Instruction Manual

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Page98
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GNAV540Use nual
7430‐0808‐01Rev.B
rMa
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Chapter11. BuiltInTest(BIT)
TheBuilt‐InTestcapabilityallowsuserstomonitorhealth,diagnostic,andsystemstatusinformationoftheunitin
real‐tim ion
e.Built‐InTestinformat istransmittedineachmeasurementpacket.
NOTE:Adiagnostictestpacket(T2)canberequestedviaGP.Tocontainsacompletesetofstatusforeachhardware
andsoftwaresubsystem.Formoreinformation,refertoTest2(DetailedBITandStatus)Packetonpage72
andGetPacketRequestonpage68.
BITStatusFields
ErrorbyABITwordconsistsoftwobytes: teandStatusbyte.
Thefirstbyte(bits0–7)isthe
Errorbyte:signaledresultsfrominternalchecks.Fourintermediatesignalsdetermine
whentoassertmasterFailandthehardwareBITsignal.Thesesignalsarecontrolledbythreecategoriesofsystems
checks:hardware(
hardwareError),communication(comError)andsoftware(softwareError).Instantaneoussoft
thesi nals
ehasoccur
failuresfromanycategorytriggers g :aflagisraised.masterFailisnottriggereduntilpersistency
conditionsaremetorahardfailur red.
Thesecondbyte(bits8–15)isthe
Statusbyte:signaledstatusalerts.Fourintermediatesignalsdeterminewhento
assertthe
masterStatusflag:hardwareStatus,sensorStatus,comStatus,andsoftwareStatus.masterStatusisthe
logicalORoftheseintermediatesignals.Eachintermediatesignalhasaseparatefieldwithanindicationflag.Each
indicationflagcanbeenabledordisabledbytheuser.Anyenabledindicationflagwilltriggertheassociated
tusflag.
intermediatesignalandmasterSta 
heBITfieldsaresummarizedin
T
s
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Table77below.Table78providesadditionalinformationabouttheprogrammable
tatusfield.
Table77DefaultBITStatusValues
BITstatusField Bits Value Configurable
ErrorBytefields(BIT)
N
masterFail 0 0:normal
1:fatalerror
rFailflagisthrownwheneitherahardfailure(fatal
orasoftfailure(persistentproblem)occurs.
Themaste
condition)
N
hardwareError 1 0:normal
hardwareerror
1:internal
N
comError 2 0:normal
icationerror
1:commun
N
softwareError 3 0:normal
1:internalsoftwareerrorormagAlignOutofBounds
NOTE:InAHRSandNAVmodes,thisbitprovidesinformationabout
ofmagneticalignment.Iftheunithasnotbeenproperly
llycalibrated,asoftwareErrorwillbeindicated
thestatus
magnetica
N
GPSError 4 0:normal
1:GPSfailure
N