X10 SBUS input gives steady flickering

[flyingw]

Jim,

I configured a DragonLink receiver to output SBUS and connected it to an X10.

The system connects, but the LED on the X10 flickers steadily at a fast rate, something 10 per second, maybe faster.

A servo connected to the X10 moves as expected on the correct channel, but it moves in a slightly "ratchety" fashion.

Any ideas?  I tried inverted SBUS on the X10 but it did not connect at all.

Thanks,

Paul

[XPS]

This is due to whatever is driving the X10+ not outputting the proper SBUS compatible frame rate.

[thebluemax]

This is due to whatever is driving the X10+ not outputting the proper SBUS compatible frame rate.

Hi Jim,

I had this same problem with your RFU outputting SBus and the X10. Back in September of 2020.  You were going to check it out after the release of the X16.

Here is the link to that thread in the RCG forum.  Post 20 and on is where it starts talking about the flickering

RFU w/Aura 8 installation - RC Groups

[XPS]

I have zero issues here with any using the RFU with X10+, X16, or X24 in SBUS mode (an the RFU set to output SBUS mode). So, I am not sure what the issue is other than maybe there is a problem with the RFU itself.

[thebluemax]

That's interesting. 

I tried this with two different RFU's, purchased brand new from XPS, with two different transmitters, at two different locations, and got the same results.

JR 11X with XPS internal 11X module.  RFU set to SBUS and X10 set to SBus.  I did it on both the V1 and V2 X10s.
JR 9303 with XPS-J1 module.  RFU set to SBUS and X10 set to SBus.  I did it on both the V1 and V2 X10s.
All of these tests flickered with this setup.

Same TX's, RFU's, and X10. V1 and V2 set to Extreme mode at same two locations.  None of these tests flickered at all.

I know the preferred method is Extreme Mode with the RFU and X10.  There was a need for them to be both set to SBus but I have gone a different way to make it work.

[XPS]

I will look into this again.  Maybe in one of the newer code changes it broke something in the RFU's SBUS?   I just grabbed a X10+ out of the spares tool box for checking, and it is very old. SBUS works perfectly with the X10+ because we have a ton of customers using them with dual SBUS receivers.  This issue would absolutely have to be with the RFU itself.

[flyingw]

I just took out a brand new X10+v2 and new RFU. I performed a factory reset on both of them. Then I configured the X10 to have SBUS as its input mode and the RFU to output SBUS. Binded the RFU to a Taranis transmitter (which was using XJT-D16 to talk to its XPS-J1 transmitter module).

When powered up the RFU plus X10+v2 combination blinked steadily like it did with the DragonLink receiver (also set to output SBUS). Servos ran notchy.

[XPS]

SBUS requires a frame rate that is different that what the Taranis outputs in XJT-D16 mode.  SBUS specification is either 7ms (fast) or 14ms (normal).  Anything outside of these is not guaranteed to work properly.

[flyingw]

SBUS requires a frame rate that is different that what the Taranis outputs in XJT-D16 mode.  SBUS specification is either 7ms (fast) or 14ms (normal).  Anything outside of these is not guaranteed to work properly.

Jim,

Ok, let's see if I understand this:

 - The Taranis outputs XJT-D16 through its external module bay to the XPS-J1 transmitter module at the frame rate of the Taranis XJT-D16 protocol.

 - Then the XPS-J1 module uses that same XJT-D16 frame rate to talk to the RFU.

 - Then the RFU outputs SBUS to the X10 at that same XJT-D16 frame rate.

 - Then the X10's green led blinks because the XJT-D16 frame rate is not consistent with the standard SBUS frame.

I reckon that the SBUS frame rate seen at the X10 is determined by the frame rate that the XPS-J1 module gets from the Taranis, is that correct?

I tried the test with the Taranis outputting PPM to the XPS-J1 module and the behavior was the same - blinking X10 led indicating frames lost.

Then it follows that the Taranis would have to send XJT-D16 or PPM SBUS frames to the XPS-J1 module at 14ms (or 7ms) in order for the X10 to be happy with the incoming SBUS frame rate.

Then why are there no lost frames (X10 led solid green) when the Taranis outputs either XJT-D16 or PPM to the XPS-J1 module, and the RFU talks Extreme protocol to the X10?  Is it because Extreme can adapt to either frame rate?

Thanks,

Paul

[XPS]

The X10+ is expecting the frame rate to be either 7ms or 14ms. There is some margin of error that it can account for (5-9ms and 12-16ms). This is because the SBUS system has a failsafe system that needs to be adhered to, and that is time based.

The XPS modules can handle any frame rate.