Research, Manufacture And Application Of Laser Water-level Gauge

Water-level, as one of the most important hydraulic parameters, impacts the safety of the habitants and towns along the downstream area of reservoirs, dams and rivers in flood season; it also relates to the operation safety and economic benefit of the power plants and factories. How to measure the water-level accurately and intelligently becomes the problem that many researchers concern.Water-level gauge is widely applied to the automatic measurement and control system in hydraulic engineering, power industry, and chemical engineering. Based on the analysis and absorbability of the research and manufacture of the existing water-level gauges, with the new technology of EDA and the laser rangefinder utilized, the laser water-level gauge developed in this dissertation is a automatic measurement equipment with high precision and high reliability. The main contents and achievements of the present dissertation are as follows: 1. The develop project of laser water-level gauge is presented. Adopting the laser rangefinder, which has high precision, outstanding anti-jamming ability and wide measure range as the sensor part, greatly improves the precision and stability of the water-level gauge; The circuits of the control system are realized through FPGA, and it makes the gauge operate more stable and intelligent.2. Through VHDL program, the control system circuits is developed based on FPGA. According to the theory of modularization, the control system is mainly divided into four function parts: procedure configuration circuit, laser rangefinder control interface circuit, SDRAM interface circuit and Flash Memory interface circuit. Each module is designed independently while four parts are arranged synthetically. The four modules are proved to befunctional by simulation and experiment. The control system can turn on/off the laser rangefinder, extract the water-level data, process data and store data in SDRAM and Flash Memory.3. Real time data transmission between the control system circuits and computer's RS-232 interface is achieved. Under the instruction of the control system circuits based on FPGA, the gauge sends data to the computer's port. And then, the water-level monitoring procedure, which is programmed with Visual C++, gets and decodes the water-level information from the port the information and the curve of the water-level is displayed.4. Based on the test of practical measure of laser water-level gauge, the error is less than 0.6mm in the measure range less than 5 meters. Compared with other field water-level measure apparatuses in common use, the precision of laser water-level gauge has obvious improvement. And this gauge can also be applied to physical modeling experiment in river engineering.