Design And Implementation Of High Precision Ultrasonic Flowmeter

Ultrasonic flowmeter is a new type of non-contact intelligent flowmeter,with a wide range of applications,low manufacturing costs,high accuracy,strong environmental impact resistance ability,etc.However,there is still a big gap between the domestic and foreign ultrasonic flowmeters in terms of cost,accuracy,process and circuit design and stability.At present,most of the ultrasonic flowmeters used in petroleum exploitation,natural gas exploration,aeronautical manufacturing,biomedical and other fields in China are foreign ultrasonic flowmeters,which are high cost and difficult to maintain.Therefore,developing a low-cost,easy to install,high-precision,intelligent ultrasonic flowmeter is very important and has lager application value.Because ultrasonic flowmeter involves many principles and algorithms,based on the existing ultrasonic flowmeter system,introducing a new time difference method,using MSP430 low power chip as the main control chip and TDC-GP22 as the time measurement chip,the purpose of this paper is to design a practical ultrasonic flowmeter which meets the national standard.Firstly,the research significance,background,research status and development trend of ultrasonic flowmeter of home and abroad are simply introduced,the algorithm principle of ultrasonic flowmeter is introduced,the influence of flow field on ultrasonic flowmeter and the calculation algorithm of compensation coefficient are analyzed,and the error factors affecting ultrasonic flowmeter is described.It is possible to avoid the influence of these factors.Then,according to the overall design of the system,the basic circuit diagram is built in terms of hardware,The hardware circuit includes an ultrasonic circuit(including a temperature detecting circuit and a transducer),a power supply circuit,an M-Bus circuit,an LCD display circuit,a light sensing button circuit,and the like.and the programming and debugging are completed through the IAR software platform according to the determined hardware performance and parameters.The third adopts digital filtering technology to prevent random errors occurring during data acquisition from affecting system instability;Fourth,the prototype is designed and tested.The M-Bus module is tested by the current high precision Drew platform,and the function of remote meter reading is analyzed and determined.Finally,the test results are analyzed,the error factors are found out,and the correction measures are given.The results show that the design can not only reduce the power consumption of the system as much as possible,but also solve the problem of manual meter reading.By replacing the button to switch the screen with the photosensitive module,the cost is reduced,and the ultrasonic flowmeter is more intelligent in function,smaller involume and lower power consumption.The main contributions of the paper are:(1)Constructed the hardware circuit diagram of the flowmeter;(2)Given the flowchart of the flowmeter;(3)Designed an ultrasonic flowmeter,and the performance test and error analysis of the prototype were carried out.