Schugy

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Walkera RX-SBus: Intermittent connection with LP, works with CF
« on: November 27, 2018, 01:08:15 am »
Hello everyone,

this old Walkera Rx issue is kind of solved with Cleanflight / CC3D_OPBL (CC3D) 2.4.0. In the Rx tab I can see 10 nicely working channels with the Rx connected to the main port. But I prefer the LP vehicle setup wizard.

I tried to move the servos with LP and there were only ~5 stuttering movements per second. I also tried dRonin but the input wizard showed the same behaviour like that one of LP.

Walkera sells quads with CF, maybe that´s why they made the Rx compatible.

Happy flying.

Re: Walkera RX-SBus: Intermittent connection with LP, works with CF
« Reply #1 on: November 27, 2018, 05:18:05 am »
That thread makes it look like that SBus receiver uses non-standard SBus and would need an additional hardware inverter to uninvert the SBus.  Skipping the hardware inverter is done by some FC to avoid the cost of the additional inverter, and so some receivers now offer non-inverted SBus.

If you are using SBus or PPM and have it configured correctly (like not having CC3D configured for PPM when receiver is actually sending SBus), then the last thing you should be aware of is that CC3D reads the receiver at full rate, and works correctly, but only sends to GCS once a second or so because that is the default for telemetry data rate.  You can set the telemetry rate higher, but do you actually need to?

If it is jittering badly and all the time, it sounds like you (the receiver) are sending one signal and have CC3D configured to read a different signal protocol.

Schugy

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Re: Walkera RX-SBus: Intermittent connection with LP, works with CF
« Reply #2 on: November 28, 2018, 02:18:59 am »
Thank you for your replay. When I use SBus inversion (non-inverted UART) the receiver isn't recognized at all. The CC3D and F3 provide an inverter on the main port and both work happily together with my Rx without any further configuration when using CF/Inav. The async_counter stays at zero. The Rx has 12 channels and CC3D shows 10 and F3 shows 12. There is no telemetry or RSSI.
The transmission duration is around 3 ms and the gap on most receivers is 6 or 11 ms. A cycle is 9 or 14 ms, a common multiple is 126 ms and maybe my servo stutter (real servo, not GCS input tab) is about twice of that. The GCS shows a flicker on channel 18 and the used channel of my Tx input or sometimes all channels maxed out.
E.g. in Inav 2.0 a Radiolink R9DS is a non-compliant receiver and the LP devs may decide to rule out the Walkera Rx but I still have little hope that there is a bug how SBUS is implemented in LibrePilot ;)