Heading difference between two ADAHRS

[skydancer]

I'm having a lot of problems to get both ADAHRS to agree with each other!!!

When I had ADAHRS-200 out for repair and ran only single ADAHRS-201 in the system, I was able to calibrate the heading within +/- 1 degree.

But when I have dual ADAHRS in the system, I could never get both ADAHRS to agree with each other.

Following were my test results, each ADAHRS was calibrated at the Airport Compass Rose:

1. After the calibration with ADAHRS-201 and manually activated ADAHRS-200, the heading shows normal, but when I switch to ADAHRS-201 and have it activated, the heading would be off > 10 degrees.

2. If I calibrate the compass with ADAHRS-200 and manually activated ADAHRS-201, the heading shows normal, but when I switch to ADAHRS-200 and have it activated, the heading would be off > 10 degrees.

So the result shows ---

Calibrated 200, activated 201 ---- normal
Calibrated 200, activated 200 ---- abnormal.

Calibrated 201, activated 200 ---- normal.
Calibrated 201, activated 201 ---- abnormal

The above test were pretty consistent.

Any one has the answer for that? Your feedback will be greatly appreciated.

 

[dynonsupport]

Are your two ADAHRS co-located? That is, one on top of the other or side-by-side? Or are they in different parts of the plane (such as one in each wing?)

What type of plane do you have?

 

[skydancer]

RV-7, both ADAHRS are located behind the baggage area, lay side-by-side on a aluminum tray, about 20" from the floor.

All mounting hardwares are nylon.

When I had ADAHRS-200 out for repair and ran only single ADAHRS-201 (secondary) in the system, I was able to calibrate the heading within +/- 1 degree.

The above statement is true if I only have primary ADAHRS-200 in the system, I confirmed that this evening.

So, the result shows, the system doesn't like to have both ADAHRS connected at the same time, can some one tell me why?

 

[dynonsupport]

We don't have an explanation for what you're seeing. We don't think there are any software issues with the magnetic heading calibration routines with multiple ADAHRS, but anything is possible. We're currently looking into if there is anything that might be going on here.