Omron CJ - PROGRAMMING MANUAL 12-2009 Programming Manual page 57

Description of Tasks
Executable and Standby
Status
Program
Task 0 (control task)
Task 1
Task 2
Task 3
Standard subroutine programs
User program ABC
Task 1 (A)
Task 2 (B)
Task 3 (C)
When creating modular programs, addresses can be specified by symbols to
facilitate standardization.
The TASK ON and TASK OFF instructions (TKON(820) and TKOF(821)) can
be executed in one task to place another task in executable or standby status.
Instructions in tasks that are on standby will not be executed, but their I/O sta-
tus will be maintained. When a task is returned to executable status, instruc-
tions will be executed with the I/O status that was maintained.
Example: Programming with a Control Task
In this example, task 0 is a control task that is executed first at the start of
operation. Other tasks can be set from the CX-Programmer (but not a Pro-
gramming Console) to start or not to start at the beginning of operation.
Once program execution has been started, tasks can be controlled with
TKON(820) and TKOF(821).
Task 0
Example: Task 0 is set to be executed at the start of operation
(set in the program properties from the CX-Programmer).
Task 1 is executable when a is ON.
Task 1 is put on standby when b is ON.
Tasks 2 and 3 are executable when c is ON.
Tasks 2 and 3 are put on standby when d is ON.
User program ABD
Task 1 (A)
Task 2 (B)
Task 3 (D)
Section 1-6
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