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    J.Cent.SouthUniv.Techno1.(2007)02026006

    DOI:lO.1OO7/sl77lO07-0052-xSpringer

    NetworkedcontrolandsupervisionsystembasedonLonWorksfieldbusand Intranet/Internet

    wuMin(吴敏),ZHAOHong(~6_),L1UGuo_ping(刘国平),SHE.hua(余锦华).

    (1.SchoolofInformationScienceandEngineering,CentralSouthUniversity,Changsha410083,China;

    2.SchoolofElectronics,UniversityofGlamorgan,PontypriddCF371DL,UK; 3.SchoolofBionics,TokyoUniversityofTechnology,Tokyo1920982,Japan)

    Abs

    act:Anetworkedcontrolandsupervisionsystem(NCSS)basedonLonWorksfieldbusandlntranet/Intemetwasdesigned.

    whichwascomposedoftheuniversalintelligentcontrolnodes(ICNs1thevisualcontrolandsupervisionconfigurationplatforills

    fVCCPandVSCP)andanIntranet/Intemet-basedremotesupervisionplatform(RSP).TheICNswereconnectedtofielddevices.

    suchassensors,actuatorsandcontrollers.TheVCCPandVSCPwereimplementedbymeansofagraplaicalprogramming

    environmentandnetworkmanagementsoastosimplifythetasksofprogrammingandmaintainingtheICNs.TheRSPwas

    employedtoperformtheremotesupervisionfunction,whichwasbasedonathree.1ayerbrowser/server(B/S)structuremode.The

    validityoftheNCSSwasdemonsatedbvlaboratoryexperiments.

    Keywords:fieldbus;LonWorks;networkedcontrol;visualcontrolconfiguration;Webdatabase

    1Intl"oduction

Accompanyingthewidespreaduseofcomputer

    nel[worksandmoderncontroltechnologies.fieldbusand Intranet/Internettechnologieshavecometobeusedina widerangeoffields.andnetworkedcontroIhasattracted manyresearchers'attention.

    Thefieldbusisanal1.digita1.serialtwo.way communicationnetworkthatconnectssensors,actuators. andcontrollerstoformdigitalhighwaysatalowlevelof processcontro1.Fieldbushasbecomemoreandmore importantincontrolsystems.sinceitofferssignificant advantages,suchasopenness,interchangeability, interoperability,quickandeasymaintenance,low cost[1-5.

    LonWorkssystemisaproprietaryfieldbussystem developedbytheEchelonCorporation.LonWbrks

    systemprovidesawiderangeofproducts,andisusedin alargenumberofprocessesinvariousfields.such asbuildings,homeautomation,transportationand factoriestv-"J.However,theLonWbrkssystemis complexandrequiresthatcontrolengineershavea thoroughunderstandingofNeuronClanguage,andvery familiarwithinternalhardwarearchitecturet13j.Thisisa largeobstacletothedesignandconfigurationofnetwork controlsystem.Furthermore.itisnoteasytouseand maintain.andthatresultsinincreasedcosts. In?lisPaDerauniversalnetworkedconoland

    supervisionsystem(Ncss)forLonWorksispresented, whichcoversauniversalintelligentcontrolnode(ICN), thevisualcontrolandvisualsupervisionconfiguration platforms(VCCPandVSCP).riththehelpofNCSSthe

    engineerscanavoidmanypitfallsencounteredin implementingLonWbrks.Besides.thedevelopmentofa remotesupervisionplatform(RSP)basedonreb technologiesisdescribed.andtheintegrationofWeband LonWbrksfieldbustechnologiesprovidesaconnection betweenofficesandfielddevicesinacompleteindustrial networkedsolution.Finally,someexperimentalresults musatetheoperationoftheNCSSanddemonstrateits validity.

    2Systemarchitectureandmainfeatures

    ThemaincomponentsoftheNCSSarethe

    universalICNs,theVCCP,VSCPandtheRSP.This sectiondescribesthearchitectureandmainfeaturesof theNCSS.

