Figure 5-6. Main Lighting Page - Garmin GNC 420A Installation Manual

5.2.6 MAIN LIGHTING Page
Select the MAIN LIGHTING Page (see Figure 5-6). This
page allows you to set display parameters that affect the
display backlight and key lighting brightness. The
DISPLAY and KEY lighting characteristics are adjusted
separately, each with the following fields:
LIGHTING
Shows the current level of display backlighting, based on the
lighting input source (lighting bus voltage, or the ambient
light if the source is PHOTO) and the settings on this
configuration page. This field has a range of 0 (zero) to 9999.
SOURCE
Selection
PHOTO
14V DC
28V DC
5V DC
5V AC
If a lighting bus (any selection other than PHOTO) is selected, and the lighting bus control is turned to its
minimum (daytime) setting, the display brightness tracks the 400 Series unit's photocell using additional
parameters (PHOTO TRANS % and PHOTO SLP/OFFST) described below.
RESP TIME - (Response Time)
Sets the speed with which the brightness responds to the input level (bus voltage or ambient light) changes.
The higher the number the slower the display responds. This field has a range of 3 to 7, and is set to 4 at
the factory.
MIN - (Minimum)
Sets the minimum brightness of the display. The higher the number, the brighter the minimum brightness.
Display minimum brightness has a range of 35 to 999, and is set to 80 at the factory. Key minimum
brightness has a range of 20 to 99, and is set to 40 at the factory. It is prudent to verify that display and key
lighting characteristics match those of other equipment in the panel under night lighting conditions.
SLOPE
Sets the sensitivity of the display brightness in proportion to changes in the input level. The higher the
number, the brighter the display is for a given increase in the input level. This field has a range of 0 (zero)
to 99, and is set to 50 at the factory.
Page 5-6
Page Rev L
Description
Backlight level is determined by the ambient light level as measured by the
photocell on the 400 Series unit.
Backlight level tracks a 14 volt DC aircraft lighting bus.
Backlight level tracks a 28 volt DC aircraft lighting bus.
Backlight level tracks a 5 volt DC aircraft lighting bus.
Backlight level tracks a 5 volt AC aircraft lighting bus.
NOTE

Figure 5-6. MAIN LIGHTING Page

400 SERIES INSTALLATION MANUAL
P/N 190-00140-02