【正文】 roller core can automatically adjust the scope, automatic temperature pensation etc. the use of manmachine dialogue can enable automatic measurement, storage, display data functions. In the actual measurement system, the Nernst equation corresponding to the actual curve often deviate the ideal curve, with the use of twopoint calibration method, we can actually calculate the actual slope and temperature. Key words: three–electrode measurement system, high resistence， the temperature pensation. 目錄 Ⅲ 目 錄 摘 要 ...................................................................................................... I Abstract ................................................................................................ Ⅱ 目錄 .......................................................................................................................... III 第一章 引言 .............................................................................................................. 1 課題背景 ....................................................................................................... 1 PH 測(cè)量系統(tǒng)研究的必要性 ......................................................................... 1 PH 測(cè)量系統(tǒng)的發(fā)展 概況 ............................................................................. 2 PH 測(cè)量系統(tǒng)的主要原理 ............................................................................. 3 第二章 測(cè)量系統(tǒng)的整體設(shè)計(jì) ............................................................................. 4 測(cè)量原理 ...................................................................................................... 4 三電極測(cè)量系統(tǒng) .......................................................................................... 5 PH 測(cè)量系統(tǒng)的測(cè)量方法 ............................................................................. 5 指示電極 ......................................................................................................... 6 參比電極 ......................................................................................................... 7 溫度對(duì)測(cè)量的影響 ............................................................................................ 8 本章總結(jié) ............................................................................................................ 9 第三章 PH測(cè)量系統(tǒng)的硬件設(shè)計(jì) .......................................................................... 10 89C52 介紹 ...................................................................................................... 10 溫度采集電路 ................................................................................................. 13 PH 信號(hào)采集電路 ............................................................................................ 16 A/D， D/A 轉(zhuǎn)換器 ........................................................................................... 17 信號(hào)輸出電路 ................................................................................................. 20 鍵盤顯示設(shè)計(jì) .................................................................................................. 21 電源電路設(shè)計(jì) .................................................................................................. 22 總線擴(kuò)展 .......................................................................................................... 23 本章總結(jié) .......................................................................................................... 27 目錄 IV 第四章 基于 MAX232通訊模塊 ............................................................. 28 系統(tǒng)設(shè)計(jì)總體方案 ......................................................................................... 28 串口通信基礎(chǔ)理論 .......................................................................................... 28 兩種接口方式 ................................................................................................. 29 串行接口方式 ............................................................................................ 29 并行接口方式 ............................................................................................ 29 51 系列單片機(jī)串行口控制寄存器 SCON ..................................................... 29 RS232 串行接口標(biāo)準(zhǔn) .................................................................................... 30 單電源轉(zhuǎn)化芯片 MAX232 ............................................................................ 31 MAX232 外圍連接電路 ................................................................................. 31 通信程序設(shè)計(jì) ................................................................................................. 32 總結(jié) .................................................................................................................. 33 第五章 PH測(cè)量系統(tǒng)的軟件設(shè)計(jì) ............................................................. 34 測(cè)量系統(tǒng)主要內(nèi)容 ......................................................................................... 34 測(cè)量系統(tǒng)主程序 ............................................................................................. 34 子程序的標(biāo)定 ............................................................................................ 36 測(cè)量子程序 ..................................................................................................... 37 本章小結(jié) ......................................................................................................... 37 第六章 誤差分析及功能測(cè)試 .................................................................. 38 誤差分析 .......................................................................................................... 38 數(shù)據(jù)分析 .......................................................................................................... 40 結(jié)論 ..................................................................................................... 41 致 謝 ................................................................................................. 42 參考文 獻(xiàn) .........................................................