Compass issues

Does anyone know which compass is the internal one inside pixhawk and which is external? There are parameters for 3 compasses… Compass 1 and 2 are the 2 I have and 3 isn’t used but I can’t figure out which compass number 1 actually is. I’ve tried turning each one on and off but I can’t figure it out that way either. I get slightly different readings from each one and it seems when both are turned on that pixhawk is averaging the 2 readings it gets from them… I keep getting compass health readings intermittently or compass not calibrated… After a power cycle or 2 the warnings are gone and it will fly… I’ve also noticed it doesn’t fly in a straight line or course… It will float off its “track” to the right but can be compensated for by pushing the roll stick slightly left.

Another thing, I’ve got no idea how to properly calibrate the compasses. I spin the copter in circles on all 3 of its axis’s in compass calibration mode and eventually get all the white dots. Also if I put the pixhawk into calibration mode in the field using the android ardupilot app how can you confirm its in compass calibration mode? Or that it’s being done right? And that it’s finished? The ardupilot app doesn’t give any notification of these things like mission planner does on the pc…

Thanks guys

-Mark

I’m pretty sure the external is compass 1 when it’s connected. When the external compass is not connected then I believe the internal becomes compass 1 again

Thanks for the help everyone!

The copter was also flying funny and circling in autopilot modes, so I calibrated the compass with its arrow pointing forward and then faced the copter to the north and with my copter connected to mission planner I then rotated the compass until mp showed the copter facing north and now she flies perfectly… Hope that helps someone… The gps puck I’m using has the ublox chip in it but it’s a cheap China made assembly so the compass might me jacked. I ordered the good Oem gps puck from 3dr so can’t wait to see how that works. If I gotta rotate that one then it’s clearly a bug in pixhawk… Also I had to calibrate the compass first and then moved it. Also between adjustments I had to move the copter in a circle to situate the new reading on mp, and if you have any metal tools near it you will be there all day trying to get it all lined up…

So after calibration face the copter in a direction your sure of and rotate or move the gps and compass puck until mission planner shows its heading the same way it’s facing… Definitely worth a try if your having compass issues or toilet bowling in loiter

The first compass is the one on your pixhawk board, the second one is on GPS module.

How did this work out for you?
I never thought of rotating the puck, that’s similar to naza’s way of doing it.
I have tbe with my 600x heli and pixhawk, thanks for the tip!