WHITE PAPER

PROFINET for the process industryAuthor: Dr. Ulla Reutner

White Paper

Table of Contents

1. Introduction:Fromfieldbusesto„EthernettotheField“ ..................................................................... 1

2. SpecialrequirementsinEthernettotheFieldprocessautomation ....................................................... 2

3. PROFIBUS PA upgraded for PROFINET ................................................................................................... 33.1 GeneralinformationonPAprofiles ................................................................................................... 3

3.2 SpecialfeaturesofPAProfile4.0 ....................................................................................................... 3

4. PROFINETredundancymodels ..............................................................................................................44.1 PROFINETS2systemredundancy ...................................................................................................... 5

4.2 PROFINETR1systemredundancy ...................................................................................................... 5

4.3 PROFINETR2systemredundancy ...................................................................................................... 5

4.4 Highavailabilitywitharingtopology ................................................................................................ 6

5. TechnicalsolutionsforEthernettotheFieldinprocessmanufacturing ............................................... 65.1 ConnectingPROFIBUSPAtoPROFINETviaaproxy ............................................................................ 8

5.2 EthernettotheFieldbasedontheAdvancedPhysicalLayer(APL) ................................................... 8

5.2.1 APLinfrastructure ........................................................................................................................ 9

5.2.2 AdvantagesofAPL ..................................................................................................................... 10

5.2.3 MigratingfromPROFIBUSPA...................................................................................................... 11

5.2.4 Outlook ..................................................................................................................................... 11

6. AvailableEthernettotheFieldsystemsinprocesstechnology ........................................................... 116.1 Processcontrolsystems/controllers .............................................................................................. 11

6.1.1 SimaticPCS7processcontrolsystem(Siemens) ........................................................................ 11

6.1.2 800xAprocesscontrolsystem(ABB) .......................................................................................... 12

6.2 Fieldbusinfrastructure ................................................................................................................... 12

6.2.1 Componentsforproxysolutions ................................................................................................ 12

6.2.2 commModuleAPL–integrationsolutionforAPL(Softing) .........................................................14

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1. Introduction: From fieldbuses to „Ethernet to the Field“

Inthepast,theprocessindustryhasenjoyedmanypositiveeffectsbyusingfieldbustechnologyfortheautomationofitsproductionlines.Thefeaturesetoffieldbusestailoredtotheneedsofprocessautomation(PROFIBUSPA,FoundationFieldbus)includessupportfordigitalcommunicationandmanufacturer-neutraldevicereplacementwhilealsoreducingcablingrequirements.Asaresult,fieldbuseshavebeenusedtoautomatemanyprocesssystemsoverthelast20to25years.

ConventionalbussystemshavekeylimitationsforusersnowwantingtoaddIndustrie4.0capabilitiestotheirsystems,however.Propertiesinherentinthefieldbusesmentionedleadtoproblemswhenimple-mentingdata-intensiveapplicationsaspartofdigitalization.Companieslookingforfuture-proofautoma-tionofprocesssystemswillnecessarilyneedtotransitiontoacommunicationsystemusingEthernetdowntothefieldlevel,sinceprocessmanufacturingupgradesforIndustrie4.0,theIndustrialInternetofThings,orBigDataneededgenetworkingstandardscapableofhandlinglargevolumesofprocess/diagnosticdatafromfielddevicesoverlongdistancesandathighspeeds.AlldatawhichispresentatthefieldlevelwillbeavailabletoIndustrie4.0applications.ViaEthernettotheField,thesedatatraversethecontrollayertohigherlevels(suchasDCSandMES)andfromhere–asrequired–tothecloud.

NOA – NAM

UR Ope

n Arch

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Enterprise Resouce Planning

Manufacturing Execution Level

Basic Automation

Field Level

Secure

Open

Figure 1: NOAasanExtensionoftheAutomationPyramid

EthernettotheFieldisafoundationalelementintheNAMUROpenArchitecture(NOA)model,whichisthenusedasthebasisforaccessingdatafromthecoreautomationsystemsusedtodateformonitoringandopti-mization(M+O)tasks.AsspecifiedbyNAMUR,therolloutofEthernettotheFieldshouldbeplannedinawaythatdoesnotendangertheavailabilityandprotectionofexistingequipment.NOArecommendsbuildingtherolloutaroundacoreofcurrentstandardslikethefieldbussystemsmentioned.1

WhilethemigrationfromconventionalfieldbusestoEthernet-basedcommunicationsolutionsatthefieldlevelhasalreadybeencompletedinfactoryautomation,theprocessindustryfacesanumberofhurdlesbeforeitcandothesame.Onechallengehereistoensurethenecessarylevelofexplosionprotection.Theseandotherrequirementshavenowbeenmetwithseveralsolutionstrategiesthatarethesubjectofthiswhitepaper.OnesuchstrategyistheproxytechnologythatnowalreadypermitsthedirectintegrationofPROFIBUSPAsegmentswithPROFINET,forexample.Onenewtransmissiontechnologystillindevelop-mentisAdvancedPhysicalLayer(APL),whichintendstomakeEthernetfullycompatiblewithdeploymentinanexplosion-protectedenvironment.

1 https://www.namur.net/fileadmin/media_www/fokusthemen/NOA_Homepage_EN_2018-06-20.pdf

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2. Special requirements in Ethernet to the Field process automation

Unlikefactoryautomation,themostimportantrequirementforEthernettotheFieldisintrinsicsafety.Inmanyareasofmanufacturingsystemsinvolvingprocess-levelactivities,intrinsicallysafeequipmentinstalla-tionsneedtobeusedtoavoidanyriskofanexplosion.Deviceshavingintrinsicallysafeignitionprotectionlimitsystemcurrentandvoltagetopreventsparkingevenintheeventofamalfunction.Evenifapotentiallyexplosivegas/airmixtureispresent,itwillnotbeignited(secondaryexplosionprotectionforATEXzone0/zone1).Devicesofthistypeworkbythrottlingtheirperformance.FieldbusesdeployedinExzonesmustalsomeetstringentsetsofrequirements:alongsideintrinsicsafety,poweroverthebusisanotherkeyfeatureforpoweringfielddevicesviathefieldbus.Thisisachievedbyusingatwisted-paircable.Conven-tionalPROFIBUSPAandFoundationFieldbusH1fieldbusescanmeettheserequirements,asmustanyEthernet-basedcommunicationsolutionsusedatthefieldlevelofprocessautomation. Otherrequirementsalsoexist,asfollows:

High availability:Plantdowntimeintheprocessindustryistime-consumingandcost-intensive.Unplannedoutagesmustthereforebeavoidedatallcosts–andforsome(e.g.exothermic)processes,evenbriefperiodsofdowntimecannotbetolerated.Itmustbepossibletorectifyfaultswithouttakingsystemsoffline.Asjustoneexample,thereneedstobeastraightforwardprocedureforhot-swappingdefectivefielddevices.Highavailabilityalsoimpliesongoingsupportforexistingengineeringtools(e.g.FieldDeviceInte-gration,FDI)thatsimplifyworkwithfielddeviceinstallations.

Redundancy:Redundancymodelspreventplantdowntimeandthereforeincreaseavailability,sinceasingleerrordoesn’tendangerplantoperationsingeneral.Redundancymodelsshouldalsobeadaptabletoprocessrequirementsandshouldbedesignedtobescalable.

Systemredundancyiscreatedbyusingtwohostcontrollers(e.g.PLCsorDCSs)thatstayperfectlysynchro-nizedwithoneanother.Twophysicallyseparatecommunicationlinesalsoensureahighlevelofavailabilityifafailoverismadeautomaticallytoasecond,intactlineintheeventofacablefailure.Mediaredundancymodelsuseringtopologiestosafeguardnetworkandplantavailability.OneapproachhereistheMediaRedundancyProtocol(MRP):ifthetransmissionpathwaygoesdown,analternativecommunicationchannelisquicklyusedasafallback.

Todate,fieldbuscommunicationsolutionshaveachievedthesegoalsonlywitharelativelyextensive–andexpensive–arrayofhardware.

Robustness and flexibility:Processfacilitiesmaybeoperatedoververylongtimeframes(upto30yearsormore).Duringthislifetime,itmustbepossibletochange,expand,andoptimizeautomationfunctions–andideallywithouttakingthesystemoffline.

Protecting investments and existing equipment: Forexistinginstallations–basedonconventionalfield-buses,forexample–modernizationmustbepossiblewithoutneedingtoreplaceallofthe‘legacy’tech-nology.Automationfornewequipmentmustbefutureproof–i.e.therelevantprocessmanufacturingconceptsrelatedtodigitalizationandIndustrie4.0mustbeaccountedforanddevelopedinparallel.

Someoftheserequirementsalreadytallywiththetypical,standardfieldbusconceptsalreadyusedinprocessautomation.FutureIndustrie4.0-compatibleequipmentmustalsomeettheserequirements:ideally,itwillenablerequirementstobemetevenmoresimplyandcost-effectively.Considerablegainsshouldalsobepossiblefordatapackagesizesandtransmissionspeeds.

