If I have to free align the FC, how mag alignment works? Is mag alignment setting in relation to the FC or drone?

Example: I have a FC which is aligned for example 90 degrees CCW (arrow pointing left), which is reflected correspondingly in the INAV settings. My mag is in default position with relation to drone (no flip, 0 deg cw/ccw). Do I have to adjust mag alignment in INAV settings to match (or counteract) the alignment of the FC board?

as i understand it, the alignment is meant in relation to your copter. mostly also in relation to the FC if it is mounted as usual, with arrow up to the front.

I currently also had this Problem (see the other thread). I havn't fully figured it out yet, but i believe the orientation of the magnetometer needs to be input in relation to the fc.

Also you need to consider, that most compass/magnetometer units have the magnetometer mounted cw270flip.

Which magnetometer do you use?

Let's figure this out!

Thanks d-beam, actually in my case should be easier...

This is part of my longrange Dogcat build which is almost finished (https://intofpv.com/t-dogcat-build)  

I have a separate baro/mag board which are soldered in parallel and connected to i2c bus.

One of the possibilites is to simply put it on the arm like below:


This is the easiest way and will probably require to align it something like mag_align_yaw=150.

Another option would be to put it under the frame like this:


Probably more preferred due to better magnetic isolation but will also require to add some standoffs or landing gear.
This also seems simple, I guess mag_align_roll=1800. Or CW180FLIP.


I still have to complete some build steps before going to setup in the Configurator and check it out. And yes my initial question in this thread is about the fact that the props/motors lean forward slightly so this will result in that on hover the quad will probably drift forward, and to compensate this I will need to align the accelerometer pitch backwards a few degrees. So the real question is do I have to add same few degrees to mag alignment. Test flight will tell!