Close Call/ Help Needed!

I hope you are able to figure this out from the .dat file. I have been testing the compass and wanted to know what the x, y and z where about. I've read here that mod should be around 1400.
So far, and I have more testing to do, I found that the compass reports the axis to the processor
and that when the aircraft is level the y ( value in sensors of the Go app) is zero(or close) when pointed north or south .
So pointed north , y=o, x= + 400 to 500, z=around 1300, mod around 1400
south y=0, x= -400 to -500, z and mod are same
east y= -400 to -500, x=0, z and mod are same
west y=+400 to 500, x=0, z and mod are same
Now what has been suggested might be a clue as when the aircraft is pitched the numbers all change in a strange way.
I wondered why we needed to point the nose down during calibration and it seems to record in the z axis.
I wonder if the pointing down angle is a bit more critical than it seems?
Is it possible if when doing the calibration we hold it down ,not at exactly a straight down angle but slightly off we record an error in the calibration data that doesn't show up except in specific pitch conditions?
It's unflyable with the weather we have next few days but I'll test as soon as I can.
The X, Y, and Z values are from the three magnetometers of the compass; one each on the X, Y, and Z axis. A magnetometer will be at maximum when it's pointed into (or parallel) to the geomagnetic flux. That's why Y is 0 when the A/C is pointed north; it's perpendicular to the geomagnetic flux.

The following is an excerpt of a post I did recently. Maybe it addresses your question.

Contrary to popular belief the compass calibration is not about discovering which way is North. Rather, it's purpose is to adjust the gain of each of the X, Y, and Z magnetometers so that they have a uniform response to the geomagnetic field. All that's really required is that the P3 be oriented in enough different directions so that each magnetometer is exposed to a range of values.The first step of the compass dance gathers that data for the X, and Y magnetometers. The second step has the Z axis pointing at the horizon so that the data can be gathered for it.It probably doesn't matter that it's the X axis pointing at the horizon instead of the Y axis. I.e., right side down should work just as well as nose down for the 2nd step.

I once did an experiment where the compass dance was done upside down. 1st step top down, and 2nd step nose up instead of down. I had carefully measured the X, Y, Z, MOD numbers before and and after and didn't see any difference. Flew fine.
 
Thanks Bud.You have restated what I had tried to say much better than I.
The pointing downward is 90 deg from level, what if it pointed downward at 80 deg?

Does the magnetometer( I called it compass for simplicity) use the z value to recalculate the x and y do you not think a variation in that would create a bad table?
The quest is to resolve the OP's problem and I didn't know if there could be an issue with this.
I plan to read the sensor values while "pitching" to see how the values adjust.
I believe the magnetometer values are adjust for temperature and accelerometer values but what might cause the OP's issue?
 
I have been looking but then had to do some real work. The overall compass mod is solid for the whole fight, starting to look at individual axis...
 
I just wanted to thank everyone who's actively trying to figure this thing out for me. Y'all are awesome!
 
Thanks Bud.You have restated what I had tried to say much better than I.
The pointing downward is 90 deg from level, what if it pointed downward at 80 deg?

Does the magnetometer( I called it compass for simplicity) use the z value to recalculate the x and y do you not think a variation in that would create a bad table?
The quest is to resolve the OP's problem and I didn't know if there could be an issue with this.
I plan to read the sensor values while "pitching" to see how the values adjust.
I believe the magnetometer values are adjust for temperature and accelerometer values but what might cause the OP's issue?
I don't think it'll make much difference if the P3 issn't oriented precisely during the calibration. I addressed that in post #41.

It's my understanding that the 3 magnetometers are independent of each other. Why would the Z value be used to recalculate the X and Y values? The flight controller takes as input the 3 magnetometer values (and several other sensors, pilot inputs, etc). to predict the orientation. Maybe this is what you're thinking about when you say the magnetometer values are adjusted for temperature and accelerometer values. If you're interested in this kinda stuff you could check out Quadrotor

If the P3 is rotated about the Y axis (i.e., "pitched") what you'll see in both the X and Z magnetometers is a sin wave. Likewise, if rotated about the X axis (i.e. rolled) the Z and Y magnetometers will produce a sin wave. You can do this by eyeballing the tablet and writing down the numbers. Or, you could get the values from the .DAT and have Excel do the plotting for you. IMHO a much more civilized approach.

Hope this answers some of your questions.
 
This sounds like every flight I've done over the smokeys in a 172. Had some very interesting and crazy wind roll off those mountains.

Sent from my SM-T810 using Tapatalk
 
have about 130 flights and never had an issue. Then yesterday happened. I was in the Smokey Mountains and wanted to get a few pics before I left. I updated to all of the latest firmwares and app updates last week. I went through all of the compass calibrations and did not have any issues during warm up. Once I got the green light I took off and let it hover for a few seconds to make sure everything was working properly. About 3 minutes into the flight, I lost signal and it started drifting away fast. I hit the RTH and eventually everything ended good for me.

I uploaded everything to healthy drones to see if I could get an idea about what went wrong but I am not too familiar with what exactly I'd be looking for. Can anyone help me out with this?

Thanks in advance! I don't want to put anyone or anything at risk flying until I know what went wrong!
How do you view the file...on a PC
 

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