The Design Of Independent Cleaning Non-linear PH Electrode

Nowadays, the water pollution problem brings the natural environment and people’s physical and mental health hazards that can not be ignored. In real life, all kinds of water should be based on water quality analysis results, to make an accurate judgment and evaluation. In the process of water quality testing, p H is an important parameter of water quality detection and it is also an important index to control sewage and industrial wastewater discharge. National Environment Administration regulations, companies and factory emissions of industrial wastewater and sewage p H should be in the range of 6-9. National Environmental Monitoring Station will also regard p H detected as an important control indicator of industrial sewage and wastewater.In recent years, with the development of instrumentation automation and intelligent, p H detection becomes more convenient and quick, the emergence of the p H tester instead of the traditional manual measurement analysis.Technological advances bring convenience, but it also reveals some drawbacks applications. When the p H tester testing p H, the mechanism of electrochemical sensors are crafted with the increase of the number of detections, and the gradual loss of electrolyte, the measurement error will gradually increase. In addition, environmental factors such as classification of garbage, oil and other impurities will pollute the electrode secondly in the testing process, decrease sensitivity,shorten the electrode life,affect the measurement results or damage the instrument. Currently, there are few p H electrode self-cleaning device, some of the device only suitable for special occasions, can not be applied to real life. Therefore, the design of self-cleaning p H electrode has important significance for the fast measurement of p H in the complex environment.In this paper, the application of new micro-control technology, designed a self-cleaning p H electrode on the basis of the existing water quality analysis sensor technology to do some in-depth research of water quality monitoring.The design based on LPC2138 ARM7 microcontroller as the main chip, using 16 bit A/D converter ADS8320 to realize high accuracy of the signal conversion, application of PWM pulse control stepping motor for accurate control of electrode cleaning device. To ensure the utilization of the power supply, AC-DC power supply automatically switching circuit was designed and it provides reliable communication port for transferring data and has a separate PC controlling interface. The design of the p H electrode can be implemented in a variety of environments online measurement of p H and temperature analysis, it can realize automatic cleaning electrode. It has small size, low power consumption, fast response, precise measurements, easy operation and other characteristics.