Mag and IMU isssues?

Tweaking a new build. I'm flying a 3dr pixhawk with a rangevideo ublox 7m compass/gps. This morning I went for a flight and had some battery failsafe issues. That was simply a mistake on my part entering the wrong capacity in the failsafe mah. Other than the battery failsafe everything else looked good and the logs indicated so.

 This evening I made another flight to test the new battery settings. All went well and after hovering awhile I tried my new position hold. I had 3d lock of 13 sats. But it acted like there was no position hold at all. The copter just drifted along like I was still in stabilize. I tried it a few times with the same results. 

When I got home I checked the logs and they indicate two issues. It say 

Test: Compass = GOOD - No MAG data, unable to test mag_field interference

Test: IMU Mismatch = WARN - Check vibration or accelerometer calibration. (Mismatch: 0.94, WARN: 0.75, FAIL: 1.50)

This morning  everything seemed fine, my logs from this morning show. 

Test: Compass = GOOD - mag_field interference within limits (12.74%)

Test: IMU Mismatch = GOOD - (Mismatch: 0.60, WARN: 0.75, FAIL: 1.50)

Any idea why the change?

I've attached the log from this evening if anyone can tell anything else from that?

27.BIN

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  • It turns out that my mag was not being recorded because it was not set to in the logs. So it appears my compass is ok since its been reported as good in both instances. I will log compass now so I can check the magfield and make sure thats working.  

    I'm still not sure on the imu mismatch. I'm going to make another test flight tonight and see what results I get. I'm also going to try the old loiter instead of position hold to see if that makes a difference. 

    • What versions of MP and AC are you using?

      Is your compass enabled in the Parameters?  Is it set to internal or external?

      • Just did a test flight, my latest log says compass is good and mag interference is within 13%. 

        Loiter seemed to work fine. So i'm going to move this over to the 3.2 thread and see if anyone can give assistance there because it seems that its not something with my hardware. Could be that my deadzones are not dead enough or something is giving input to keep it from holding in position hold. 

      • MP 1.3.16 AC 3.2

        Compass is enabled and Compass is set to external. 

  • In my initial setup parameters I have set the compass orientation to pixhawk. But noticed it always reverts to "manual: rotation none". Is this normal?

    • Mine always does that!

      In Standard parameters how did you have your Arming_Check configured?  If it was fully enabled you shouldn't have been able to arm with a compass not working.

      I would go back through initial setup on compass and Accel.

      • Just got back from another test. Exact same results.

        I recalibrated my compass in mission planner. I redid my accel calibration (which failed numerous times until I wiped my sdcard and tried again). I have 3d lock in mission planner and my compass heading indicates the right direction and moves correctly as I spin my quad. 

        But upon flying I have zero position hold. In position hold it acts exactly the same as altitude hold. When I look at my logs I have the same errors as above. 

        I'm lost. 

      • I did have arming_check configured. I'm really confused as to what the problem is. 

        I think trying a setup and calibration again is the best move. Ill report back. 

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