數字流量計

電子機電論文編號:JD891  論文字數:14226,頁數:67

目   錄
緒   論 6
第一章  系統總體設計 7
1-1  應用開發過程 7
1-1-1 總體論證 7
1-1-2 系統設計 8
1-1-3 硬件及軟件開發及聯機調試 8
1-2  系統設計 9
1-2-1 系統原理 9
1-2-2 系統結構 9
第二章  系統硬件電路設計 11
2-1  放大部分 11
2-1-1 霍爾傳感器 11
2-1-2 放大電路設計 14
2-1-3 整形電路設計 16
2-2  計數部分 19
2-2-1 門控電路設計 19
2-2-2 計數器設計 19
2-3  主控部分(CPU選用) 20
2-3-1 復位電路 23
2-3-2 振蕩電路 23
2-3-3 系統電源穩壓濾波電路 24
2-4  液晶顯示器（LCD） 25
第三章  系統軟件設計 27
3-1  系統軟件設計概述 27
3-2  幾個關鍵的軟件模塊設計 29
3-2-1 軟件定時器中斷服務模塊 29
3-2-2 流量數據處理及轉換模塊 30
第四章  結束語 31
致   謝 32
參考文獻 33
附錄A：源代碼 34
附錄B：系統原理圖 67

摘    要
目前人類已經步入數字時代，本文設計的數字式流量計由霍爾傳感器、放大器、門控電路、計數器、單片機CPU處理器和液晶（LCD）顯示系統組成。霍爾傳感器是采用霍爾效應做成的磁性傳感器。具有穩定性好，受漂移電壓的影響較小，線性好等特點。78E58B單片機具有自帶程序存儲器，不需要擴展外部存儲器的優點。液晶顯示器（LCD）是一種顯示清晰、高可靠、高壽命、低功耗、低價格工作電壓的顯示器件，廣泛應用于計算器、萬用表、各種便攜式儀器和低功耗應用系統中。
本文采用單片機技術來設計數字式流量計。首先，利用霍爾傳感器檢測渦輪的轉動頻率，放大器將霍爾傳感器輸出的比較弱的表示轉動頻率的脈沖信號放大，門控電路用于控制檢測周期，然后通過計數器計數將脈沖數目輸入給CPU——78E58B單片計算機，用78E58B單片機計算出檢測信號的轉動頻率值，采用查表方式，每一轉動頻率值對應流量值，最后，液晶（LCD）顯示器將測量過程中輸入和需要輸出的控制信息以及測量結果通過液晶顯示器顯示出來。用單片機技術和數字電路設計的數字式流量計克服了傳統機械表頭式流量計的一些弊端。
本文介紹了數字式流量計的系統總體結構、系統的硬件電路設計和系統的軟件設計。數字式流量計廣泛應用在工業生產特別是在化工和能源等領域對液體、氣體等流體的流量進行計量。
                                                           

關鍵詞：數字式流量計 、流量、單片機
Abstract
Current mankind have already followed the arithmetic figure ages,this text the arithmetic figure type that design the floweter spread to hall,englarger,single slice the machine CPU the processor to show the system with LCD to constitute.
The hall spreads to adopt the made-up magnetism of hall effect dpread to hall sensor.The stability that have the influence is good,and suffer the drift electric voltage small,and characteristics of line is good.78E58B is only a slice advantage for machine tool having from taking the procedure rom,not needing expanding the exterior rom.It’s clear that liquid crystal display(LCD) is a kind of manifestation,high dependable,the high life span,low cost,low price work the electric voltage’s display piece,extensive application is in the calculator every kind of instrument with the system inside of low cost application.
We use single-chip computer technology to design digital flowmeter. Firstly，use hall sensor to sense running frequency of turbine flowmeter. Secondly， use amplifier to amplify the weak frequency signal(analog signal) outputted by sensor,  gating circuit is used to control measurement cycle. Then, use counter to translate the analog frequency signal into digital signal which can be processed by computer, and input to 78E58B single-chip computer. Use 78E58B singlechip computer comput frequency value, and find corresponding flow value of each frequency value through table. Lastly, LCD display system display the control and  measurement information.
The  system  framework, hardware circuit design and software design  of  digital flowmeter are  presented in the paper. The extensive application of flowmeter of arithmetic  figure type produces in the industries to especially wait the realm with energy at the chemical engineering to liquid, air……etc. the fluid dischange processds to calculate.
                                                           

Keywords: Digital flowmeter、 Flow、 Singlechip computer