四环电极电导率检测系统设计

文中设计了一种四环电极电导率检测系统,可有效避免测量时因电极极化效应、电极污染带来的误差,提高检测精度。系统采用模块化设计,主要分为3个主要功能模块:激励模块、调理模块及采集传输模块。系统利用差分接收方式采集感应电极的输出电压,通过同步解调得到具有幅值信息的直流信号,经滤波放大后进行A/D采集,最终通过串口将数据发送到上位机中进行计算并实时显示。同时采用Pt1000温度传感器进行温度采集与温度补偿,利用最小二乘法进一步减小误差。结果表明,该系统能够实时检测电导率,有效避免了电极极化效应,电导率测量的相对误差在0.5%以内,电导率测量可达40 mS/cm。

Design of Four-ring Electrode Conductivity Detection System

A four-ring electrode conductivity detection system was designed to effectively avoid errors caused by electrode polarrization effects and electrode contamination during measurement,and improved detection accuracy.The system adopted a modular design and was mainly divided into three main functional modules,an incentive module,a conditioning module,and an acquisition and transmission module.The system used the differential receiving method to collect the output voltage of the induction electrode,obtained a DC signal with amplitude information through synchronous demodulation,and performed A/D acquisition after filtering and amplification.Finally,the data was sent to the host computer through the serial port for calculation and real-time display.Pt1000 temperature sensor was used for temperature acquisition and temperature compensation,and the least square method was used to further reduce the error.The results show that the system can detect the conductivity in real time,effectively avoid the electrode polarization effect,the relative error of the conductivity measurement is within 0.5%,and the conductivity measurement can reach 40 mS/cm.