{HEAD ~ A set up circuit} is coupled to {TAIL ~ sensor}, the power source, and the wire feeder 
is coupled to
{ HEAD ~ A set up circuit } is coupled to { TAIL ~ sensor } , the power source , and the wire feeder
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH