Big MagZ p2p - do I need to worry?

[BorisTheSpider]

Brand new Mavic, aircraft SN 08QDE2701202UW manufactured on the 7th of February 2017 according to DJI Mavic Pro Serial Number Decoder so it should have the twisted rear motor wires.

Latest firmware, 01.03.0500

First flight yesterday, nothing eventful - no loss of GPS or anything, but as a precaution I used the latest csview 1.0.6 to read the DAT files.

I'm seeing peak-to-peak of about 700 in MagZ.back vs about 300 in MagZ.front

http://imgur.com/a/XMhaY[/IMG]

According to GPS and compass failure in Sport mode the scaling factor in the latest firmware for MagZ has changed, so in terms of pre .500 firmware, those numbers would be somewhere around 250 on the back compass, and 120 on the front. I've seen reports of GPSHealth drops and unexpected ATTI mode reversions with numbers like 140 on the back and much lower on the front!!!

GPSHealth was fine, no issues yet - should I be worried? Perhaps I've misinterpreted the new scaling?

DAT file: Send and download large files, no registration needed

 

[BudWalker]

Brand new Mavic, aircraft SN 08QDE2701202UW manufactured on the 7th of February 2017 according to DJI Mavic Pro Serial Number Decoder so it should have the twisted rear motor wires.

Latest firmware, 01.03.0500

First flight yesterday, nothing eventful - no loss of GPS or anything, but as a precaution I used the latest csview 1.0.6 to read the DAT files.

I'm seeing peak-to-peak of about 700 in MagZ.back vs about 300 in MagZ.front

http://imgur.com/a/XMhaY[/IMG]

According to GPS and compass failure in Sport mode the scaling factor in the latest firmware for MagZ has changed, so in terms of pre .500 firmware, those numbers would be somewhere around 250 on the back compass, and 120 on the front. I've seen reports of GPSHealth drops and unexpected ATTI mode reversions with numbers like 140 on the back and much lower on the front!!!

GPSHealth was fine, no issues yet - should I be worried? Perhaps I've misinterpreted the new scaling?

DAT file: Send and download large files, no registration needed

I looked the .DAT. I didn't see any evidence of a noisy back compass caused by high currents associated with full elevator in Sport mode. Except for a few narrow spikes the current was about 10 amps. There needs to be an interval where the current is >= 20 amps in order to determine if twisting the wire bundle would help with a noisy compass.

If you do another flight to obtain the requisite data I suggest that you use just that data in that flight. The data provided in the .DAT in the for Firmware 01.03.0500 makes it easy to do this. It's difficult to make comparisons against data from different Mavic, flying in different conditions, with different (and unknown) scaling factors,etc.

I'm supposing that the feature you were basing your conclusion on occurred around 492 secs. The back compass is noisier than the front. But, it's because the front is quieter than in other regions, e.g. around 344 secs.


This is associated with full pitch down (for non-Sport mode) with a heading in a southerly direction. The geoMagnetic field itself is noisy and it would seem that with this attitude there is less coupling of that noise into the front compass. Don't know why that's not also true of the back compass.