Encoders on the opposite end of the shaft

My old P&W Tape'O'Matic is set up with the motors coupled 1:1 with
the ball screws with cogged tooth belts. The tach is on the motor. The
encoder is on the opposite end of the shaft than the drive cog. Although
this beast has yet to run for me, it was obviously running this way before
it went brain dead. It's very likely that the lash/flex in the cogged belt
was much more than the twist of the ball screw, thereby making the decision
as to what end of the shaft to sense a moot point. This design might be
easier to implement than a rigidly coupled motor.

Brad