温度传感器信号采集系统设计-英文文献翻译

ResearchofIntelligentGasDetectingSystemDetectingsysteminthispaperadoptssingle-chipmicrocomputerascontrolcomputer;theoverallschematicdiagramofsystemisshowninFigure1.Thereasonforselectingsingle-chipmicrocomputerasacontrolcoreisthatitpossessesadvantagesofsmallsize,highreliability,lowpricewhichmadeitverysuitabletobeusedinindustriesofintelligentinstrumentandrealtimecontrol.TheoperatinginterfaceofsystemisshowninFigure1.Numberatupperrightcornershowsthedefaultoruser-definedgasconcentrationvalue,numberatupperleftcornershowsdetectedgasconcentrationvalue.Onealarmlampisequipped.Allfunctionsarecontrolledbykeysarrangedonthecontrolpanel,includingPOWERkey,RESETkey,DATACOLLECTIONkey.Otherkeysincludingtennumberkeys,ADJUSTVALUEkeyandENTERkeyareusedtochangethresholdvaluesFig.1TheoperatinginterfaceofsystemBasicoperatingproceduresareasfollows:FirstlypressPOWERkey,thesysteminitialized.PressDATACOLLECTIONkey,LEDatupperrightcornerdisplaysthethresholdvalue1.00;UsercancustomizedthresholdvaluebypressADJUSTVALUEkeyandtennumberkeys,thenpressENTERtoconfirmthechange.SystemstartstodetectgasconcentrationanddisplaytheseparametersonupperleftLEDarea,atmeantimetransmitreal-timedatabyRS-485tohostcomputeraboveground.TheHardwarearchitectureofsystemmainlyincludingmaincontrolunit,sensorsandsignalamplifiercircuit,A/Dconvertermodule,sound-lightalarmingcircuit,keyboardanddisplaymodule,serial-communicationmodule.Featuredbyhighintegrationlevel,smallsizeandlowprices,Singlechipmicrocomputerhasbeenwidelyusedinabroadrangeofindustrialapplicationsincludingprocesscontrolling,datacollection,electromechanicalintegration,intelligentinstrument,householdappliancesandnetworktechnology,andsignificantlyimprovedthedegreeoftechnologyandautomation.Fig.2MaincontrolunitTwofactorsaretakenintoaccounthereinchipselecting,firstoneisanti-interferenceability,increasetheinterferencesinSCMapplicationsystems,sotheSCMmusthavehighresistancetooutsideinterference;secondoneistheperformance-priceratiooftheSCM.Consideringtheaforementionedfactors,weadoptedtheAT89S52developedbyATMELasmaincontrolunit,andthefinalschemeofmaincontrolcircuitconsistsofAT89S52,timerandresetcircuit.Acrucialissueingasdetectingsystemdesignishowtoselectgassensors.Commongassensorsaremetaloxidesemiconductorsuchastinoxide,zincoxide,titaniumoxideandaluminumoxide.Problemsencounteredwiththesesensorsarelackofflexibility,poorresponsetimesandoperatedatelevatedtemperature.Anewmethodofch4detectingbasedoninfraredtechniqueswaspresentedinrecentyears,butitisstillinprogressandmuchworkshouldbedonebeforeitcanbeappliedtosolvethepracticeproblems.ThissystemadoptedcatalyticcombustiontypegassensorMC112developedbySUNSTARgrouptomeasurethegas(ch4)concentration.Figure4showstheoutsideviewandinternalcircuitofMC112,table1liststhemaintechnologyparametersofMC112.MC112gasdetectorexploitscatalyticcombustionprinciple;thetwo-armbridgeiscomprisedofmeasureandcompensatecomponentspairs.Whenitisexposedtocombustiblegases,measurecomponentsresistanceRSincreasedandtransmitoutputvoltageparameterthroughmeasuringbridge,thevoltageparameterisdirectlyproportionaltothegasconcentrationvalue.Thecompensatecomponentworksastemperaturecompensationandreference.MainfeaturesofMC112includegoodrepeatability,workstably,reliability,linearoutputvoltage,andquickresponse.Theminesafetyrulesstatedthatifmethanegasconcentrationexceeds1%,safetysystemshouldmakeanalert,ifgasconcentrationexceeds2%,allpeoplemustevacuateimmediately.SincethedetectingrangeofMC112forlowconcentrationmethaneis0%-2%.Fig.3OutsideviewItisnecessarytoamplifytheweakelectricalsignaldetectedbyMC112(1%gasconcentrationfluctuationwillresultin16mvvoltagechange).ThesystemadoptedAD623developedbyADCompanyasthehighperformanceinstrumentationamplifier.Ithasmanymerits:(1)outputwith3-12vsinglesupply(2)easytomodifysignalgainthoughanexternalresistor,itwillbeactasaunitgainwithoutexternalresistorandsignalgaincanreachto1000withanexternalresistor;(3)lowpowerconsumption,large-scaleoperationvoltage,goodlinearity,goodthermalstabilityandhighreliability.Theschematicdiagramofsignalamplifiercircuitisshowninfigure4.Fig.4SignalamplifiercircuitAsshowninFigure5,thismoduleconsistsofmultiplexerCD4051,samplingholderLF389,A/DconverterAD574AandparallelI/Ochip8255A.Asacorepart,AD574Aisa12-bitsuccessive-approximationA/Dconverterchipwiththree-statebuffer,itsconversiontimeisabout25μs.AD574AcandirectlyconnectedtoAT89S52withoutadditionalinterfacelogiccircuit,withinternalhighaccuracyreferencepowersupplyandclockcircuit,AD574Acanoperatenormallywithoutexternalclocksourceandreferencepowersupply.Fig.5A/DconvertermodelTraditionalLCDmoduleisunsuitableinthissystembecausetheworkingenvironmentmainlyliesdeepindarkcoalminetunnel.LEDwithsoftlightshouldbethealternative.Itissuitablefortheadversecircumstancesundercoalminefeaturesbydamp-proof,excellencetemperaturecharacteristicsandlongdistancevisualeffects.Inthissystem,a6-bitLEDisadoptedtodynamicallydisplaythech4gasconcentrationvalue,withthesegmentportandbitportconnectedwithPAportandPBportof8155(1)separately.Inkeyboardinputmodule,wearranged13keysincluding10numberkeysand“Datacollection”key,“Enter”key,“reset”key.Adoptedoppositedirectionconnectmethod,PBportandPCportof8155(2)connectedtokeyboard’srowcircuitandcolumncircuitrespectively.TheserialcommunicationsmoduleisshownattheleftpartinFigure9,signalofmicrocontrolleristransmittedtohostcomputerabovegroundbyRS-485,andMAX485isusedtoconvertthevoltage.RS-485isamulti-pointtwo-wayhalf-duplexcommunicationlinkbasedonsinglebalanced-wirecircuitfeaturedbyhighnoisesuppression,hightransferrate,longdistancetransmissionandWidecommon-moderange,itsmaximumtransferratereachesto10Mbps,maximumcabledistancereachesto1200m.Theprimaryfunctionsofthesoftwarecontrolsystemincludingsysteminitializing,thresholdvaluesetting,methanegasconcentrationdatacollectinganddisplaying,serialcommunicationsetc.Toachievetheabovefunctions,wedevelopedserialprogramsusing51serialsmicrocontrollerassembleprogramlanguageincludingmainprogram,keyboardscanningprogram,A/Dconverterprogram,alarmingprogram,serialcommunicationsprogram,datadisplayprogram,systemalarmingdiagnosisprogram,double-bytemultiplyprogram,triple-bytetobinary-coded-decimalprogramandwatchingdogprogram.Thesystemiscomprisedofmanymodules,Owingtolimitedspaceweintroducemainprogramonly.mainprograminitializingsinglechipmicrocomputer’sregistersandI/Oports,thenscanningkeyboardtoseeifthedatacollectionkeyispressed,ifno,keepscanningkeyboarduntildatacollectionkeyispressed.Whenthecollectionkeyispresseddown,defaultthresholdvalue1.00isshownonthepanel,ifuserwantstoresetthresholdvalue,justpresstheADJUSTVALUEkeytosetanewvalue,andpressENTERkeytofinishthisstep.WhenENTERkeyispressed,systemstarttheoperatingofdatacollectionandA/Dconversion,thentransmittheconverteddataintobinaryformatbycallingasubprogramofdouble-bytemultiply.Weneedthreestorageunitstoholdthesedatabecausetheyare24bitsdatainbinaryformat.Next,systemwilltransmitthesebinaryformatdataintobinary-coded-decimalformatbycallingasubprogramoftriple-bytetobinary-coded-decimal.Inthelaststep,comparingthevaluewithpre-setthresholdvaluetodecideifthesystemshouldsendanalarmsignal.Inthemeantime,thesedatawillbesendingtohostcomputerabovegroundthroughRS-485serialcommunicationsunit.Still,thesystemwillsendapositivepulsetoresetthewatchdogtimerevery1.6sec.theCrystalOscillatorfrequencyoftheSCMadoptedinthissystemis12MHZ,withtimer/counterTO,workinginmode1(16bittimer/counter),itsmaximaltimingintervalisabout66ms,sothesystemwillsendafeedingdogsignaltowatchdogcircuitevery66ms.Inthisstudy,anintelligentgasdetectingsystemispresented.Itcanbeusedtoreal-timemonitoringthemethanegasconcentration.Themeasuringscopeofthissystemrangefromzeroto2percent,thesensitivityofthesensorreachto0.01percent.Itisequippedwiththequickspeedandhighperformance12-bitA/Dconverter,theoperatingenvironmenttemperaturerangedfrom-20℃～+70℃.Stillthissystemfeatureswithhighreliability,easytooperate,highperformance-priceratio.Inthispaper,thetotalplanandsoftwareandhardwaredesignofagasdetectingsystemarepresented,byusingProteustotesthardwarecircuitandusingKeiltotestassemblelanguagesourceprogram,thesimulationtestresultshowsthissystemisofhighaccuracy,quickresponseandisfeasible.