Research On Automatic Calibration System For NSA2860 Pressure Transmitter

Pressure transmitters are instruments and equipment that can convert continuous pressure physical signals into corresponding standard electrical signals according to the set scale.Pressure transmitters are usually used in defense industry,astronautics,geological prospecting and other industrial applications.As the domestic pressure transmitter industry is developing rapidly,its low production efficiency,high labor intensity and output reliability need to be further optimized.Therefore,pressure transmitters need to be improved in calibration methods.According to the internal structure of the pressure transmitter,the specific adjustment of the pressure transmitter calibration is the parameters of the signal conditioning chip inside the pressure transmitter.In this thesis,an automatic digital calibration system is designed for the NSA2860 signal conditioning chip produced in China.In the full temperature zone,the output curve of the pressure transmitter is adjusted.The main contents are as follows:1)Depending on the characteristics of the NSA2860 signal conditioning chip,a calibration algorithm is designed to calibrate the transmitter by solving the coefficients in the actual output curve of the transmitter.The specific calibration method is to collect the ADC values of the internal temperature channel and pressure channel of the transmitter under three sets of temperature points at three temperature points,fit the actual curve of the transmitter by the third-order nonlinear calibration method,and realize the solution of the calibration coefficient,which solves the nonlinear output problem of the transmitter in the full temperature zone.2)Depending on the actual needs of the enterprise,the pressure transmitter auto-calibration system was implemented using a combination of embedded platform and instrumentation technology.The automatic calibration system mainly includes interface device module and host computer software module.(1)Interface device module,aiming at the problem of slow manual calibration time,designed 16 transmitter batch calibration channels,through the main control chip to switch the channel;(2)Upper computer calibration software,based on Lab VIEW for developing the software platforms,the main functions include the implementation of the interfacing device control,the control of the pressure controller and the incubator,and the implementation of the calibration algorithm.In view of the errors that are easy to occur due to human factors,the calibration system is automatically processed to reduce the errors caused by the system.To facilitate later analysis of pressure transmitter capabilities,the calibration system also designed a review module and a report record module.The double-check module calculates the error by comparing the actual transmitter outputs with the digital outputs to determine whether the actual outputs of the pressure transmitters are qualified;The report recording module can record the original data,calibration coefficients,and retest data during the calibration process,which is convenient for the analysis of the performance of the pressure transmitter.Experimental testing by live platform.At room temperature,the auto-calibration system for pressure transmitters reduces the calibration time several times compared to the manual calibration system,and the calibration precision satisfies the requirements.Depending on the laboratory analysis resulted,the pressure transmitter automatic calibration system designed in this thesis can be satisfied with the actual industrial production requirements,enhancing the production efficiency of enterprises,and has potential application value.