摘要

科學(xué)地解決能源三氣的計(jì)量問題，一直是業(yè)界困擾的問題。進(jìn)入二十一世紀(jì)以來，用于測量氣體流量的超聲波流量計(jì)以其無壓損、無阻力、量程比寬、受流體限制少等優(yōu)點(diǎn)受到業(yè)界的廣泛關(guān)注。隨著國內(nèi)人民生活水平的提高，科技不斷地進(jìn)步，控制不斷地完善，從而促使超聲波技術(shù)在氣體流量檢測系統(tǒng)領(lǐng)域占據(jù)主導(dǎo)權(quán)，也使得氣體流量測量儀被廣泛應(yīng)用。在超聲波設(shè)計(jì)領(lǐng)域中，氣體流量檢測技術(shù)成為目前一處亮麗的風(fēng)景線，因?yàn)槠溟_發(fā)資源眾多，開發(fā)經(jīng)驗(yàn)豐富，最重要的是成本較低，控制在用戶可承受的范圍內(nèi)，使用超聲波的方式搭建氣體流量檢測系統(tǒng)，氣體流量測量儀逐漸成為世界各國關(guān)注的重點(diǎn)。

軟件程序上選用KeilC語言編寫，主要包括初始化配置模塊、脈沖發(fā)射模塊、數(shù)據(jù)采集模塊、流速及流量計(jì)算模塊、LCD驅(qū)動(dòng)及顯示模塊等。完成硬件電路的設(shè)計(jì)、焊接和軟件程序的編寫，進(jìn)行系統(tǒng)的整機(jī)調(diào)試，對實(shí)際中出現(xiàn)誤差的可能性做具體的分析。

本文主要介紹氣體流量測量儀的設(shè)計(jì)，首先介紹超聲波檢測的基本原理以及其發(fā)展歷史、目前現(xiàn)狀等。然后對設(shè)計(jì)中的數(shù)字式氣體流量測量儀的總體設(shè)計(jì)及各功能模塊進(jìn)行了探討，確定了氣體流量測量儀設(shè)計(jì)的解決方案并對系統(tǒng)解決方案中的主控芯片和可編程邏輯控制芯片進(jìn)行了選型。之后重點(diǎn)研究數(shù)字化氣體流量測量儀系統(tǒng)的硬件設(shè)計(jì)，包括超聲波的發(fā)射電路，接收電路，信號調(diào)理電路以及數(shù)據(jù)采集處理系統(tǒng)的設(shè)計(jì)和實(shí)現(xiàn)。最后介紹了氣體流量測量儀系統(tǒng)的軟件設(shè)計(jì)，對系統(tǒng)軟件設(shè)計(jì)的總體流程、超聲波激勵(lì)脈沖信號產(chǎn)生、數(shù)據(jù)采集系統(tǒng)的邏輯控制以及回波信號的數(shù)據(jù)處理進(jìn)行了介紹。

關(guān)鍵詞：超聲波氣體流量計(jì)；單片機(jī)；LCD，數(shù)據(jù)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.

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.

This paper mainly introduces the design of gas flow measuring instrument, first introduces the basic principle of ultrasonic detection and its development history, current situation and so on. Then the overall design and functional modules of the digital gas flow measuring instrument in the design are discussed, and the design solutions of the gas flow measuring instrument are determined and the main control chip and programmable logic control chip in the system solution are selected. Then focus on the digital gas flow measuring instrument system hardware design, including ultrasonic transmission circuit, receiving circuit, signal conditioning circuit and data acquisition and processing system design and implementation. Finally, the software design of gas flow measuring instrument system is introduced, and the overall process of system software design, the generation of ultrasonic excitation pulse signal, the logic control of data acquisition system and the data processing of echo signal are introduced.

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

目錄

摘要............................................................................................................................. I

Abstract................................................................................................................... III

第一章 緒論............................................................................................................. 1

1.1引言............................................................................................................. 1

1.2研究目的與意義........................................................................................ 2

1.3國內(nèi)外研究現(xiàn)狀........................................................................................ 3

1.4課題研究內(nèi)容及章節(jié)安排........................................................................ 5

第二章 超聲波檢測基本原理及方法................................................................... 7

2.1超聲波的定義及基本性質(zhì)........................................................................ 7

2.1.1超聲波定義及特點(diǎn)......................................................................... 7

2.1.2超聲波的速度及波長.................................................................... 7

2.1.3超聲波的衰減................................................................................. 8

2.2超聲換能器................................................................................................. 8

2.2.1超聲換能器的定義......................................................................... 8

2.2.2超聲換能器的主要性能參數(shù)........................................................ 8

2.3流量測量原理及方法................................................................................ 9

2.3.1測量原理......................................................................................... 9

2.3.2測量方法......................................................................................... 9

2.4機(jī)械振動(dòng)與超聲波.................................................................................. 10

2.4.1超聲場的基本物理量和超聲波波型......................................... 10

2.4.2金屬探傷中的超聲波波型.......................................................... 11

2.5超聲場及介質(zhì)的聲參量.......................................................................... 12

2.5.1描述超聲場的物理量.................................................................. 12

2.5.2介質(zhì)的聲參量............................................................................... 13

第三章 系統(tǒng)硬件設(shè)計(jì).......................................................................................... 14

3.1系統(tǒng)硬件整體結(jié)構(gòu)框圖.......................................................................... 14

3.2主控制器設(shè)計(jì).......................................................................................... 15

3.2.1芯片介紹....................................................................................... 15

3.2.2時(shí)鐘電路設(shè)計(jì)............................................................................... 17

3.2.3復(fù)位電路設(shè)計(jì)............................................................................... 18

3.3超聲波控制電路...................................................................................... 19

3.3.1超聲波傳感器............................................................................... 19

3.3.2超聲波電路設(shè)計(jì)........................................................................... 20

3.4激勵(lì)電路設(shè)計(jì).......................................................................................... 20

3.5A/D轉(zhuǎn)換電路設(shè)計(jì)................................................................................... 21

3.5.1 A/D 轉(zhuǎn)換器的選擇...................................................................... 21

3.5.2 ADC0832 的介紹........................................................................ 21

3.5.3 單片機(jī)對 ADC0832 的控制原理的介紹............................... 22

3.6顯示電路設(shè)計(jì)......................................................................................... 23

第四章 系統(tǒng)軟件部分設(shè)計(jì).................................................................................. 25

4.1主程序流程圖.......................................................................................... 25

4.2主程序流程圖.......................................................................................... 26

第五章 系統(tǒng)仿真調(diào)試部分.................................................................................. 28

5.1? 軟件研發(fā)的背景................................................................................... 28

5.2? 軟件程序設(shè)計(jì)....................................................................................... 28

5.3? 基于Proteus電路圖繪制.................................................................... 29

第六章 結(jié)束語....................................................................................................... 31

參考文獻(xiàn)................................................................................................................. 32

致謝.......................................................................................................................... 34