Why LSM303AH sensors provide different value of magnetic value

[rimbaud]

Hello,

I have two LSM303AH sensors, both of them give different value of magnetic field (sqrt(x² + y² + z²) ) when they exposed on the same situation, the first one is around 100 the second one is around 200 .

What is the wrong with this behavior ? one of them is broken ? Can i diagnosis this with self-tests ?

The LSM303AHs are based on STEVAL-MKI173V1.

Regards

[Uwe Bonnes]

You have to compemsate offset and think about specified scale errors. You get the offset by taking the x,y and z values in one known orientation and than rotatiing 180 degree in x , then in y and then in z while remaining in the same x/y/x coordinate. The offset is half of the difference in the changed x or y or z value.