Sea Tel Base Exit User manual

Procedure, Field Replacement, Level Cage Kit, Base Exit
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Page1of9
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Document No
135266 Rev B
Copyright © Sea Tel, Inc 2011 - The information contained in this document is proprietary to Sea
Tel, Inc.. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 

1. BriefSummary:
Troubleshootingdocumentfordiagnosingafaultwithandreplacingthelevelcageassembly.
2. Checklist:
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VerifyRemoteTilt
VerifyInitialization
VerifySensorOutputsusingDacRemP
AzimuthandRelativeTargeting
DriftandSensorMonitoring
3. TheoryofOperation:
Thelevelcagecontains4sensors.Theseareafluidfilledtiltsensorwhichisusedasthesystemshorizonreference(level
position)andlongtermstabilizationreference,and3solidstateratesensors,oneforeachaxiswhichactsasthe
antennasshorttermstabilizationreference.Afaultysensorinsidethelevelcagewillcausetheantennatolosestability
andmispointfromthesatelliteunderdynamicconditionsalthoughthesystemmayappeartobeoperationalintheport
whenthereisnomotiontocounteract.Thisdocumentwillrunthroughtestingthesensorsinsidethelevelcage,
replacingthelevelcageassemblyandcalibratingthesystemsremotetiltsetting.
4. VerifyRemoteTilt:
Ifthepedestalishavingstabilityproblemsfirstlychecktheremotetiltsettingbylookingatthelevelbubbleontopofthe
levelcage(note:oldersystemsdidn’thaveabubbleinstalledontopofthelevelcage).Ifthebubbleisn’tascloseto
centralaspossibletheremotetiltsettingisn’tcorrectlycalibrated,meaningtheratesensorswon’tbecorrectlyaligned
withtheiraxis.ThiswillcausetheratesensorstooutputincorrectfeedbackintothePCUscontrolloop,potentially
causingastabilizationissue.Calibratetheremotetiltsettingaspertheinstructionsattheendofthisdocumentand
continuetotestthelevelcageusingthefollowprocedures.
5. VerifyInitialization:
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Powercyclethepedestal
1. Brakesrelease(ifapplicable)
2. Levelcagedrivestoitsendstop,thenbacksoffexactly45degrees
3. Elevationaxisdrivesto45degreesbasedonthelevelcageshorizonreference
4. Crosslevelaxisdrivestolevelbasedonthelevelcageshorizonreference
5. Unlimitedazimuthsystemsdriveclockwiseuntilthehomeflagandsensormakecontact
6. Limitedazimuthsystemsdriveclockwiseintotheazimuthendstop,thenbackoffto630degreesof
relative
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Ifanyofthesestepsfail,ortheACUreportsmodel"xx03/xx04",theantennasN0parameterneedscalibratingand
verifieditsavescorrectly.Adriveissueorpedestalerrorrequiresfurthertroubleshooting.
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Procedure, Field Replacement, Level Cage Kit, Base Exit
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Page2of9
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Document No
135266 Rev B
Copyright © Sea Tel, Inc 2011 - The information contained in this document is proprietary to Sea
Tel, Inc.. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 

6. VerifyStabilization:
Thepurposeofthisprocedureistophysicallymovethesystemsaxisunderstaticconditions,introducingerrorintothe
PCU’scontrolloopandthenverifythesystemisabletoreturntoitslevelposition(stabilizeitself)efficiently.Thesetests
canbeperformedbymonitoringthesensoroutputsonDacRemPoralsobyphysicallymovingtheantennaandobserving
howitresponds.
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1. TurntrackingoffandOpentheDISP_VscreenofDacRemP,itwillnowplotthelevelpositionofthetiltsensor.
Alternativelyobservethepedestal.Normaltraceis+/‐4divisionsfromredline.
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2. VerifyCrossLevelresponse:
Pushthecrosslevelbeamdowntotheleft(CCW)andholditinposition.VerifythattheCLtraceonDacRemP
movesdownanequalamounttothemovementexertedontheaxis.ReleasetheAxisandverifytheDacRemPtrace
returns(orthesystemsaxisreturns)backtoitsoriginalpositioninstantly,withoutdeviatingortakingtimetosettle.
Nowpushthecrosslevelbeamdowntotherightandholditinposition.VerifythattheCLtraceonDacRemP
movesupanequalamounttothemovementexertedontheaxis.ReleasetheAxisandverifytheDacRemPtrace
returns(orthesystemsaxisreturns)backtoitsoriginalpositioninstantly,withoutdeviatingortakingtimetosettle.
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3. VerifyLevel(Elevation)response:
PushtheReflectorupinElevation(CCW)andholditinposition.VerifythattheLVtraceonDacRemPmovesdown
anequalamounttothemovementexertedontheaxis.ReleasetheAxisandverifytheDacRemPtracereturns(or
thesystemsaxisreturns)backtoitsoriginalpositioninstantly,withoutdeviatingortakingtimetosettle.Pushthe
ReflectordowninElevation(CW)andholditinposition.VerifythattheLVtraceonDacRemPmovesupanequal
amounttothemovementexertedontheaxis.ReleasetheAxisandverifytheDacRemPtracereturns(orthe
systemsaxisreturns)backtoitsoriginalpositioninstantly,withoutdeviatingortakingtimetosettle.
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IfusingDacRemPthetraceshouldlooksimilartothisimage,notehowaftereachmovementthesystemreturnstoits
levelpositionefficientlywithouttakingtimetosettle.
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Procedure, Field Replacement, Level Cage Kit, Base Exit
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Page3of9
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Document No
135266 Rev B
Copyright © Sea Tel, Inc 2011 - The information contained in this document is proprietary to Sea
Tel, Inc.. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 

