单片机AVR与PLC.docx

单片机AVR与PLC.docx

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单片机AVR与PLC

English：

AVRmicrocontrollerandPLC:

AVRMicrocontrollerATMELCorporationin1997,developedbytheenhancedbuilt-inFlashoftheRISC（ReducedInstructionSetCPU）high-speed8-bitRISCmicrocontroller.AVRmicrocontrollercanbewidelyusedincomputerperipherals,industrialreal-timecontrol,instrumentation,communicationsequipment,householdappliancesandotherfields.

Highreliability,strongfunction,highspeed,lowpowerconsumptionandlowcosthasalwaysbeenanimportantindicatortomeasureperformanceofSCM,SCMalsocapturethemarket,anecessaryconditionforsurvival.

SCMwasmainlyduetotheearlylowleveloftechnologyanddesign,highpowerconsumptionandanti-jammingperformancewaspoor,sotosecuretheprogram:

thatthehigherfrequencycoefficientsoftheclockfrequency,solonginstructioncycle,implementationisslow.AlthoughthefutureuseofCMOSsinglechiptoimproveclockfrequencyandreducethefrequencycoefficientsandothermeasures,butthisstatehasnotbeenradicallychanged（51and51compatible）.AlthoughsomehereRISCmicrocontroller（RISC）comeout,buthasfollowedthepracticeoftheclockfrequency.

AVRmicrocontrollerintroduction,completethedesigntobreaktheoldpatternoftheabolitionofthemachinecycle,abandonedcomplexinstructioncomputer（CISC）instructionstopursueacomprehensiveapproach;usingreducedinstructionset,inwordasacommandunitoflengthandthecontentisrichandtheoperandarrangementsamongopcodeword（instructionfocusedthemajorityofsingle-cycleinstructionsareso）,takethatshortperiod,canprefetchinstructions,achievingasmoothandfastitcanexecutecommands.Ofcourse,thisspeedjumpontherise,backedbyitshighreliability.

AVRmicrocontrollerhardwareto16-bit8-bitmachineandthemachine'scompromisestrategythatiskeptbythelocalregisterstack（32registerfile）andthesinglehigh-speedinput/outputoftheprogram（ie,inputcaptureregisters,registersandthecorrespondingoutputcomparematchcontrollogic）.Improvedinstructionexecutionspeed（1Mips/MHz）,toovercomebottlenecksandenhancethefunction;whilereducingthecostofperipheralmanagement,simplifyingthehardwarestructureofarelativelylowercost.Therefore,AVRmicrocontrollerinsoftware/hardwarecosts,speed,performanceandcosttoachievetheoptimalbalancebetweenthemany,iscost-effectivesinglechip.

AVRmicrocontrollerembeddedhigh-qualityFlashprogrammemory,eraseeasily,supportISPandIAP,easydebuggingofproducts,development,production,updating.EmbeddedlonglifeEEPromcriticaldatacanbestoredforalong,toavoidpowerloss.Large-capacityRAMchipcannotonlymeetthegeneraluse,butalsosupporttheuseofmoreeffectiveproceduresforhigh-levellanguagedevelopmentsystem,andcanXiangMCS-51microcontrollerasextendedexternalRAM.

AVRmicrocontrollerI/Olinescanbesetwithallthepull-upresistorcanbesetindividuallyasinput/outputcanbeset（initial）highimpedanceinput,drivecapability（eliminatingtheneedforpower-drivendevices）andotherfeaturessothatthegainsI/Oportresources,flexible,powerful,andcanbefullyutilized.

AVRmicrocontrollerchipwithmultipleindependentclockdivider,respectively,forURAT,I2C,SPIuse.Onewith8/16bittimerwithupto10-bitwithprescaler,canbesetbysoftwaretoprovideavarietyofsub-frequencycoefficientsgraderegulartime.AVRmicrocontrollerunique"tothetimer/counter（single）two-wayformatrianglewavecount,andthenregisterwiththematchwithoutputcomparetogenerateavariabledutycycle,variablefrequency,variablephasesquare-wavedesignmethod（ie,pulsewidthmodulationoutputPWM）"isrefreshing.

Enhancedhigh-speedsynchronous/asynchronousserialportwithhardwaregeneratedcheckcode,hardwaretestingandverificationdebug,tworeceptionbuffer,thebaudrateautomaticallyadjuststhelocation（whenreceived）,shieldingframe,whichcanimprovethecommunicationreliability,easyprogramming,amoreconvenientformofdistributednetworksandcommunicationsystemstoachievecomplexmulti-machineapplications,functionwelloverMCS-51/96serialCOMport,combinedwithhigh-speedAVRmicrocontroller,theinterruptservicetimeisshort,itcanbehighwaveSpecialratecommunications.

Byte-orientedhigh-speedserialinterfacehardware,TWI,SPI.TWIandI2Cinterface,compatiblewiththehardwaretosendandACKsignalidentification,addressidentification,thebusarbitrationfunction,abletomaster/slave/receiveall4combinationsofmulti-machinecommunication.SPIsupportsmaster/slaveandother4groupsofmulti-machinecommunication.