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3. PROFIBUS PA upgraded for PROFINET

PI(PROFIBUS&PROFINETInternational)definedPAProfile4.0withtheaimofdevelopingapurelyEthernet-basedplatform.DevelopmentworkwascompletedinJune2018andtheprofilefulfillsthecriterionforcommunicationprotocolindependence.AllparametersandfunctionsareusablebothoverPROFINETandviaPROFIBUS.WhilereferenceisalsooftenmadetoPROFINETPAinthiscontext,PAProfile4.0isjustonecomponentforEthernettotheFieldintheprocessindustry:fortheEthernettobeuseditself,2-wireconnectivity,poweroverthebus,and–aboveall–intrinsicsafetymustallbeimplemented.AlloftheserequirementswillbemetwiththeAdvancedPhysicalLayer(APL,seesection5.2),whichisstillindevelopment.

3.1 General information on PA profiles

Foreachdeviceclass,PAprofiles(PROFIBUSprofilesforprocesscontroldevices,PA=processautomation)defineasetofdeviceparametersthataffectcommissioning,operation,maintenance,anddiagnostics.Theseprofilesalsodescribethemechanismusedtolinktheparameters.AprofileGSD(GeneralStationDescription)enablesadevicetobereplaced–evenwithacompatibledevicefromanothermanufacturer–withoutneedingtochangethenetworkconfigurationoftheautomationsystem.Thisreplacementcanbesupportedbytheuseofafielddevicetoolthatstoresthenecessary(profile-/manufacturer-specific)deviceparameters.

Onekeyaspectofdigitalcommunicationisdiagnostics,andPAprofilesarebasedonNAMURrecommenda-tionNE107(‘Self-MonitoringandDiagnosisofFieldDevices’).

3.2 Special features of PA Profile 4.0

Asmentionedabove,PAProfile4.0hasbeendevelopedwithaneyeondeploymentoptionsinthecontextofEthernettotheField.Akeyaspectoftheprofilespecificationistherigorousseparationoftheapplica-tionlayers(withdevicefunctions)fromthecommunicationprotocols.Dedicatedsupportisalsoofferedformanufacturer-neutraldevicereplacementwiththe‘start-upparameters’thatanewdevicereceivesfromthecontrollerforprovisionalcommissioning.Theseformpartofthedevicedescription(PROFIBUS:GSD,PROFINET:GSDML).InthenewPAProfile4.0,theGSDisorientedondevicemeasurementprinciplesandcontainsfulldetailsoftherespectivemeasurementprocedure(e.g.coriolisflowmeasurement),includingassociatedNAMURdiagnostics.

EarlierProfile3.02-basedPAinstallationsareintegratedtoensureretentionofexistinginstallations.PAProfile4.0isusedprimarilywithPROFINET:inmixed-profileplants,asuitableprocesscontrollercanbeusedtoensurethesimultaneousoperationof3.02(e.g.PROFIBUSPA)and4.0(e.g.PROFINET)devices.Inthisway,PAProfile4.0helpsensurefutureviability.

ForPROFINETPAdevices,thePROFINETspecificationapplies(asperIEC61784-2CP3/4,CP3/5,orCP3/6),whichcomplieswiththe“ProcessAutomation”applicationclass.ThetransmissiontechnologyusedisEthernet(asperIEEE802.3).AforthcomingversionofthePROFINETprotocolspecificationwillalsoofferfullsupportfor2-wireconnectivity.The10MBit/stransmissionspeediscurrentlyoneofthekeyobstaclestoimplementingthissupport.

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PROFINET for PA supports:

• Scalablenetworkredundancy• S2 and DR redundancy • Simpledevice/controllerreplacementsandexpansion/modificationwithzerodowntime

(ConfigurationinRun(CiR)andDynamicReconfiguration)• DiagnosticsasperNAMURRecommendationNE107

(e.g.color-codedfaultindication:red-orange-yellow-blue-green)

4. PROFINET redundancy models

NetworkingsystemcomponentsoverPROFINETallowsthecreationofreliable,high-availabilitysystems.Thisassurescompliancewithoneimportantrequirementfromprocessmanufacturing:keepingproduc-tiondowntimetoaminimum.Theeffortrequiredtodosoislessthanthatrequiredfortraditionalfieldbussystems.PROFINETSystemRedundancy(PROFINETSR)isachievedwithredundantcontrollers,redundantEthernetasamedium,and/orredundantdevices.3

Systemredundancyisessentiallyachievedbysettingupmultipleconnectionstoadeviceorcontroller.IfdevicesandcontrollersutilizemultiplePROFINETinterfaces–orNetworkAccessPoints(NAPs)–theycankeepconnectionsaliveevenintheeventofhardwarefaults.Withcontrollerredundancy,devicescansupportmultipleApplicationRelationships(ARs)–inwhichthedataexchangeisembedded–viaaNAP;thisenablesthedevicetotoleratethelossofacontroller.

PROFINET utilizes the redundancy configurations S1, S2, R1, and R2.

This terminology is explained below.

S(single):PROFINETnodewithoneNAP–thenodecanconnecttoasinglenetwork.

