科学地解决能源三气的计量问题，一直是业界困扰的问题。进入二十一世纪以来，用于测量气体流量的超声波流量计以其无压损、无阻力、量程比宽、受流体限制少等优点受到业界的广泛关注。随着国内人民生活水平的提高，科技不断地进步，控制不断地完善，从而促使超声波技术在气体流量检测系统领域占据主导权，也使得气体流量测量仪被广泛应用。在超声波设计领域中，气体流量检测技术成为目前一处亮丽的风景线，因为其开发资源众多，开发经验丰富，最重要的是成本较低，控制在用户可承受的范围内，使用超声波的方式搭建气体流量检测系统，气体流量测量仪逐渐成为世界各国关注的重点。

本文主要从基础研究出发，对超声波测量技术进行深入分析，并设计出实际电路，通过对实际电路调试，提出可行性改进措施，为今后的研究打下基础。采用基于改进型时差法的测量原理，能够较好地克服温度和声速对流量测量的影响，提高系统的精度。

系统设计上，硬件电路主要分为模拟电路和数字电路，模拟电路包括超声波发射电路、开关切换电路、超声波接收电路、限幅电路等。数字电路包括单片机控制电路、ADC转换电路、LCD显示电路等。

软件程序上选用KeilC语言编写，主要包括初始化配置模块、脉冲发射模块、数据采集模块、流速及流量计算模块、LCD驱动及显示模块等。完成硬件电路的设计、焊接和软件程序的编写，进行系统的整机调试，对实际中出现误差的可能性做具体的分析。

关键词：超声波气体流量计；单片机；LCD，数据采集

Abstract

It has always been a perplexing problem for the industry to solve the measurement problem of energy three gases scientifically. Since the beginning of the 21st century, ultrasonic flowmeter used to measure gas flow has been widely concerned by the industry for its advantages of no pressure loss, no resistance, wide range ratio and less fluid restriction. With the improvement of the living standard of the domestic people, the continuous progress of science and technology, and the continuous improvement of control, so as to promote the ultrasonic technology in the field of gas flow detection system occupy the dominant right, but also make the gas flow measurement instrument is widely used. In the field of ultrasonic design, gas flow detection technology has become a beautiful landscape at present, because of its development resources, rich experience, the most important is the low cost, control in the user's affordable range, the use of ultrasonic way to build gas flow detection system, gas flow measurement instrument has gradually become the focus of the world.

This paper mainly starts from the basic research, carries on the in-depth analysis to the ultrasonic measurement technology, and designs the actual circuit, through the actual circuit debugging, puts forward the feasible improvement measures, lays the foundation for the future research. The effect of temperature and sound velocity on flow measurement can be overcome and the accuracy of the system can be improved by using the improved time difference method.

System design, hardware circuit is mainly divided into analog circuit and digital circuit, analog circuit including ultrasonic transmitting circuit, switching circuit, ultrasonic receiving circuit, limiting circuit, etc. Digital circuit includes MCU control circuit, ADC conversion circuit, LCD display circuit, etc.

The software program is written in KeilC language, including initial configuration module, pulse transmission module, data acquisition module, flow rate and flow calculation module, LCD driver and display module. Complete the hardware circuit design, welding and software program writing, the system debugging, the actual error of the possibility to do a specific analysis.

Keywords: Ultrasonic gas flowmeter; Single chip microcomputer; LCD, data acquisition