Switched to Backup IMU

[IShouldBeWorking]

Hi all! Saturday evening as I was flying my last battery I got a warning I hadn't seen before: Switched to Backup IMU. I was about 16 minutes into the flight and the aircraft continued to perform normally. So I finished my shots and brought it home about five minutes later. No problems whatsoever the whole way, but when I search MavicPilots I do see that this message does come up in some posts related to crashes. Should I just recalibrate the IMU and move on with my life or should I be more concerned than that? Here's the line from my logs for that flight:

E

16m 13.7s

P-GPS

17

104.3ft

36.4ft

0.3mph

906.2ft

39%

14.89V

3.731V

3.727V

3.722V

3.710V

0.012V

100%

Switched to Backup IMU

There wasn't anything else in the log that was out of the ordinary. And this bird has always been rock solid reliable. I did take it to Hawaii earlier this month. So it flew in conditions it normally doesn't and it traveled in my carry on, for 5 flights. Not sure if that's related or not.

 

[Mossiback]

You might find your answer here: Search results for query: backup imu

 

[IShouldBeWorking]

Thanks @Mossiback! Yeah. I'd read most of those before I posted. They all seem to describe disconnects, crashes and other unusual behavior associated with the switch to backup. My case seems to be kind of unique because it switched to the backup but everything else continued to work as normal. No trouble at all during the whole flight. Maybe I'll just recalibrate and call it good.

 

[Mossiback]

... My case seems to be kind of unique because it switched to the backup but everything else continued to work as normal. No trouble at all during the whole flight. Maybe I'll just recalibrate and call it good. ...

I guess you can say that the backup worked as designed since there was no other trouble. If it keeps happening at different locations then I would suspect the primary is failing which, hopefully, would be covered by warranty if still in effect.

 

[IShouldBeWorking]

Good point. I'm glad the Mavic 2 has two IMUs and my backup performed like it should. I'm under warranty until December so I'll just keep on flying.

 

[DrGary]

The same thing happened to me when I was flying on a cloudy evening near sunset and it was getting dark fast. I attributed it to the lack of ambient light. The next morning all was fine, and it has not happened since.

 

[IShouldBeWorking]

The same thing happened to me when I was flying on a cloudy evening near sunset and it was getting dark fast. I attributed it to the lack of ambient light. The next morning all was fine, and it has not happened since.

Thanks for the info @DrGary! That's exactly the circumstance I experienced. Sun was nearly down and the light was fading fast. Hoping all will be fine next time I fly as well.

 

[paulatkin73]

Hi all! Saturday evening as I was flying my last battery I got a warning I hadn't seen before: Switched to Backup IMU. I was about 16 minutes into the flight and the aircraft continued to perform normally. So I finished my shots and brought it home about five minutes later. No problems whatsoever the whole way, but when I search MavicPilots I do see that this message does come up in some posts related to crashes. Should I just recalibrate the IMU and move on with my life or should I be more concerned than that? Here's the line from my logs for that flight:

E

16m 13.7s

P-GPS

17

104.3ft

36.4ft

0.3mph

906.2ft

39%

14.89V

3.731V

3.727V

3.722V

3.710V

0.012V

100%

Switched to Backup IMU

There wasn't anything else in the log that was out of the ordinary. And this bird has always been rock solid reliable. I did take it to Hawaii earlier this month. So it flew in conditions it normally doesn't and it traveled in my carry on, for 5 flights. Not sure if that's related or not.

get the .dat file from the device, open it in the csvview and compare 2 similar signals from the imu_atti 0 and 1, as shown below. if one of them stopped producing data completely or you see a significant on-going non-correlating mismatch - it may be worth sending those logs to dji support and opening a case.
may be worth to recalibrate imus first and fly again to confirm if it is a calibration issue or a hardware issue.

 

[IShouldBeWorking]

get the .dat file from the device, open it in the csvview and compare 2 similar signals from the imu_atti 0 and 1, as shown below. if one of them stopped producing data completely or you see a significant on-going non-correlating mismatch - it may be worth sending those logs to dji support and opening a case.
may be worth to recalibrate imus first and fly again to confirm if it is a calibration issue or a hardware issue.

View attachment 76287

Thank you! I"ll pull the full dat file from my iPad and compare the signals before I fly again. I appreciate the info!

 

[paulatkin73]

Thank you! I"ll pull the full dat file from my iPad and compare the signals before I fly again. I appreciate the info!

no prob. also - do not get me wrong - a random switch between IMUs is not necessarily an issue by itself, as long as it remains random, does not happen often and is not accompanied with a consistent diff between signals.

 

[IShouldBeWorking]

I finally had a minute at the computer to pull the dats from Saturday off my iPad. When I looked at the signals from both IMUs from all three flights that night, they were both sending the whole time and the plots very nearly overlapped the whole way. I think we're looking at just a random switch here. I'm going to charge up and calibrate, then just maybe do one battery in a test flight this weekend before going back to flying like normal.

Thanks again for the tip for looking at my data in CSVView. First time using it. Very cool tool. I can't believe all the info it gives me access to. Previous to this, I'd only looked at the basic stuff I could see in AirData. CSVView is a whole new level!