Abstract:In order to meet the requirements of a photoelectric theodolite, a 24-bit photoelectric shaft angle encoder codesubsystem of an absolute constant light source was designed. The encoder uses 16-bit absolute optical encoder, the codeplate is engraved with coarse code, through the circle code, in the precision code and precision code, the line logarithm ofthe precision code is 16384 (14 bits). The processing circuit of the azimuth and high-low encoder was designed on a cir.cuit board. Using a piece of DSP as the host, the 64 channel code plate photoelectric signals output by 6 reading headswere respectively input to DSP through amplification shaping and A/D conversion. DSP completes data collection, subdivi.sion, decoding, correction and other processing, the shaft angle into 24 natural binary angle code output and upload. Usageindicated: that the structure and layout of the optical machine of the encoder were reasonable, the performance was stable,the circuit board and components were few, the operation was simple, the angle measurement precision was high, whichmet the requirements of a certain type of photoelectric theodolite for the encoder system. It has higher practical value.