Herelink/PX4 lag over UART

  • I’m using the latest version of firmware as of writing this; updated both air and ground unit
  • I’m also working with a pixhawk flight controller running PX4 (1.11.3).
  • Using a Workswell Wiris Pro, which wasn’t working until we got help from this fix: No image HereLink HDMI 720p (WIRIS PRO)

We’re noticing a large amount of delay in everything related to the UART (Telemetry) connection. Arming the drone, disarming, loading missions, everything has an extremely inconsistent delay ~10-20 seconds. The RC inputs to the flight controller, however, are working as expected.

Looking through a flight log reveals that the commander, navigator, and mavlink loggers are logging vehicle_command lost messages around 30 times a second.

Is anyone else experiencing this issue? Is Hex aware of it?

The delay in the telemetry signal is there whether or not I use the streaming fix for the workswell camera.

@Michael_Oborne any ideas

Can you try to re-flash the controller with flasher?

If the RC is unaffected, looks like something is flooding the QGC.

Are you usually stable firmware on the herelink?

We’ve been following standard procedure in that manual, using the flasher. Not sure how I would even load anything other than standard firmware. Is there an instruction guide/github on that?

One thing that I’ve noted this morning on further inspection is that the flight modes tab remains red in QGC when we don’t have any flight modes/buttons assigned. It also throws the preflight warning “One Or more vehicle components require setup prior to flight.” Wondering if this is part of the issue flooding QGC.

I think this is because there are some mandatory setup not completed.


This manual: Configure Modes & Mavlink Buttons - CubePilot

Does not say anything about the Flight modes page within QGC. I’m starting to become more sure that this is the problem, but your documentation doesn’t say what to do with this page. Is there a recommended procedure here?

what baudrate do you have the port set as?

Also you are using the physical uart? And not trying to push a very high data rate through it?

Hi, we are experiencing the same latency but we are using arducopter latest beta version. Both in Solex and in QGroundcontrol we have the same proplem, 10 to 15 second delay for UART/telemetry.
Video stream is okay and also remote RC functions.
Any ideas what can be the reason for this?
Cheers from Norway

Can you try if arducopter stable have the same problem?

The Baud rate is 57600. Yes, it’s the physical UART, connected directly from the FC to the herelink. This happens without trying to stream HDMI.

Can you generate a bug report and share it?

Working on that bug report.

More information: We’ve started pinpointing it down to a parameter within PX4 that has been causing this lag. MNT_MODE_IN: RC, when turned on, makes the delay appear. We were not experiencing this issue with previous firmware versions. (We are using a gremsy gimbal). I’m wondering how we can go about getting older versions of the firmware to try to track it backwards? (812.1 KB)