sorry i forgot to say i initially had it working with mach3 before i changed to acorn . the nema 34 reverses and pops out the locking pawl no problem . the macro counted steps between tools position then reversed a set amount after the locking pin was fired to pop out the pawl to lock in place . it counted by a proximity switch picking up 8 capscrew heads on a disc coupled to the shaft . i didnt know how to get it to work with centroid so i took it off and fitted a dixon style toolpost.