Study And Design Of Ultrasonic Flowmeter

Industry 4.0 is a big change in the field of industrial control. As one of the three most important parameters of modern industry, the accurate measurement of the flow has its significance. As a new type of flowmeter, ultrasonic flowmeter has obvious advantages, compared to the traditional flowmeter. Ultrasonic flowmeter can measure the flow rate by ultrasonic, without contacting with the measured medium. So it can not only expand the range of the measurable liquids, like some corrosive, non-conductive, or radioactive liquids, which can not be measured before, but also significantly reduce the effect on the flow rate of the liquid, which improves the accuracy. On the basis of domestic and foreign design of flowmeter, the use of the TDC-GP21 chip will get a high-precision measurement of time interval, and the added GSM module enhances the capacity of information transmission of the flowmeter.This paper introduces the development status and the classification of the flowmeter, and highlights the history and status of ultrasonic flowmeter. It also introduces the different methods to measure the flow rate by ultrasonic based on different principles. Among them, as the object of study, the principle of travel-time-difference method, especially the technique of time interval measurement is highlighted. Then it introduces the tools used in this article, such as the PADS, used to design the hardware, and the Keil uVision4, used to write and debug the program of the microcontroller. Then is the overall analysis to the entire instrument on feasibility, user needs and function.The ultrasonic flowmeter I designed has three main moudules. The first is the system control module based on STM32F103C8T6, whose main function is to control the functions of the ultrasonic flowmeter and process the data. The next is the measurement module based on the TDC-GP21 chip. Its main function is to control the transmission and reception of ultrasonic waves and measure the propagation time and the temperature of the fluid, under the control of the microcontroller. The third is the input and output module. Its function is to download the program, set the parameters and output the result, by using RS232, SWD, LCD, buzzer, LED, and so on.The software of the flowmeter is mainly the control program in the microcontroller, which consists of the main program, the measurement module and the input and output module. I choose the Keil uVision4 to write, debug and download the control program.Finally, I make a prototype according to the design, and test its performance. Because of the limits of the experimental conditions, I do not test the full functionality of the flowmeter. Based on the existing conditions, I test the time measurement module, which can obviously affect the final measurement results.