The extent of opening of the sectors 12a and 12b and {HEAD ~ the count N} of the up down counter 42 have {TAIL ~ a pre established relationship} 
have
The extent of opening of the sectors 12a and 12b and { HEAD ~ the count N } of the up down counter 42 have { TAIL ~ a pre established relationship }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL