Start Logging results in empty logfile: Howto required.
« on: July 08, 2017, 09:23:11 am »
Have a Z-84 Wing with BG revo mini and working oplink and GPS. My Groundstation is an Acer Aspire One with Fedora 25 and GCS 16.09. The Netbook is a bit underpowered, but works. OPlink Connection shows Data and Config is possible.

Now I want to get a flightlog saved on the netbook.

Flight Data Tab updates too slow, so I go to HITL-Tab to do "Start Logging" (Ctrl-l). I get a Dialog to set the filename and filepath. After Flying around I press Ctrl-l again. The files have only 2.1kByte Size and there is nothing in it, Replay does not show any data at all.

Whats wrong? Did I miss an important thing?

Re: Start Logging results in empty logfile: Howto required.
« Reply #1 on: July 08, 2017, 04:23:12 pm »
Really no instructions needed.  If telemetry is working, just do Tools -> StartLogging.

Was it "Connected" (lower right corner)?

Are you able to change settings via the OpLinks?

What is the range of the current setup?  Many things can affect the range:
- power setting on both sides
- antennas
- antenna placement

One other thing is that you should change the data rate to 56k on both sides.

It's important to note that there is an issue with making changes to OpLink settings.  Even though you can change the settings in the aircraft via OpLink, you can't change OpLink settings of the aircraft via OpLink.  Whether GCS or aircraft, only use USB to change OpLink settings, and when changing GCS OpLink, make sure that the aircraft is powered off.  Also note that if you "export uav settings" using OpLink that it will have aircraft settings for flight stuff, but GCS settings for OpLink stuff, so you should probably just always do export (and import) settings with USB.
« Last Edit: July 08, 2017, 04:44:01 pm by TheOtherCliff »

Re: Start Logging results in empty logfile: Howto required?
« Reply #2 on: July 08, 2017, 06:23:30 pm »
Did another dry-test in the garden today, this time without flying, only carrying the plane around:

OPLink is connected, GCS shows all parameters of the plane. Update via OPLink does work, I see all changed settings after powercycling both sides. The telemetry even shows turns (horizon) and GPS-data (on the map). I even get a 3D fix from GPS although i have issues on MAG and only 5 to 7 satellites between the buildings. Its 56k on both sides.

So i do:
-> start logging
-> set output file
-> run around with the plane
-> stop logging

All I get is a file of 2.1kb (maybe only one block on the file-system..)
I've attached one of these files. Maybe its only the file header included.
This is made on fedora 25 XFCE with GCS 16.09 from parched/librepilot.

I will try logging with a win10 box tomorrow. Maybe its a Fedora specific issue.

Thanks for support.

« Last Edit: July 08, 2017, 06:30:50 pm by altermac »

Re: Start Logging results in empty logfile: Howto required.
« Reply #3 on: July 08, 2017, 11:35:06 pm »
About the only thing it could be then is that you don't have good range.  What is the range of the telemetry?

Fedora Copr parched/librepilot: Logging issue
« Reply #4 on: July 09, 2017, 02:47:21 pm »
So it's definitive an issue of the Fedora-Version. Did a dry-test with another AcerAspire One with Win10 and GCS 16.09 with same setup and location. Logging works, files are now way bigger. Replay from connected (Win10-) logfile shows all data.

So next weekend I will try logging my flights with Win10.

Maybe it's not only fedora, maybe the old Aspire One 110  is way to slow for logging.

Re: Start Logging results in empty logfile: Howto required.
« Reply #5 on: July 09, 2017, 04:59:37 pm »
So a file that you thought was empty was not actually empty?  I can imagine that.  There is a setting that makes the system faster by not constantly updating the file meta-data (directory entry).  Maybe that is it?  The data is actually there, but the size doesn't change when you expect it to?

Re: Start Logging results in empty logfile: Howto required.
« Reply #6 on: July 09, 2017, 06:35:53 pm »
I use two netbooks for GCS 16.09 one on fedora 25 (copr parched/librepilot) and one on Windows 10.

Every logfile on the fedora25-netbook is 2.1kb large, all are the same. I attached one on post #3.

Same plane connected via OPLink the Windows 10-netbook, same situation, logging for 2 or three minutes and the file is 110kb large.

The Fedora Linux netbook doesn' write any log-data after opening the logfile. Maybe someone can read the file of post #3. I can't see any errors, seems to be only a file header with some static data.

I try looking for this "faster" option. Maybe it helps.

Re: Start Logging results in empty logfile: Howto required.
« Reply #7 on: July 09, 2017, 09:34:21 pm »
It is an option in the file /etc/fstab under Linux.

It doesn't keep the file from growing.  It just doesn't update the file meta data as often.  If the file truly doesn't have the data, then this is not the problem.

Are you using the same OpLink on Windows and on Linux?

Maybe the Linux partition is out of data space.  I had assumed you had checked that...  A small amount of data is not stored in the data area and maybe that is what you are seeing a small amount.  Make sure all your partitions have plenty of room left.  Start a command prompt and use the df ("disk free" command, no options) to see the free space on all your mounted partitions.

There is also an option that limits the amount of data that a user can write, but it is not common to change this.

Re: Start Logging results in empty logfile: Howto required.
« Reply #8 on: July 10, 2017, 04:36:57 pm »
Same OPLink and plane on linux and Windows, more than 500MB Freespace for /usr/home. Working connection, even data showing in GCS. I don't think connection gets lost: On dry-test the distance between plane and GCS is only about 5m with free line of sight.

Any caching issues should be solved on fileClose. But all (Linux)-log files have nearly equal size of 2.1 KByte. Seems like logging stops after writing the file-header, but GCS menue shows "Stop logging" even after some  10 minutes of flighttime. So logging is active all the time.

I better stop wasting time on this and use Windows.

Re: Start Logging results in empty logfile: Howto required.
« Reply #9 on: July 10, 2017, 06:02:22 pm »
500MB isn't much free space.  There are rules that limit writing the disk to super user only once you get below a certain amount of free space.  You could look at "man tune2fs" or try running GCS as super user (put sudo or gksudo in front of the command that runs it in the desktop link).

sudo tune2fs -m 0 /dev/whateveryourrootdeviceis

reboot and try again