文献翻译——温度传感器与无线模块

第1页外文文献资料TemperaturesensorandwirelessmoduleThispaperisdesignedaDS18B20temperaturedataacquisitionsystem,thesystemmainlyconsistsofthemicrocontrollercircuitandadigitalsensorDS18B20based.Software,weusekeilsoftwarewritinganddebuggingtheprogram,thehardwareside,wepassedProteuscircuitsimulationsoftware,hardware,andtest,thesystemissimple,lowpowerconsumption,throughLCD1602displaythemeasuredtemperature.Temperaturemeasurementaccuracyofthesystemisrelativelyhigh,andstablecommunicationwiththemicrocontrollerandPC.DS18B20temperaturesensorisAmericanDALLASSemiconductorslatestsmarttemperaturesensor,animproved,comparedwiththetraditionalthermistortemperaturemeasurementdevices,whichcanbereaddirectlymeasuredtemperature,andcanbebasedonactualrequirementsthroughsimpleprogramming9to12toachieveadigitalreadoutmode.Thisdesignisasimpleandpracticalsmalldigitalthermometer,themaincomponentsusedwithasensor18B20,microcontrollerAT89S52,oneoffourcommoncathodeLED,resistorcapacitornumber.18B20supportbuslineinterface,measurementtemperaturerange-55to+125.Withinrange-10to+85,accuracyof0.5.18B20pooraccuracyof2.Temperaturedirectlytothescenebuslinedigitaltransfer,whichgreatlyimprovesthesystemsinterference.Thesiteissuitablefortemperaturemeasurementinharshenvironments,suchas:environmentalcontrol,equipmentorprocesscontrol,temperatureandotherconsumerelectronicsproducts.Thedigitalthermometerdesignisdividedintofiveparts,themaincontroller,LEDdisplaysection,thesensorpart,theresetpart,clockcircuit.Thatispartofthemastercontrollermicrocontrollerforstoringprogramsandcontrolcircuit;LEDdisplaysectionreferstothefourcommonanodedigitaltube,todisplaythetemperature;sensorpart,thatthetemperaturesensorisusedtocollecttemperature,temperatureconversion;resetsectionthatresetcircuit.Thetotalprocessmeasurementisthe第2页temperaturesensortotheexternalenvironment,andconvertedspreadSCM,SCMaftertreatmenttodeterminethetemperaturewaspassedtothedigitaldisplay.Thisdesigncancompletetemperaturemeasurementrangeis-55to+128,duetolimitedcapacity,cannotachievethealarmfunction.DS18B20worksasfollows:DS18B20internaloscillatorisalowtemperaturecoefficientoftheoscillationfrequencyoftheoscillatorwithtemperaturechangesverylittle,providingastablefrequencycountpulsecounter1.Ahightemperaturecoefficientoftheoscillationfrequencyoftheoscillatorisverysensitivetotemperatureoscillatorprovidesafrequencyvarieswithtemperaturepulsecounter2count.Whichalsoimpliescountingdoor,thedoorisopenedwhenthecount,DS18B20ontheclockpulseafteralowtemperaturecoefficientoftheoscillatoriscounted,andthencompletethetemperaturemeasurement.Countingthedooropentimeisdeterminedbythetemperature,coefficientoscillator,beforeeachmeasurement,thecorrespondingfirstbasewereplacedin-55andsubtractioncounteratemperatureregister,subtractioncounter1andthetemperatureregistersarepresetinthecorrespondingtoabasevalue-55.Subtractioncounter1lowtemperaturecoefficientofthecrystalpulsesignalgeneratedbysubtractioncountdowncounterwhenapresetvaluereducedtozerovalueofthetemperatureregisterwilladdasubtractioncounterpreset1willbere-loaded,subtractioncounterare-startofthelowtemperaturecoefficientcrystalpulsesignaliscounted,sothecycleuntilthecountdowncounter2to0:00,stopaccumulatingtemperatureregistervaluewhenthetemperatureregistersisthemeasuredtemperaturevalue.Aslongasthecounthasnotclosedthedoortorepeattheprocess,untilthetemperaturereachesthemeasuredtemperaturevalueregistervalue,whichistheprincipleofDS18B20temperature.Inaddition,duetotheDS18B20singlewirecommunicationisdonesharinghisstrictconceptslots,sothetimingisveryimportanttoreadandwrite.DS18B20internalcomparatortoquantifythewaytodeterminethetemperatureregistersroundingtheleastsignificantbit.Aftertwocounterstopscounting,thecomparatorwillcounteracountintheremainingvalueisconvertedtotemperaturevaluesarecomparedwith0.25,iflessthan0.25,thelowestbittemperatureregisterissetto0;ifhigherthan0.25,thelowestbitissetto1;ifgreaterthan0.75,thelowestbittemperatureregisterissetto0andthencarry.第3页Thus,aftercomparingthevalueobtainedafterthetemperatureisthetemperatureofthevalueofthefinalregisterread,anditslastrepresentatives0.5,roundingthemaximumquantizationerroris1/2LSB,namely0.25.Temperatureregistertemperaturevaluesexpressedinninedataformat,thehighestbitisthesignbit,theresteightbinarycomplementform,saidtemperature.Attheendofthetemperaturemeasurement,whichisninedatadumptemporarymemoryofthefirsttwobytes,thesignbitofthefirstbyteoccupied,eighttemperaturedataoccupythesecondbyte.DS18B20usingspecifictemperaturemeasurementtechniquestomeasuretemperature.DS18B20lowtemperaturecoefficientofinternaloscillatorfrequencysignaltoproduceastable;thesamehightemperaturecoefficientoscillatorwillbeconvertedintoafrequencysignalmeasuredtemperature.Whencountingthedooropen,DS18B20countadooropeningtimeisdeterminedbythehightemperaturecoefficientoscillator.Therechipslopeaccumulatorcanbecompensatedfornonlinearityfrequency.Temperaturemeasurementresultisstoredintheregister.Temperatureundernormalcircumstancesshouldbenine,butthesignbitextensionintohigheight,soIfinallyreadouttothe16scomplementform.Inaddition,thisdesignalsoappliedtothewirelessmodulenRF24L01.nRF24L01wirelesscommunicationschipsin2.4GHz2.52GHzlicense-freeISMband,efficientGFSKmodulation,anti-jammingcapability;theoperatingfrequencycanbedividedinto125channels,supportshigh-speedfrequencyhoppingcanunimpededintheglobalwirelessmarket.nRF2401supportmulti-pointcommunicationsbetweenamaximumtransferrateofupto1Mb/s.MeanwhilenRF2401chippowerconsumptionisverylow,theoperatingvoltageof1.9V3.6V,with0dBmofpower,1Mb/stransferratetransmitter,theoperatingcurrentisonly11.3mA,theoperatingcurrentisreceivedonly11.7mA,power-downmodeis900nA1,2.nRF24L01iscurrentlythesmallestandleastpowerconsumption,lowcostexternalcomponentsatleastoneRFsystem-on-chip.nRF24L01generalburstmodeisoftenusedtotransmitandreceivedata.Whentransmittingdata,firstnRF24L01configuredtotransmitmode:thenthereceivingnodeaddressTX_ADDRTX_PLDaccordancewiththetimingandvaliddataiswrittenbytheSPIportnRF24L01bufferzone,TX_PLDmustbewritteninacontinuouslowCSN,whilewritingatthetimeoflaunchTX_ADDRtheonce,thenCEissethighforatleast10s,transmitdatadelayedafter130s;ifauto-第4页answeristurnedon,thenenterthedataimmediatelyafterthelaunchnRF24L01receptionmode,receivestheresponsesignal(automaticresponsereceivingaddressshouldreceiveTX_ADDRconsistentnodeaddress).Ifyoureceiveareply,thenthatthecommunicationissuccessful,TX_DSsethigh,whileTX_PLDremovedfromtheTXFIFO;ifnoreplyisreceived,itisautomaticallyre-transmitthedata(automaticretransmissionisturnedon),ifthenumberofretransmissions(ARC)limitisreached,MAX_RTsethigh,TXFIFOdataretentionforretransmissionagain;MAX_RTorTX_DSsethigh,solowIRQinterruptisgeneratedtonotifyMCU.Thelastsuccessfullaunch,ifCEislowthenenteridlemodenRF24L011;ifsendingdatastackandCEishigh,thefirstlaunchintothenext;ifnodataissentinthestack,andCEishigh,thenenteridlemode2.AndtotransmittheaddressanddataintotheFIFOstackareafromnRF24L01chipmicrocontroller.nRF24L01whentransmittingdata,thedataisautomaticallytransmittedtoaddtheprefix,addressandCRCchecksum,thenhigh-speedlaunch.Ifyouturnthechipauto-answerfeature,AfternRF24L01chipdatatransmissionintoreceivemodeimmediately,inordertoreceivetheresponsesignal.Ifyoureceiveareply,thenthecommunicationissuccessful;ifnoreplyisreceived,itisautomaticallyre-launch,ifthenumberofretransmissionsreachestheupperlimitsetbythehigh-profilepositionMAX_RTregister,indicatinglossofcommunication.nRF24L01whenreceivingdata,youmustfirstbeconfiguredtoreceive,afteradelayof130sentersthereceivingstate.WhennRF24L01receiveddata,ifitdetectsavalidaddressandCRC,whenthedataisautomaticallyheaderandCRCcheckcodeisremoved,andthevaliddatapacketstoredinthereceivestack.Ifauto-answeristurnedon,thereceiveratthesametimereturnintothelaunchstateresponsesignal.Afterreceivingprocessiscompleted,nRF24L01noticemicrocontrollerreadsdata.nRF24L01RFprotocolcanbewrittentothecorrespondingconfigurationwordthroughtheSPIportofthechipconfigurationregisterstoreflect.Configurationwordburstmodetotal30B,ismainlyusedtosettheoperatingmode,thetransmissiondatawidth,addresswidth,address,channel,transmissionfrequency,transmissionpower,CRC,workstatus,auto-answerisenabled,thenumberofautomaticretransmission,etc.Onceconfigured,theprocessnRF24L01work,justchangeitscorrespondingbitconfigurationregisterREXNcontent,you第5页cansendandreceivemodetoswitchbetweenmodes.Hardwaredebuggingisrelativelysimple,firstchecktheinductanceoftheweldingiscorrect,thenusedmultimetertestorpowertest.Softwaredebuggingcanwriteyourprogramanddisplayhardwarecorrectnesstest,thenwerethemainprogram,subroutinesreadtemperature,temperatureconversioncommandsubroutinetocalculatethetemperaturedatarefreshsubroutinesubprogramsandrealityprogramminganddebugging,etc.BecauseDS18B20andmicrocontrollerserialdatatransfer,therefore,DS18B20read/muststrictlyensuretheread/writetimingwhenwritingprogram;otherwiseitwillnotreadthemeasurementresults.FornRF24L01debugging,youneedtocollectandtransfertheprogramreceivewrittenprocedures.ThisprocedureusesthemicrocontrollerwritteninassemblerorClanguageprogramminganddebuggingKeilC51compiler.Softwaredebuggingtonormalradiotransmitterandreceiveranddisplaytemperatureandtemperaturechangeswhenthetemperaturechangeisdisplayed,itbasicallycomplete.Performancetestsareavailableandhavebeenmakingmachinefinishedtemperaturethermometertomeasuresimultaneouslycompare.第6页中文翻译稿温度传感器与无线模块本论文是基于DS18B20设计了一种温度数据采集系统，系统主要由单片机电路和一个DS18B20数字传感器构成。软件方面，我们采用keil软件对程序进行编写以及调试，硬件方面，我们通过Proteus软件对硬件电路进行仿真以及测试，该系统结构简单，功耗较低，通过LCD1602显示所测温度。系统的测温精度比较高，并且能稳定的与单片机和PC机通讯。DS18B20温度传感器是美国DALLAS半导体公司最新推出的一种改进型智能温度传感器，与传统的热敏电阻等测温元件相比，它能直接读出被测温度，并且可根据实际要求通过简单的编程实现912位的数字值读数方式。本设计是一款简单实用的小型数字温度计，所采用的主要元件有传感器18B20，单片机AT89S52，四位共阴极数码管一个，电容电阻若干。18B20支持“一线总线”接口，测量温度范围-55+125。在-10+85范围内,精度为0.5。18B20的精度较差为2.。现场温度直接以“一线总线”的数字方式传输，大大提高了系统的抗干扰性。适合于恶劣环境的现场温度测量，如：环境控制、设备或过程控制、测温类消费电子产品等。本次数字温度计的设计共分为五部分，主控制器，LED显示部分，传感器部分，复位部分，时钟电路。主控制器即单片机部分，用于存储程序和控制电路；LED显示部分是指四位共阳极数码管，用来显示温度；传感器部分，即温度传感器，用来采集温度，进行温度转换；复位部分，即复位电路。测量的总过程是，传感器采集到外部环境的温度，并进行转换后传到单片机，经过单片机处理判断后将温度传递到数码管显示。本设计能完成的温度测量范围是-55+128，由于能力有限，不能实现报警功能。DS18B20的工作原理如下：DS18B20内部的低温度系数振荡器是一个振荡频率随温度变化很小的振荡器，为计数器1提供一频率稳定的计数脉冲。高温度系数振荡器是一个振荡频率对温度很敏感的振荡器，为计数器2提供一个频率随温度变化的计数脉冲。其中还隐含着计数门，当计数门打开时，DS18B20就对低温度系数振荡器产生的时钟脉冲后进行计数，进而完成温度测量。计数门的开启时间由高温,度系数振荡器来决定，每次测量前，首先将-55所对应的基数分别置入减法计数器1和温度寄存器中，减法计数器1和温度寄存器被预置在-55所对应的一个基数值。减法计数器1对低温度系数晶振产生的脉冲信号进行减法第7页计数，当减法计数器1的预置值减到0时温度寄存器的值将加1，减法计数器1的预置将重新被装入，减法计数器1重新开始对低温度系数晶振产生的脉冲信号进行计数，如此循环直到减法计数器2计数到0时，停止温度寄存器值的累加，此时温度寄存器中的数值即为所测温度。只要计数门仍未关闭就重复上述过程，直至温度寄存器值达到被测温度值，这就是DS18B20的测温原理。另外，由于DS18B20单线通信功能是分时完成的，他有严格的时隙概念，因此读写时序很重要。DS18B20内部的比较器以四舍五入的量化方式确定温度寄存器的最低有效位。在计数器2停止计数后，比较器将计数器1中的计数剩余值转换为温度值后与0.25进行比较，若低于0.25，温度寄存器的最低位就置0；若高于0.25，最低位就置1；若高于0.75时，温度寄存器的最低位就进位然后置0。这样，经过比较后所得的温度寄存器的值就是最终读取的温度值了，其最后位代表0.5，四舍五入最大量化误差为1/2LSB，即0.25。温度寄存器中的温度值以9位数据格式表示，最高位为符号位，其余8位以二进制补码形式表示温度值。测温结束时，这9位数据转存到暂存存储器的前两个字节中，符号位占用第一字节，8位温度数据占据第二字节。DS18B20测量温度时使用特有的温度测量技术。DS18B20内部的低温度系数振荡器能产生稳定的频率信号；同样的，高温度系数振荡器则将被测温度转换成频率信号。当计数门打开时，DS18B20进行计数，计数门开通时间由高温度系数振荡器决定。芯片内部还有斜率累加器，可对频率的非线性度加以补偿。测量结果存入温度寄存器中。一般情况下的温度值应该为9位，但因符号位扩展成高8位，所以最后以16位补码形式读出。此外，本设计还运用到了无线模块nRF24L01。nRF24L01无线通讯芯片工作在2.4GHz2.52GHz免许可证ISM频段，高效GFSK调制，抗干扰能力强；工作频率可分为125个信道，支持高速跳频，能够在全球无线市场畅通无阻。nRF2401支持多点间通讯，最高传输速率达1Mb/s。同时nRF2401芯片能耗非常低，其工作电压为1.9V3.6V，以0dBm的功率、1Mb/s的传输速率发射时，工作电流只有11.3mA，接收时工作电流只有11.7mA，掉电模式下为900nA1，2。nRF24L01是目前体积最小、功耗最少、外围元件最少的低成本射频系统级芯片之一。nRF24L01一般常采用突发工作模式进行数据的收发。发射数据时，首先将nRF24L01配置为发射模式：接着把接收节点地址TX_AD