The controller varies {HEAD ~ the output pressure} of the pressure source, {TAIL ~ e.g. a rotary compressor}, based, at least in part, on the head position information provided by the head position sensor 
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The controller varies { HEAD ~ the output pressure } of the pressure source , { TAIL ~ e.g. a rotary compressor } , based , at least in part , on the head position information provided by the head position sensor
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH