High-precision displacement measuring instrument based on PSoC3

CHEN Peng-jie， LU ling-xia， LI Hua-ming
（College of Electrical Engineering， Zhejiang University， Hangzhou 310027， China）

Abstract： In order to reduce production costs and the volume of high-precision displacement measuring instrument based on the the linear variable differential transformer（LVDT），and to make the products more competitive，taking the advantage that the PSoC3 is more system monolithic than traditional single-chip，a new design for displacement measurement system was proposed based on CY8C3866AXI by analyzing its working principles. The displacement of high-precision measurements was achieved through the use of PSoC3 within the digital module（DMA and LCD），the analog modules（AD，DA，PGA，etc.），and the signal modulation circuit was designed by oneself which is consisted of the rectifier circuit，filter circuit，and the subtraction circuit. The combination of ARM and AD698 product in the past was replaced by this design which has accuracy of 0.2 μm. The results indicate that this program has advantages such as high integration，good linearity and a low disbursement.
Key words： displacement measuring instrument； linear variable differential transformer（LVDT）； PSoC3； signal modulation