R(redundant):PROFINETnodewithasetofredundantNAPs–eithertwointerfacemoduleseachwithaPNinterfaceoroneinterfacemodulewithtwoPNinterfaces.Nodecanconnecttoaredundantnetwork(e.g.doubleline,doublering).

Thenumbers1or2areusedtoindicatethepotentialnumberofapplicationrelationships(AR).WithanS1NAPorR1NAP,eachPROFINETinterfacecanthereforeestablishexactlyoneapplicationrelationshipwithanotherPROFINETinterface(suchasanIOcontroller).WithanS2orR2NAP,aPNinterfacecanbeassignedtotwoPROFINETnodesalthoughitusesonlyoneoftheseactivelyfordatatransfers.Thesecondconnec-tionisactivatedduringafailoverevent.

Ascanbeseen,S1systemredundancydoesnotincreaseplantavailabilityandisnottechnicallyaredundantsetup.S2andR1ontheotherhandaretrulyredundantconfigurationsthatpreventdatatransferoutagesandofferasuitablesolutionforawiderangeofapplicationsintheprocessindustry.Lastly,R2supportshigh-availabilitymodelsbutis“over-specified”formanyapplications.

2 CiRenablesthereconfigurationorreplacementofdevicesormodules(e.g.duetoadevicefault)withouttakingthesystemoffline(i.e.withoutstoppingthecontrolapplication).Thisisachievedbyusinga‘CiRobject’thathasthefunctionofaplaceholderinthesystemconfiguration.

3 See also https://profinetuniversity.com/system-redundancy/redundancy-terms-s1-s2-r1-r2

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4.1 PROFINET S2 system redundancy

HigheravailabilityiscreatedbyS2systemredundancy,whichinvolvesaninterfacedevicehavingaPROFINETinterfaceaswithS1butbeingabletoutilizetwoapplicationrelationships–byusingtwocontrol-lers,forexample.Onerelationship(primaryAR)isusedfordatatransferwhilethesecondisheldinreserve(backupAR),andactivatedasandwhennecessary.

Thisprovidesadequatecommunicationsredundancyformanyapplications.IftheS2device’sinterfacedevelopsafault,however,thenthedevicewillbeunabletoconnecttoeitheroftheredundantcontrollers.

S2S1

Figure 2: S1 and S2 Redundancy in PROFINET

4.2 PROFINET R1 system redundancy

AredundantsystemcanalsobesetupbyusinganR1deviceequippedwithtwoPROFINETinterfaces.Thisisachievedwithtwointerfacemoduleswithoneinterfaceeachorwithaninterfacemodulethatispopulatedwithtwointerfaces.Eachinterfacemaintainsanapplicationrelationshipwithonecontroller.Thissolutionistypicallychosenforredundantringorlinetopologies.

4.3 PROFINET R2 system redundancy

Inthisconfiguration,eachdeviceusestwoPROFINETinterfaces,witheachoftheseinterfacesmaintaininganapplicationrelationshiptotwocontrollers,whichresultsinfourpotentialapplicationrelationships.Intheeventofafault,thedeviceswitchestooneoftheothercommunicationchannels,wherebythechannelchosen depends on the nature of the fault.

R1 R2

Figure 3: R1 and R2 Redundancy in PROFINET

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4.4 High availability with a ring topology

HighavailabilityissupportedbytheMediaRedundancyProtocol(MRP),whichisastandardizedmechanismforconstructingaringtopologyusingoff-the-shelfcomponents.Unlikealinetopology,communicationisstillmaintainedevenifalinegoesdown.IftheCPUdetectsalineinterruptionorastationoutage,theCPUreversesthedirectionofthetelegramsthataresentthroughthering.Thefaultisalsoflagged:theoperatorcanthenresolvethisfaultwithoutneedingtostoptheprocess.

Therearelimitsonthiskindofringstructure,however.Loop-poweredtrunks,asareenvisagedbytheAdvancedPhysicalLayer,forexample,cannotbeusedinaringtopology.Inthiscase,ringstructurescanbeimplementedonlyasfarasthepowerswitch.

5. Technical solutions for Ethernet to the Field in process manufacturing

WhendevelopingsolutionsthatenableEthernet-basedcommunicationdowntothefieldlevelofprocessautomation,buildingonexistingfieldbusstandardsisarecommendedapproach.ThiscomplieswiththedemandsmadebyNAMURaspartoftheNOAmodelandprotectsinvestmentsandexistinginstallations.ThefollowingsectionprovidesathoroughintroductiontoEurope’sleadingstandardPROFIBUSandillus-tratesthetransitionfromPROFIBUSPAtoPROFINET.