研究智能气体检测系统在本文中，检测系统采用单片机作为控制计算机。选择理由：单片机作为控制核心，它具有体积小尺寸，高可靠性，低价格，使其成为行业使用非常合适智能仪表、实时控制领域。系统的操作界面如图1所示。在右上角号码显示默认的或用户定义的气体浓度值，在左上角显示检测到的气体浓度值。报警灯的设置。所有的功能通过设置控制面板上的按键控制，包括电源键，复位键，数据采集的关键。其他键包括十个数字键，调整值键和回车键来改变阈值。基本操作程序如下：首先按下电源键，系统初始化机数据采集的关键，LED在右上角显示的阈值1；用户可以定制阈值调整值的按键和数字键，然后按回车键确认更改。系统开始检测气体浓度和上显示这些参左叶面积，同时实时数据的传输，通过RS-485总线主机地面上的。主要包括主控单元系统的硬件结构，传感器和信号放大电路，A/D转换模块，声光报警电路，键盘显示模块，串口通信模块。具有集成度高,体积小,价格低，单片机已广泛应用于工业过程中广泛应用包括控制，数据采集，机电一体化，智能仪表，家用电器和网络技术，以及显著提高的程度技术和自动化。考虑在芯片选择两个因素，一是抗干扰的能力，提高单片机应用系统的干扰，图1系统运行界面图所以单片机必须有较高的外界干扰；二是单片机的性能价格比。考虑到上述因素，我们采用了Atmel公司的AT89S52作为主控单元，和主控电路的最终方案包括AT89S52单片机，定时器和复位电路。如图2所示。图2主控制单元在气体检测系统设计的一个关键问题是如何选择的气体传感器。常见的气体传感器的半导体金属氧化物如氧化锡，锌coxide，钛氧化物和铝氧化物。遇到的问题与这些传感器缺乏灵活性，可怜响应时间和在升高的温度下操作[10]。甲烷检测新方法基于红外技术是近年来提出的，但它仍然是在进步和很多工作之前应该可以应用于解决实际工程问题。本系统采用催化燃烧式气敏元件MC112开发海星集团来测量气体（CH4）的浓度。图3显示了外面观和MC112内部电路，表1列出了主要技术参数MC112。MC112气体检测器利用催化燃烧原理的两个臂；桥是由测量与补偿元件对。当它被暴露可燃气体，测量元件电阻增大，输出通过测量电桥电压参数，参数的电压成正比的气体浓度值。补偿元件的工作温度补偿和参考。对MC112主要功能包括可重复性好，工作稳定，可靠，线性输出电压，和快速的反应。煤矿安全规程表示，如果甲烷气体浓度超过1%，安全系统应警报，如果瓦斯浓度超过2%，所有的人都必须立刻疏散。自检测低浓度甲烷MC112范围为0%-2%。图3传感器外观要放大微弱电信号的检测采用MC112（1%气体浓度波动将导致16MV电压变化）。采用扭矩传感器系统广告公司开发的高性能的仪表放大器。它有优点：（1）单电源和12V输出（2）易于修改信号增益虽然外部电阻器，它将作为无外部单位增益电阻和信号增益可达1000与一个外部电阻；（3）低功耗消耗，大规模的操作电压，线性度好，热稳定性好，高可靠性。信号放大器电路原理图如图4所示。图4信号放大电路如图5所示，该模块由多路CD4051，采样保持器lf389，A/D转换器AD574A和并行I/O芯片8255A作为核心的一部分，AD574A是一个12位的逐次逼近A/D转换器芯片三的状态缓冲区，其转换时间约为25μS.AD574A能够直接连接到单片没有额外的接口逻辑电路，内置高精度的参考功率电源和时钟电路，无需外部时钟源AD574A能够正常运行参考电源。图5A/D转换器模块传统的液晶显示模块是不适合在这个系统中由于工作环境主要是在黑暗的矿井隧道深。LED软灯应选择。它是在煤矿的特点为不利的情况下适用防潮，卓越的温度特性和长距离的视觉效果。在本系统，采用6位LED动态显示CH4气体浓度值，与段端口和位端口与PA口和PB端口连接8155（1）分别。在键盘输入模块，我们安排了13个键，包括10个数字键和“数据收集”键，“进入”键，“复位”键。采用相反的方向连接的方法，PB口和8155PC端口（2）连接到键盘的行和列电路电路分别。串行通信模块，信号控制器发送到主机计算机上通过RS-485，和MAX485是用于转换电压。RS-485是多点双向半双工通信基于单平衡线电路具有高噪声抑制链接，传输速率高，传输距离长、宽共模范围，其最大传输率达到10Mbps，电缆的最大距离达到1200。P21和P10AT89S52将声光报警单元控制时甲烷气体浓度的检测值超过设定值。软件控制系统包括系统初始化的主要功能，阈值设定，甲烷气体浓度数据采集和显示，串行通信等。为了实现上述功能，我们开发了串行程序采用51系列单片机汇编程序语言包括主程序，键盘扫描程序，A/D转换程序，报警程序，串口通讯程序，数据显示程序，系统报警诊断程序，双字节乘法程序，三字节二进制程序看狗程序。该系统是由许多模块，由于有限的空间，我们介绍主程序。主程序初始化单片机寄存器，I/O端口，然后扫描键盘看数据采集键被按下，如果没有，继续扫描键盘按键直到数据收集。当收集键被按下，默认的阈值1显示面板上，如果用户想复位阈值价值，只是按调整值设置一个新值，然后按回车键完成这一步。当按下Enter键，系统开始数据采集的运行和A/D转换，然后将转换后的数据为二进制格式调用一个子程序的双字节乘法。我们需要三个存储单元存储这些数据是因为他们24位二进制数据格式。接下来，系统会将这些二进制格式的数据转换成二进制编码的十进制格式，通过调用一个子程序三字节的二进