Omron NJ-series User Manual page 552

Appendices
Setting the Task Period
The task period is set based on the average real processing time of the task that is calculated as above.
The task is the primary periodic task.
The value of the task period must be larger than the average real processing time of the task that you
calculated. More specifically, you should allow sufficient margin and set the task period value to at least
1.1 times as large as the average real processing time of the task.
Task period  Average real processing time of task  1.1
Because the average real processing time of the task that is calculated above is 403 s, the task period
is set to 500 s, which is larger than 1.1 times the average time.
The task execution times in the physical Controller depends on the logic operations that are performed
in the user program, the presence of communications commands and data links, on whether data trac-
ing is performed, and on other factors. The task execution time for a periodic task depends on whether
it is interrupted for the execution of tasks with higher execution priorities.
Use the physical Controller and verify the task execution time with the Task Execution Time Monitor.
NJ-series CPU Unit Software User's Manual (W501) A-25