Designing And Realizing The Instrument Of Methane's Detecting Based On NDIR

This paper study a methane's detecting equipment based on DSP of infrared. It is widely applied to the methane's detecting of secure consistency in the industrial estate or the superscale of the gas in coal mine, to the deleterious gas detecting in atmosphere or the leakage of the pipeline's gas in family and so on because of its small body, long-life, blast-defended and exact detection precision.The methane that is seen to a chemical material and a flammable gas can be found in lots of areas in which we are living and working. Now the leakage accident about methane have increased along with the development of the petroleum & gas industry in the world. The methane is also the main gas which arise green house and it consist in the gas of superscale of motor vehicle. These factor have threatened our living. So a increasing number of people are concerning about the methane's detection and the leakage of methane. But, at present, the methane detection equipments in our country have some disadvantage, such as the small detection area, slow reaction, easy aging and invalidation, regular adjusting, a big body, high cost and so on. The equipment don't meet people's requirement of detecting consistency of methane. In last century 80s' age the new DSP(Digital Signal Processor) came into being. It can complete the basic mathematical operation such as add subtract multiply and divide in a cycle, and its feature is strong and fast mathematical operation and the big ability of memory and storage which is used in signal processor, image manipulation and industry control etc. This technology is coming forth the 4^th product to this day.In view of this reason, the design try to realize the methane detection instrument of a small body, high exactly, no need regular adjusting.The article expatiate on the infrared absorption theory, the basic theory of infrared detection of methane and the structure and soft flow of the methane detection instrument of infrared. The error of system is analyzed in this paper. And DSP's feature and performance, DSP's development, the DSP's soft platform of CCS(Code Composer Studio),AVR which is MCU(Microprocessor Control Unit) , AVRStudio and WinAVR which are the AVR's composer soft are also briefly introduced in the article.The paper mainly introduced the overall design method of infrared detection system, the design of infrared power, weak-signal detection and signal amplifier. In contrast to generic filter arithmetic FIR which is high exactly arithmetic should be used in this design. The instrument of NDIR(Non-Dispersive Infra-Red) and the project of difference methane's monitoring based on infrared absorption theory of single air chamber are major presented. TMS320F2812 DSP which are analyzed and compared by common MCUs are also introduced.The research of the paper is useful for the design of else gas monitoring such as carbon monoxide, carbon dioxide and sulfur dioxide.