PROFIBUSsolutionsthathavebeenusedtodatetoconnectfielddevicesinprocessautomation:

• Innon-Exzones–connectionof4…20mAdevicesviaremoteI/OtoPROFIBUSDPordirectconnectionofPROFIBUSDPdevices

• InExzones–PROFIBUSPAforconnectingspecializedPROFIBUSPAdevices(2-wire,low-powerdevices;intrinsicsafetypossible);segmentswithmultiplePAdevicesareconnectedtocontrollerswiththeaidofasegmentcouplerviaPROFIBUSDP.

ThesesolutionsareunabletomeetthedemandsofIndustrie4.0.PROFINETmeetstheIndustrialEthernetstandard(IEEE802.3),however,andisafuture-proofsolutionforthedigitalizationoffield-levelprocesses.

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ThefollowingtablepresentsthekeydifferencesbetweenPROFINETandPROFIBUSPA.

Comparison of PROFINET/PROFIBUS PA properties

PROFINET PROFIBUS PA

Data transfer rate 100Mbit/s 31.25kBit/s

Datapacketsize upto1,500bytes upto244bytes

Potentialstations 1,024 Exzones:6–12*Non-Exzones:32

Physical layer 4-wirecopper/fiber-opticcable,wireless

MBPorMBP-IS (ManchesterencodingBusPowered–IntrinsicallySafe)

Devicepowersupply SeparateorPowerover Ethernet(PoE) Viabus(MBP-IS)

Max.length Forcoppercable,100m betweenindividualdevices

Fromsegmentcoupler:1,900mfornon-ExandEExibapplications1,000mforEExiaapplications

*Dependingonpowerdrawfromindividualstations,max.total120mA

PROFINETthereforemeetstherequirementsofIndustrie4.0forhightransmissionspeedsandlargedatavolumes.Incontrast,whilePROFIBUSPAoffersconsiderablylowertransmissionspeedsandsmallervolumes,thephysicallayeruseddoesallowintrinsicallysafeinstallations.PROFINETforPAisintendedtocombinethebenefitsofPROFINETandPROFIBUS.

AspartofaPROFINETmigration,thefollowingoptionsareavailableforconnectingfielddevices:

• ConnectingtraditionalI/OfielddevicesviaremoteI/O(non-Exzones)• ConnectingPROFINETfielddevicestoEthernetviaswitches(non-Exzones)• NEW:connectingsegmentswithPROFIBUSPAfielddevicestoPROFINET(Ethernet)viaaproxymodel

(thisisEx-compatible!)• FUTURE:useofthenewAdvancedPhysicalLayer(APL)toconnectviaswitches

(alsosuitableforExzones)

Productsfromarangeofmanufacturersarealreadyavailableforthefirstthreeoptions,including:control-lers;remoteI/Os,gateways,andpowersuppliesthatsupportredundancymodels;networkinfrastructure;andvariousfielddevices(gages,actuators,datarecorders,etc.).SomeprovidershavenowalsoannouncedcomponentsthatsupportAPL.Selectedproductsareintroducedinsection6.

ThefollowingsubsectionslookatthecommunicationsolutionsbasedonaproxymodelandAPL,whicharesuitableforExzonesandthereforepredestinedforuseinprocessautomation.

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5.1 Connecting PROFIBUS PA to PROFINET via a proxy

BydirectlyconnectingPROFIBUSPAnetworksinExzonestoPROFINETwithoutaPROFIBUSDPintermediatesegment,futureproofinstallationscannowalreadybeimplemented,offeringlong-termadvantagesthatincludebothdiagnosticsandavailability.Thisinvolvestheuseofgateways(proxies)thatcontainanumberofmodules,includingasubmodulethatactsasaPROFIBUSPAproxy(an‘interpreter’).ThePAgatewaytoPROFINETisinstalledinplaceoftheformerDP/PAsegmentcouplerviawhichthePAsegmentswereconnectedtoPROFIBUSDP.ThankstodirectconnectivitybetweenthePAsegmentsandPROFINET,thenewsolutionavoidsthe‘detour’viaPROFIBUSDP.Dependingonperspective,thegatewayactssimultaneouslyasaPROFINETdeviceandasaPROFIBUSPAmaster,offeringsupportforthebasicrequirementsofprocessmanufacturingandespeciallytheredundancymodelsrequiredforPROFINETthatguaranteeahighlevelofavailability.

Thegatewayitselfshouldalsobeeasytointegrate–byusingstandardintegrationtoolslikeFDI(FDT/DTMtools),forexample–andshouldenablestraightforwarddeviceparametersetting.ItisalsoimportanttoensurethatthereisaclearandsimplemigrationpathwaytofutureEthernettotheFieldsolutionssuch asAPL.

TheproxysubmoduleshouldsupportthefollowingPROFINETfunctions:

• TransmissionofI/Odata• Transmissionofalarms• Data recording

Inthesameway,DPnetworksinnon-ExzonescanbeconnectedtoPROFINETviaDPproxies.

