【正文】 RS increased and transmit output voltage parameter through measuring bridge, the voltage parameter is directly proportional to the gas concentration value. The pensate ponent works as temperature pensation and reference. Main features of MC112 include good repeatability, work stably, reliability, linear output voltage, and quick response. The mine safety rules stated that if methane gas concentration exceeds 1%, safety system should make an alert, if gas concentration exceeds 2%, all people must evacuate immediately. Since the detecting range of MC112 for low concentration methane is 0%2%. Fig. 4. Outside view Signal Amplifier Circuit It is necessary to amplify the weak electrical signal detected by MC112 (1% gas concentration fluctuation will result in 16mv voltage change). The system adopted AD623 developed by AD Company as the high performance instrumentation amplifier. It has many merits: (1) output with 312v single supply (2) easy to modify signal gain though an external resistor, it will be act as a unit gain without external resistor and signal gain can reach to 1000 with an external resistor。 參考文獻(xiàn) (略 ) 外文原文 Research of Intelligent Gas Detecting System Abstract. According to statistic data of China in recent years,Gas leakage occurs, Pose a great threat to the personal safety. So the gas detection And monitoring system is required as a safety device applied in the family. In this paper, an intelligent gas detecting system is designed. This detection instrument adopts SCM AT89S52 as its control hardcore and uses catalytic bustion type gas sensor element MC112 as the sensor for gas (CH4) main functions of this system are as follows: monitoring the realtime concentration of CH4 and displaying the concentration value。然而，系統(tǒng)會(huì)發(fā)送一個(gè)正脈沖復(fù)位看門狗定時(shí)器每 。 該系統(tǒng)是由許多模塊，由于有限的空間，我們介紹主程序。在本系統(tǒng)，采用 6位 LED動(dòng)態(tài)顯示 CH4氣體濃度值，與段端口和位端口與 PA口和 PB端口連接 8155（ 1）分別。 圖 4. 外觀 要放大微弱電信號(hào)的檢測采用 MC112（ 1%氣體濃度波動(dòng)將導(dǎo)致 16MV電壓變化）。 本系統(tǒng)采用催化燃燒式氣敏元件 MC112開發(fā)海星集團(tuán)來測量氣體（ CH4）的濃度。 具有集成度高 ,體積小 ,價(jià)格低，單片機(jī)已廣泛應(yīng)用于工業(yè)過程中廣泛應(yīng)用包括控制，數(shù)據(jù)采集，機(jī)電一體化，智能儀表，家用電器和網(wǎng)絡(luò)技術(shù)， 以及顯著提高的程度技術(shù)和自動(dòng)化。 系統(tǒng)的操作界面如圖 2所示。中文 2816字 研究智能氣體檢測系統(tǒng) 摘要 根據(jù)統(tǒng)計(jì)數(shù)據(jù)，中國近年來，煤氣泄漏時(shí)有發(fā)生，對人身安全造成很大威脅，因此氣體檢測 和監(jiān)控系統(tǒng)是需要作為一個(gè)安全裝置 在家庭應(yīng)用 。選擇理由 ： 單片機(jī)作為控制核心，它具有體積小尺寸，高可靠性，低價(jià)格，使其成為行業(yè)使用非常合適智能儀表、實(shí)時(shí)控制領(lǐng)域。 3氣體檢測系統(tǒng)的硬件系統(tǒng)設(shè)計(jì) 主要包括主控單元系統(tǒng)的硬件結(jié)構(gòu)，傳感器和信號(hào)放大電路， A/D轉(zhuǎn)換模塊，聲光報(bào)警電路，鍵盤顯示模塊，串口通信模塊。甲烷檢測新方法基于紅外技術(shù)是近年來提出的，但它仍然是在進(jìn)步和很多工作之前應(yīng)該可以應(yīng)用于解決實(shí)際工程問題 [ 11 ]。自檢測低濃度甲烷 MC112范圍為 0% 2%。它是在煤礦的特點(diǎn)為不利的情況下適用防潮，卓越的溫度特性和長距離的視覺效果。為了實(shí)現(xiàn)上述功能，我們開發(fā)了串行程序采用 51系列單片機(jī)匯編程序語言包括主程序，鍵盤掃描程序， A/D轉(zhuǎn)換程序，報(bào)警程序，串口通訊程序，數(shù)據(jù)顯示程序，系統(tǒng)報(bào)警診斷程序，雙字節(jié)乘法程序，三字節(jié)二進(jìn)制程序看狗程序。在這期間， 這些數(shù)據(jù)將被發(fā)送到上位機(jī)通過 RS485串行地通信單元。在本文中，總規(guī)劃軟件和氣體檢測系統(tǒng)的硬件設(shè)計(jì)提出了利用 Proteus，測試硬件電路，采用 KEIL測試組裝語言源程序，仿真試驗(yàn)結(jié)果表明該系統(tǒng)具有較高的精度，快速響應(yīng)是可行的。 (3)low power consumption, largescale operation voltage, good linearity, good thermal stability and high reliability. The schematic diagram of signal amplifier circuit is shown in figure 5. A/D Converter Module As shown in Figure 6, this module consists of multiplexer CD4051, sampling holder LF389, A/D converter AD574A[12] and parallel I/O chip 8255A. As a core part, AD574A is a 1