Logix5000 Controllers General Instructions - SLAC Confluence

466 Program Control Instructions (JMP, LBL, JSR, RET, SBR, JXR, TND, MCR, UID, UIE, AFI, NOP, EOT, SFP, SFR, EVENT)Trigger Event Task (EVENT)The EVENT instruction triggers one execution of an event task.Operands:Relay LadderOperand Type Format DescriptionTask TASK name event task to executeThe instruction lets you choose other types oftasks, but it does not execute them.EVENT(task_name);Structured TextThe operands are the same as those for the relay ladderEVENT instruction.Description:Use the EVENT instruction to programmatically execute an event task:• Each time the instruction executes, it triggers the specified eventtask.• Make sure that you give the event task enough time to completeits execution before you trigger it again. If not, an overlapoccurs.• If you execute an EVENT instruction while the event task isalready executing, the controller increments the overlap counterbut it does not trigger the event task.Programmatically Determine if an EVENT Instruction Triggered aTaskTo determine if an EVENT instruction triggered an event task, use aGet System Value (GSV) instruction to monitor the Status attribute ofthe task.Status Attribute of the TASK ObjectAttribute Data Type Instruction DescriptionStatus DINT GSVSSVProvides status information about the task. Once the controller sets a bit, youmust manually clear the bit to determine if another fault of that type occurred.To determine if:Examine this bit:An EVENT instruction triggered the task (event task 0only).A timeout triggered the task (event task only). 1An overlap occurred for this task. 2Publication 1756-RM003I-EN-P - January 2007