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442729/A
Verifyingtheinstallationparametersforthe
motionreferenceunit(MRU)
Thephysicallocationofthemotionreferenceunit(MRU)relativetothetransduceris
requiredtoallowtheST90toadjustforrollandpitchasaccuratelyaspossible.Thistask
isonlyapplicableisyouareusinganexternalmotionreferenceunitonyourST90.
Prerequisites
Foraccuratelocationofthemotionreferenceunit(MRU),youneedthedetailedvessel
drawings.Theinformationabouttheinstallationanglesmustberetrievedfromthe
reportsprovidedbythepersonnelthatinstalledtheequipment.Neithertoolsnor
instrumentsarerequired.TheST90systemisturnedonandoperatesnormally.
Context
Theinformationfromamotionreferenceunit(MRU)(normallyheave,rollandpitch
information)isimportedintotheST90toincreasetheaccuracyoftheechodata.The
ST90isprovidedwithabuilt-inmotionsensor.ItisplacedinsidetheMotorControl
Unit.Forimprovedoperationalaccuracy,anexternalmotionreferenceunit(MRU)may
beused.Themotionreferenceunit(MRU)measurestherollandpitchmotionsofthe
vessel.Somesensormodelsalsomeasureheave.
OntheMRUpage,youmustdenethephysicallocationofthemotionreferenceunit
relatedtothereferencepointyoucreatedontheShippage.TherotationaroundtheX,Y
andZaxisisusedtocompensateformisalignmentsmadeduringthephysicalinstallation
ofthemotionreferenceunit.Suchmisalignmentsoccurifthesensorisnotplacedin
parallelwiththevessel’shorizontaland/orverticalplanes.Therequiredaccuracyofthe
offsetandrotationanglesdependsontheaccuracyrequirementfortheST90data.
Procedure
1OpentheSetupmenu.
2OntheSetupmenu,selectInstallation.
ObservethattheInstallationdialogboxopens.Thisdialogboxcontainsanumber
ofpagesselectedfromthemenuontheleftside.
3OntheleftsideoftheInstallationdialogbox,selectthesmallwhitetrianglenextto
InstallationParameters.
Observethatamenuopenswithaccesstoalltheindividualpages.
4SelectMRUtoopenthepage.
aFromthevesseldrawings,extracttherelevantoffsetinformation,andinsert
thosevalues.
SimradST90HarbourAcceptanceTest