janban

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Revo onboard MAG very strange values (with GPS Neo6M)
« on: July 03, 2018, 09:27:29 pm »
Hello everybody,

I have a Revo and i am trying to get my GPS (NEO6M with auxmag) working.
GPS:FlexiIO is working. I am getting about 10 sats. I already set home and altitude.
AuxMAG via I2x on FlexPort: i2c is green.
AuxMag virtual rotation is Pitch 180°. (Virtualboard is 0,0,0)

Values of the Aux mag are looking fine: :)
Nose north & down about X=+400 and tail north & down X=-400 and so one.

The values of the internal mag seems strange:  :o
Nose north & down about X=+336 and tail north & down X=+66
right side north & down Y=-220  left side north & down  Y=-550
bottom north & down Z=-270  top side north & down  Z=-550

So my difference between both mags is never zero.
I want to use GPS Navigation (INS13)
I have Altitudehold mode activated (I read somewhere this can be an issue??)

Furthermore I can not calibrate the mag sensor. I always get the error no matter how far away from anything I am. I am even using MiniOPLink.

I don't know what else to do...  :'(

The picture shows: Nose pointing north & down. and comparison of onboard vs. auxmag (below) settings.

Re: Revo onboard MAG very strange values (with GPS Neo6M)
« Reply #1 on: July 04, 2018, 03:22:47 am »
Maybe the FC is close to a magnet.  Standard LiPo alarm has two speakers with magnets.

Airplanes have magnets to hold the canopy down.

So where you are on earth the magnetic declination points down?  For me in USA Georgia is is about 60 degrees down.

You may need to degauss the FC?

If onboard is just broken, you can still use that FC by calibrating both mags with a different FC and copying the mag calibrations to the bad FC.  New FC and GPS/mag must be mounted in the model to keep their relative orientation locked in during calibration.  In any case you usually want to run "Aux Only" mag so it never uses the OnBoard mag.  I have not had a failing OnBoard mag.  It's possible that you can jut press Save after a failed mag cal and it will save what it has, which includes a working AuxMag.  Then you set to use just AuxMag.
« Last Edit: July 04, 2018, 06:19:30 am by TheOtherCliff »

janban

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Re: Revo onboard MAG very strange values (with GPS Neo6M)
« Reply #2 on: July 04, 2018, 10:23:03 am »
So where you are on earth the magnetic declination points down?  For me in USA Georgia is is about 60 degrees down.

You may need to degauss the FC?
For me it was about 62 degrees down and that is what forgot to say when I said "nose north & down".

Just be sure. I want to use the GPS for position hold and maybe return to home. I thought that GPS13 attitude estimation algorithm needs both mags in oder to work...
Or can i use auxmag only for that?

I might try another fc, does it have to be Revo too? because i have a normal cc3d that i could get the calibration values from.

Re: Revo onboard MAG very strange values (with GPS Neo6M)
« Reply #3 on: July 04, 2018, 03:29:29 pm »
I think you are suffering the same issue as me.  Mine shows  as if it's level on the flight instrument on the flight data tab, but the illustration shows the drone nose north and down which might be the reason mine flips rearwards on take-off.  I've just added GPS (Ublox 7m) on mine and gone through all the calibrations.

Extent of my issues here: https://forum.librepilot.org/index.php?topic=4340.0

janban

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Re: Revo onboard MAG very strange values (with GPS Neo6M)
« Reply #4 on: July 11, 2018, 09:51:27 pm »
Hello again,

I am confused, can someone please explain.

  • I thought that is not possible to use GPS autonomous flight with aux only. I thought that we have to use both mags
  • So what is the calibration procedure? Do i need to calibrate onboard mag before installing aux mag (with gps) an then calibrate aux mag only?
.

Thank you very much...

Re: Revo onboard MAG very strange values (with GPS Neo6M)
« Reply #5 on: July 12, 2018, 02:55:53 am »
Best to use Aux Only.  Believe me.

Once you have installed in aircraft and configured (including aux mag rotation) the aux mag so it knows how to talk to it, then whenever you calibrate mags, it calibrates both mags.