Table 5-46 Photocell Configuration Procedure - Garmin GI 275 Installation Manual

Photocell Configuration - Enhanced Lighting De-selected
The Display Lighting and the Knob Lighting curves must be set individually as noted per Table 5-46.
Step
Under Source Selection, set Photocell as the source
1
for Display Source.
Under the Photocell Configuration, set the Photocell - Response Time to a low level (e.g., 2 sec) to allow the
2
display to adjust more quickly to light conditions.
Touch Lighting Curve Configure and then Display
Lighting. It is recommended to start configuration
3
with a Slope of 50%. This can be done by selecting
Slope and entering the value (refer to Figure 5-10).
4 Turn on all instrument panel and cockpit lighting.
Minimize photocell input levels by simulating night conditions in the cockpit. Complete steps 6 - 11 with the
5
goal of achieving consistency between all cockpit lighting.
If the display is too bright, lower the Min Level and/or
6 adjust the lighting Slope to achieve the desired
brightness.
If the display is not bright enough, raise the Min Level
7
to the desired brightness.
8 Simulate direct maximum sunlight in the cockpit.
Verify that the display produces maximum brightness
9 on the backlight output level. Adjust Max Level if
needed.
10 Simulate average sunlight conditions/average input conditions in the cockpit (average Source Input Level%).
If the display is too bright or too dim, vary the Slope
11 and/or Offset percentage to achieve desired
brightness at mid-range lighting input levels.
Verify that the lighting Slope, Offset, and Min Level still maintain the low-light visibility requirements achieved
12
in previous steps. Repeat any steps necessary to re-adjust night lighting settings.
13 Adjust the Response Time to smooth changes to brightness, as required.
14 Verify that adjustments made in the preceding steps are appropriate for all expected lighting conditions.
190-02246-10
Rev. 11

Table 5-46 Photocell Configuration Procedure

Photocell Curve
Display Knob
Under Source Selection, set Photocell as the source
for Knob Source.
Touch Lighting Curve Configure and then Knob
Lighting. It is recommended to start configuration
with a Slope of 50%. This can be done by selecting
Slope and entering the value (similar to Figure 5-10
for display lighting).
If the keys are too bright, lower the Min Level and/or
adjust the lighting Slope to achieve the desired
brightness.
If the keys are not bright enough, raise the Min Level
to the desired brightness.
Adjust the Cutoff percentage as shown in
Figure 5-11, such that the key backlighting is
switched off in bright light.
If the key is too bright or too dim, vary the Slope
and/or Offset percentage to achieve desired
brightness at mid-range lighting input levels.
GI 275 Part 23 AML STC Installation Manual
Page 5-39