The magnitude of the extra rotation of said motor has to be set to a value which reliably covers {TAIL ~ at least the possible tolerances} of said valve element and any slacks within the force transmission path between the motor and {HEAD ~ the valve element} 
The magnitude of the extra rotation of said motor has to be set to a value which reliably covers { TAIL ~ at least the possible tolerances } of said valve element and any slacks within the force transmission path between the motor and { HEAD ~ the valve element }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD