User manual

SimradES70
Topics
•NationalMarineElectronicsAssociation(NMEA)onpage264
•NMEAtelegramprinciplesonpage264
•StandardNMEA0183communicationparametersonpage264
•NMEAsentencestructureonpage265
NationalMarineElectronicsAssociation(NMEA)
TheNationalMarineElectronicsAssociation(NMEA)hasdenedcommunication
standardsformaritimeelectronicequipment,andtheES70echosounderconformsto
thesestandards.ThemostcommonstandardisNMEA0183,andtheNationalMarine
ElectronicsAssociationdescribesitasfollows:
TheNMEA0183InterfaceStandarddeneselectricalsignalrequirements,data
transmissionprotocolandtime,andspecicsentenceformatsfora4800baudserial
databus.Eachbusmayhaveonlyonetalkerbutmanylisteners.
—NationalMarineElectronicsAssociation
FormoreinformationabouttheNationalMarineElectronicsAssociationandtheNMEA
0183standard,refertotheorganization'swebsiteathttp://www.nmea.org
.
NMEAtelegramprinciples
Tomoveinformationbetweentwoelectronicunits,thedataarecollectedintelegrams.
Thecontent(protocol)ofeachtelegramisdenedbytheNMEAstandard,andseveral
telegramtypesexisttoallowdifferenttypeofdatatobedistributed.
Thephrasedatagramisalsofrequentlyusedaboutthiscommunicationmethod.
Unlessyouwishtowriteyourownsoftware,youdonotneedtoknowhowthese
telegramsaredesigned.However,wheneveryousetupequipmentinterfaces,youneed
toensurethateachsystemonyourcommunicationlineissetuptosendandreceivethe
sametelegram.Thestandardallowsonesystemtosenddata(a“talker")andseveral
otherstoreceivedatasimultaneously("listeners")onthesameline.Therefore,youmust
ensurethatallproductsreceivingdataonacommunicationlineissetuptoreceivethe
sametelegram(s)thatthetransmittingproductprovides.
StandardNMEA0183communicationparameters
ThecommunicationparametersdenedforNMEA0183are:
•Baudrate:4800bitspersecond
•Databits:8
•Parity:None
•Stopbits:One
Someinstrumentswillalsoofferotherparametersand/orchoices.
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