Hypertherm systems equipped with a machine torch and the rear panel CPC port have a signal called “arc transfer” (pins 12 and 14 on the CPC port). This signal is a dry relay contact closure that closes every time the arc current is sensed on the work cable. This very accurately provides a signal that the cutting arc has started. As soon as this contact closure occurs you should then use the exact pierce delay times listed in the operators manual. Jim Colt