Thetechnologiesusedbythesesolutionswillbeintroducedinsection6.

5.2 Ethernet to the Field based on the Advanced Physical Layer (APL)

TheconnectionofPROFIBUSPAsegmentsviagatewayswithproxymodules(see 5.1)isanimportantmilestonebeforerollingoutEthernettotheField.TheAPL(AdvancedPhysicalLayer)projecttakesthisonestepfurther,havingsetitselfthegoalofdevelopinganewphysicallayerfortheIP-basedfieldcommunica-tionofthefuture.ThisisintendedtoovercomepriorobstaclestotheuseofEthernetinexplosionhazardareas.ThesearetheobjectivesofthestandarddevelopmentorganizationsPI,FieldCommGroup,andODVA,aswellasseveralmajorprocessmanufacturingsupplierswhoaresupportingdevelopmentoftheAdvancedPhysicalLayer(APL).APLisintendedtoenablethedirectconnectionofsuitablefielddevices(e.g.withPAProfile4.0)toEthernetinapotentiallyexplosiveatmosphere(Exzone0,zone1).

Inthefuture,APLwill

• enabledatatransferratesof10Mbit/s(inthefirstphaseofdevelopment;talksareongoingaboutasecondphasewithupto100Mbit/s)andsosupportIndustrie4.0anddigitalization

• permithightransmissionspeeds(upto300xfasterthanpreviousprotocols)• enablecomparablecoverageforPAasachievedbycurrentfieldbusprotocols• workindependentlyofexistingprotocols(identicalphysicallayerforOPCUA,EtherNet/IP,HART-IP,

andPROFINET)• supplypowertofielddevicesaswithcurrentPAfieldbuses(loop-poweredfielddevices)• beasrobustandfault-resistantasthesefieldbusesand• bedeployableinexplosionhazardareasandenableintrinsicsafety(whenusingintrinsicallysafe

fielddevices)

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Thenewcommunicationsstandardforsingle-pairEthernetaccordingto10BASE-T1LisbeingdevelopedaspartoftheIEEE802.3cgproject(amendmenttotheIEEE802.3Ethernetstandard).

5.2.1 APL infrastructure

APLmodifiesonlythephysicallayerandnottheprotocolsforIndustrialEthernet.ThislayeressentiallyconsistsofphysicalEthernetplusanAPLfrontend.Thetypicalstructureisthereforeasshownbelow:

5-7: Session / Presentation / Application Layer

4: Transport Layer

3: Network Layer

2: Data Link Layer

1: Physical LayerEthernet PHY

(according to IEEE 802.3 cg 10 Mbps or 100 Mbps)

Ethernet (real-time, non-real-time, TSN)

IP

Front End for Advanced Physical Layer

TCP/UDP

Figure4: CommunicationLayerswithAPL

Thisstructurecanmakeuseofflexibletopologiessuchasstar,trunk-and-spur,orring.

ThebasicAPLcomponentsinvolvedare:• APLpowerswitches(eitherincontrolroomordistributionbox):forconnectingtostandardEthernet,

thesepowerAPLfieldswitchesandfielddevices

• APLfieldswitches(inzone1or2,div.2):distributecommunicationsignalsandelectricalenergyviaspurs

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Example: Withthetrunk-and-spurtopologyoftenchosenforprocessautomation,theinstallationcould lookasfollows:

Sensor Sensor

Engineering Control

APLPowerSwitch

APLFieldSwitch

AssetManagement OptimizationandMonitoring

Sensor

Figure 5: TypicalAPLSystemStructure

• FromcontrollertoAPLpowerswitch(increasedsafety;inzone2/div.2),connectionviaavailableEthernettechnology(copper/fiber-optic)

• Poweradapteroutputwithupto60Wforupto50fielddevices,eachofwhichcanreceiveup to500mW

• BidirectionalfromAPLtrunkporttoAPLfieldswitches(trunkupto1,000mcablelength)withupto10Mbit/sinversion1,bidirectionaltoAPLfieldswitches

• FromAPLfieldswitchviaspurontofielddevicesinzone2orinzone0and1/div.1,2;alsoExispurconnectiontofielddevices,spursupto200m

5.2.2 Advantages of APL

Ethernet/APLdoesn’tjustenablethedigitalizationofprocessplantsbymakinguseofInternettechnologiesandhigh-speedcommunications:italsofundamentallysimplifiestheinstallation,configuration,andmain-tenanceofinstrumentsandautomationsystems.Theengineeringandintegrationworkloadisalsoreduced,becauseonlyonestructure(Ethernetnetwork)isnowneededforremoteI/O,fieldbus,and4…20mA(andHART)devices.Sinceinstallationshavereversepolarityprotection,thisresultsinlowererrorratesandlessneed for training.