AVRMicrocontrollerwithautomaticpower-onresetcircuit,anindependentwatchdogcircuit,lowvoltagedetectioncircuitBOD,multipleresetsources（upanddownautomaticallyreset,externalreset,watchdogreset,BODreduction）,canbesettostartafterthedelayWhenrunningtheprogram,enhancethereliabilityofembeddedsystems.

AVRmicrocontrollerwithavarietyofpowersavingsleepmode,andcanbewide-voltageoperation（5-2.7V）,anti-jammingcapability,8-bitmachinecanreducethegeneralanti-jammingdesignworkinsoftwareandhardwareusage.

AVRmicrocontrollertechnologyembodiesthemulti-microcontrollerdevices（includingFLASHprogrammemory,Watchdog,EEPROM,with/asynchronousserialport,TWI,SPI,A/Danalog,timer/counter,etc.）andavarietyoffeatures（enhancedreliabilityreductionsystemstoreduceinterferenceinthesleepmodepowerconsumption,widevarietycategoryinterruptsystem,withinputcaptureandoutputcomparematchdiversefunctionssuchastimers/counters,areplacementfunctionofI/OPort......）inafullyembodiedtheSCMtechnologyfromthe"filmfromthewar"to"SystemonChipSoC"transitionthedirectionofdevelopment.

Referstothenewcomputertechnology-basedindustrialcontroldevices.In1987,theInternationalElectrotechnicalCommission（InternationalElectricalCommittee）issueddraftstandardsonPLCPLCmadethefollowingdefinition:

"PLCisdesignedforapplicationsinindustrialenvironmentsdesignedfordigitalarithmeticoperationsoftheelectronicdevice.Itusesthepreparationofprogrammemorycanbeusedtoimplementlogicinitsinternalmemoryoperations,orderofoperations,timing,countingandarithmeticoperations,etc.operatinginstructions,andcanbedigitaloranaloginputandoutput,controlvarioustypesofmachineryorproductionprocesses.PLCanditsrelatedperipheralsshouldbeeasyandindustrialcontrolsystemsbytheformationofawhole,easytoextenditsfunctionalitytotheprinciple."

Highreliabilityisthekeytoperformanceofelectricalcontrolequipment.PLCastheuseofmodernlargescaleintegratedcircuittechnology,usingthestrictproductionprocess,theinternalcircuitstotheadvancedanti-jammingtechnology,withhighreliability.Forexample,theproductionofFseriesMitsubishiPLCMTTFupto300,000hours.SomeusetheredundantPLCCPU,theaveragetimebetweenfailuresislonger.PLCofthemachinefromoutsidethecircuit,constitutesuseofPLCcontrolsystems,andthesamesizecomparedtorelaycontactorsystem,electricalwiringandswitchcontactshavebeenreducedtohundredsoreventhousandsoftimes,faultalsogreatlyreduced.Inaddition,PLChardwarefailurewithself-detection,failurealarmtimelyinformation.Intheapplicationsoftware,applicationarealsoincorporatedintotheperipheraldevicefaultdiagnosisprocedure,thesystemisinadditiontoPLCcircuitsanddevicesotherthantheaccessprotectionfaultdiagnosis.Inthisway,thesystemoffershighreliabilityisnotsurprising.

PLCtotoday,hasformedalarge,mediumandsmallseriesproductsofallsizes.Canbeusedforoccasionsofallsizesofindustrialcontrol.Inadditiontothelogicalprocessingfunctions,themostmodernPLCprocessingpowerwithcompletedatacanbeusedforavarietyofdigitalcontrolinthefield.Inrecentyears,thefunctionsofPLCunitsinlargenumbers,topenetratetothePLCpositioncontrol,temperaturecontrol,CNCandotherindustrialcontrol.EnhancedcommunicationcapabilitieswithPLCandhumaninterfacetechnology,theuseofPLCcontrolsystemcomposedofavarietyofveryeasily.

PLCasacommonindustrialcontrolcomputer,isforindustrialandminingenterprisesintheindustrialequipment.Itinterfaceseasily,programminglanguageseasyforengineerstoaccept.Ladderlanguage,graphicsymbolsandexpressionsandrelaycircuitisveryclose,onlyasmallamountofswitchingcapacityPLClogiccontrolinstructionscaneasilyachievethefunctionsofrelaycircuits.Wasnotfamiliarwithelectroniccircuits,computerprinciplesandassemblylanguagedonotunderstandpeoplewhousecomputersinindustrialcontroltoopenthedoor.

PLClogicwithmemorylogicinsteadofwiring,greatlyreducingthewiringoutsidethecontrolequipmenttocontrolsystemdesignandconstructionofmuchshorterperiod,whilemaintainingalsobecomeeasily.Moreimportantly,thesameequipmenttomaketheproductionprocessthroughthechangeprocesschangepossible.Thisissuitableformanyvarieties,smallbatchproductionsituations.

Ultra-smallPLC,forexample,thebottomofthenewlyproducedvarietiessizeoflessthan100mm,weighslessthan150g,onlyafewwattspowerconsumption.Sincesmallsizeiseasytomounttheinternalmachineryistoachieveanidealcontrolequipment,electromechanicalintegration.

Currently,PLChasbeenwidelyusedindomesticandforeignsteel,petroleum,chemical,power,buildingmaterials,machinerymanufacturing,automobile,textile,transportation,environmental