GRT Avionics, Inc.
May 2019
Sport SX Install. Manual
25
Rev. A
e. If changes greater than +/- 2 degrees are noted, either relocate the
magnetometer or the offending wiring/metallic materials. Recheck.
The most common causes for magnetometer errors are simply magnetic disturbances
near the magnetometer. They can be caused by ferrous metal (any metal that a magnet
will stick to), control cables or cables carrying electrical currents, such as those for
navigation or landing lights, being too close to the magnetometer. If there is any doubt
about a location, try moving the magnetometer to another location. Use tape or other
temporary means to hold it in place, roughly aligned with the orientation of the AHRS, and
repeat the test.
5-9: Analog Magnetometer Wiring Problems
– Sport SX200
(Legacy WS and HS Only)
Some wiring problems will be detected by the AHRS
’s built-in test functions. They will
result in an
“AHRS Attitude Fail” message and an "AHRS: Magnetometer X, Y or Z-Axis
Failed" message on the status page (accessed by the STATUS button from any page). If
this message is present, the wiring to the magnetometer should be checked.
It is also possible that no built-in-test failure will be reported, while the wiring is still
incorrect. This can occur if the magnetometer X, Y, Z inputs are swapped. To check for
this, point the airplane at various directions listed in the table below, with the
magnetometer in an approximately level position (it may need to be removed from the
airplane and held by hand). Use the AHRS Maintenance page to observe the
"Magnetometer X, Y, Z Raw Data."
The following should be observed:
● The raw data readings will appear to shift left and right on the screen once per
second as the signs change for a brief moment. This is normal, and the brief sign
changes should be ignored when using this table of the expected readings.
● The Z Raw data will be greatly influenced by where on the earth the test is
performed. Positive values will be observed in the northern hemisphere while
negative values will appear in the southern hemisphere.
5-10: Set Final Magnetometer and Instrument Orientation
Once the chosen magnetometer location is verified to have acceptable levels of
interference, set the orientation of the magnetometer.
1. Go to Set Menu > AHRS Maintenance > Set Magnetometer Orientation. Answer
the prompts on the screen to begin automatic orientation of the magnetometer. For
maximum accuracy, this procedure should be performed when the ambient
temperature is between 50-90°F.