Hello,

I have small problem, or at least i think it is problem. So i did IMU calibration few times, on level wooden surface with no metalic parts around, with Phantom 4 newly turned on, so temperature of phantom was around 20C. After those calibrations i have always the same behaviour of ACC. different between ACC 1 and 2 is around 10units. Is it normal or i should do somthing about it. Compass and GYRO is ok.

Situation looks to be perfectly normal. My IMUs behave in exactly the same way. There will always be some slight variations between different components. You will usually see some variation in Gyroscope and Compass readings as well (tap 'Compass' tab at top of that screen).

This is totally normal.

Oh that ok then, just I'm asking because i read somewhere that difference between component should be around 2units. And it is not more than 2 units on GYRO and Compass. Its only ACC showing more as it visible in picture.

Drshiwas Posted at 2017-9-14 02:44
Oh that ok then, just I'm asking because i read somewhere that difference between component should be around 2units. And it is not more than 2 units on GYRO and Compass. Its only ACC showing more as it visible in picture.

After you've initially calibrated IMU and compass then they only need to be redone if prompted by system or if there is some erratic flying behaviour that needs investigation.

It seems working good. Is there any error message on the app? Or how about the performance of it?

If the colour is green, they say it is excellent, so I wouldn't worry because it is within spec.  If the colour goes orange or red I would begin to worry.  Three decimal places is a very small amount.

DJI Thor Posted at 2017-9-14 04:31
It seems working good. Is there any error message on the app? Or how about the performance of it?

I would say it behave normally, but sometimes it says "redundancy switch" and switching from ACC1 to ACC2. Overall Phantom flying good enough, except that wobble after FW update.

Drshiwas Posted at 2017-9-14 06:37
I would say it behave normally, but sometimes it says "redundancy switch" and switching from ACC1 to ACC2. Overall Phantom flying good enough, except that wobble after FW update.

It is confirmed that this is normal. No worries. If the bias value of ACC1 and ACC2 exceed 0.08g when the drone standing on the ground, you can calibrate the IMU again.

DJI Thor Posted at 2017-9-14 23:29
It is confirmed that this is normal. No worries. If the bias value of ACC1 and ACC2 exceed 0.08g when the drone standing on the ground, you can calibrate the IMU again.

thank you DJI Thor for confirmation.

Drshiwas Posted at 2017-9-15 01:32
thank you DJI Thor for confirmation.

You are welcome. Should you have any further questions, please feel free to contact us. We'd glad to help.