    2.1Systemarchitecture

    ThearchitectureoftheNCSSconsistsofthree

    levels:thefieldcontrolleve1.theuppersupervisionlevel andtheremotesupervisionleve1.asdepictedinFig.1. ThefieldconollevelmainlycontainsICNs.each

    ofwhichisconnectedtothedevices.Itrunsapplications independentlytocarryoutcontroltasks.andcomm. Founda~onitem:Project(6042531o1supportedbytheNationalNaturalScienceFoundation

    ofChina;Project(2006AA04Z172)supportedbytheHighTech

    ResearchandDevelopmentProgramofChina

    Receiveddate:2006——06——24;Accepteddate:200607——27

    Correspondingauthor:wumin,Professor;Tel:+86-73

    8836091;Fax:+86-731-8836091;E-mail:min@mail.CSU.edu.cn

wuMin,etal:NetworkedcontrolandsupervisionsystembasedonLonWorksfieldbusandlntr

    ane1em

    unicateswithupper-levelcomputerandotherICNsover fieldbus,usingLonTalkthatistheLonWorksnetwork protoco1.

    Fig.1ArchitectureofNCSS

    Attheuppercontrol1eve1.thesoftwareplatforms VCCPandVSCPareinstalledontheupper-level computer.Besidesausualnetworkcard,thereisanother onenamedPCNSSontheupper-levelcomputer,whichis especiallyforcommunicatingwiththeICNson LonWorksfieldbus.

    Attheremotesupervision1eve1.theInanet/

    Internet-basedRSPusesaB/Sstructuremodewiththree levels:adatabaseserver,aWebserverandaWeb browser.ThedatabaseandWebserverscommunicate withtheupper-leve1computeroverIntranetbymeansof theTCP/IPprotoco1.Remotesupervisioniscarriedout ontheRSPbyusingtheWebbrowsersovertheInternet. 2.2Mainfeatures

    TheNCSShasseveralimportantfeatures.

    1)AuniversalICNprovidesdigitalinput(DI), digitaloutput(D0),analoginput(AI),andanalogoutput fA01channels,andacommunicationinteffacebasedon theLonWorksstandard.Itcanbeconnecteddirectlyto allkindsofdigital/analogdevice.otherICNs,andthe upper.1evelcomputerthrougl1PCNSSnetworkcard. 2,TheVCCPprovidesthevisualcontrolcon

    figurationfunctionsfortheICNs.whichhasmany functionblocksthatcarryoutanumberofbasicand advancedcontrolalgorithms.Thegraphicconfiguration manneroftheVCCPisverysimpleandmakesit

    unnecessarytoprogramtheICNsusingtheNeuronC, theprogramlanguagespeciallyforLonWorks. 3,TheVSCPprovidesthevisualsupervision

    configurationfunctionsforthereal-timemonitoringof processes.Thesefunctionsincludethecreationof processdiagrams,tables,curvesanddatabases,database manipulation,andreal-timecommunications. 4,TheRSPisusedtoremotelysuperviseprocess controlsystemoverInanet/Internetinreal-time.

    TheNCSSdevelopedinthisstudyisabasicsystem. anditisanopensystemwithgoodflexibility.Usingitas afoundation,varioustypesofprocesscontroland supervisionsystemscanbeconstructedtomeetavariety ofneeds.

