Garmin GNC 420A Installation Manual

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Garmin GNC 420A Installation Manual Manual pdf 35 page image

400 SERIES INSTALLATION MANUAL Page 4-7P/N 190-00140-02 Rev N4.4 MAIN INDICATOR4.4.1 Main Indicator FunctionThe Main Indicator displays both lateral and vertical deviation from selected course, To/From indications,lateral and vertical flags and superflags.The “CDI” key on the bezel of the GNS 430 takes the place of remote “NAV/GPS” switches, and is usedto toggle between display of GPS and VOR/ILS navigation display on a remote indicator. The Navigationsource is annunciated on the display above the ‘CDI’ key. The Navigation method is optionallyannunciated externally by connecting to the VLOC ANNUNCIATE output (P4001-1) and GPSANNUNCIATE output (P4001-2). GPS and VOR/ILS navigation may be toggled externally when theCDI SOURCE SELECT input (P4001-73) is momentarily grounded. See section 4.5 for more informationon the external annunciators and switches.An OBS resolver connection to the GPS is preferred, but not required. For the GNS 430, an OBS resolvertypically is connected to the MAIN OBS inputs for use with the GNS 430 VOR receiver.4.4.2 Main Indicator Electrical Characteristics4.4.2.1 DeviationPin Name Connector Pin I/OMAIN +LEFT P4001 21 OutMAIN +RIGHT (2.5V COMMON) P4001 22 OutMAIN +UP P4001 27 OutMAIN +DOWN (2.5V COMMON) P4001 28 OutThe deviation output is capable of driving up to three 1000 Ω meter loads with ±150 mV DC ±10% for full-scale deflection. The drive circuit provides for more than full-scale deflection with a maximum coursedeviation output voltage of ±300 mVDC ±10%.4.4.2.2 TO/FROMPin Name Connector Pin I/OMAIN +TO P4001 25 OutMAIN +FROM (2.5V COMMON) P4001 26 OutThe output is capable of driving up to three 200 Ω meter loads. When indicating TO, MAIN +TO is+190 ±40 mV DC with respect to MAIN +FROM. When indicating FROM, MAIN +TO is -190 ±40 mVDCwith respect to MAIN +FROM. When invalid information is present (Flag IN VIEW) the TO/FROMoutput is 0 ±10 mVDC.4.4.2.3 FlagPin Name Connector Pin I/OMAIN LATERAL +FLAG P4001 23 OutMAIN LATERAL -FLAG (2.5V COMMON) P4001 24 OutMAIN VERTICAL +FLAG P4001 29 OutMAIN VERTICAL -FLAG (2.5V COMMON) P4001 30 OutThe Flag output is capable of driving up to three 1000 Ω meter loads. When valid information is present(Flag OUT OF VIEW) the Flag output is 375 ±80 mVDC. When invalid information is present (Flag INVIEW) the Flag output is 0 ±25 mVDC.