A desired trace range is set to achieve {HEAD ~ tracer control} without {TAIL ~ the provision} of limit switches 
without
A desired trace range is set to achieve { HEAD ~ tracer control } without { TAIL ~ the provision } of limit switches
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH