| The pressure transmitter refers to a pressure sensor that is output as a standardized signal.At present,pressure transmitter has been widely used in national defense construction,petroleum exploration,machinery manufacturing,meteorological monitoring,aerospace,metallurgical smelting,biomedical,geological exploration and other fields.The calibration of the pressure transmitter refers to the process of adjusting the input and output curve of the pressure transmitter to the standard input and output curve.The calibration process of the pressure transmitter is an important part of the production of the pressure transmitter and is a crucial step in detennining the output range of the pressure transmitter.By using the traditional manual digital calibration method to adjust the input and output curves of pressure transmitter,there are some problems,such as low precision and low efficiency,and the traditional method can not effectively analyze the performance of pressure transmitter.In order to solve the existing problems,an automatic calibration system of 32-way pressure transmitter is designed,suitable for current output pressure transmitters with embedded programmable gain amplifier 308,automatic calibration of pressure transmitters and analysis of its output characteristics.In this paper,a new calibration method is designed,which analyzes the output characteristics of the pressure transmitter,fits the output curve of the pressure transmitter by using the average slope method,quantitatively analyzes the zero migration and the range migration,and can realize the calibration of the pressure transmitter.Aiming at the problem of the characteristics of the hardware circuit and the system error introduced by the signal acquisition,the calibration method is optimized,and the influence of the system error on the calibration accuracy is reduced.Aiming at the shortcoming of the slow calibration speed of manual digital calibration method,the design scheme of batch calibration of 32-way calibration channel is developed,which improves the time utilization rate and reduces the average calibration time.According to the design scheme,the automatic calibration system of pressure transmitter is designed.The system is composed of the hardware circuit and the calibration software,and realizes the calibration of 32 pressure transmitters.The hardware circuit uses MSP430 as the main control chip,communicates with the host computer software through serial port,and can control the normal switching work of 32 calibration channels.In order to solve the problem that the manual digital calibration process is cumbersome,the operation is complex,and the output current data of the manual reading transmitter is easy to introduce error,the calibration software is developed and designed in VB6.0 software development platform,and the calibration method of the pressure transmitter is applied,combined with the hardware circuit to realize the automatic calibration of the system simplifies the original calibration process,the calibration process is fully automatic,no manual operation,automatic acquisition of output current data.Aiming at the defects that the existing manual digital calibration can not analyze the output characteristics of the pressure transmitter,the automatic calibration system of the pressure transmitter designs the reexamination function.On the one hand,the reexamination function can calculate the reference error of the pressure transmitter,if the reference error meets the requirements,the output precision of the pressure transmitter is qualified,and conversely,if the reference error is too large,the output accuracy of the pressure transmitter is not qualified.On the other hand,the re-inspection function can also provide a detailed output performance analysis report on the linearity,hysteresis and repeatability of the pressure transmitter.The experimental results show that the designed pressure transmitter automatic calibration system can accurately calibrate the pressure transmitter,the calibration accuracy can reach 0.0063%,the average calibration time from the original 51.2 seconds to reduce the present to 9.9 seconds,after the calibration is completed,the system can detect whether the output of the pressure transmitter meets the requirements,at the same time can provide detailed pressure transmitter output characteristic analysis report.The automatic calibration system of pressure transmitter has the average calibration speed,high accuracy and obvious efficiency,and the application of the system in actual industrial production can improve the production efficiency and has a wide application prospect. |
