The skip input cannot be made conditional so it does not show up in the ladder AFAIK.
When writing G31 routines or macro's it is customary to have a protected positioning move, this is a routine that would typically be used to move the probe to initial position in say rapid, IOW, any move of the probe should include a G31.
The standard G31 input is sent from PLC to CNC via the BMI, an optional High speed skip input is available through an add on board and option parameter that directs the high speed G31 skip input directly to the CNC side.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.