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指导教师:
赵肖宇
所在学院:
信息技术学院
专业:
通信工程
中国·
大庆
2011年5月
[原文]
IndustrialEthernetandIntelligentBuilding
1IndustrialEthernetthebackground
1.1Unifiedfieldbusstandardsdashed,thetemptationremains
In1984theUnitedStatesproceedtodevelopinternationalstandardsfieldbus,afewyears,themajorcompaniesforcommercialinterests,Fieldbusstandardscannotalwaysuniform.Throughmultiplevoting,consultation,inJanuary2000announcedthatthefieldbusinternationalstandardsIEC61158willbeeightbus(Prefabs,Interfuse,P-NET,World,etc.)
network(TCP/IPEthernet),inordertoachieveintegratedmanagementofitsnetworkstructure。
(2)IntelligentBuildingoftheurbaninformationsystemintegration,thedevelopmentofdigital,intelligentbuilding(includingintelligentresidentialdistrict),hasbecomeadigitalcity'
sinformationsite,inordertoachieveinformationsharing,theneedtoachievecontrolnetworkandinformationnetworkofverticalintegration,thatis,ControlnetworkandTCP/IPEthernetintegration.
Asvarioussubsystemsandcommunicationsequipmentatthesceneagreementisdiversifiedandintegratedthesetwomodelsmustbedevelopedgateways,inordertoachievetheconversionagreementandunity,thishasincreasedthecomplexityofsystemintegrationtechnologyandincreasecosts.ItwasboldlyputforwardcanuseTCP/IPprotocolasaunifiedagreement,thesceneofthesubsystemsandequipmentdirectlyfromEthernettosimplifythesystemintegrationoftechnicaldifficulty,lowercosts,sothatcontrolsignalsdirectlyfromtheEthernettransmission,SotheconceptofindustrialEthernethasbeenraised.
2EthernetandCSMA/CD
2.1Ethernet
Ethernet(Ethernet)1975bytheUnitedStatesXEROXcompanysuccessfullydeveloped,asapassivemedium(suchastwistedpair,coaxialcable,etc.)todisseminateinformation,tothehistoryofthespreadofelectromagneticwavesknownasthe"
Ethernet"
(Ether)Toname.
1980bytheDEC,INTEL,XEROXjointlylaunchedathreeEthernetV2,istheworld'
sfirstLANstandard.1983IEEEE802CommitteeDIXEthernetV2basedintroducedIEEE803,usingtheCSMA/CDMACtechnology.802.3refertoaCSMA/CDnetworks,andEthernetDIXEthernetV2fromthestandarddefinition,notstrictlyinthecircumstances,canbecalled802.3LAN,whichisEthernet.
Tothemodernmanufacturingindustryasanexample,itsmodernmanufacturingautomationmodelinFigure.IndustrialEthernetisthecommercialapplicationofEthernettoindustrialcontrolsystems,thetwonetworksisnotessentiallydifferentfrom,thetwoarecompatible.
2.2CSMA/CD(CarrierSenseMultipleAccesswithCollisionDetection
Multi-carriermonitoringvisit/conflictdetection)
CSMA/CDarethefirstimprovementcomesfromCSMA.
(1)CSMA(Carriermonitormultipleaccess):
stoptryingtosendasignal,firstofalltomonitorbus,todeterminewhetherthereisothermedia,tostopthesignal.
•Ifthemediaisfree,youcansend;
•Ifthemediaareinworkingcondition,thenwaitsometryagainaftertheinterval,whenheardinabusystatemedia,CSMAThereareseveraldifferentwaystodealwith,theavailabilityofinterceptionofsignal:
adheretonon-CSMA,1-adheretoCSMA,P--ConsistentlyCSMA.
(2)CSMA/CDtohearnotonlythefirst,butalsoBaitingBainhair,abusintheconflict,butoncetheconflictwasdetected;
theystoppedsendingtheframe,togiveuptheirownframe.Inordertoknowthatotherstationscanalsohaveaconflict,listeningtotheconflicttothebusstationonthespreadofablockingsignalinterference,informedthebusstationintheconflicthavetakenplace,thecapacityofthischannelwillnotbesentbecausetheframewasdamagedandwaste.Withtheincreasednetworkload,thecollisionwouldincreasetheopportunities,networkefficiencydecreasedsignificantly.
3IndustrialEthernettheexistingproblems
FieldBusisusedforindustrialcontrolandcomplexandharshenvironmentofindustrialdesignatthescene,thesystemofreal-timeandresponsetimehavestrictdemandsonelectricityuseoftheenvironment,therearespecialrequirements.SinceEthernetisdesignedforinformationandcommunications,industrialcontrolfortheexistenceofthefollowingquestions:
(1)usingEthernetCSMA/CDAccessProtocol,whichisanon-deterministicnetwork.Thehighdemandforreal-timecontrolsystems,thisuncertaintywillresultintherequestedinformationcannotconvey.Theso-callednetworksegmentisevensharedthesamebusnetwork,youcanlistentothemessagesentbytheotherside,atthesamecollisionregionalconflict(aconflictthatwillimpacttheregion)ofworkstationsandserverstoconnectthenetworkarea.Forexample,inacollisionconflictintheregionhaveaworkinggroup(fromaserverandworkstationcomponentsmultiple),whenmorethanonevisitaserverworkstation,duetotheCSMA/CDboundbythesametimeallowingonlyaworkstationandserverCommunications,canonlywaitfortheotherworkstations.Competitionfortheworkstationcommunicationchannelsothatthecommunicationworkstationshavedelayed,andthisextension
Whenthetimeisuncertain,workstationsmorecompetitionforcommunicationsforthelongerthissituationknownastheloadwasmoreseverethelongerthewaitingtime.
Ifinacollisiondomain,assumethattwoworkinggroups,inacollisiondomain,thefirstworkgroupservers,workstationsaccesstocompetitivebroadbandnetworks(suchas100M),anotherworkinggroupofallworkstationsandserversAreinawaitstateandcannotrun.Thetwoworkinggroupstosplittheoriginalbroadbandnetwork(100M),aworkinggroupwork,mustwaitforanothergroup,thishasnotonlydelayed,andthisdelayisuncertain.AsCSMA/CDhaveunforeseendelay,particularlyintheheavyload,themorereal-timedatatransmissioncannotbeguaranteed.ThereforeEthernetcontrolsystemmustbesolvedforreal-timeanduncertainty.
(2)EthernetinreliabilitythanBusatthescene.FieldBusisdesignedforindustrialcontrol,abletoadaptflammable,explosive(suchaschemicals,pharmaceuticals),stronginterferenceandotheroccasionspoorenvironmentoccasions.Fieldbushaveshielding,groundingandexplosion-proofmeasures,suchasEthernetandtheneedtoaddresstheseissues.
(3)Fieldbusspecificationsonthenetworksegmentwithapowersupply.Forallnon-self-poweredequipmenttopowerandEthernetdoesnotprovidepower,theneedforadditionalelectricitysupplylines.
4feasibilityoftheapplicationofIndustrialEthernet
IndustrialEthernetforindustrialcontrol,theabove-mentionedproblems,withtheEthernettechnologydevelopmentandtheimplementationofcorrespondingmeasures,infact,andtheuncertaintycanbemadegreatimprovements:
(1)ContinuouslyimproveEthernetrate:
therateinrecentyearsEthernetfrom10Mbps,100Mbpsto1000Mbpsandhasbeenwidelyapplied.Atpresent10GapsEthernethasbeencommercialized,greatlyshorteningthedatatransmissiontime,improveresponsetime,thesystem'
sreal-timeandnonuncertaintieshaveimproved.
(2)usingEthernetswitchtechnology:
astheworksitesharedEthernetchannelcompetitionarisingfromtheconflictaffectedthecollisionofreal-timesystemanduncertainty,Ethernetswitchtechnologycanbeusedtobeimproved.Ethernet-basedexchangeusedinEthernetswitch,switchbetweentheportatthesametimecancreateanumberofdatachannels,eachconnectedtoanetworkport,theportframebetweentheinputandoutputnolongersubjecttoCSMA/CDMACboundbytheagreement.Whenthesystemincludesanumberofworkinggroups,ingeneralsothateachgroupformedaseparatenetworksegment,eachoftheoccupationoftheexchangenetwork(of)aport(showninFigure4switchesareA,B,C,D4net),netofmostofthetimetheworkisindependent,whenanytwooftheneedforinformationexchangenetwork,theswitchintwoindependentnetworkofinformationbetweenthechannel.Oncetheendoftheexchangeofinformation,accessisdisconnected.
ThisshowsthatswitchedEthernetsharedEthernetcanbeovercomeexistingproblems:
•Switchesoneachportcanconnectanetworksegment;
eachofthenetworkbandwidthcanbeexclusive;
•switchesoneachport,thenetworkofaccessbetweentheindependentandisolated,suchastheneedforinter-networkofinformationandcommunication,itcantemporarilyestablishaninformationchannel,aftertheswitchisolation,cangreatlyreducetheprobabilityofconflictToimprovethereal-timeanduncertainty;
•switchVLANtechnologycommonlyusedtoexchangecontrolsystemcanbeallocatedtotheproprietaryinformation,accessandbandwidth,thusensuringthenetwork'
sbusiesttime,thecontrolsystemisstillcomfortableenoughbandwidthtoenableEthernettransmissionofreal-timeinformationAnduncertaintyremainedlargelytheoreticallevel.
(3)Insomeapplicationstoallowthecircumstances:
trytocontrolnetworkandinformationnetworkstouseseparate,inordertoavoidreal-timedataandnon-real-timedataofthecollision,betweentheindustrialsiteforindependentEthernetnetworksegment,Therebyimprovingthereal-timeanduncertainty.Inaddition,full-duplextechnologycanbeusedtoreducenetworkload,andEthernet+TCP/IPprotocolonthebasisofauniformandapplytotheindustrialfieldofapplication-levelcontrolmeasuressuchastechnicalspecifications.TheabovemeasurescanbetakensothatinsomeindustrialEthernetmilitary,industrial,civilianareasofthesitehasbeeninitiallyappliedinthemeasurementandcontrol.Forexample,manycountriesabroadnuclearacceleratorastheEthernetmonitoringa