7. RateSensorMonitoring:
RatesensoroutputscanalsobemonitoredusingtheDISP_WscreenofDacRemPtoverifyanydeviationsunderstatic
conditions.Thetracesshouldremainconsistent,anydriftingorspikesareanindicationthesensorsvoltageoutputis
changingandthesensorisdefective(providednoforcesarebeingexertedonthesystem).Normaltraceis+/‐1division
fromredline.
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8. AzimuthTargeting:
Shouldtheantennahaveissuestargeting,suchasnotaccuratelyfindingthesatelliteorrepeatedlyfindingthesatellitein
differentazimuthpositions,thenit’simportanttoascertainifthesystemismispointinginazimuthorrelative.Relative
feedbackfromtheAZencodercanbeverifiedbyinitializingthesystem,verifyingitcalibratesitselfcorrectlyandthen
drivingthepedestalclockwisein90degreeincrementsovera360degreerotation,notingthatthesystempoints
correctly(bow,starboard,aft,port,bowandstarboard)andthatnoAZreferenceerrorisflaggedbythePCU.A
mechanicalproblemsuchasthebeltskippingonthesprocket,oranotherphysicalrestriction,couldalsocausethiskind
oferror.Skewingtheantennainazimuthbyholdingtherightorleftarrowkeytodrivetheantennaslowlymayalso
presentanissue.
Ifthesystemkeepsfindingthesatelliteatdifferentazimuthpositionsbutatthesamerelative,thentheencoderis
functioningcorrectlyandtheazimuthratesensoriscalculatingthemovementincorrectlycausingtheantennato
mispoint.
9. Drift:
Anotherfailurewhichcanoccurisifaratesensorstartsdrifting.Thismeansthesensorsvoltageoutputdeviatesfrom
whatthePCUisexpecting(2.5VDC),whichintroduceserrorintothecontrolloop.It’smorecommontoseethisinthe
AzimuthaxisastheCLandELaxishavethetiltsensorastheirlongtermreference(althoughshouldtheratesensorsdrift
belargeenoughtooverpowerthetiltsensoryouwouldseethesystemdrivingintooneoftheCLorELendstops).
ToverifyifthesystemisdriftinginAzimuthturnofftrackingandmonitortherelativeposition,understaticconditions
(i.e.whenthevesselsheadingisn’tchanging),itshouldremainstill.Iftherelativevaluebeginstoincrease/decreasefrom
itsnominalpositionthentheazimuthratesensorisdrifting,feedingerrorintothePCU’scontrolloopwhichiscausing
thePCUtobelievethevesselsheadingischangingandinturndrivingtherelativeintheoppositedirectionto
compensate. 

Procedure, Field Replacement, Level Cage Kit, Base Exit
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Page4of9
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Document No
135266 Rev B
Copyright © Sea Tel, Inc 2011 - The information contained in this document is proprietary to Sea
Tel, Inc.. This document may not be reproduced or distributed in any form without prior written
consent of Sea Tel, Inc. 

