【正文】 o display the concentration of methane，monitoring circuit is to monitor the overstep limit of methane concentration結(jié)構(gòu)簡(jiǎn)單，成本低。報(bào)警電路對(duì)超限瓦斯?jié)舛冗M(jìn)行報(bào)警。A/D 轉(zhuǎn)換電路把放大了的電壓信號(hào)由模擬信號(hào)變?yōu)閿?shù)字信號(hào)送入單片機(jī)。敏感元件是準(zhǔn)確檢測(cè)瓦斯氣體含量的主要元件之一，其輸出是與瓦斯?jié)舛认鄬?duì)應(yīng)的電壓信號(hào)。 系統(tǒng)由 AT89C51單片機(jī)、敏感元件、看門(mén)狗監(jiān)控電路、小信號(hào)放大電路、A/D轉(zhuǎn)換電路、通信電路、顯示電路、報(bào)警電路等組成。I單片機(jī)的瓦斯報(bào)警系統(tǒng)的設(shè)計(jì)摘要 本文設(shè)計(jì)的用單片微機(jī)控制的瓦斯?jié)舛缺O(jiān)控報(bào)警系統(tǒng)，是采用熱催化原理(俗稱黑白元件)探頭制成的甲烷濃度測(cè)量?jī)x，適用于煤礦井下各作業(yè)場(chǎng)所中測(cè)量空氣中的瓦斯?jié)舛?。儀器能夠根據(jù)瓦斯?jié)舛葓?bào)警限(%)進(jìn)行聲、光報(bào)警，并啟動(dòng)排風(fēng)設(shè)備，同時(shí)具有通信功能。其中 CPU是監(jiān)控儀的核心，完成數(shù)據(jù)采集、處理、輸出、顯示等功能。小信號(hào)放大電路則是用來(lái)放大敏感元件輸出的電壓信號(hào)。顯示電路則顯示實(shí)時(shí)瓦斯?jié)舛取? 該系統(tǒng)的特點(diǎn)是測(cè)量范圍寬，精度高?？煽啃院头€(wěn)定性好，是一種電路設(shè)計(jì)新穎、參數(shù)測(cè)量準(zhǔn)確、操作方便的礦用瓦斯?jié)舛缺O(jiān)控報(bào)警系統(tǒng)。 The feature is new design，accurately measure parameter，convenient to operate and so on. Keywords: AT89C51，sensitive element，A/D transformation Circuit.III目錄摘要 ..............................................................................................................................IABSTRACT................................................................................................................II目錄 ...........................................................................................................................III第 1 章 緒論 ...............................................................................................................1 瓦斯的介紹 ......................................................................................................1 煤礦安全系統(tǒng)概況 ..........................................................................................3 測(cè)量?jī)x器的基本性能 ......................................................................................4 測(cè)量?jī)x器的概念 ......................................................................................4 測(cè)量?jī)x器的基本性能 ..............................................................................5第 2 章 研究?jī)?nèi)容方法和原則 ...................................................................................8 研究?jī)?nèi)容方法 ..................................................................................................8 設(shè)備和功能 ..............................................................................................8 計(jì)時(shí) ..........................................................................................................9 主要實(shí)現(xiàn)方法 ..........................................................................................9 設(shè)計(jì)原則 ..........................................................................................................9 總體設(shè)計(jì)的原則 ....................................................................................10 課題研究的總體思路 ....................................................................................11第 3 章 監(jiān)控系統(tǒng)工作原理 .....................................................................................12 瓦斯?jié)舛葯z測(cè)系統(tǒng)原理分析 ........................................................................12 分類 ........................................................................................................12 熱催化元件的結(jié)構(gòu)及工作原理 ....................................................................13 熱催化元件的結(jié)構(gòu) ................................................................................13 敏感元件工作原理 ................................................................................14 整機(jī)工作原理 ........................................................................................14第 4 章 硬件電路設(shè)計(jì) .............................................................................................16 微控制器 CPU .................................................................................................16IV AT89C51 ..................................................................................................16 敏感元件 ........................................................................................................19 .....................................................................................19 敏感元件的組成及作用 ........................................................................21 小信號(hào)放大電路 ............................................................................................22 A/D轉(zhuǎn)換電路 .................................................................................................22 ADC0809的內(nèi)部結(jié)構(gòu) .............................................................................22 通信電路 ........................................................................................................27 串行通訊 ................................................................................................27 信號(hào)的調(diào)制和解調(diào) ................................................................................29 芯片的選擇 ............................................................................................29 串行通信的軟件 ....................................................................................30 可編程看門(mén)狗電壓監(jiān)控電路 ........................................................................33 顯示電路 ........................................................................................................37 聲光報(bào)警電路 ................................................................................................38 光報(bào)警電路 ............................................................................................38 聲報(bào)警電路 ............................................................................................38 排風(fēng)電路 ........................................................................................................39 .......................................................................................................41第 5 章 軟件設(shè)計(jì) .....................................................................................................46 系統(tǒng)軟件設(shè)計(jì)原則 ........................................................................................46 軟件實(shí)現(xiàn)功能 ................................................................................................46 主程序流程圖 ........................................................................................46 定時(shí)器中斷服務(wù)程序 .............................................