designing Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
5-2 Task System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
5-2-1 Overview of Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
5-2-2 Specifications of Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
5-2-3 Basic Operation of Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
5-2-4 Event Task Execution Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
5-2-5 Event Task Execution Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18
5-2-6 Operation When Execution Condition Is Met Again before
Execution of the Event Task Is Completed . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
5-2-7 Tag Data Link Service and System Services . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
5-2-8 Processing Performed in and Execution Timing of the Tag
Data Link Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26
5-2-9 Processing Performed in and Execution Timing of the System Services . . . 5-29
5-2-10 Assigning I/O Refreshing to Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31
5-2-11 Assigning Tasks to Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32
5-2-12 Parameters for Primary Periodic Task and Periodic Tasks . . . . . . . . . . . . . . 5-33
5-2-13 Ensuring Concurrency of Variable Values between Tasks . . . . . . . . . . . . . . . 5-35
5-2-14 Variable Access from Outside the Controller . . . . . . . . . . . . . . . . . . . . . . . . . 5-39
5-2-15 Instructions Related to Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42
5-2-16 System-defined Variables Related to Tasks . . . . . . . . . . . . . . . . . . . . . . . . . 5-43
5-2-17 Errors Related to Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-45
5-2-18 Monitoring Task Execution Status and Task Execution Times . . . . . . . . . . . . 5-47
5-3 Task Design Methods and I/O Response Times . . . . . . . . . . . . . . . . . . . . 5-51
5-3-1 Checking the Task Execution Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-51
5-3-2 Checking the System Service Monitoring Settings . . . . . . . . . . . . . . . . . . . . 5-53
5-3-3 Examples of Task Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-53
5-3-4 System Input and Output Response Times . . . . . . . . . . . . . . . . . . . . . . . . . . 5-54
Designing Tasks