The behaviour of the unit can be customized with a panel.xml file. This file should reside in the panel folder next to the PANEL.CFG file.

<PlaneHTMLConfig>
    <Instrument>
        <Name>KLN90B</Name>
	<BasePath>html_ui/Pages/VCockpit/Instruments/NavSystems/GPS/KLN90B</BasePath><!-- Only needed, if you bundle the KLN with your aircraft. No trailing slashes -->
        <VFROnly>false</VFROnly> <!-- true, if this instrument is not rated for IFR -->
        <Input>
            <AltimeterInterfaced>true</AltimeterInterfaced> <!-- true if the altimeter is interfaced via gray code. Required for IFR. Irrelevant when Airdata.IsInterfaced is set to true  -->
            <ObsSource>1</ObsSource> <!-- 0 to disable, otherwise 1 or 2. Required for approach approval. Synced with L:KLN90B_ObsSource -->
            <HeadingInput>false</HeadingInput> <!-- true, when the KLN receives heading input -->
            <ElectricitySimVar>CIRCUIT ON:1</ElectricitySimVar> <!-- this boolean SimVar will be used to determine if the KLN 90B receives electricity.If an index is used, it is synced with L:KLN90B_ElectricitySimVarIndex -->
            <Airdata>
                <IsInterfaced>false</IsInterfaced> <!-- Will also provide altitude data -->
                <BaroSource>0</BaroSource> <!-- 1 or 2 if the baro setting of the respective altimeter is transmitted -->
            </Airdata>
            <FuelComputer>
                <IsInterfaced>false</IsInterfaced>
                <Unit>GAL</Unit> <!-- GAL,IMP,L,KG or LB -->
                <Type>Avgas</Type> <!-- Avgas, JetA1 or JetB -->
                <FOBTransmitted>true</FOBTransmitted> <!-- false if Fuel On Board must be entered by the pilot manually -->
                <FuelUsedTransmitted>true</FuelUsedTransmitted> <!-- false if this fuel computer does not transmit Fuel Used -->
            </FuelComputer>
            <ExternalSwitches>
                <LegObsSwitchInstalled>false</LegObsSwitchInstalled> <!-- true, when an external switch is installed, that toggles between LEG/OBS mode. Recommended for approaches. -->
                <AppArmSwitchInstalled>false</AppArmSwitchInstalled> <!-- true, when an external switch is installed, that arms approach mode. Required for approach approval. -->
            </ExternalSwitches>
        </Input>
        <Output>
            <ObsTarget>0</ObsTarget> <!-- 0 to disable. If 1 or 2 is set, the KLN writes the OBS to this device. Synced with L:KLN90B_ObsTarget -->
            <AltitudeAlertEnabled>false</AltitudeAlertEnabled> <!-- false if altitude alert is disabled completely. even if true, you will need to include an AvionicSounds entry for kln_short_beep and kln_long_beep in your sound.xml-->
            <WriteGPSSimVars>true</WriteGPSSimVars> <!-- if true, the KLN90 will write various GPS SimVars, which can be used for the HSI, RMI etc.  Synced with L:KLN90B_WriteGpsSimvars -->
        </Output>
    </Instrument>
</PlaneHTMLConfig>

Name: Required to be KLN90B in order to find the right tag

VFROnly: If set to true, then a warning screen will be displayed at startup

BasePath: Only necessary when bundling the KLN with your aircraft.

AltimeterInterfaced: true if the altimeter is interfaced via gray code. Required for IFR. Irrelevant when Airdata.IsInterfaced is set to true

ObsSource: disabled with 0. Otherwise it will read Nav OBS:1 or Nav OBS:2 for the current OBS setting. The KLN 90B will warn the user if the current OBS setting is not correct for the current leg. You may change this value on the fly by writing L:KLN90B_ObsSource.

HeadingInput: If set to true, then the NAV 5 map can be oriented to the aircraft heading. The heading will also be used for wind calculations.

