基于STC單片機的電子稱重系統設計

電氣自動化論文編號:ZD1107    論文字數:17943,頁數:48

目 錄

摘  要 I
Abstract II
目 錄 III
1  緒  論 1
2  總體方案設計 3
2.1  設計制作要求 3
2.2  設計思想 3
2.3  系統總體結構 4
2.4  主控芯片介紹 6
3  系統硬件設計 7
3.1  系統硬件模塊框架圖 7
3.2  測量模塊 7
3.2.1  稱重傳感器 7
3.1.2  儀表放大器 9
3.2  單片機系統 11
3.2.1  A/D轉換器 11
3.2.2  單片機控制模塊 13
3.2.3  EEPROM 15
3.3  人機對話模塊 15
3.3.1  多功能LED顯示模塊 15
3.3.2  鍵盤輸入模塊 17
3.4  串口通訊模塊 17
3.4.1  MAX232芯片 17
3.4.2  9針串口 19
3.4.3  通信連接電路 19
3.5  復位電路和時鐘電路 20
4  系統軟件設計 22
4.1  監控程序設計 22
4.2  功能處理程序設計 24
4.2.1  質量的數字顯示功能程序設計 24
4.2.2  去皮功能程序設計 26
4.2.3  數字參數設置的輸入顯示功能程序設計 27
4.2.4  計算總價數字顯示的功能程序設計 28
4.2.5  上傳通訊功能程序設計 30
5  系統的調試 32
5.1  系統開發平臺 32
5.1.1  Keil C軟件集成開發環境 32
5.1.2  Proteus ISIS軟件 34
5.2  設計制作的系統 36
5.2  系統調試 37
5.2.1  軟件仿真調試過程 37
5.2.2  硬件調試過程 38
5.2.3  系統的改進方向 39
5.2.4  調試總結 40
6  總  結 41
致 謝 42
參考文獻 43
附 錄 44

摘  要

 本次畢業設計是基于STC單片機電子稱重系統的設計和制作。電子秤是一種常用的測量器具，與普通器具相比，數字電子秤具有稱重速度快、讀數直觀、性能穩定、測量準確等優點。本文提出的電子稱重系統采用低功耗，低成本的控制芯片STC 12系列自帶A/D轉換的單片機，設計一種體積小，低功耗、稱量準確、使用方便、多功能顯示、能夠與微機進行串行通訊的低成本電子秤。    本次畢業設計所設計的電子稱重系統通過電阻應變式稱重傳感器將被測物體的重量轉換成毫伏級的模擬電壓信號。較小的電壓信號通過儀表放大器進行準確、線性的放大，以滿足模/數轉換器對輸入信號電平的要求。放大后的模擬電壓信號經過模/數轉換電路將模擬量轉變成數字量，然后由單片機控制系統經過數據轉換處理之后把數字信號存入寄存器。通過鍵盤功能鍵可以將數字信號送入顯示電路，由4位LED七段數碼管來顯示出測量結果，也可以通過切換功能鍵輸入數字單價、得到總價格的數字顯示，而且還可以將測量結果上傳至微機實現串口通訊的功能。

關鍵詞： 單片機；電子稱重系統；稱重傳感器
 

Abstract

 This graduation project is the design and production of electronic weighing system which is based on the STC single-chip microcomputer. Electronic scale is a commonly used measurement instruments. Compared with ordinary equipment, digital electronic scale has such characteristics as rapid weighing, intuitive readings, stable performance, accurate measuring.
 In this paper, the electronic weighing system uses low power, low-cost controller chips STC 12 Series comes with A/D converter single-chip microcomputer to design a small size, low power, accurate weighing, easy to use, low-cost electronic scale with multi-function display and it has the ability of serial communication with PC.
 The electronic weighing system designed in this graduation project uses resistance strain gauge load cell to convert the weight of detected objects to millivolt level analog voltage signal. The small voltage signal is amplified accurately and linearly through the instrumentation amplifier to to meet the A / D converter input signal level required. The amplified analog voltage signal through A / D conversion circuit convert to digital, the single-chip microcomputer control system then processed through the data conversion before The digital signal stored into the register. Through the keyboard function keys,it can transport digital signals into the display circuit and the measurement results can be displayed by the four seven-segment LED digital tube. It can also switch the function key to input the numbers keys as the unit price,or figure out the total prices and displayed . Moreover,it has the function of serial communication ,and the measurement results can be uploaded to PC.

Keywords： Single-chip microcomputer；Electronic weighing system；Load cell