【正文】 本科畢業(yè)論文（設計） 流水線自動稱重和計數(shù) 流水線的自動稱重和計數(shù) 摘 要 本稱重系統(tǒng)采用單片機 AT89C51 為控制核心，實現(xiàn)稱重儀的基本控制功能。系統(tǒng)的硬件部分包括數(shù)據(jù)采集和數(shù)據(jù)處理兩大部分，其中 數(shù)據(jù)采集部分由稱重儀模擬器、信號的前級處理（采用儀表放大器 INA121）和 雙積分 A/D 轉(zhuǎn)換部分組成。由于稱重儀設計中電路的精度及抗工頻干擾能力要求較高，故選用精度較高的儀表放大器 INA121 和抗工頻干擾能力較強的雙積分 A/D 轉(zhuǎn)換器MC14433。 計數(shù)系統(tǒng)指導思想是利用紅外發(fā)光管發(fā)射紅外線，紅外接收管接收此紅外線，并將其放大、整流形成低電平信號 .當有人或物擋住紅外光時，接收管沒有接收到紅外信號，放大器將輸出高電平，同時將這個電平信號送入單片機進行控制計數(shù)，并且使數(shù)碼管顯示數(shù)值。本系統(tǒng)通過應用傳感器，各種 芯片及單片機使得該系統(tǒng)的實際操作性更強，便于應用于工業(yè)上。 關(guān)鍵詞 ： 雙積分 A/D 轉(zhuǎn)換，儀表放大， AT89C51 單片機，自動計數(shù)，數(shù)碼管 Pipeline automatic weighing and counting Abstract This system is based on single chip AT89C51, it can make electronic scale39。s basic control function e true. System39。s hardware includes smallest system board and the acquisition of data. The smallest system part mainly realizes the demonstration of the diodes and the control of keyboard ,the part of data’s acquisition is consists of the simulator of weighing meter , signal level processing (amplifier INA121) and the fraction of the double integral A/D conversion . Because of the high request in precision of the electric circuit of the weighing meter design and the ability of antipower frequency disturbance, the selection of the high precision appliance such as the amplifier INA121 and double integral A/D switch MC14433. The guiding ideology is using infrared luminescence tubes launch infrared, infrared receiving tube receiving this infrared, and put the amplification, rectifier form low level signals. When someone or something blocking infrared, receiving tube without receiving infrared signal, amplifier output high level, at the same time will the level signal into SCM control counted, and making digital tube display Numbers. So get to statistics, the number of people or things. Key words ： double integral A/D transformation, measuring appliance enlargement， Scm, Automatic counting , Digital tube I 目 錄 緒論 ................................................................................................................................. I 1 課題的研究意義和目的 ............................................................................................ 1 自動稱重和計數(shù)的現(xiàn)狀及前景 ............................................................................. 1 課題研究內(nèi)容 ......................................................................................................... 2 2 基于單片機構(gòu)成的產(chǎn)品自動計數(shù)器 的設計 ............................................................ 2 方案論證 ................................................................................................................. 2 系統(tǒng)總體框圖和原理 ............................................................................................. 3 系統(tǒng)單元電路設計 ................................................................................................. 3 電源供電電路 ...................................................................................................... 3 橋式整流電路 ...................................................................................................... 4 濾波電路分析 ...................................................................................................... 5 穩(wěn)壓電路 .............................................................................................................. 6 紅外線檢測部分 .................................................................................................. 6 數(shù)碼管顯示部分 .................................................................................................. 6 LED 數(shù)碼管的特點 ................................................................................................ 7 數(shù)碼管動態(tài)掃描 ..................................................................................................... 8 數(shù)碼管驅(qū)動部分 ..................................................................................................... 8 單片機計數(shù)及控制部分 ......................................................................................... 9 復位電路 ............................................................................................................... 12 上電復位 ............................................................................................................. 12 看門狗復位 ......................................................................................................... 13 3 自動稱重系統(tǒng)的設計 .............................................................................................. 14 硬件的選擇 ........................................................................................................... 14 轉(zhuǎn)換電路芯片選擇 ............................................................................................ 14 主控芯片選擇 .................................................................................................... 16 儀表放大器選擇 ................................................................................................ 17 電源選擇 ............................................................................................................ 18 顯示模塊選擇 .................................................................................................... 19 電路總體原理框圖設計 ....................................................................................... 19 主芯片引腳應用 ................................................................................................... 20 控制模塊與轉(zhuǎn)換模塊的連接 ............................................................................... 23 前級放大模塊 INA121......................................................................................... 24 自動稱重模塊 ....................................................................................................... 25 II 顯示模塊與控制模塊的連接 ............................................................................... 25 系統(tǒng)測試 ......