Figure 4-26 Magnetic Interference Test Harness - Garmin GI 275 Installation Manual

4.6.1.1 Magnetic Interference Test
The Magnetic Interference Survey is used to identify an aircraft location with acceptable levels of
magnetic interference to mount the GMU 11/44B. This section describes the materials, precautions, setup,
and procedures required to successfully conduct the magnetic interference survey
Required Materials
1. DC Power Source - A DC power source capable of supplying 7 - 34 VDC/1 A is required to
supply power to the GI 275 and magnetometer during the Magnetic Interference Test.
2. GI 275 - The GI 275 is required to run the Magnetic Interference Test in installations with a
GMU 11 and recommended in installations with a GMU 44B. Installations with a GMU 44B can
use the GMU 44 Location Survey Tool and a PC in lieu of the GI 275 display. Refer to AHRS/
Magnetometer Installation Considerations (P/N 190-01051-00).
3. Stopwatch or Watch with a Second Hand - During the survey test sequence, it is required to use
a stopwatch or watch with a second hand to measure the time for turning equipment on and off.
4. Magnetic Interference Test Cable - In order to perform the magnetic interference survey, it is
required to use a test cable fabricated by the installer. Fabricate a test cable in accordance with
Figure 4-26.
GI 275 w/ ADAHRS
AIRCRAFT POWER 1
AIRCRAFT GROUND
NOTES
POWER AND GROUND WIRES FOR THE GI 275 ARE NOT REQUIRED IF A CHARGED BACKUP BATTERY IS
1
INSTALLED PER SECTION 4.4.2.
THE GI 275 CAN BE CONNECTED TO AIRCRAFT POWER OR AN EXTERNAL DC POWER SOURCE CAPABLE
2
OF SUPPLYING 7 - 34 VDC / 1A.
190-02246-10
Rev. 11
Fabricate length as necessary
P2751
A 49
RS-485
B 69
s
LRU PWR OUT 20
LRU GROUND 19
RS-232 OUT 1 38
s
OUT 38
IN 57
RS-232 1
GND 77
s
20
LRU PWR OUT
19
LRU GROUND
s
2
41

Figure 4-26 Magnetic Interference Test Harness

P441
24 AWG
3
24 AWG 2
1
24 AWG
6
24 AWG 4
24 AWG 5
OR
P111
24 AWG 4
24 AWG 5
24 AWG 6
s
7
24 AWG
24 AWG 9
s
1
22 AWG
22 AWG
GI 275 Part 23 AML STC Installation Manual
GMU 44B
MAGNETOMETER
GMU 11
MAGNETOMETER
2
Page 4-39