Raymarine E-Series - Data Master

awholenetworkofmarineelectronicsfromany
manufacturertocommunicateonacommonbusvia
standardizedmessagetypesandformats.
SeaTalk
SeaTalkisaprotocolwhichenablescompatible
instrumentstoconnecttoeachotherandsharedata.
TheSeaT alkcablesystemisusedtoconnect
compatibleinstrumentsandequipment.Thecable
carriespoweranddataandenablesconnection
withouttheneedforacentralprocessor.
Additionalinstrumentsandfunctionscanbeaddedto
aSeaTalksystem,simplybypluggingthemintothe
network.SeaT alkequipmentcanalsocommunicate
withothernon-SeaT alkequipmentviatheNMEA
0183standard,providedasuitableinterfaceisused.
NMEA0183
TheNMEA0183DataInterfaceStandardwas
developedbytheNationalMarineElectronics
AssociationofAmerica.Itisaninternational
standardtoenableequipmentfrommanydifferent
manufacturerstobeconnectedtogetherandshare
information.
TheNMEA0183standardcarriessimilarinformation
toSeaTalk.Howeverithastheimportantdifference
thatonecablewillonlycarryinformationinone
direction.ForthisreasonNMEA0183isgenerally
usedtoconnectadatareceiverandatransmitter
together,e.g.acompasssensortransmitting
headingtoaradardisplay.Thisinformationis
passedin‘sentences’,eachofwhichhasathree
lettersentenceidentier.Itisthereforeimportant
whencheckingcompatibilitybetweenitemsthatthe
samesentenceidentiersareusedsomeexamples
ofwhichare:
•VTG-carriesCourseandSpeedOverGround
data.
•GLL-carrieslatitudeandlongitude.
•DBT-carrieswaterdepth.
•MWV-carriesrelativewindangleandwindspeed
data.
NMEABaudrates
TheNMEA0183standardoperatesatanumber
ofdifferentspeeds,dependingupontheparticular
requirementorequipmentcapabilities.Typical
examplesare:
•4800baudrate.Usedforgeneralpurpose
communications,includingFastHeadingdata.
•38400baudrate.UsedforAISandotherhigh
speedapplications.
3.7Datamaster
Anysystemcontainingmorethanonenetworked
multifunctiondisplaymusthaveadesignateddata
master.
Thedatamasteristhedisplaywhichservesasa
primarysourceofdataforalldisplays,italsohandles
allexternalsourcesofinformation.Forexample
thedisplaysmayrequireheadinginformationfrom
theautopilotandGPSsystems,usuallyreceived
throughaSeaTalk
ng
orNMEAconnection.Thedata
masteristhedisplaytowhichtheSeaT alk,NMEA
andanyotherdataconnectionsaremade,itthen
bridgesthedatatotheSeaTalk
hs
networkandany
compatiblerepeatdisplays.Informationsharedby
thedatamasterincludes:
•Cartography
•Routesandwaypoints
•Radar
•Sonar
•Datareceivedfromtheautopilot,instruments,the
engineandotherexternalsources.
Yoursystemmaybewiredforredundancywithdata
connectionsmadetorepeatdisplays.Howeverthese
connectionswillonlybecomeactiveintheeventofa
faultand/orreassignmentofthedatamaster.
Inanautopilotsystemwhichdoesnotcontaina
dedicatedpilotcontrolheadtheDatamasteralso
actsasthecontrolfortheautopilot.
Planningtheinstallation
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