Raymarine A series - Page 173

•Marinepontoons.
•Metal-hulledvessels.
•Underseacables.
Note:Youcanspeed-upthelinearizationprocess
bycompletinga360degreeturn(ataspeedof3
–15knots).Youcanalsorestartthelinearization
processatanytimebyselectingtheRestart
Compassmenuitem.
Usethecompassdeviationindicator
Theuseofthecompassdeviationindicatoronthe
pilotcontrolheadmaybeusefulinthisprocess,
particularlyiftheEVunithasbeeninstalledin
alocationonthevesselwherethelevelsof
magneticinterferencearetoohighfortheEVunit
tocompensateappropriately.Ifthisisthecase,
thedeviationdisplaywillindicateavalueof25
degreesorhigher.Inthisscenario,Raymarine
highlyrecommendsthattheEVunitismovedand
re-installedinalocationwhichissubjecttoless
magneticinterference.If“--”isdisplayedasthe
Deviationvalue,itmeansthatlinearizationhasnot
beensuccessfullycompletedyet.
Checkthecompassheadingdata
Aspartoftheautopilotsystemcommissioning
process,Raymarinerecommendsthatyoucheckthe
compassheadingvaluedisplayedonyourautopilot
controlheadormultifunctiondisplay,againstagood
knownheadingsourceonvariousheadings.This
willhelpyoutodeterminewhentheEVunithas
completeditslinearizationprocess.
Note:Oncethelinearizationprocesshas
completed,itispossiblethattheheadingvalue
mayhaveaslightoffsetof2to3degrees.This
iscommonwhereinstallationspaceislimited,
andtheEVunitcannotbeproperlyalignedtothe
vessel'slongitudinalaxis.Inthiscase,itispossible
tomanuallyadjustthecompassoffsetvalueusing
thepilotcontrolheadormultifunctiondisplay,and
ne-tunetheheadingtoanaccuratevalue.
Note:DoNOTrelyontheheadingaccuracyuntil
youaresatisedthatcompasslinearizationand
alignmentiscomplete.
Systemmonitoringandadaptation
Toensureoptimumperformance,aftertheinitial
linearizationprocessiscompletetheEVcontinuesto
monitorandadaptthecompasslinearizationtosuit
currentconditions.
Iftheconditionsforlinearizationarelessthanideal,
theautomaticlinearizationprocesstemporarily
pausesuntilconditionsimproveagain.Thefollowing
conditionscancausethelinearizationprocessto
temporarilypause:
•Boatspeedislessthan3knots.
•Boatspeedisgreaterthan15knots.
•Rate-of-turnistooslow.
•Signicantexternalmagneticinterferenceis
present.
Compasslock
Onceyouaresatisedwiththecompassaccuracy,
youcanlockthesettingtopreventtheautopilot
systemfromcompletingafurtherautomatic
linearizationinthefuture.
Thisfeatureisparticularlyusefulforvesselsin
environmentsthatareexposedtostrongmagnetic
disturbancesonaregularbasis(suchasoffshore
windfarmsorverybusyrivers,forexample).Inthese
situationsitmaybedesirabletousetheCompass
lockfeaturetodisablethecontinuouslinearization
process,asthemagneticinterferencemaybuilda
headingerrorovertime.
Note:Thecompasslockmaybereleasedatany
time,toallowthecompasscontinuouslinearization
torestart.Thisisparticularlyusefulifplanninga
longvoyage.Theearth’smagneticeldwillchange
signicantlyfromonegeographicallocationto
another,andthecompasscancontinuously
compensateforthechanges,ensuringyou
maintainaccurateheadingdatathroughoutthe
voyage.
Autopilotcontrol
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