Garmin GNS 480 Installation Manaul page 102

Post-Installation Configuration & Checkout
3.3.1.1.3 VDI Test
The VDI TEST page allows testing of the VDI deviation outputs for both the Main and Auxiliary CDI
outputs. While on the TEST menu page, press the VDI TEST line select key to display the VDI TEST
Page. Press the SELECT line select key to toggle between MAIN and AUX VDI deviation tests. The
AUX VDI test screen is shown in Figure 3-22, and the MAIN VDI test screen is identical.
When on the appropriate page turn the large, outer knob to select the desired VDI deviation test. The test
is initiated as soon as it is selected. There are five VDI tests in the following order:
•
VDI Triangle Test: gradually drives the VDI needle up and then down
•
VDI Down Test: drives the external VDI needle full scale down (i.e. output set to 150mV down)
•
VDI Mid Test: drives the external VDI needle to center (i.e. output set to 0mV)
•
VDI Up Test: drives the external VDI needle full scale up (i.e. output set to 150mV up)
•
VDI Manual Test: allows manual input of VDI outputs (from 10D to 10U in 15mV steps, with 10
corresponding to a full scale output of 150mV, and 0 corresponding to the center)
As a minimum, perform the DOWN, MID and UP tests for the vertical deviation needle of each CDI
connected to the GNS 480.
For some HSI's the glideslope indicator may not be visible unless it is receiving a valid
signal from the localizer (ILS Energize is present). If this is the case, leave these signals
set to VALID following completion of the FLAG TEST in order to see the glideslope
indicator.
Press the TEST or BACK smart key to return to the Ground Maintenance Test menu.
3-22
Figure 3-22. Auxiliary VDI Test Page
NOTE
560-0982-01 Rev L GNS 480 (CNX80) Installation Manual