Applicance Research Of Capacitive Sensor In Sandstone Measuring System

With the development of construction, market's demand to concrete quality becomes more and more strict. So various kinds of controlling quality methods and equipments are produced at home and aboard. Among them the sandstone dynamic on-line measuring system is an important portion for controlling product quality. Appling capacitive material level sensor, this paper develops a kind of new-type sandstone measuring system, which will improve measuring system's precision and reliability, so improves concrete quality. The research object in this dissertation is the sandstone measuring system. The main results are as follow: 1.For the system characterized by the capacitive material level sensor's small capacitance, analyzing and comparing various kinds of measuring capacitance methods, charge/discharge method has been adopted. Two projects have been designed based on charge/discharge method, makes the practical circuit of this method, and selects the better. The paper researchs "Driving Cable "technology appliance and designs the more suitable method in charge/discharge method. 2.Based on MATLAB system and on the base of method research, this paper presents the related curve of capacitive material level sensor output voltage and sandstone level, and mathematical model of the capacitive material level sensor character has been established . 3.The system adopts AT89C51 single chip microprocessor to realize intelligentized instrument and completes the hardware & software design and manufacture. For the designed on-line measuring system, the successive function and performance experiments prove that it is characterized by high reliability and bright prospect for development and application.