    3Designofnetworkedcontrolandsuper-

    visionsystem(Ncss)

    ThedesignofaNCSSinvolvesthedesignof

    hardwareandsoflware.Themainpieceofhardwareis theuniversalintelligentcontrolnodefICN1,which containsacircuitboardwiththebasicLonWorks componentsandmodularI/0channels.AnICNcanbe connecteddirectlytoallkindsofdevices,suchassensors oractuators,andalsotootherICNs.Thesoftware includestheVCCP.VSCPandRSP.Thevisual

    graphicblockmanneroftheVCCPandVSCPsimplifies thetediousworkofprogramming,andtheusersarenot requiredtohaveathoroughgraspofgreatknowledge abouthardwareandNeuronC1anguage.Soitis

    significantlyreducedthecostanddevelopmenttimeofa controlsystem.Furthermore,theRSPdevelopedusing

    Webtechnologiesmakesiteasetoimplementtheremote supervisionofindustrialprogressesthroughIntranet/ Internet.

    3.1Intelligentcontrolnode(ICN)

    ThearchitectureofanICNisshowninFig.2.It mainlycontainsaTMPN3150B1AFNeuronchip.which isthemostimportantchipoftheICNtocarryoutcontrol tasksatthefieldleve1.TheFTT.10Amoduleisa transceiver,bywhichICNcornrnunicatesover LonWorksnetworkusingtheLonTalkprotoco1.There arean8.channelAI/AOmoduleanda4.channelDI/D0 module,whicharetheinput.outputinteffacestoexternal sensorsandactuatorsembeddedinanICN.andwhich canbeuseddependingonthestyleofdevicestowhichit isconnected.EachAI/AOchannelhasaninputand outputrangeofeither15Vor4-20mA(setwitha

    iumperwire).TheICNautomaticallyidentifiesthetype ofI/OmodulewhenitisturnedonandhasaPlug.and.

262J.Cent.SouthUniv.~cMo1.2007,14(2)

    playfunction.SignalsfromoutsidearefedtotheI/O pinsoftheNeuronchipviatheAIandDIchannels. TheEPROMandthenonvolatileRAM(N,,]RA^)are thestoragedevicesofICN.

    Fig.2ArchitectureofICN

    3.2Visualcontrolconfigurationplatformf,,ccP) TheNodeBuilderisakindoftoolsoftwareof LonWorks.whichisusedtodevelop.compileand debugthecontrolcodeforanICNandtodownloaditto

theICN.However.inpractice.itisquitedicultto

    programandmaintainthousandsOfICNsbythismethod. TheVCCPdevelopedishelpfulforovercomingthe obstacle.

    ThefunctionalarchitectureoftheVCCPisshownin Fig.3.Itintegratesagraphicprogrammingenvironment andnetworkmanagementintoasinglepackage,which hasthreemainfunctions:graphconfiguration,graph editingandrealtimecontro1.TheVCCPconsistsof29 typesofcontrolblocksand5typesoflineblocksaswell, whichprovidesaconvenientconfigurationediting interfaceandalibraryoffunctionblocks.andusersonly needtoclickanddragblocks,andconnectthemwiththe mouse,asinCAD.Userscanalsousethegraphediting functiontoadd,deleteandcorrecttheVCCPdiagram filesvisuallyandeasily~Therealtimecontrolfunction

    enablesuserstodownloadthecontrolconfiguration diagramstothegivenICNsandrunthematanytime, andtodownloadandmodifytheparameterso~ine. ThetechnologYinvolvedintherealtimecontrol

    functionincludescommunicationoverLonWorks fieldbus.ThecommunicationmoduleoftheVCCP employsasetofspecialcommunicationrules.Thedata structureofthecommunicationparametersisdefinedto forlilaframe.Themaster/slaveresponsemodefor communicationservicesismainlyusedtosendcontrol configurationprogramsfromtheVCCPtoICNsinorder tocontroltheiroperation.

    Inthisstudy,themaximumlengthofadatapacket wassetto45bytesinconsiderationoftherestrictionson

    transmissiontimeandthesizeofmessages.Everypacket iscomprisedof6components:messagecode(Code), nodeaddresscode(NodeAddr),commandcode(Cmd), configurationparameterdata(Data),packetsequence code(PacketNo),andcheckcode(Check). Thepossiblevaluesofeachcomponentareas follows.

