Plane 3.8.1 - Pixhawk. Cannot download DataFlash Logs when armed

Small flying wing (PopWing) with a MicroPix controller.
Upgraded from Plane 3.7.1 to 3.8.0 and latest 3.8.1. With 3.7.1 I could download the logs with the plane armed (from Mission Planner 1.3.49). Now after the upgrades to 3.8.0/1 i get this error message (see attachment below).

After some investigation I think I found the reason for the error, the plane needs to be unarmed when connectet to the computer in order to obtain the log list and to be able to download it. It looks that this requirement is different from earlier firmwares.

I prefer not to enable the Safety Switch (BRD_SAFETYENABLE=1) or any arming requirements (left/right rudder stick) for this small wing. The plane is trimmed and tuned and flying fine in all modes including missions. I hope there is some other way to make the logs available (armed) as the controller is buried in the wing and the SD card not readily accessible.

I don’t know if this is a FW or Mission Planner issue, please feel free move it as neccessary…

Thank you for any suggestions!
Regards Jan

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After some investigation I think I found the reason for the error, the plane
needs to be unarmed when connectet to the computer in order to obtain the
log list and to be able to download it. It looks that this requirement is
different from earlier firmwares.

As far as I’m aware this isn’t a new requirement on any vehicle type we
support, however the code resposible for this check has been made common
across the frame types recently.

It is working as intended, sorry!

The reasoning for this behaviour is that transfering the logs is a
significantly CPU-intensive (and bandwidth-intensive!) task, and isn’t
something we want accidentally triggering in-flight.

Could I suggest you could disarm the vehicle before starting your log
downloads? Just because it starts armed doesn’t mean you can’t disarm it
:slight_smile:

Tanks for your reply and explanations!

As I don’t have rudder stick arming/disarming enabled, I see no way I can disarm the controller with my current setup :slightly_frowning_face:
The best option for me now is probably to set ARMING_RUDDER=2 (or 1?).
The plane then needs to be armed by 4-5 seconds right rudder at the field, no big deal! As a result the controller will be disarmed when connected to the PC via USB and Mavlink, and I shall be able to download logs.

As I said this happend on this plane after I upgraded Arduplane from 3.7.1 (possibly 3.8.0 Beta6) to 3.8.0/1.
Also with my Bixler 2 with Arduplane 3.5.2 on a Pixhawk Lite there have been no issues downloading logs when armed. Same with a TekSumo, a Drifter and a X5 with MiniAPM’s, all with Arduplane 3.4.0.

Anyway, if anybody with a similar PixHawk setup as mine, run into the same problem upgrading FW and downloading logs, maybe this thread will be of some help.
Cheers and thanks for a great work!
-Jan

As I don’t have rudder stick arming/disarming enabled, I see no way I can
disarm the controller with my current setup :slightly_frowning_face:

Isn’t there a big “disarm” button in the same GCS you’re using to download
the logs?!

:flushed:
… found it! Below “Actions”. (Now this is my best action - see EDIT below). Thank You!
-Jan

EDIT
Well, it wasn’t that easy. I need to enable ARMING_REQUIRE in the parameters to make the “Arm/Disarm” button work (Error:command rejected by MAV), resulting in the controller disarmed when powered up in the field. Then again I need stick arming enabled to arm (ARMING_RUDDER=2) , looks like that is the best solution.

-Jan