基于无线信号传输的喷头水量分布测试系统

现有喷头水量分布测试中存在雨量筒移动难,雨量传感器寿命低,水量分布软件无法展现水量分布图全貌的问题。该文提出了一套基于无线信号传输的喷头水量分布测试系统的解决方案。该系统采用Zig Bee无线技术和霍尔无触点开关改进了传统的双翻斗雨量筒。试验时按照水量分布测试要求将雨量筒以方格或径向布置在整个试验场,每个雨量筒都被编号并作为终端设备于整个网络中发送雨量信号,信号经路由器转送给Zig Bee协调器节点接收数据,最后通过串口由上位机接收。上位机采用Matlab的GUI编写水量分布测试软件,可以实时接收并绘图,计算相关参数、调整水量分布图观察角度和预测组合喷头喷洒情况。通过雨量筒试验,测试了雨量筒的精度和接收灵敏度,雨量筒精度误差不超过0.1 mm/h,接收无遗漏。最后该文对S800型喷头进行了水量分布测试并计算相关参数和绘制水量分布图,测试表明该文的喷头水量分布测试系统满足试验需求。

Water distribution test system of sprinkler based on wireless transmission technology

Abstract: In sprinkling irrigation, evaluation of spraying quality mainly depends on water distribution test systems. Commonly, there are at least dozens of test points needed in the water distribution test, and sometimes hundreds of them are used in some particular cases. The space between rain gauges ranges from 0.5 m to 2 m by the coverage diameter of sprinkler which commonly requires high mobility and convenient reading functions. Traditionally, the test requires measurements of hundreds of points by use of standard measuring cup. Following that, a great deal of data from the test cups are collected for the calculation of sprinkler irrigation uniformity, and then water distribution map were manually drawn. All of those bring problems like heavy workload or low precision of the measured results. The water distribution testing software implemented can be used to draw the map of water distribution or the calculation, but it may not realize the function of real-time plot with the separation of water collecting apparatus. Moreover, the data downloaded into computer from the measuring apparatus cannot be exported to Excel, which may cause errors. Moreover, the drawings of water distribution map can only be printed in a specified angle and the outline of the water distribution cannot be viewed in a time. In order to improve the sprinkler performance and optimize the water distribution, a new approach of using wireless to test water distribution of sprinkler was proposed based on ZigBee technology, a new short-distance wireless network standard for sensor network with the distinct advantages of low energy consumption, low latency, and long battery lives, and Matlab in the double tipping bucket rain gauge, in which a wireless module ZigBee, and a hall sensor were installed to receive and store signal generated by the tipping bucket rain acquisition parts by CC2530 module. The rain gauges were arranged in the test field in a rectangular and radial direction and each one was numbered uniquely in the entire network. The frequency of communication between receiver and upper computer was 2.4GHz. In order to avoid signal congestion, the number of routing nodes was enlarged and tree type networks were used in the rain gauges. Terminal nodes were responsible for collecting signal and delivering it to the routing nodes during working conditions and the routing nodes transmitted the signal to the coordinators. The ZigBee coordinator node received signal and delivered it to the upper computer in which a real-time analytic software was developed by graphical user interfaces (GUI) of Matlab. The software allowed us to analyze data precisely with intuitive three-dimension image. The new developed test system had distinct advantage like improved generality, easy expansibility, high reliability and interoperability compared to the traditional one. A water distribution test was conducted as to the S800 rotating sprinkler produced by the Toro Company. The error of this system and manual measurement was less than 0.1mm/h. It can bear at least 2940 reversal per hour without leak. The software system calculated 11 combination sprinkler irrigation Christiansen uniformity coefficients with the combination spacing coefficient ranged from 1.0 to 2.0. The test results showed that the Christiansen uniformity coefficients of sprinkler reached 70.6%. The Christiansen uniformity coefficients corresponding to the combination spacing coefficient of rectangle ranged from 1.0 to 1.6 and that of triangle range from 1.0 to 1.2 or 1.5 to 1.7 were up to 75%, which met the expected requirements. The entire system provided reliable data collection method and functional data analysis software for researcher to develop new sprinklers.