The Development Of Intelligence Electrical Conductivity Measurement System

The measure of electrical conductivity has always abroad applied such fields as environmental inspection, industrial flow control, medical sanitation, science research and products' quality check. The checking to water quality and the assessing to electron industrial water are the most evident. With the development of industry, there is a growing concern over the electric conduction function and component of the medium in increasing products and technology. Furthermore, the higher demands are needed for the real-time and accuracy. This paper presents a intelligence type of electrical conductivity measurement system developed and introduces its developed background, designed ideology , applied effect. The measuring result can be monitored by the host computer through the wireless transmission. The system can be used in industry for real-time measurement and monitor in a long distance. The main works are listed as follows:(1) Using C8051F020 singleship microcomputer, developed a intelligence type of solution conductivity measurement instrument. The measuring range is rather wide from 0μS·cm^-1 to 105μS·cm^-1.The full scale error is less than±1%.It achieves auto-gearing, temperature compensation, exceeding conductance limit alarm, water inlet and outlet valve autocontrol. The instrument is excited by bi-directional square wave pulse voltage source. Through fast bi-directional voltage switching, the polarization erect is abated. During the data acquisition, the system is regarded as being excited by a constant direct voltage point, which can improve the rate of data acquisition and simplify the circuit of electrical conductivity instrument system.(2) Through multiple measurements of standard resistance, the proposed instrumentwas calibrated by adopting linearity fitting method using Matlab and six calibration modelswere obtained in different measurement range.(3) Using 51 singleship microcomputer as the core, developed the wireless communication net. The host computer communicates with the slave by the wireless communication. Compared with lineate communication, wireless communication can avoid the defect of waste of distance laying line and high cost. The wireless communication can make Cyclic Redundancy Check and code the sending message to advance the dependability of data sending. The monitor computer read the managed data through 232 serial implement directly .