ElectricitySimVar: If specified, the KLN 90B will check this boolean SimVar for electricity. If the value is 0, then no electricity will be available and the KLN 90B will stay or turn off. If this is an indexed value (seperated by a colon), then the index may be changed on the fly by writing L:KLN90B_ElectricitySimVarIndex.

IsInterfaced: If set to true, then the OTH 9 and OTH 10 pages will become available. The airdata computer will also provide altitude information which is more accurate than gray code.

BaroSource: Normally, the altimeter transmits pressure altitude and the pilot must enter the barometer setting for indicated altitude. Some air data computers may transmit the barometer. If set to 1 or 2, then KOHLSMAN SETTING HG:1 or KOHLSMAN SETTING HG:2 will be read.

IsInterfaced: If set to true, then the OTH 5, OTH 6, OTH 7 and OTH 8 pages will become available.

Unit: The unit, the computer uses. GAL,IMP,L,KG or LB

Type: The fuel type used when calculating GAL, IMP or L. Defaults to Avgas

FOBTransmitted: false if Fuel On Board must be entered by the pilot manually

FuelUsedTransmitted: false if this fuel computer does not transmit Fuel Used

LegObsSwitchInstalled: If set to true, the MOD 1 and MOD 2 pages become readonly and an external switch must to used to toggle between the LEG and OBS mode. Use GPS OBS ACTIVE to toggle between OBS and LEG mode. For more details, see External Annunciators.

ObsTarget: If set to 1 or 2, then the current OBS value is written using the VOR1_SET or VOR2_SET K Event. You may change this value on the fly by writing L:KLN90B_ObsTarget.

AltitudeAlertEnabled: If set to false, the SET 9 page will display FEATURE DISABLED. Note: In order to use the altitude alerter, you will need to include an AvionicSounds entry for kln_short_beep and kln_long_beep in your sound.xml

WriteGPSSimVars: If set to true, the following GPS SimVars are written:

• GPS OVERRIDDEN
• GPS MAGVAR
• GPS CDI SCALING
• GPS IS ACTIVE WAY POINT
• GPS IS ACTIVE FLIGHT PLAN
• GPS WP CROSS TRK
• GPS WP DESIRED TRACK
• GPS COURSE TO STEER
• GPS WP BEARING - Please see RMI
• GPS WP TRUE BEARING- Please see RMI
• GPS WP DISTANCE
• GPS POSITION LAT
• GPS POSITION LON
• GPS GROUND SPEED
• GPS GROUND TRUE TRACK
• GPS WP ETE
• GPS WP ETA
• GPS ETE
• GPS ETA
• GPS FLIGHT PLAN WP COUNT
• GPS FLIGHT PLAN WP INDEX
• GPS WP PREV VALID
• GPS WP PREV ID
• GPS WP PREV LAT
• GPS WP PREV LON
• GPS WP NEXT ID
• GPS WP NEXT LAT
• GPS WP NEXT LON
• GPS OBS VALUE
• GPS OBS ACTIVE
• GPS IS APPROACH ACTIVE
• GPS APPROACH MODE 0 = ENROUTE, 1 = APR ARM, 2 = APR ACTIVE, 3 = Selftest (ARM and ACTIVE should both be lit on external annunciators. Only used during selftest, not during normal operation)
• GPS GROUND MAGNETIC TRACK
• GPS WP TRACK ANGLE ERROR

Since the KLN 90B cannot output vertical information, the following SimVars are set to 0:

• GPS GSI SCALING
• GPS VERTICAL ANGLE
• GPS VERTICAL ANGLE ERROR
• GPS VERTICAL ERROR
• GPS HAS GLIDEPATH

Additionally, the device will sync FPL 0 back to the internal simulator flightplan if this setting is true. You may change this value on the fly by writing L:KLN90B_WriteGpsSimvars.

Please create an issue if you are missing a GPS SimVar.