The characteristics of the instrument using computer technology, in line with the national standard GB / T 6062 and ISO, DIN, ANSI and JIS four criteria, can be widely applied to the production site, to measure surface roughness of various machined parts, measured according to the selected Conditions calculate the corresponding parameters, clearly shows all the measured parameters on the LCD monitor for measuring the surface roughness, the sensor on the measured surface of the workpiece, driven by the drive mechanism inside the instrument to do along the tested surface sensor Speed ​​Skating line sensor through the built sharp stylus feel measured surface roughness, when the measured surface roughness of the workpiece caused stylus displacement, the displacement amount sensor inductance coil inductance changes, resulting in a phase-sensitive rectifier generated at the output proportional to the measured surface roughness column analog signal, the signal after amplification and level conversion into the data acquisition system, the data will be collected DSP chip digital filtering and parameter calculation, measurement results are displayed on a liquid crystal display , and can communicate with the PC, data analysis and printing.