APM 2.8 - Setting new offsets for compass #1 failed

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1

So i finally have time to pick up the APM and look further. So far i’ve:

  • Struggled getting the correct USB driver
  • Downloaded and installed the correct 3.2.1 arducopter firmware as
    that’s the latest that could fit on the device.
  • Hooked up the GPS and removed the jumper to use the compass from the
    GPS.
  • Read up on a lot of stuff :slight_smile:

Now, the APM 2.8 that i’ve is giving me some trouble. I get “Setting new offsets for compass #1 failed” which i can’t seem to resolve. If i understand C# correctly, it’s actually writing the offset of the compass to the board and is failing. It’s a bit strange, other parameters (like BATT_CAPACITY for example) do write to the APM. This happens for both built-in and external compass.

Now, of course i looked for the error and found a lot of complains about the APM 2.6 (and later) board that it’s not supported or just old hardware and should buy something better. I know that the hardware had limits in terms of firmware, but now it nearly seems that any online resource i find is telling me that i’ve bought something that people shouldn’t sell anymore. I know this stuff will never be ‘just work’ hardware, but at the moment I seem to be stuck and will never be able to get it to work.

2

When calibrating the compass what version of missing planner are you using as it is likely that you need to use an older version of mission planner around the same release date as theV3.2.1 firmware, so I suggest you try Mission Planner 1.3.9 - http://firmware.eu.ardupilot.org/Tools/MissionPlanner/archive/

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3

I experienced the same thing with my APM 2.8. One thing that worked for me was to just install a completely different firmware eg. Heli, then revert back to the old firmware for your copter, and redo all the calibration. I hope this helps.

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4

There is nothing wrong with an APM. I’ve had a 2.6 for 3 years and it has been flawless. I also have a Pixhawk.

I’m not that familiar with the 2.8, but if it has an internal compass you need to disable it if you want to use an external compass. This was a known issue with the 2.5 and its the main reason a 2.6 does not have an internal compass.

Pixhawk has an internal compass, but the offsets are always on the high side. The good thing is the firmware for Pixhawk supports multiple compass chips, and you can select the one with the lowest offsets as the Primary… Works like a charm…

Switching to an older version of Mission Planner is wrong. The latest version of MP works just fine.

5

Having this same type of compass calibration problem on no less that three separate APM’s has convinced me it is time to switch over to a Pixhawk (or something better) if I want to get my hex airborne some time this year. All three APM’s were purchased on-line from supposedly reputable distributors, but all three turned out to be counterfeit units - they looked real, but they sure didn’t perform like they were made by someone who knew their craft. I now have over $700 worth of parts sitting on the work bench and still haven’t got 5 minutes of flying time since last May.