Floathing head plasma setting ?

Hi ! I’m running cnc plasma that i build . Using mach 3 and sheetcam. I’ve install my floating head but thats doesnt work . I’ve try mach3 plasma thc with scribber post and also try MP1000-THC-scriber post. Anyone work . I’ve set my floating head switch as homing z . When i click homing that work , z stop when clicking the switch . When i open test programme ( cercle test ) , the z down but when clicking swich , it keep going down … maybe somewhere on mach 3 setting i miss ??