10. Diagnostics:
Anyincorrectreadingsfromtheabovetestswouldrelatetoanerrorintheantennascontrolloopcausingthesystemto
notstabilizecorrectly.Themostlikelycauseofthisisadefectivesensorinthelevelcage.Thenextstepwillbetoreplace
thelevelcageandrepeatthetestwhichtheantennafailedtoverifyifthesystemisnowfunctioningcorrectly.
Shouldtheproblempersistotherpossibilitiesareabadconnectiononthereferenceharnessbetweenthelevelcageand
PCUcorruptingthefeedback,orpossiblythePCUitselfnotcalculatingthefeedbackcorrectly.Howeverasthelevelcage
isthemostlikelycomponenttobecausingthisissuereplacingitisthefirststepinthetroubleshootingprocedure.
Oncetheproblemhasbeenrectifieditsgoodpracticetorefittheoriginallevelcageandseeifthefaultreturns.It’s
possiblethattherewascorrosiononthepinsofthereferenceharnessandbyconnectingthereplacementlevelcagethe
pinshavebeencleaned,allowinggoodmetaltometalcontactandgivingtheimpressionthatreplacingthelevelcage
rectifiedthefault(cleaningthepinsonthePCUendofthereferenceharnessisalsoadvisable).
11. FurtherInformation:
Shouldthesystemfailtotargetthecorrectelevation(physicallypointingatadifferentpositiontothereadingonthe
DAC)orhaveissuesdrivingpastacertainelevationpositionthenthemostlikelycauseisadefectivelevelcagemotor.
Ifthesystemisdisplayingapedestalerror(error8)thenthereisadriveissuewiththeantennaandattentionwillneedto
bepaidtothemotorandmotordriver(servoamp)fortherelevantaxis.Adefectivelevelcagewon’tflaganerror8asthe
PCUdoesn’tknowifthefeedbackfromthelevelcageiscorruptwhichiswhytheantennawillmispointifthelevelcageis
defective.
Anotherpotentialissuewhichcouldcausetheantennatolosethesatelliteisifthevesselsgyrocompassisdrifting,
accumulatingerrorwhichisthenfedintothecontrolloop.ThiscanbeverifiedbyrunningaDacRemPlogfileatseato
monitorthepedestalsreadingswhentheAGCdrops,orbyputtingthesystemintosatellitereferencemodetobypass
thegyrofromtheazimuthcontrolloop.
12. 2406LevelCageConfiguration:
Tousethelevelcage(partnumber:122937‐1)onthe2406pedestal,itwillneedtobeconvertedintoa122937‐2.Thisis
donesimplybyreconfiguringtheendstopsonthebackofthelevelcageassemblyasperthebelowimage.Thestandard
122937‐1levelcageshastheendstopsontheleft‐handside,thesewillneedtobemovedtotheright‐handsidetouse
thelevelcagesonthe2406pedestal.

122937‐1122937‐2

Procedure, Field Replacement, Level Cage Kit, Base Exit
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consent of Sea Tel, Inc. 
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13. XX06LevelCageInstall:
*Note:Howthenylocknutisinstalled,tensioningthecentrecollarofthebearing,preventingthelevelcagefrommoving
fromsidetosideonthespindle,notovertightenedsoitcanmovesmoothly.


14. ReplacingtheLevelCageAssembly:
14.1. Tools.

2mmFlatBlade(Terminal)ScrewDriver
#1PhillipsScrewdriver
½”Wrench/Spanner
14.2. Procedure.
Procedureforreplacingthelevelcageassembly,SeaTelkitpartnumber:135343(levelcageassemblypartnumber:
122937‐1)andtensioningthelevelcagebelt.TheprincipalisthesamefortheXX06levelcage,althoughit’sinstalled
inadifferentorientation(asshownabove).

*CAUTION:Powerdownthepedestalbeforefollowingthis
procedure.
1.Usinga2mmflatbladescrewdriverloosenthescrews
securingthereferenceharnessD‐Subconnectortolevelcage.


Procedure, Field Replacement, Level Cage Kit, Base Exit
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
2.Usinga#1Phillipsscrewdriver,loosenthefourscrews
attachinglevelcagemotortotheELpan(donotfully
remove).
3.Slidethemotortowardsthereflectorandremovethebelt
fromlevelcagemotorsprocket.


4.Usinga½”socketorwrenchremovetheNylocknut
securingthelevelcagetothespindle.


5.Takecarenottoremovethelevelstandoffspacerfromthe
spindle.


6.Installthereplacementlevelcageontothespindle,slipping
thebeltoverthelevelcagepulleyandmakingsureitsend
stopsarealignedcorrectly.Secureitwiththe1/2”Nylocknut,
tightenedsoitslightlypreloadsthebearings.
7.Rotatethelevelcagebyhandandverifyithas90degreesof
motionandthatthecagerotatesfreelywithoutrubbing
againsttheELpan.



