A Design Of High Precision Resistance Strain Data Acquisition System

With the development of science and technology,the demand of strain test is increasing.In the complex measurement environment,the strain electrical measurement method is efficient and reliable.It is important to design a resistance strain data acquisition system with high acquisition accuracy and easy to use.This paper takes the high-precision resistance strain measurement technology as the research topic,and focuses on four parts: proportional dynamic feedback bridge method,low-noise signal conditioning channel,high-precision bridge excitation and strain data filtering and compensation algorithm.The system optimizes the design from four aspects: measurement method,hardware conditioning,bridge excitation and data processing to achieve high-precision resistance strain data acquisition.In terms of measurement methods,the system uses the proportional dynamic feedback bridge method to measure the resistance strain,which greatly reduces the strain measurement error caused by long line voltage drop and excitation jitter in principle;In terms of hardware conditioning,the pre-differential amplifier,program-controlled amplifier and low-pass filter can effectively suppress noise,improve signal-to-noise ratio,and provide guarantee for high precision sampling conversion in the later stage;In the aspect of bridge excitation,the DC voltage excitation with low noise and high stability is designed to drive the bridge,so as to reduce the interference of the excitation source to the output signal of the bridge;In the aspect of data processing,the results of proportional measurement are processed by window adaptive moving average filter,which takes into account the dynamic response and filtering effect,and the thermal output of strain measurement data is compensated by segments to further reduce the measurement error.After testing and verification,the resistance strain data acquisition system designed in this paper can access more than 30 kinds of 120 ? 5000 ? resistance strain sensors.The resistance strain data acquisition accuracy is 0.03% FS,the root mean square error of 2.5 V DC voltage excitation is not more than 16.2,and the indication error of the built-in programmable bridge arm in the common resistance value is not more than4.6%.Other functions of the system meet the design requirements,and meet the actual use requirements.To a certain extent,it solves the problems of zero temperature drift compensation of resistance strain gauge,the contradiction between system volume and channel number,and the historical problems of traditional strain acquisition system..