UNIT CONVERSION DEVICE FOR LASER LENGTH MEASURING INSTRUMENT

摘要

PURPOSE:To reduce the cost of constituent components by adding and subtracting conversion coefficient data consisting of M digits (M: integer) every reference length units of the laser length measuring instrument and outputting a distance signal according to a carry to or a borrow from (M+1) digits. CONSTITUTION:A laser beam LB1 emitted by a laser oscillator 1 is passed through an interferometer 2 and a reflecting mirror 4a to become a reflected beam LB2. The beams LB1 and LB2 are supplied as a composite beam LB12 from the interferometer 2 to a receiver 3, which converts interference fringes formed with the beam LB12 into two scale signals SA and SB of phases A and B. Then the signals SA and SB outputted from the receiver 3 are inputted to the pulse converter 51 of the unit conversion device 5 to output a movement- direction signal S+- and a position clock signal SP. When this signal SP is supplied from the converter 51 to a register 54, the register 54 supplies added data DS2 to an adder subtracter 53. The adder subtracter 53 outputs a distance pulse signal SL every time a carry to the (M+1) digits or a borrow from (M+1) digits is generated.