Raymarine i70 - Page 32

Manuallycalculateacalibrationfactor
Newcalibrationfactorscanbecalculatedmanuallyfollowingthestepsbelow
.
Prerequisites:
•Y ouwillneedtobeunderway,withsufficientspacetomaneuverunhindered.
•Toensureaccuracy,waterconditionsshouldbecalmwithzerotideandzerocurrent.
•Y ouwillneedtocalibrateeachcalibrationspeedpoint,startingwiththelowest
1.Runyourvesselatasteadyspeed,approximatelythatoftheselectedcalibrationspeed,overa
measureddistancemakinganoteof:.
•Themeasureddistanceinnauticalmiles
•Thecurrentspeedvalueinknots
•Thetimeinminutesittakestocoverthemeasureddistance
2.Calculatetheactualspeedoverthemeasureddistanceusingthecalculation:(Speed=(60x
Distance)/Time)‘60’isusedtoensurethecalculationisinminutesratherthanhoursortenths
ofanhour.
e.g.Distance(D)=14nauticalmiles,Time(T)=105minutes(1hour45minutes)so:
•S=(60xD)/T
•S=(60x14)/105
•S=840/105
•S=8kts
Ifthecalculatedspeedis:
•thesameasthecurrentspeed,(notedduringtheSpeedRunCalibration)thenthecalibrationis
correctatthisspeedsonoactionisrequired.
•notthesameasthecurrentspeed.Calculateanew,correctedcalibrationfactor,asfollows:e.g.if
actualspeedequals8kts,indicatedspeedwas7.5ktsandtheoldcalibrationfactorwas1.4then:
–newcalfactor=actualspeedxoldfactor/indicatedspeed
–newcalfactor=8x1.4/7.5
–newcalfactor=11.2/7.5
–newcalfactor=1.49
AddingaCalibrationpoint
CalibrationpointscanbemanuallyaddedtotheCalibrationtable.TheamountofCalibrationpoints
thatcanbestoredisdeterminedbythetypeofspeedtransducerandmethodofconnection.
FromtheTransducersetupmenu:
Menu>Set-up>Transducerset-up>Continue:
1.Selectthedevicethatthetransduceryouarecalibratingisconnectedto.
Alistofavailabletransducerdataisdisplayed.
2.
(1)
Select Speed.
Important:
(1)S teponlyapplicabletoiTC-5.
3.Select SpeedCalibration.
4.SelectAdvanced.
5.SelectAdjustCalibration.
6.Select
Start.
ThecurrentCalibrationtableisdisplayed.
7.SelecttherelevantCalibrationpointfromthetable.
8.Select Options.
9.Select Addcalpoint.
10.Usethe Upand DownbuttonstoadjustthedisplayedLogspeedtomatchcurrentSOGif
availableortomatchyourestimatedactualspeed.
11.Select
Add.
12.SelectOK.
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