$IF ONCE

When the condition is fulfilled the first time, the instruction section is executed once. The instruction section is no longer executed in later run-throughs, even if the condition is fulfilled.

Programing Example

$IF ONCE

; Define real-time cycle

#RT CYCLE [SCOPE = PROG]

  ; Query ACS position of X axis

  $IF ONCE V.RTA.ACS.ACT_POS.X > 200

    ; Output M function

    M100

  $ENDIF

#RT CYCLE END