Micro-capacitance measuring system and measuring method

Abstract

The invention discloses a micro-capacitance measuring system. The micro-capacitance measuring system comprises a signal generating module, a capacitance / voltage converting module, a signal collectingand processing module, a CPU and a communication module. The signal generating module comprises a DDS sinusoidal signal generator and a digital-to-analog converter, the signal collecting and processing module includes a programmable amplifier, an analog-to-digital converter and a digital demodulator, an output end of the DDS sinusoidal signal generator is in series connection with the digital-to-analog converter, the capacitance / voltage converting module, the programmable amplifier, the analog-to-digital converter, the digital demodulator and the CPU, a signal input port of the other end of the digital demodulator is connected to the DDS sinusoidal signal generator, and the CPU is also connected to the DDS sinusoidal signal generator, the programmable amplifier and the communication module. The micro-capacitance measuring system can overcome the problem of particle charge interference when charge injection, zero point drift and a measuring object are gas-solid two-phase flow, and the measurement precision is improved. The invention further provides a micro-capacitance measuring method.

Description

technical field [0001] The invention relates to the technical field of two-phase flow quality measurement, in particular to a micro capacitance measurement system and a measurement method. Background technique [0002] With the rapid development of industrial technology and scientific level, gas-solid two-phase flow containing powder particles plays an increasingly important role in the national economy and human life. Powder pneumatic conveying system is widely used in chemical industry, metallurgy, power, light industry and military industry and other departments, and the problems related to powder conveying have also attracted people's attention. Due to the complex flow process of industrial gas-solid two-phase fluid, it is difficult to find its flow law. In the field of modern industry, the measurement of the mass flow rate of gas-solid two-phase fluid has become a very important topic. Many scientific researchers in industrially developed countries have A lot of work h...

AI Technical Summary

Problems solved by technology

[0004] The most commonly used micro capacitance measurement circuits mainly include the charge-discharge method and the AC method. The charge-discharge method capacitance measurement circuit was first used for capacitance detection due to its advantages of simple structure, low cost, and low power consumption. However, it is different from the AC method. Compared with problems such as zero drift and charge injection, it is easy to cause measurement deviation

When the measurement object is a gas-solid two-phase fluid, the particle charging phenomenon will cause a certain charge to be induced on the sensor electrode, thereby generating a certain voltage output in the measurement circuit, which will have a certain impact on the capacitance measurement, sometimes It may even cause the measurement system to fail, which restricts the further improvement of the detection accuracy of tiny capacitance

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