基于LabVIEW的微小电容测量

Micro Capacitance Measurement Based on LabVIEW

摘要:

针对电容层析成像技术中的微小电容测量的问题,以数字相敏检波原理为基础,LabVIEW软件及NI采集卡为核心设计了微小电容测量系统;LabVIEW程序控制NI采集卡产生激励信号加在微小电容两端,C/V转换电路将其转换为电压信号,NI采集卡将采集的电压信号传送到PC机中,并在LabVIEW程序中通过数字相敏检波算法对数据进行处理及显示;最终,通过对数据进行线性化,得到相应的测量电容值;实验结果表明,该系统具有精度高,线性度好,稳定性好等优点,可以满足电容层析成像系统中对微小电容的测量的要求。

Abstract:

In view of the problems of micro capacitance measurement in electrical capacitance tomography technology, micro capacitance measurement system is designed, which is based on digital phase sensitive detection principle and the core of LabVIEW and NI acquisition card. The excitation signal produced by NI acquisition card which is controlled by the LabVIEW program is loaded on the capacitance, and the capacitance is converted into voltage signal by the C/V converting circuit, and the voltage signal is changed to data by NI data acquisition card which is controlled by LabVIEW program and passed on to PC, and the digital phase sensitive detection algorithm can be realized in LabVIEW program, and then the data can be displayed. In the end, the corresponding capacitance value is obtained by linearization of the data. Experimental results show that the system has the advantages of high precision, good linearity, good stability, and can meet the requirements of micro capacitance measurement in electrical capacitance tomography system.