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