基于同步采样方法的电导率测量系统设计

提出了基于同步采样方法的电导率测量系统的设计方案.系统采用双极性方波作为测量电导率的激励信号,并且实现了其幅度和频率均可调.数据采样采用同步采样方法,将待测电压和电流的峰峰值幅度转化为直流量,不仅提升了测量精度,同时简化了单片机内ADC对信号的处理.实验数据既可以通过液晶屏显示,也可在LabVIEW搭建的平台中显示和存储.利用本系统进行电导率测量实验,实验表明,当激励信号振幅较大时,测量误差超过可控范围,而较小的振幅有助于提升系统测量的准确性.

Design of a conductivity measuring system based on the synchronous sampling method

The design proposal of a conductivity measurement system based on the synchronous sampling method has been exhaustively investigated.In the measuring system,bipolar square wave is used as excitation signal for the measurement of electrical conductivity and the adjustable amplitude and frequency are realized at the same time.In terms of data sampling,the system have used synchronous sampling method to convert the measured voltage and current peak amplitude to the direct flow,which improve measurement accuracy and simplify the signal processing for ADC in the microcontroller.The experimental data can be displayed on the LCD screen and it can be also demonstrated and stored in the platform built by LabVIEW software.The experiments for the measurement of electrical conductivity are carried out in the conductivity measuring system,the results show that the measurement error is exceeded the controllable range when the excitation signal amplitude is relatively large,and that is to say,relatively small excitation signal amplitude helps to enhance the accuracy of the measuring system.