8.Placethebeltonthelevelcagesprocketandthenslipit
overthesprocketofthelevelcagemotor.


Procedure, Field Replacement, Level Cage Kit, Base Exit
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consent of Sea Tel, Inc. 
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
9.Tensionthebeltbyslidingthemotorassemblybyhand
awayfromlevelcageandtightenoneofthefourscrews.


10.Increasethebelttensionuntilthebeltcanonlybeeasily
twistedjust¼turnwithyourfingers.
11.Ifthebelttensionistootight/loseadjustuntilcorrectand
thensecurethemotor.


12.PlugthereferenceharnessbackintothelevelcageD‐Sub
connectorandtightentheretainingscrews(noneedto
Loctiteassplitwashersareinstalledontheharness).




Procedure, Field Replacement, Level Cage Kit, Base Exit
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consent of Sea Tel, Inc. 
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15. CalibratingtheRemoteTiltSetting:
Thisprocedureisrequiredtocalibratethelevelcagesothatallthesensorswillbeaccuratelyalignedtotheiraxis.The
fluidfilledtiltsensorprovidesatwodimensionalhorizonreference.Thesystemisnotabletoautomaticallycalculatethe
exactcentervalue,thereforeitisnecessarytoperformthisproceduretomanuallyenteranyoffsetrequiredtomakesure
thePCUreceivesatruehorizonreference.

1. Turndishscanoff:
EnterintotheSetupMenubypressingandholdingthearrowstogetheruntiltheELTrimorAutoTrim
parameterisdisplayed.
Usethearrowkeytoscrollthroughthemenuuntilthedishscanwindowisdisplayed.
Pressthearrowtoactivatethewindowandthenpressthearrow,followedbythebuttontoturn
dishscanfromontooff.
*Note:Whenyoupressthearrowtoturndishscanoffyouwon’tseethedisplaychangeuntilyoupressthe
button.

(Steps2‐7requiresassistancetoobserveandoperateantennasimultaneously)

2. EnterintotheSetupMenubypressingandholdingthearrowstogetheruntiltheELTrimorAutoTrim
parameterisdisplayed.

3. PushthearrowkeyuntiltheRemoteTiltwindowisdisplayed.

4. PushthearrowkeytoactivatetheRemoteTiltsetting.

5. Usethearrowkeystopositionthebubbleasclosetothecenteraspossible.Eachpressofanarrowkeyonthe
directionalpadwillmovetheRemoteTilt½adegree.Itisadvisedthatyouonlypressthebuttononceandwaitfor
theaxistomovebeforepressingitagain.

Whenstandingbehindtheantennalookingatthebubble,ifthebubbleisovertotheright,youneedtopressthe
(right)arrowtobringthebubbleintothecenter.Ifthebubbleisdowntowardsyou,youneedtopressthe
(down)arrowtobringittowardsthecenter.Ifthebubbleistotheleft,youneedtopressthe(left)arrowandif
thebubbleisuptowardsthetop,youneedpressthe(up)arrowtomoveittowardsthecenter.


Procedure, Field Replacement, Level Cage Kit, Base Exit
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consent of Sea Tel, Inc. 

Whencorrectthebubbleshouldbeasclosetothecenterofthefluidaspossible


6. WhenthebubbleisascentralaspossiblepressthebuttontodeactivatetheRemoteTiltsetting.

7. Turndishscanon:
EnterintotheSetupMenubypressingandholdingthearrowsuntileithertheELTrimorAutoTrim
parameterisdisplayed.
Usethearrowkeytoscrollthroughthemenuuntilthedishscanwindowisdisplayed.
Pressthearrowkeytoactivatethewindowandthenpressthearrowkey,followedbythebuttonto
turndishscanfromofftoon.
*Note:Whenyoupressthearrowtoturndishscanonyouwon’tseethedisplaychangeuntilyoupressthe
button.

8. SavetheRemoteTiltsettinginthePCU:
PressthearrowkeyuntiltheRemoteParameterswindowisdisplayed.
Pressthearrowkeytoactivatethewindowfollowedbythebutton(you’llseeaconfirmationonthe
displaysaying“Saved”).

9. AsgoodpracticemakeanoteofyourN4andN5parametersonceyouhavecorrectlysettheremotetilt.TheN4and
N5parametersareanumericreadoftheremotetilt.Todothisgototheremotecommandwindowandkeyin
N4999toreadtheCLsetting,followedbyN5999toreadtheELsetting.
