The Research And Development Of The On-line Water-quality Monitoring System

Water resource protection is a great thing related to the development of industry and agriculture and people's health, so people concern the research and development of the water-quality monitoring system extremely. At an earlier time, the traditional electronic measuring instruments are used to monitor water quality mainly. Because the operating process is complicated and the variation of water quality is very difficult to be detected continuously, this conventional water-quality monitoring system has very great limitation in using. The on-line water-quality monitoring system can measure water quality uninterruptedly, what making water quality monitored at any time.After the thesis outlines the theory of the water quality measure, a designing method of an on-line water-quality monitoring system is explained. And the thesis analyses the design plan of this system's hardware and software.The hardware part of this system is the expansion circuit which takes AT89C52 singlechip micro-computer as the core, including A/D, D/A, voltage-current converting circuit, external clock and memory circuit, liquid crystal display circuit, serial communication circuit and the analog signal isolated circuit made up of operational amplifier, optocoupler and filter, etc. The system's software part includes the Data Acquisition program compiled with c, assemble language and the PC program compiled with a sort of Virtual Instrument programming language-LabVIEW. The PC program is a combination of the subprogram for the serial communication between PC and singlechip micro-computer, the data analysis subprogram, the process monitoring subprogram and other subprogramsThis thesis explains the whole design of AC/DC single-chip switching power supply for the water-quality monitoring system, a designing plan of remote control based on RS-232 Serial Bus and a designing method for linearly isolating analog signals by using general optocoupler emphatically and explains how to use LabVIEW programming language to compile program in a big way.Finally, the thesis analyses the experimental data from the debugged system. The analytic result shows the design of the system introduced in this thesis is feasible and conforms to the practical requirements. Then the thesis discusses future prospect of this system.