Your complete guide to building an NMEA 2000® network

ContentsWho are the NMEA and What is NMEA 2000? 33 Who are the NMEA?3 What is NMEA 2000?3 The Network That CAN3 DeviceNet3 Certification

Minimum Network Requirements and Network Limitations 44 MinimumNetworkRequirements4 CommonPhrases

NMEA 2000 Network Limitations 5

Actisense Starter Kits 66 TheoriginalActisensestarterKit6 RIBStarterKit6 SmallBoatNetwork

Powering and fusing the network 77 PowerT-Piece7 MicroPowerCable7 SmallBoatNetwork8 QuickNetworkBlock

T-Pieces and Termination Resistors 99 MicroT-Pieces9 Micro4-WayT-Pieces

Connecting Devices and Extending the backbone 1010 TrunkandDropCable10 BulkCable

Field Fit Connectors 1111 FieldFitConnectors

5 Steps to Field Fit Installation Success 12

The Quick Network Block 1313 AtaGlance14 DetailedOverview14 RaymarineSeaTalkNGSolution Network Diagnosis 1414 Glandedoption15 AdequatePowerSupply&TerminationResistance16 DiggingDeeper17 Checkingavailibilityandaccuracyofdataonthenetwork

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Who are the NMEA and What is NMEA 2000?

Who are the NMEA?TheNMEAstandsforNationalMarineElectronicsAssociation.Inanutshell,they’reanotforprofitorganisationwhosemissionistoimprovedatacommunicationsbetweenmarineelectronicsmanufacturers.Readmoreatwww.nmea.org

What is NMEA 2000?NMEA2000isanopenstandarddesignedbytheNMEAtohelpthemachievetheirmissionbystandardisingthemessagesandconnectorsystemusedfordevicesinthemarineindustry.Thereisacommonmisconceptionthattheterm‘openstandard’meansfreelyavailablewheninfactitmeansthatthestandardisavailabletobuyatareasonablecostfromtheirwebsite.ItisimportanttorememberthattheNMEAisnotforprofit(NFP)andthestandardscreateanimportantsourceofincomesothattheycancontinuetoexist.

The Network That CANNMEA2000isbasedonasystemknownasCANwhichstandsfor‘ControllerAreaNetwork’.OneofthereasonstheNMEAchosethissystemoversomethinglikeEthernet(forexample)whichhasamuchwiderbandwidth,andcansupportRADARandvideo,isbecauseCANhastheabilitytoguaranteemessagedeliveryevenwhenthenetworkis100%loaded.AnimportantfeaturewhenyouconsiderthatthenetworkislikelytocontainimportantGPSinformation.

DeviceNetTheNMEAadopted the ‘DeviceNet’ standard for thehardware (cablesandconnectors) that is used to createanNMEA2000network. TheDeviceNetstandardwasalready inuseby theautomotiveandagricultural industries (tonamea few)so it isaprovenrobustsystemandcanwithstandtheharshconditionsofthemarineenvironment.

CertificationThere isacertificationprocess inplace forNMEA2000. Thishelpstheuser tounderstandthat ifadevicecarriestheNMEA2000logotheycanrestassuredthatitiscompatiblewithanNMEA2000networkandanyother‘NMEA2000Certified’device. Somecommonterms for theuser tobeawareofare ‘CANbusapproved’or ‘NMEA2000Compatible’astheseareunlikelytohavegonethroughtheNMEA2000certificationprocess.

‘NMEA2000Approved’isatermusedforcablesandconnectorsthatmeettherequirementsforNMEA2000astheydonotrequirethesamecertificationprocess.

http://www.nmea.orghttp://www.nmea.org/

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Minimum Network Requirements and Network Limitations

Minimum Network RequirementsThefollowingaretheessentialcomponentsofanyNMEA2000network:• Powerinsertionpoint-fused.• 2xNMEA2000certifieddevices(atleast1xTXand1xRX)andameanstoconnectthemtothenetwork.ThiscanbeviaT-piecesorotherproductswhichwillbediscussedlater.• Terminationresistors-Precisely2,nomore,noless.

Common PhrasesYouwillhearsomecommonphrasesusedwhendiscussingNMEA2000networks.Here’swhattheymean:Backbone:Themaintrunkofcablethatrunsthroughtheboattoformthenetwork.T-piecesareconnectedalongthenetworkfordevicestopluginto.Instrumentdrop:ThelengthofcablethatconnectsanNMEA20000devicetothebackbonePGN:Standsfor‘ParameterGroupNumber’.ThemessagesusedbyNMEA2000devicesforsharinginformation.

ThediagrambelowillustrateshowanNMEA2000networkisputtogether:

Cable Type Max Length Max Amp Power Pair Data Pair

Per drop cable 6m

Sum of all drop cables 72m

Micro/Lite Backbone(Terminator to terminator) 100m 3 22 AWG 24 AWG

Mid backbone(Terminator to terminator) 250m 4 18 AWG 20 AWG

Mini/Heavy Backbone(Terminator to terminator) 250m 8 15 AWG 18 AWG

NMEA 2000 Network Limitations

Actisense Starter Kits

ActisensecanprovideyouwitheverythingyouneedtogetstartedwithanNMEA2000networkinavarietyofflavours.Here’sanoutlineoftheircontents.Eachindividualitemwillbediscussedinmoredetailinfutureepisodes,alongwithotheritemstocomplementyourNMEA2000network.

The original Actisense starter Kit• PowerT-piece-ContainsatwinpairofpowercablesforevenpowerdistributionacrosstheNMEA2000network.

• 2x T-pieces - for extending the network from the power T-piece and connectingNMEA 2000devicestothenetwork.

• 2xterminationresistors-Tomaintainsignalintegrity.• 1x2metrecable-forextendingthelengthofthebackboneifneededortoconnectanNMEA2000devicetoaT-piece.FittedwithovermouldedDeviceNetstandardconnectorstoprotectfromwateringress.

RIB Starter Kit• 1x4-wayT-piece-providinginstrumentdropsforupto3devices(oneportisusedforpower).• 1xMicropowercord-canbepluggedstraightintoanyavailableportonthe4-wayT-piecetoprovidenetworkpower.• 2xTerminationresistors-Tomaintainsignalintegrity.• Networkcanbeextendedbytemporarilyremovingaterminationresistor,plugginginadditionalT-piecesandreplacingtheterminationresistorattheendofthebackbone.

Small Boat Network• Spacefor4xinstrumentdrops.• Overmouldedpowercordattached.• 2xTerminationresistorsbuiltin.

45132

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45132

+_ S _

FemaleNET-HNET-LShieldNET-CNET-S

MaleNET-HNET-LShieldNET-CNET-S

Powering and fusing the network

Power T-PieceTheActisensepowerT-piecehasatwinpairofpowerwires,oneforeachsideoftheT-piece.Bothpairsmustbeconnectedtoa12/24Voltpowersupply(viafusepanel)sothattheelectricalloadcanbedistributedevenly.

Whenusing24Vsystems,awarningmustbeinstalledonthenetworktoensureanyoneinstallingnewdevicesisaware.ThisisbecausetheNMEA2000specificationdoesn’tofficiallysupport24Vbutthislevelofpowersupplycanbeusedifinstalleddevicesarecapableofsupportingit.AllActisensedevicessupport24Vpowersupplies.

TheillustrationbelowdetailstheinternalwiringoftheActisensepowerT-piece.Notethepairofpositiveandnegativepinsoneachside.

Micro Power CableThiscableisdesignedforsmallinstallationsthatwillbeusedwiththeRIBStarterKitsoitonlyhasasinglepairofpowerwires.TheMicroPowerCablehasaMicroDeviceNetconnectorsothatitcanbeeasilypluggedintothemostsuitableportonthe4-wayT-pieceprovided.

TheMicroPowerCableshouldneverbeusedonlargerinstallations.

Small Boat NetworkThepowercordfortheSmallBoatNetworkisovermouldedtothecaseofa4-wayT-piecetopreventwateringress.Powerisavailabletoall4portsoncethepairofbarewiresisconnectedtoa12Vor24Vpowersupply.

Quick Network BlockTheActisenseQuickNetworkBlock(QNB)providesaversatileandeasytoinstallsolutionforanyNMEA2000,largeorsmall.ThissectionillustrateshowtheQNBcanbeusedforprovidingpowertoyournetworkandtheaddedbenefitsofitsfeatures.Otherbenefitswillbeshownlaterinthisdocument.(See“TheQuickNetworkBlock”onpage13)

Note:TheQNBwillnotregulatethevoltagethatisbeingprovidedtothenetwork.

Power Insertion

Fuses

Fuse 1 status LED

Power LED

Polarity LED

Presence of data LED

Fuse 2 status LED

T-Pieces and Termination Resistors

Micro T-PiecesT-piecescanbeconnecteddirectlytothePowerToryoucanusealengthofNMEA2000approvedcablingtoextendthebackboneandjointheT-piecetotheendofthecable.Theinstrumentdropmustconnectedatrightanglestothebackbonesoitisclearwhatisthebackboneandwhatisaninstrumentdrop.

Micro 4-Way T-PiecesThe photos on the right illustrate the different T-piece options available fromActisense.Theyareshowninactualsize(ifthisPDFhasbeenprintedtoA4size)anddemonstratethespacesavingthatthe4-wayT-piececanprovide.

Termination ResistorsAteachendofthebackboneaterminationresistormustbeinstalled.Each termination resistor is 120Ohms and is connected in parallelacrossthedatapairofwireswhenpluggedintoNMEA2000approvedcables and connectors. Thisprovides a total of 60Ohms resitanceacrossthenetworkandisessentialtodataintegrity.

Connecting Devices and Extending the backbone

Trunk and Drop CableIfthelengthofcablerequiredbetweenT-pieces/devicesisknown,pre-assembledcablescanbeusedforextendingthebackboneorpluggingindevicestothenetwork.Thisoptionsavesalotoftimenothavingtocutthecableandwireaconnectortoityourself.ActisenseNMEA2000approvedcablingisavailableinthefollowingsizes:

• 0.25m• 0.5m• 1m• 2m• 3m• 4m• 5m• 6m(maximumlengththatcanbeusedforaninstrumentdropasdefinedbytheNMEA2000specification)• 8m• 10m

Bulk CableIfcustomisedlengthsofcableareneeded,orlengthsofcablegreaterthan10metres,bulkcableisavailablein100metrereels.ThiscanbeusedtogetherwithActisensefieldfitconnectors.

Field Fit Connectors

Field Fit ConnectorsWhenbulkcableisusedaconnectorwillneedtobewiredtotheendssothatthecablecanbepluggedintothenetworkoradevice.Followourfivestepstofieldfitinstallationsuccessonthenextpagethatillustratesthebestmethodforinstallingfieldfitconnectors,includingwhichcolourwiresconnecttowhichpins.TheNMEA2000wiringcoloursystemisstandardisedsothecoloursandpinnumberswillbethesameforanywireandconnectorcombinationthatusesthesameDeviceNetstandard.

Actisensefieldfitconnectorsareavailableasstraightorrightangledoptionsandinmaleandfemalevariantstosuitanyinstallationrequirement.

Note the plastic sleeve that coversthecentrepin. This is toprevent thebarewiresthatextrudefromtheother4pinsmakingcontactwiththecopperand creating a short. Not all field fitconnectorshavethisplasticsleeve.

5 Steps to Field Fit Installation Success

Backbone connectionsInstrument drops

Labels are the same for both sides and for both variants of QNB-1.

See the next page for more information on the different variants available.

Panelmountedwireconnectorsareavailableasastandaloneproductfor creating through bulkhead connections.They can also be used to replace theconnectorsintheQNBifneeded.

Blankingplugsarealsoavailable toprotectanyunusedpanelmountedwireconnectorsfromwatersplashes.

The Quick Network Block

At a GlanceThenextpageprovidesamoredetailedoverviewoftheQuickNetworkBlock.Pleasereferto“Poweringandfusingthenetwork”onpage7forfulldetailsofthepowerinsertionfeaturesoftheQuickNetworkBlock.

Wire Colour Connects to

Red NET-S

Black NET-C

White NET-H

Blue NET-L

Bare/green Shield

Detailed OverviewTheActisenseQuickNetworkBlock(QNB)providesasimple‘networkinabox’solution.Itcanbeusedinareasofhighinstrumentdensitywhendevicesareupto12metresapart fromeachother (6metredropfromdevicetoQNBperdevice). Anotherpopularuse for theQNBiswithengineersthathaveaneedtocreateasmallNMEA2000testenvironmentonaworkbench(forexample).

Raymarine SeaTalkNG SolutionAlessobviousbenefittotheQNBistheabilitytomixandmatchDeviceNetstandardconnectorswithRaymarineSeaTalkNG(STNG)connectors.AsSTNGusesexactlythesamedataasNMEA2000butchoosesnottousetheDeviceNetstandardforit’sconnectorsystem,adaptercablesareneededtochangetheconnectortypewheninstallingSTNGdevicesonNMEA2000networks,orviceversa.

STNGcablescanbestrippedbackandwireddirectlytotheterminalsinsideeithervariantoftheQNB-1,whichmeansthatyoucanmixandmatchSTNGwithDeviceNet.ThewiringcoloursinsideSTNGcablesarethesameasDeviceNetcables.

Removingtheconnectors fromthePMWvariant isnotadvisedastheQNB-1will lose itswatertight integrity. Instead,werecommendsimplyconnectinganSTNGbackbonecablethroughoneorbothofthebackboneglandstoenablethemix&matchingoptionsdescribedabove.

Glanded optionA glanded option of the QNB is available for more customisedinstallationsusingActisensebulkcable. Arubber,self-tighteningsealinsideeachglandclampsaroundthecablewhenitisinstalledandthescrewistightened.

Panel Mounted Wire connector option (PMW)The PMW option is the simplest to install as all the connectors arepre-wiredandprovideplug&playconnectivity.Thebackboneshouldalwaysbeinstalledthroughtheglandsprovidedthatarefurthestfromthepowerinsertionpoint.

NET-SNET-CNET-LNET-HSHIELD

Network Diagnosis

Nomatterhowrobustanetworkis,howsimpleitistoinstall,orhowwellithasbeendocumentedandmanagedtherewillinvariablybeissuesthatneedtacklingatsomepoint.ThisepisodewillhelptoidentifysomegoodplacestostartwhendiagnosinganNMEA2000network.

Adequate Power Supply & Termination Resistance• TestvoltageatentrypointEnsuringthenetworkisreceivingapowersupplyisalwaysthebestplacetostart.Assomedevicesmaybepoweredbythenetwork,knowingthatthesedevicesareworkingisaquickwinforthistest.Thepowerattheentrypointshouldnotexceed14Vfroma12Vsupply.

• TestvoltageatnetworkextremitiesWithnetworkdevicesusingupsomeofthesuppliedpowerandimpedancefromcablingalsodroppingthevoltage,itisimportanttoknowthatthevoltageattheendofeachbackbonelegisadequate.TemporarilyremoveaterminationresistorfromtheendofthenetworkanduseavoltmetertomeasureacrosstheNET-SandNET-Cpins.Themeasuredvalueshouldbeatleast9V.ThediagramsbelowwillhelpyoufindthesepinswhenusingActisenseconnectors.

AnActisensePanelMountedWire(PMW)connectorisagreattoolforpluggingintoaspareT-piecetoquicklyidentifythecorrectpinsviathewiringcolours.ItisrecommendedthateachwirefromthePMWisterminatedinsideaterminalblockpriortopluggingitintothenetworkasvoltagemaybepresentacrosstheNET-SandNET-Cpins.

• CheckforthecorrectterminationresistanceTurnoffnetworkpowerandcheckresistanceacrossNET-HandNET-LterminalsofanyT-pieceonthenetwork.Themeasuredresistanceshouldread60Ohms.

If120Ohmsismeasured,onlyoneterminationresistorisinstalled.Asecondresistorwillneedtobeinstalledattheoppositeendofthenetworktotheonethatisalreadypresent.

If40Ohmsisobserved,thereare3terminationresistorsinstalledonthenetworkso1willneedtoberemoved.Ifit’snotobviouswherethethirdresistoris,checkforanydevicesonthenetworkwithinstalledterminationresistorsandensuretheyareswitchedoff.

NetworkdeviceswithterminationresistorsinstalleddonotachieveNMEA2000certificationasthispracticecancauseconfusiononthenetwork.

Digging DeeperIfissuesremainwhenthecorrectpowerandresistancehavebeenprovedonthenetwork,furtherinvestigationwillberequired.

• HalfsplitmethodDisconnectonehalfofthebackboneandmovetheterminationresistortothenew,temporaryendofthenetwork.Iftheissueremainsyouhavenarroweditdowntothehalfofthenetworkthatisstillpoweredandactive.Iftheissuedoesnotremainitisinthehalfofthenetworkthathasbeendisconnected.Keepperformingthishalfsplitmethoduntilyouareabletonarrowitdowntoasingledevice,ifpossible.Don’tforgettomovetheterminationresistoreachtimetoensurethenetworkiscorrectlyterminated.

Oncetheissuehasbeennarroweddown,tryswappingoutt-piecesorcablingwithonesthatareknowntobegood.IfFieldFitConnectorshavebeenused,checkthewiringconnectionsinsidetoensurethattheyarecorrectandfirmlysecuredinplace.

Ifpossible,checkthewiringinsidethedeviceisproperlyandsecurelyterminated,ensuringtoobserveanti-staticprecautionsifexposinginternalelectronics.Itisalwaysbesttocheckthatthisisokwiththedevicemanufacturerbeforeperformingthissteptoensureyoudonotvoidanywarranty.

Ifanissuestillremainsyounowknowthereisaproblemwiththedeviceandit’stimetocontactthemanufacturerofthatdevice.

Checking availibility and accuracy of data on the network

• ActisenseNMEA2000toPCGateway(NGT-1)TobeabletoseeallofthedataontheNMEA2000networkandanalyseit,youwillneedtobeabletosendittoaPC.NMEA2000datacannotbereadbyaPCwithouttheuseofagateway,liketheNGT-1.

TherearetwooptionsofNGT-1available:

USBoption(NGT-1-USB):ThisistheeasiesttoconnecttoaPCasitcanbepluggedstraightintoyourPCsUSBport.TheNGT-1willbepoweredandactiveoncetheUSBdrivershavebeensuccessfully installed.DependingonyourOSsettingsthisshouldhappenautomatically ifyouhaveaworkinginternetconnection.IftheUSBdriversdonotinstallautomatically,thesameUSBdriversareavailableontheCDprovidedwiththeproductorformtheNGT-1downloadspageontheActisensewebsite.

ISOoption(NGT-1-ISO)TheISOoptionisforusersthatpreferaserialconnectiontotheirPC,insteadofUSB.IthasbarewiresonthePCsideforconnectingtoaserial(RS232)port.TheISOoptionispoweredbytheNMEA2000network.

ThedefaultbaudrateforbothoptionsofNGT-1is115200whichcanbechangedusingNMEAReader.

• NMEAReaderNMEAReaderissoftwarethatletsyouseeallofthedatabeingsenttoyourPCfromtheNMEA2000networkviatheNGT-1.TherearealsooptionsforconfiguringActisensedevices.NMEAReaderisfreelyavailabletodownloadfromtheActisensewebsite.

• ActisenseToolkitToolkitisnewsoftwarefromActisensethatiscurrentlyusedforconfiguringtheEngineMonitoringUnit(EMU-1)fromActisense.ItwillsoonsupportconfigurationofallconfigurableActisenseproductsandwillreplaceNMEAReaderwhenthe‘DataView’featurehasbeenadded.

FormoreinformationonhowtousetheNGT-1,NMEAReaderorToolkit,pleaserefertothemanualatactisense.com

http://www.actisense.com/media/?type=downloads

Who are the NMEA and What is NMEA 2000?Who are the NMEA?What is NMEA 2000?The Network That CANDeviceNetCertification

Minimum Network Requirements and Network LimitationsMinimum Network RequirementsCommon Phrases

NMEA 2000 Network LimitationsActisense Starter KitsThe original Actisense starter KitRIB Starter KitSmall Boat Network

Powering and fusing the networkPower T-PieceMicro Power CableSmall Boat NetworkQuick Network Block

T-Pieces and Termination ResistorsMicro T-PiecesMicro 4-Way T-Pieces

Connecting Devices and Extending the backboneTrunk and Drop CableBulk Cable

Field Fit ConnectorsField Fit Connectors

5 Steps to Field Fit Installation SuccessThe Quick Network BlockAt a GlanceDetailed OverviewRaymarine SeaTalkNG Solution

Network DiagnosisGlanded optionAdequate Power Supply & Termination ResistanceDigging DeeperChecking availibility and accuracy of data on the network