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5.2.3 Migrating from PROFIBUS PA

APLenablesasimplemigrationfromPROFIBUSPAfielddevicestoPROFINETAPLfielddevices.Cables(typeA),topology(usuallytrunk-and-spur),andcablelengthsareallidentical.

5.2.4 Outlook

FollowingthecompletionofIEEE802.3cg(theamendmentisscheduledforthesecondhalfof2019),thecorrespondingtechnicalIECspecificationsthatenabletheinstallationofEthernetdevicesviaAPLinexplosionhazardareaswillalsobedraftedbeforetheendoftheyear.For2020,ODVA,PI(PROFIBUS&PROFINETInternational),andFieldCommGroupplantoupdatethecurrentIndustrialEthernetspecifica-tions.By2021(nolaterthan2022),thefirstinfrastructurecomponentsandcompatiblesingle-pairfielddeviceswillthenbeavailable.

6. Available Ethernet to the Field systems in process technology

SeveralmanufacturersofprocesscontrolsystemsandinfrastructurecomponentshavealreadymasteredthetechnicalrequirementsneededtouseEthernet-basedcommunicationsolutions–currentlyviaproxiesandlaterviaAPL.Aselectionoftheseproductsareintroducedinthefollowingsections.

6.1 Process control systems / controllers

6.1.1 Simatic PCS 7 process control system (Siemens)

Version9.0oftheSimaticPCS7PCShasbeendevelopedwithafocusonbringingdigitalizationtothefieldlevel.ThefollowingaccessoryhardwaresupportsPROFINET(IndustrialEthernet):

Simatic CPU 410 E

• Controllerforapplicationswithfewprocessobjects• WithtwoPROFINETinterfacesandonePROFIBUSinterface• PROFINETY-switchforredundantsetups

Simatic ET 200SP HA4

• DistributedI/OsystemwithredundantPROFINETconnections(copper/fiber-opticcable)• PROFINETIOcommunicationstandard• Upto56distributedI/Omodulesperstation• ModulescanbeinsertedandpulledusingConfigurationinRun(dynamicreconfiguration)

4 https://www.automation.siemens.com/w2/efiles/pcs7/pdf/76/FL/FL_ET200SPHA_en_04_2017_Web.pdf

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6.1.2 800xA process control system (ABB)

TheABBAbility800xAPCSsupportsPROFINET,DeviceNet,Ethernet/IP,IEC61850,andModbusalongsideFoundationFieldbusandPROFIBUS.

ABBAbilitySystemNetworksofferarangeofnetworkcomponents,includingmodulartransceiversforwirednetworksandswitches(forrack/DINrailinstallation)plusrouters/firewalls.

ThefollowingcomponentsareofparticularinterestforEthernet-basedcommunication:

800xA controller with PROFINET IO CI871

CI871• CommunicationinterfaceforPROFINETIOoverEthernet• WithtwoRJ45Ethernetinterfacesandone100MBit/sPROFINETinterface

Select I/O• Ethernet-basedsingle-channelI/Osolution• Zone2andclass1div.2certification• SupportsfullredundancyuptotheSCMsignalprocessingmodule

S800 I/O• Distributed,modularprocessI/Osystem• Permitsmodulehot-swapping• Supportsredundancyconcepts/redundancyalsoatI/Omodulelevel• I/Omoduleswithintrinsicallysafeinterfaces

6.2 Fieldbus infrastructure

6.2.1 Components for proxy solutions

As indicated in section5.1,fieldbusinfrastructurecanalreadybesetupbasedonPROFIBUSPAand FoundationFieldbusH1withtheaimofprovidingfutureproofsupportforEthernet-basedcommunication.Inthesescenarios,gateways(proxies)actas‘interpreters’fortheprocesscontrolsystemandareusedtoconnectfieldbussegmentsdirectlytoEthernet.Thissolutionisroundedoffbyappropriatepowersupplyunits,physicallayerdiagnostics,fielddevicecouplers,andterminatingresistors.ThefollowingsectionsintroducesuitablecomponentsfromSoftingandR.Stahlasexamples.

pnGate PA (Softing): proxy system gateway

ThePROFINETtoPROFIBUSPAMasterGatewaypnGatePAenablesdirectintegrationofPROFIBUSPAsegmentsintoPROFINETnetworkswithouta‘detour’viaPROFIBUSDP.PROFIBUSDP/PAsegmentcouplerscanbesimplyswappedout.MigrationtoEthernetAPLisalsosupportedbypnGatePA–existingPAsegmentsdonotneedtobemodified.ThepnGatePAgatewayactsasbothaPROFINETdeviceandPROFIBUSPAmaster(proxy).

