Development Of A Closed Ultrasonic Level Gauge For Open Channel Irrigation

The remote metering gate control system has functions such as remote measurement and control,flow metering and water distribution control,it is a key component to achieve efficient and scientific water transfer in the whole basin of the irrigation district,which can also effectively solve the problems of artificial water separation and low water transfer efficiency.The scientific dispatching of water resources in the irrigation area is realized by the remote metering gate control system through the control of the gate opening degree and the water level monitoring before and after the gate.Obviously,the liquid level measuring sensor is the most important component in the gate control system and is also the basis for accurate measurement.In order to adapt to the complex field environment,the ultrasonic level gauge should be easy to install and debug in the field environment,it also should have strong anti-interference ability,so that it can achieve high measurement accuracy and strong stability.The paper mainly analyzes the measurement principle and method of various open channel liquid levels,and summarizes its advantages and disadvantages.A new measurement method for measuring the liquid level of open channels in closed pipelines is proposed in this paper,and the propagation mode of ultrasonic waves in closed pipelines in detail is analyzed to verify the feasibility of the program.The overall design of the closed ultrasonic level gauge is mainly composed of hardware module and software algorithms.The hardware module is mainly composed of the power supply circuit,the minimum system circuit of the main control chip,the ultrasonic transceiver circuit,the temperature acquisition circuit and the serial communication circuit.As for the algorithm part,it is about the echo signal acquisition program,the liquid surface echo recognition program,the echo front edge judgment program,the temperature acquisition subroutine,the average filtering algorithm and the serial communication program to complete the measurement and communication of the closed ultrasonic level gauge..After completing the hardware design and software algorithm preparation,the indoor test platform and the actual irrigation area test platform are set up.And the indoor static water experiment,the water quality sediment impact test,the high and low temperature environment test and the measurement experiment in the actual irrigation channel are executed to make the performance testing for the closed ultrasonic level gauge.The measurement results show that the closed ultrasonic level gauge can effectively isolate external interference.In the measurement range of 0.2m～2.5m.the absolute error value in the actual irrigation channel is within 3mm,and the relative error value is 1.2‰,and the repeatability standard deviation is 0.9mm.Besides,its volume is small,which is easy to use and install in the field and can be well integration with existing remote metering gate systems,it has high adaptability to the environment,and has achieved the expected design goals.