Trigger Event Task (EventTrigger)
The EventTrigger instruction triggers one execution of an event task.
Use the EventTrigger instruction to programmatically execute an event task.
Each time the instruction executes, it triggers the specified event task.
Make sure that you give the event task enough time to complete its execution before you trigger it again. If not, an overlap occurs.
If you execute an EventTrigger instruction while the event task is already executing, the controller increments the overlap counter, but it does not trigger the event task.
EventTrigger instruction can be used to trigger Event Task with all the trigger types.
Available Languages
Ladder Diagram
FactoryTalk Design Studio
DSL - Ladder DiagramEventTrigger(task_name);
Operands
Ladder Diagram
Operand | Type | Format | Description |
|---|---|---|---|
Task | TASK | name | Event task to execute. If a task is specified that is not the Event task, the specified task will not be executed. |
Affects Math Status Flags
No
Major/Minor Faults
None specific to this instruction. See Common Attributes for operand-related faults.
Execution
Ladder Diagram
Condition | Action Taken |
|---|---|
Prescan | N/A |
Rung-condition-in is false | N/A |
Rung-condition-in is true | The instruction executes. |
Postscan | N/A |
Examples
Example 1
A controller uses multiple programs, but a common shut down procedure. Each program uses a program-scoped tag named Shut_Down_Line that turns on if the program detects a condition that requires a shut down. The logic in each program executes as follows.
If Shut_Down_Line = on (conditions require a shut down) then
Execute the Shut_Down task one time
Ladder Diagram
Program A
Program B
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