Consideration for a high resolution of magnetic rotary encoder

The structure of a magnetic rotary encoder is very simple compared with an optical type and is not affected in dust and mist conditions. However, a magnetic rotary encoder with an upper limit of encoder resolution of 2000 pulses per revolution (ppr) per track has lower resolution compared with an optical encoder. In this paper, a high resolution magnetic rotary encoder with 4000 ppr per track resolution utilizing a minimum number of magneto-resistive elements has been developed by using a double interpolation method. A parameter analysis of the magnetization and the detection processes for the main magneto-resistive output voltage using a finite element method is described.