基于CDC技术的微小电容测量系统

为了解决电容层析成像技术中的微小电容检测问题,设计了一种以电容数字转换器(CDC)芯片Pcap01为核心,以STM32F103为控制芯片,以PC机为上位机的微小电容测量系统.采用CDC芯片将被测电容转换为成比例的数字信号,通过I2C总线传给STM32F103,使用STM32F103对数据做初步处理,并通过串口传递给上位机.上位机使用Qt软件平台进行数据的读取、处理、显示和存储.实验结果表明,该系统具有精度高、抗杂散能力强和实时性好等优点,可以满足电容层析成像系统中对微小电容在线测量的要求.

Micro-capacitance measurement system based on CDC technology

In order to solve the problem of micro capacitance measurement in the electrical capacitance tomography technology, a micro capacitance measurement system was designed through taking capacitance to digital converter （CDC） chip Pcap01 as core, STM32F103 as control chip and PC as upper machine. The capacitance to be measured was converted into the proportional digital signals with CDC chip, and the signals were sent to STM32F103 with the I2C bus pass. In addition, the preliminary processing of data was performed with STM32F103, the data were sent to the upper machine via the serial port, and the data were read, displayed and storied with the Qt software platform in the upper machine. The experimental results show that the proposed system has such advantages as high accuracy, strong anti stray capability and good real time performance, and can meet the requirements in the on line measurement of micro capacitance for the electrical capacitance tomography system. 