Simrad ST90 - Page 38

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8SelectReceptionTesttostartanautomatictestoftheindividualtransducerelements.
ThereceptiontestvalidateseachsingleelementintheST90transducer,andreturns
thestatususingasimplecolourcoding.
•Green:Thetransducerelementisfullyoperational.
•Red:Thetransducerelementoffersreducedperformance.
•Black:Thetransducerelementisnotworking("dead").
Formoreinformation,observethetooltipprovidedforeachelementrectangle.
9Verifythatthemaximumnumberofunserviceable("dead")elementsdoesnot
exceed3.
Asmallnumberofunserviceabletransducerelementsareaccepted,evenfor
operationaluse.Thisisregardedas"gracefuldegradation”.
TheST90operateswith384individualchannelshandledby12transceiverboards.
Ifasinglechannelfailsduringnormaloperation,youarenotlikelytodetectit.
Evenifseveralchannelsfail,youmaynotseeit.
Thedetectionofafaultychanneldependsonthephysicallocationoftherelevant
transducerelement.Iffaultychannelsaregroupedtogetheronthetransducerface,
thismaycauseavisibledefectintheST90presentation.Iftheyarescattered,
thevisibledefectmaybealothardertosee.Inallcases,theechoesfromthe
neighbouringchannelscauseaninterpolationthatwillrestorealotofthedegraded
presentation.
Note
Forfurtherinvestigationsofthisissue,usethefunctionalityofferedbytheElement
BITE(ElementBuiltInTestEquipment)dialogbox.
10Iftheresultfromthereceptiontestshowsanumberoftransducerelementsthatare
eitherdefectiveorofferreducedperformance,repeatthetest.
Withthevesselinport,theenvironmentalconditionsarenotsatisfactory.Inthe
shallowwatersoftheport,noisefromothervessels,dockyardworkersormachinery
willcauseunreliabletestresults.Ifyoudothistestsinabusyharbour,orwithnoise
sourcespresent,thesensitivereceiverswilldetectallthenoiseinthenearbywaters.
Excessivenoiseorinterferencemaybemisinterpretedasphysicaldefects.
Youmayneedtorepeatthetestseveraltimes,and-ifnecessary-implementa
"silentship"toimprovetheconditions.
11Finishthetest.
aClosetheBITE(BuiltInTestEquipment)dialogbox.
bSetTxPowertoOff.
cHoistthetransducerbackuptoitsupperposition.
SimradST90HarbourAcceptanceTest