Hello:

I own a P3A. Haven't flown it for a year or so. Got it out to fly and it said I need to calibrate the IMU. I've made repeated attempts to calibrate (following the instructions) and I keep getting the following error - Unknown error occurred. Recalibration required (see attached screen shot). Can anyone help? Thanks,

Phil

Hello there Phil. I am sorry for the trouble this has caused and thank you for reaching out. Kindly please check if the firmware of the said DJI drone is on its latest one. Just a reminder when trying to perform the IMU calibration the said DJI drone must be placed on a level surface before the IMU calibration is conducted. If all of this process will not work and you still receive the same problem I would recommend sending the unit into our repair facility for further evaluation of your unit. If you wish to contact our support, kindly refer to the link below. For additional information, the repair fee would depend on the outcome of the investigation on your drone and if the unit is still under the warranty period. Thank you.

https://www.dji.com/support

I would add that not only a flat surface but also well away from any metal!

cheddar-man Posted at 5-10 23:27
I would add that not only a flat surface but also well away from any metal!

I would add that not only a flat surface but also well away from any metal!
When you say metal, what you really mean is steel, because you are thinking of the effect on the compass and most metals have no effect on a compass.

But ... there's no need to keep the drone away from steel objects to calibrate the IMU.
Being close to steel makes no difference at all to the IMU or it's calibration.
The only thing that's important is that the surface is level.

True, in theory, but with any electronic circuitry it is possible for strong magnetic fields to affect some of the components, they can induce unwanted currents in transformers, for example, and any other component with a metallic element. Just to be safe, I always do any calibration in doors, on the big, FLAT dining table.

Any way, mpromney, HERE's a link to one of many detailed instruction available on the WWW for IMU calibration.

cheddar-man Posted at 5-12 00:01
True, in theory, but with any electronic circuitry it is possible for strong magnetic fields to affect some of the components, they can induce unwanted currents in transformers, for example, and any other component with a metallic element. Just to be safe, I always do any calibration in doors, on the big, FLAT dining table.

Any way, mpromney, HERE's a link to one of many detailed instruction available on the WWW for IMU calibration.

True, in theory, but with any electronic circuitry it is possible for strong magnetic fields to affect some of the components,
You are being far too over-cautious.
Calibrate the IMU anywhere that's a level surface.
It's just some gyro sensors and a baromeric sensor that are being calibrated.

It there really was an issue, you'd expect it to be highlighted in your manual ... but it isn't.
It's just another of many common forum myths.

cheddar-man Posted at 5-12 00:01
True, in theory, but with any electronic circuitry it is possible for strong magnetic fields to affect some of the components, they can induce unwanted currents in transformers, for example, and any other component with a metallic element. Just to be safe, I always do any calibration in doors, on the big, FLAT dining table.

Any way, mpromney, HERE's a link to one of many detailed instruction available on the WWW for IMU calibration.

Thanks much for the helpful responses. I'll give it a try again.

Labroides Posted at 5-12 02:55
True, in theory, but with any electronic circuitry it is possible for strong magnetic fields to affect some of the components,
You are being far too over-cautious.
Calibrate the IMU anywhere that's a level surface.

"You are being far too over-cautious."
60 + years in the electronics business I've concluded you can't be too cautious, Only MHO.
Another is "if it isn't broken, don't mess with it"!. By far the majority of posts on these forums is where people have messed about (usually with the firmware) and bu...ered up a perfectly good drone!

cheddar-man Posted at 5-13 23:33
"You are being far too over-cautious."
60 + years in the electronics business I've concluded you can't be too cautious, Only MHO.
Another is "if it isn't broken, don't mess with it"!. By far the majority of posts on these forums is where people have messed about (usually with the firmware) and bu...ered up a perfectly good drone!

By far the majority of posts on these forums is where people have messed about (usually with the firmware) and bu...ered up a perfectly good drone!
Apart from those pushing total myths like avoiding steel when you calibrate your IMU.
Honestly, it really, really won't make any difference.

I've never had this problem with a P3 but I've seen it several times with various P2s.  Sometimes the gyro(s) will get stuck so that repeated calibrations won't help.  On a P2, replacing the FC with a good used one or new one will solve the problem.  I've read of people who will remove the FC and rap it on a hard surface to loosen the gyros.  I've never tried that myself.   

I am not sure how this applies to a P3.

Good luck.  

All - thanks for the helpful suggestions. I've tried repeatedly to calibrate the IMU and still get the same error. Frustrating. I have verified that the firmware is up to date. Did the compass calibration and everything else I could find for troubleshooting the problem and it still won't calibrate the IMU. Drone worked flawlessly when I last used it 1+ yr ago. Called a local drone repair company and they suggested replacing the entire board with the IMU (if I could find one) for $150-$200. This drone has been used very little (less than 10 hrs) and has never crashed or had any other problems. I don't understand why I'm having this problem. Any parting suggestions or words of advice would be appreciated. Thx.

You can probably get a complete P3A for that sort of money. Quite a few on Ebay here in the UK.
Not much help I know but the brains have run out of ideas except - With being idle for so long, is it possible the gyro has become "stuck"? By their very nature they must have a rotating mass inside them (I think) and this needs bearings to run. on - unlike the accellerometers which are solid state.
I have heard of people "tapping" the IMU to free up the gyro.

Just a thought but maybe worth a try before spending money..............