High Accuracy Calibration System for Angular Encoders

Abstract

This paper describes an automatic calibration system for various angular encoders with high resolution and high accuracy. The system has a photoelectric encoder as a reference standard with 225000 P/R, and object encoders are compared with the reference standard. Using the time conversion method, the relative angle position errors are detected with 0.001"" resolution, and all graduations are automatically measured. The reference standard is automatically calibrated by the self-checking method used the other encoder. As the calibration results, the calibration values of the reference standard were obtained with an accuracy of approximately ±0.5 arc second, and the accuracy of the calibration values were presumed to be approximately 0.05 arc seconds.