Garmin GDL 90 Installation Manual

Also see for GDL 90: Installation manual

Installation ProceduresGDL 90 Installation Manual 560-1049-00 Rev B 2-15Ext External connectionsON = One or more external systems have disconnected or failedOFF = No external system failureGPS GPS StatusFlashing = GDL 90 is acquiring GPS positionSteady ON = GPS position has been acquiredOFF = system failureStatus GDL 90 System StatusON = GDL 90 has failed. Perform troubleshooting procedure andmaintenance check.OFF = GDL 90 is functioning satisfactorily.2.8.4 DISCRETE OUTPUTDiscrete outputs can be used to drive annunciator lamps or provide status information to other equipment.Unless otherwise indicated, they are active low (i.e. grounded when active, and open otherwise) and opencollector output capable of sinking up to 400 mA.2.8.4.1 UAT Fail / GPS Status OutputP2-25 UAT Fail OutThe UAT Fail Out (P2-25) is used to indicate the status of the GDL 90 or status of its internal GPSengine. The function of this discrete output can be configured via the APM setup (refer to Section 3.0.)Using the APM initialization, the UAT Fail Out can be configured to behave as follows:As UAT Fail Indicator The UAT Fail Out will be grounded when the GDL 90 has detected asystem failure. This output will be open otherwise.As GPS Status Indicator The UAT Fail Out will be grounded when the GDL 90 has acquiredvalid GPS position. The UAT Fail Out will flash (i.e. alternate betweenbeing open and grounded) at a 1 Hz rate when the GDL 90 is searchingbut has not acquired a position. The UAT Fail Out will be open if theGDL 90 has detected a system failure.2.8.4.2 Transponder Suppression OutputP2-21 Suppression OutThe Suppression Out is used to indicate to on-board transponder that the GDL 90 is transmitting andtherefore inhibit the transponder from transmitting. The Suppression Output is an active signal and willbe active high when on-board transponder should be suppressed and grounded when transponder is freeto transmit.