A machine table driven by closed loop positioning system consists of a motor, gearbox, lead screw and an optical encoder. The lead screw has a pitch of 0.200 in/rev and is coupled to the motor by way of a gearbox having a gear ratio of 5:1 (5 turns of motor for 1 turn of lead screw). The optical encoder generates 200 pulses per revolution of the encoder. The table has been programmed to move a distance of 5.0 in. at a feed rate of 16.0 in./minute.
a) If the encoder is connected directly to the lead screw determine: How many pulses are received by the control system to verify that table has moved exactly 5 inches? Motor speed that corresponds to the specified feed rate.
b) If the encoder were to be connected to the motor instead of the lead screw determine: How many pulses does the encoder output for one revolution of the lead screw? How many pulses are received by the control system to verify that table has moved exactly 5 inches?
c) Which of the above encoder configuration would you use for high precision application? Explain.