【正文】 ........................................................................................................... 1 本課題的研究背景及意義 ................................................................................. 1 國內外發(fā)展概況和研 究方向 .............................................................................. 2 課題主要研究內容與要求 .................................................................................. 3 2 系統(tǒng)總體設計 ................................................................................................................. 4 系統(tǒng)設計模塊 ..................................................................................................... 4 系統(tǒng)功能描述 ...................................................................................................... 4 3 硬件設計 ......................................................................................................................... 6 硬件系統(tǒng)設計 ...................................................................................................... 6 信號采集電路 ...................................................................................................... 6 瓦斯傳感器的種類 ................................................................................... 6 接觸燃燒式氣體傳感器結構及原理 .................................................... 7 MQ5 介紹 ............................................................................................... 11 熱阻體式氣體傳感器原 理 .................................................................... 15 A/D 轉換電路 ..................................................................................................... 16 A/D 轉換器的主要技術參數 .................................................................. 21 的內部邏輯結構 ...................................................................... 22 ADC0809 引腳結構 ................................................................................. 23 應用說明 .................................................................................. 24 顯示電路 ............................................................................................................ 25 1602A 引腳說明 ...................................................................................... 26 1602A 自 定義字符說明 .......................................................................... 27 聲光報警電路 .................................................................................................... 28 單片機最小系統(tǒng) ............................................................................................... 29 時鐘電路 ................................................................................................ 29 復位電路 ................................................................................................ 29 單片機概述 ....................................................................................................... 30 STC89C52 特性 ..................................................................................... 30 STC89C52 參數 ..................................................................................... 30 STC89C52 工作模式 ............................................................................. 31 STC89C52I/O 口復用功能說明 ............................................................ 31 4. 軟件設計 ..................................................................................................................... 32 概述 .................................................................................................................... 32 系統(tǒng)流程圖 ........................................................................................................ 32 編程語言的選擇 .................................................................................... 33 keiiC51 編程環(huán)境 .................................................................................... 34 C51 與標準 C 的主要區(qū)別 ................................................................... 34 仿真 ....................................................................................................... 35 5 總結 .............................................................................................................................. 38 致謝 .................................................................................................................................. 39 參考書目 .......................................................................................................................... 40 附錄 .................................................................................................................................. 41 1 本課題的研究背景及意義 我國是煤炭生產大國，隨著煤礦機械化程度的提高，礦井生產能力和生產效率普遍加大，煤炭年產量居世界首位， 2020年全國煤炭產量完成 37億噸左右，產煤量占世界總產煤量的 20%。 A/D converter circuit。 display circuit displays the realtime gasconcentration。 sensitive element that is used of the accurate detection of gas content is one of the main ponents, and its output isthe voltage signal which is corresponding to the gasconcentration。 該儀器的特點是測量范圍寬，精度高；結構簡單， 體積小， 成本低；可靠性和穩(wěn)定性好，是一種電路設計新穎、參數測量準確、操作方便的礦用瓦斯?jié)舛缺O(jiān)控儀。 儀器由 CPU、敏感元件、 A/D 轉換電路、顯示電路、報警電路等組成。 摘要 本課題設計的是用單片機控制的瓦斯?jié)舛葓缶O(jiān)控儀，是采用 以金屬氧化物 SnO2為主體 材料 制成的 N 型半導體氣敏元件制成的 瓦斯?jié)舛葴y量儀，適用于中小型煤礦井下各作業(yè)場所中測量空氣中的瓦斯?jié)舛?。儀器能夠根據瓦斯?jié)舛葓缶?(%)進行聲、光報警。其中 CPU 是監(jiān)控儀的核心，完成數據采集、處理、輸出、顯示等功能；敏感元件是準確檢測瓦斯氣體含量的主要元件之一，其輸出是與瓦斯?jié)舛认鄬碾妷盒盘枺?A/D 轉換電路把放大了的電壓信號由模擬信號變?yōu)閿底中盘査腿?CPU；顯示電路則顯示實時瓦斯?jié)舛?；報警電路對超限瓦斯?jié)舛冗M行報警。 關鍵詞： CPU； A/D 轉換 ；氣敏元件；報警 II Abstract This paper designs gas alarm monitor, which is made of metal oxide SnO2 as the main material for ntype semiconductors gas sensor. It is applicable to small and mediumsized coal mine in the measurement of workplace air concentration of gas. Apparatus, which is according to gas concentration alarm limit (1%), carry out sound and light alarm. Apparatus consists of CPU, sensitive element, A/D conversion circuit, display circuit