{HEAD ~ Detectors} are provided in {TAIL ~ each working group} of the production line to output signals to a microcomputer 
{ HEAD ~ Detectors } are provided in { TAIL ~ each working group } of the production line to output signals to a microcomputer
HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH