Design And Implementation Of Remote Monitoring System For Open Channel Flow

Water quantity in irrigated area is the basic work of irrigation water management in irrigated area.Reasonable allocation of irrigation water,calculation of utilization coefficient of irrigation water and implementation of charging system based on square are all inseparable from water quantity in irrigated area.Variety of equipments in the amount of irrigation water and method,the velocity-area method,instrument type of flow measurement method,AD hoc water equipment of measurement method and water-flow relations and so on are widely used,but it can also satisfy the low cost,high precision,small head loss and convenient measuring rarely require the amount of water equipment,such as many irrigation area is still difficult to find a satisfied with the amount of water equipment.In order to solve the above problems,realize the automation and intellectualization of flow measurement and reduce the input of labor cost,this paper proposes a new remote monitoring system of open channel flow in irrigation district by using ARM embedded processor,combining 4G communication technology,cloud server technology and B/S architecture technology.In the stage of theoretical analysis,the common flow measurement methods of open channel are analyzed and compared.According to the complexity and cost factors of system design,the flow-area method is selected as the basic measurement method of this system.Since temperature and humidity have great influence on the accuracy of ultrasonic ranging,BPNN is used as temperature and humidity compensation algorithm to compensate the error of ultrasonic propagation speed in order to improve the measurement accuracy of ultrasonic sensor.System design and implementation stage,the hardware design of the system hardware schematic diagram,and make the corresponding printed circuit board.Software based on THE RT-Thread operating system for multi-threading design,different functions according to the importance of different priorities,each Thread through the semaphore,message queue Thread synchronization and communication,to ensure the safety of threads.In terms of temperature and humidity compensation algorithm software implementation,a three-layer BPNN model was established in MATLAB,and the sound velocity data measured under different temperature and humidity were used as training samples for neural network training,which verified the feasibility of BPNN in temperature and humidity compensation.Then the BPNN model parameters are derived,and the BPNN is transplanted into STM32F103ZET6 microcontroller by C programming language.In the system test stage,hardware test,software test and system integration test were carried out to verify the feasibility of the remote communication function,data transmission function,LCD display function and cloud server monitoring function of the system.In the actual working test stage,the flow measurement data of the designed prototype is compared with that of the electromagnetic flowmeter as a reference.The results show that the relative error of the flow measurement of the designed prototype is less than 0.5%,which can meet the accuracy requirements of the industrial site.