基于單片機(jī)的稱重系統(tǒng)設(shè)計

電氣自動化論文編號:ZD1089    論文字?jǐn)?shù):23072,頁數(shù):62

目 錄
摘 要 Ⅱ
Abstract Ⅲ
目 錄 Ⅳ
1  緒論 1
 1.1  電子稱重技術(shù)的現(xiàn)狀 1
 1.2  電子稱重技術(shù)的發(fā)展趨勢 1
 1.3  項目研究背景 3
 1.4  本文的主要工作 4
2  系統(tǒng)方案論證與選型 5
2.1  控制器部分 5
2.2  數(shù)據(jù)采集部分 6
     2.1.1  傳感器的選擇 6
     2.2.2  放大電路選擇 9
 2.2.3  鍵盤處理部分方案論證 13 
2.3  顯示電路部分的選擇 13
2.4  超量程報警部分選擇 13
2.5  通訊接口部分方案論證 13
3  系統(tǒng)硬件電路設(shè)計 15
3.1  STC12C5A16S2的最小系統(tǒng)電路 15
 3.1.1  STC12C5A16S2單片機(jī)介紹 15
 3.1.2  單片機(jī)管腳說明 17
 3.1.3  STC12C5A16S2的最小系統(tǒng)構(gòu)成 19
3.2  數(shù)據(jù)采集部分電路設(shè)計 19
       3.2.1  傳感器和其放大電路與STC12C5A16S2單片機(jī)接口電路設(shè)計 19
   3.2.2  測量算法 20
3.3  鍵盤輸入電路與STC12C5A16S2單片機(jī)接口電路設(shè)計 21
3.4  LED顯示電路與STC12C5A16S2單片機(jī)接口電路設(shè)計 22
 3.4.1  LED顯示器結(jié)構(gòu)與原理 22
 3.4.2  LED顯示器與顯示方式 22
3.5  變平器與STC12C5A16S2單片機(jī)接口電路設(shè)計 23
 3.5.1  RS-232C機(jī)械連接器及引腳定義 23
 3.5.2  RS-232電平轉(zhuǎn)換芯片及電路 24
4  系統(tǒng)軟件設(shè)計 26
4.1  系統(tǒng)主程序 26
4.2  鍵盤管理模塊 27
4.3  數(shù)據(jù)處理模塊 29
4.4  計價模塊 29
4.5  上位機(jī)通訊 30
  4.5.1  MSComm控件的使用 30
  4.5.2  通訊過程 31
5  系統(tǒng)調(diào)試與分析 32
5.1  調(diào)試系統(tǒng)簡介 32
5.2  調(diào)試故障及原因分析 32
6  結(jié)  論 32
6.1  主要工作成果 33
6.2  存在的不足 34
致  謝 35
參考文獻(xiàn) 36
附錄 37

摘  要
 
 現(xiàn)代社會的發(fā)展，對稱重系統(tǒng)提出了更高的要求。目前，臺式電子秤在商業(yè)貿(mào)易中的使用已相當(dāng)普遍，但存在一定的局限性，雖然在體積，成本控制方面有所改進(jìn)，但需要工頻交流電源供應(yīng)、攜帶不便、應(yīng)用場所受到制約，且隨著信息技術(shù)的發(fā)展，某些領(lǐng)域人們需要對所得數(shù)據(jù)進(jìn)行處理，期待測量更準(zhǔn)確、價格更低廉且具有與PC機(jī)相連功能的電子秤投放市場。
 本文設(shè)計的電子秤以STC單片機(jī)為主要部件 ，用C語言進(jìn)行軟件設(shè)計，硬件則以全橋傳感器FAB-80 為主，量程為0~10kg，隨時可改變上限閾值，并達(dá)到閾值報警的功能。在文中論述了稱重系統(tǒng)的工作原理，給出了系統(tǒng)電路設(shè)計與軟件流程，進(jìn)行實物制作并調(diào)試。
   本文設(shè)計的基于單片機(jī)的電子稱重系統(tǒng)主要由電源、稱重傳感器、單片機(jī)、鍵盤/開關(guān)、LED顯示器,串口通信等構(gòu)成智能稱重系統(tǒng)電路板，從而實現(xiàn)自動稱重系統(tǒng)的各種控制功能。可以說,此設(shè)計所完成的電子秤很大程度上滿足了應(yīng)用需求。
關(guān)鍵詞: 串口通信; 稱重傳感器;STC 單片機(jī); LED顯示器；FAB-80
  The development of the modern society has put forward higher request on weighing   technology. The desk-top electronic scales have been great application in commercial trade, but they have many shortcomings such as large volume, high cost, AC supplypower and not covenience to carry, so they are restricted to use. And with the development of information technology, some areas that people need to process the data So they have been expecting cheap portable electronic scales which can measure accurately and nd has the function of PC-linked electronic scale on the market.
 This electronic scale designed to take STC microcontroller as the main components, with using C language to Compile software in the thesis. And the hardware is based by full-bridge sensors FAB-80, its range is 0 ~ 10 Kilogram. Limited threshold value can be changed at any time to reach the alarm threshold function. The thesis discusses the working principle of weighing system, giving circuit design and software process and making physical production with debugging. 
 The microcontroller-based electronic weighing system consists of power supply, load cell, microcontroller, keyboard / switch, LED display, serial communications. All of them constitue an intelligent weighing systems board to achieve a variety of control functions of automatic weighing system. It can be said that the completion of the design of electronic scale meets the application requirements to a large extent.
  
Keywords: serial communication; load cell; STC microcontroller; LED display; FAB-80