    11Code

    0:Packetfromupper-levelcomputer;

    1:Packetfromlocalnode.

    2,NodeAddr

    Theaddressofthenodetowhichthepacketwillbe sent.

    31Cmd

    1:Thepacketcomainsparameters;

    2:Thepacketcontainsoperatingcommands. 4,PacketNo

    Thesequencenumberofthepacket,andnumber 255meansthatnopacketisreceived.

    51Data

    Configurationparametersandinformationdata. 6,Check

    Checkcode.

    3.3Visualsupervisionconfigurationplatform (VSCP)

    TheVSCPisavisua1.multifunctionaldrawing. supervisingandgraphicconfigurationplatformfor LonWorksfieldbusdevelopers,whichprovidesgraph controlandeditingfunctionsthatenablesupervisionof

    therealtimeoperationofthesystem.Themainfunctions includedrawinghistorytrendgraphs,plottingrealtime

    curves,makingdatareports,andproducingwarning signalsbymeansofmultiplemedia,suchassoundsand lights.ThefunctionalarchitectureoftheVSCPisshown inFig.4.

    Fig.3FunctionalarchitectureofVCCP

WUMin,etal:NetworkedcontrolandsupervisionsystembasedonLonWorksfieldbusandIn

    tranet/Internet263

    Fig.4FunctionalarchitectureofVSCP

    ThegraphcontrolsoftheVSCPareusedto

    representcommoncontrolobjectswhichmakesiteasy f0ruserstodrawsupervisiondiagrams.Therearetwo typesofgraphcontrols:staticanddynamic.Theformer handlesthestaticinformationthatisunrelatedtothe database,suchasallthepipecontrolsforvarious directions.whiletheatterhandlesdynamicinformation thatchangesfrommomenttomomentinassociationwith thedatabase.Dynamicgraphsuserea1.timedata,suchas therea1.timeoperationaldata,therealrimecontrollaws.

    TheCADmodeofthegrapheditingfunctionsupports bothageneralgrapheditingfunction,justasgeneral drawingsoftwaredoes,andarealtimeonlineediting

    function.Therea1.timesupervisionfunctionisusedto

    displayrealtimedatasupervisedinseveraldisplay modes,i.e.datasheet,CHrVeandcom12oongraph.The remotesupervisionfunctioncanrealizethetransmission ofdatafromandtoaremotecomputerthrough

    Intranet/Internet.

3.4Remotesupervisionplatform(RSP)

    InthispapertheIntranet/InternetbasedRSP

    employedathree.1ayerB/Sstructuremodeforthe remotesupervisiondesign,consistsofabrowser,aWeb serverandaWebdatabase.Inthisarchitecture.all complextasksarecarriedoutontheWebserver,and onlytheresultsarepresentedontheclientcomputerwith theWebbrowsers.Asaresult.itsimplifiesthe requirementsforaclientmachine,reducesthetime neededforsoftwaredevelopment,andmakestheclient computereasytooperate,maintainandupgrade. ThefirstrequirementforaRSPistheestablishment ofarobustchannelbetweentheupper.1evelcomputer andthedatabaseserverusingtheTCP/IPprotocoland programmedsockets.Itiscompletedintwosteps.First, theupper-levelcomputersendsaconnectionrequestto thedatabaseserver.Then,thedatabaseserversendsa confirmationbacktotheupper-levelcomputerafterthe requesthasbeenreceived.Oncearobustchannelhas beenestablished,theupper.1evelcomputersendsthe rea1.timedatatodatabaseserver.whichchecksand storesitinadatabase

    TheWebanddatabaseserversareconnectedusing anActiveXdataobjectrADO).

    Fornewdataonthefieldpresentedtotheclient computertimely,theWebpageisrefresheddynamically. Theupdateperiodcouldbesetflexiblyaccordingtothe demandsofthesituation.DifferentuDdateperiodswere testedexperimentally,andthebestonewasfoundtobe about2s.

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