ADA4557自动标定方法的研究

Research on automatic calibration method based on ADA4557

压力变送器是一种将原始压力变量转换为可量化的标准电信号输出的仪表,它的电信号与压力变量存在着连续函数关系。传统的手动标定方法在标定过程中需要人工操作去校准压力变送器,极易引入误差,可靠性差。为了解决传统标定的某些缺陷,研究了基于ADA4557信号调理芯片的自动标定方法,用3组已知压力点下的实际输出值和标准输出值用最小二乘法求出二阶方程的曲线系数从而计算出校正系数并写入压力变送器完成标定。经过计算验证,该标定方法大幅度缩减了标定时间,由传统平均标定时间50缩减至14s,能顺利实现压力变送器的自动标定,且标定效果明显。

The pressure transmitter is an instrument that converts the original pressure variable into a quantifiable standard electrical signal output,and its electrical signal has a continuous function relationship with the pressure variable.The traditional manual calibration method requires manual operation to calibrate the pressure transmitter during the calibration process,which is easy to introduce errors and has poor reliability.In order to solve some of the shortcomings of traditional calibration,this paper studies the automatic calibration method based on the ADA4557 signal conditioning chip.Using the actual output value and standard output value under three sets of known pressure points,the curve coefficient of the second-order equation is obtained by the least square method.Thus,the correction coefficient is calculated and written into the pressure transmitter to complete the calibration.After calculation and verification,the calibration method has greatly reduced the calibration time,from the traditional average calibration time of 50 to 14 s,which can smoothly realize the automatic calibration of the pressure transmitter,and the calibration effect is obvious.