If the stage velocity is greater than {TAIL ~ the specified value}, the stage velocity is decreased to avoid exceeding a velocity limit at which {HEAD ~ continuous exposure} is impossible 
If the stage velocity is greater than { TAIL ~ the specified value } , the stage velocity is decreased to avoid exceeding a velocity limit at which { HEAD ~ continuous exposure } is impossible
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH