Raymarine AIS650 - Chapter 2: AIS350 Receiver; System Protocols

Systemprotocols
Yourproductcanbeconnectedtovariousproductsandsystemsto
shareinformationandsoimprovethefunctionalityoftheoverall
system.Theseconnectionsmaybemadeusinganumberof
differentprotocols.Fastandaccuratedatacollectionandtransferis
achievedbyusingacombinationofthefollowingdataprotocols:
•SeaT alk
ng
•NMEA2000
•NMEA0183
Note:Youmayndthatyoursystemdoesnotuseallofthe
connectiontypesorinstrumentationdescribedinthissection.
Seatalk
ng
SeaTalk
ng
(NextGeneration)isanenhancedprotocolforconnection
ofcompatiblemarineinstrumentsandequipment.Itreplacesthe
olderSeaTalkandSeaT alk
2
protocols.
SeaTalk
ng
utilizesasinglebackbonetowhichcompatible
instrumentsconnectusingaspur.Dataandpowerarecarriedwithin
thebackbone.Devicesthathavealowdrawcanbepoweredfrom
thenetwork,althoughhighcurrentequipmentwillneedtohavea
separatepowerconnection.
SeaTalk
ng
isaproprietaryextensiontoNMEA2000andtheproven
CANbustechnology.CompatibleNMEA2000andSeaTalk/
SeaTalk
2
devicescanalsobeconnectedusingtheappropriate
interfacesoradaptorcablesasrequired.
NMEA2000
NMEA2000offerssignicantimprovementsoverNMEA0183,most
notablyinspeedandconnectivity.Upto50unitscansimultaneously
transmitandreceiveonasinglephysicalbusatanyonetime,
witheachnodebeingphysicallyaddressable.Thestandard
wasspecicallyintendedtoallowforawholenetworkofmarine
electronicsfromanymanufacturertocommunicateonacommon
busviastandardizedmessagetypesandformats.
NMEA0183
TheNMEA0183DataInterfaceStandardwasdevelopedby
theNationalMarineElectronicsAssociationofAmerica.Itisan
internationalstandardtoenableequipmentfrommanydifferent
manufacturerstobeconnectedtogetherandshareinformation.
TheNMEA0183standardcarriessimilarinformationtoSeaT alk.
Howeverithastheimportantdifferencethatonecablewillonly
carryinformationinonedirection.ForthisreasonNMEA0183is
generallyusedtoconnectadatareceiverandatransmittertogether,
e.g.acompasssensortransmittingheadingtoaradardisplay.This
informationispassedin‘sentences’,eachofwhichhasathree
lettersentenceidentier.Itisthereforeimportantwhenchecking
compatibilitybetweenitemsthatthesamesentenceidentiersare
usedsomeexamplesofwhichare:
•VTG-carriesCourseandSpeedOverGrounddata.
•GLL-carrieslatitudeandlongitude.
•DBT-carrieswaterdepth.
•MWV-carriesrelativewindangleandwindspeeddata.
NMEAbaudrates
TheNMEA0183standardoperatesatanumberofdifferent
speeds,dependingupontheparticularrequirementorequipment
capabilities.Typicalexamplesare:
•4800baudrate.Usedforgeneralpurposecommunications,
includingFastHeadingdata.
•9600baudrate.UsedforNavtex.
•38400baudrate.UsedforAISandotherhighspeedapplications.
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AIS350/AIS650Installationinstructions