Logix5000 Controllers General Instructions - SLAC Confluence

For/Break Instructions (FOR, FOR...DO, BRK, EXIT, RET) 473When enabled, the FOR instruction repeatedly executes the Routineuntil the Index value exceeds the Terminal value. This instructiondoes not pass parameters to the routine.Each time the FOR instruction executes the routine, it adds the Stepsize to the Index.Be careful not to loop too many times in a single scan. An excessivenumber of repetitions can cause the controller’s watchdog to timeout,which causes a major fault.Arithmetic Status Flags:not affectedFault Conditions:A Major Fault Will Occur If Fault Type Fault Codemain routine contains a RET instruction 4 31Conditionprescanrung-condition-in is falseExecution:Relay Ladder ActionThe rung-condition-out is set to false.The controller executes the subroutine once.If recursive FOR instruction0s exist to the same subroutine, the subroutine is prescannedonly the first time. If multiple FOR instructions exist (non-recursive) to the samesubroutine, the subroutine is prescanned each time.The rung-condition-out is set to false.Publication 1756-RM003I-EN-P - January 2007