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BenefitsofferedbypnGatePA:

• SupportsPROFINETredundancytoincreaseavailability• SupportsPROFINETengineeringtoolslikeTIAPortal,Step7,PCWorxs,800xAControlBuilder• Existingpowerconditionerscancontinuetobeusedasbefore• SimpleintegrationwithFDT/DTMtoolsbyusingaCommDTM• DeviceparameterizationwithEDD/SiemensSimaticPDMispossible

pnGatePAisavailableinthreeseparatemodels:

• pnGatePAfor2PROFIBUSPAsegments(forupto32PAdevices)• pnGatePAfor4PROFIBUSPAsegments(forupto64PAdevices)• pnGatePAforStahlcarriersfor4PROFIBUSPAsegments

PAC/PLC PAC/PLC

PROFINET Device

PROFINET Device

PlantAssetManagement

pnGate PBPROFIBUS DP

ENGINEERINGe.g. TIA Portal

ETHERNET

Switch

pnGate PA

PROFIBUS PAPROFIBUS PA

PROFIBUS PAField Barrier

Power Conditioner

Switch

FieldDevice

PROFINET Device

FieldDevice FieldDevice

PROFINET Device

FieldDevice

Figure 6: pnGateApplicationScenarios

pnGate PB for proxy systems (Softing)

ThefunctionalityandbenefitsofferedbypnGatePBareverysimilartopnGatePA.Thismodelsupports2PROFIBUSPAsegments(upto32PAdevices)and1PROFIBUSDPsegment.

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Fieldbus power supply series 9412 – ISbus (R. Stahl)

ThisfieldbuspowersupplyunitissuitableforthesimpleorredundantpoweringofFoundationFieldbusH1segmentsorPROFIBUSPAsegments.Offeringhigh-poweroutputofupto28V/500mA,theunitenablestheoperationofnumerousdevicesevenatgreatdistances.Forveryhighpowerrequirementsofupto1A,twopowersupplyunitscanbeusedinboostmode.

ThepowersupplyfeaturesintegrateddiagnosticscompliantwithNAMURRecommendationNE123(jitter,signallevel,voltage/current,noise,asymmetries,etc.).

Field device coupler (R. Stahl)

Thisfielddevicecouplerwithpowermanagementminimizestrunkcurrentloads,limitingrushandshort-circuit currents.

Availableas:

• Exifielddevicecoupleraszone1andzone2modelwith4or8channels(forzone1fielddevices)• Execouplerfor4or8non-intrinsicallysafefieldbusdevices• Exncoupler:4-,8-and12-channelvariantforExicandnon-intrinsicallysafefieldbusdevices

6.2.2 commModule APL – integration solution for APL (Softing)

AdvancedPhysicalLayer(APL)isintendedtoenableEthernet-basedcommunicationatthefieldlevelofprocesstechnology(see 5.2).APLwillbesuitableforloop-poweredandintrinsicallysafedevices,allowtransmissionspeedsof10Mbit/s,andensurecontinueduseforexisting2-wirefieldbuses.ThefirstAPLcomponentshavebeenannouncedfor2021,andwillenablethedirectintegrationofautomationprotocolssuchasPROFINETorEthernet/IPwith2-wirefielddevices.ThiswillalsomaketheuseofOPCUApossibleforfielddevices.

ThecommModuleAPLintegrationsolutionhelpsfielddevicemanufacturersmakethetransitiontoEthernet-capabledevices.IntegratingcommModuleAPLwithHARTandModbusdevicesisstraightforward.ItactsastheinterfacetoAPLandcommunicatesviaHARTorModbuswiththefielddevices.Inthefuture,thisuniversalhardwarewillenablemanufacturerstosupportfielddevicecommunicationoverEthernet/APLviatheprotocolsPROFINET,EthernetIP,andOPCUA,forexample.

ThisworksinasimilarwaytoSofting’scurrentcommModuleMBP,whichenablestheuseofdevicesforPROFIBUSPAandFFH1.Devicemanufacturerssimplyneedtocreateacorrespondingscript,whichistheninterpretedbycommModule.InthepackagedcommKitsolution,SoftingsuppliescommModulewiththecommScriptersoftwaretool,whichusesthetextualdescriptionofdevicefunctionality(script)togeneratethemappingtablesincommModule,soastoavoidanyextraprogrammingeffort.

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HARTorModbusFieldDevice

+

commKit

Requirementspecificdeviceparametrizationmapping onto FoundationFieldbus or PROFIBUS PA

Fully functional standard firmwarewithprotocolstack

commModuleMBP

Figure7: FunctionalityofthecommKitMBP

ThissolutionoffersfielddevicemakersafairlystraightforwardpathtowardsupgradingtheirdevicestothefutureAPL-basedEthernetcommunicationstandard.commModuleAPLwillbeavailablefrom2021.