SBUS does not work

[tilmanb]

I'm still flying my dodgy decoders, they work with the high channel hack and never failed in flight so far.
But it's crazy to do. It is a very expensive model and my favourite right now. And well capable of killing someone if out of control. (At least it's only Ailerons on s-bus)
I must get in contact with Fr-Sky to replace them. I'm just too lazy.
Should I get in contact with Fr-Sky directly? Or should I try to convince Giantshark (local low cost distributor) that there is a issue with them, ans ask him to take the bare boards back?

Perhaps I should just buy new ones. With some luck T9 has all the parts in stock this time.


PS: Who else sells good S-Bus decoders? I'm sure FR-Sky aren't the only ones.

[Tomkfly]

Futaba
http://www.ebay.co.uk/itm/like/20098125 ... =83&ff19=0
Almost 5 times the price and only decodes 3 channels.

Tom

[tilmanb]

Futaba
http://www.ebay.co.uk/itm/like/20098125 ... =83&ff19=0
Almost 5 times the price and only decodes 3 channels.

Tom

Fuuuuq
Futaba....

[MikeB]

So the next thing you know, someone will be programming an Arduino mini as an SBUS decoder!

Mike.

[ShowMaster]

So the next thing you know, someone will be programming an Arduino mini as an SBUS decoder!

Mike.

Tease!

[Helle]

Hy,

S-Bus Decoder with Arduino pro micro is running.

[Tomkfly]

I'm quite confident that the last two I bought work as they should.

Tom

[ShowMaster]

Hy,

S-Bus Decoder with Arduino pro micro is running.

More info please

[Bill]

http://diydrones.com/profiles/blogs/fut ... engineered
http://mbed.org/users/Digixx/notebook/f ... d-by-mbed/

[ShowMaster]

Thanks

[Helle]

hy,

sbus decoder with arduino pro micro to PPM1-16 or PPM1-8 or PPM9-16 and 8 Servos Ch9-16 out
http://openrcforums.com/forum/viewtopic ... sed#p63918

Helle

[Tomkfly]

I'm quite confident that the last two I bought work as they should.

Tom

I'm now finding the SBUS a bit flakey and wouldn't trust it in a largish model. I find I have to switch the RX on and of a number of times before it syncs. Sometimes at switch on it actually operates the wrong channels, sometimes the servos cycle and other times nothing works. These are the second two decoders I bought and initially thought they were okay.

Tom

[ShowMaster]

Darn! I have one of the first ones and don't know if it's worth trying to get aloft to replace it especially if the latest ones are in trouble also.
I may just write it off and salvage the parts and cables for the parts box. Maybe wait 6mo and try again?
I'm assuming Frsky will have to solve this as more Taranis radios are delivered and other require the sbus decoder a to work reliably?

[Tomkfly]

Darn! I have one of the first ones and don't know if it's worth trying to get aloft to replace it especially if the latest ones are in trouble also.
I may just write it off and salvage the parts and cables for the parts box. Maybe wait 6mo and try again?
I'm assuming Frsky will have to solve this as more Taranis radios are delivered and other require the sbus decoder a to work reliably?

I'm not sue my last two are the latest spec. They came from HK and the date is right on the line for the change.
I also think I might get problems that others may never come across, as I am really pushing them to the limits. The problems only showed up when I introduced a function using the TIM function and curves, which involves very fast switching.(switching LEDS for gunfire simulation)
It was Okay using a similar, but slower function, for moving a pilots head.

Tom

[AlexC]

I just bought one from Aloft dated 09/08/13. I assume this will not have the most recent firmware.

EDIT: Wayne at Aloft has offered a refund or exchange for the up to date version.

[Tomkfly]

Yes that will be an old version. According to Fr'Sky the change was "the middle of September".

Tom

[Spoogy]

Hi,

I interestedly read trhough this thread and all the provided "side" threads from the posted links, as I'm setting up my first model with a FrSky S.BUS decoder. It's a 4 meter wingspan glass fiber model with a 10 servo assigments aerobatic glider (Lunak). I was planning to use decoders for the wing servos (three on both wings). I got couple decoders last year summer time, but I think those are with old firmware.

And the questions are: should I get them changed right away or should I try them first? What if they seem to work perfect, even that they are with old firmware. May there come a situation that they suddendly they stops working on the air? If I want to change those, should I contact directly to FrSky or via HK where I bought those?

Also I want to mention that there is a guy in here Finland who makes decoders for Futaba S.BUS version 1 and 2 (full support for both). They don't need any channel changer. Those are assigned via transmitter. Could those work on X8R? Is that S.BUS protocol same? Those costs only 15€

Here are some links for early version for those Finnish made S.BUS decoders. They are even more evolved now. Manual is for v1 and in Finnish language... :\ The second version has this S.BUS-2 support but I don't see manual available for that (yet).

-Spoogy

[Spoogy]

Okay, I tested my two SBUS decoders today which are dated 20/08/2013 (both) and I found out that there's 4 states where they are initialized:

I assigned channels from 9 to 12 for both decoders starting from pin header 1. So, pin header 1 was channel 9 where I attached a servo. From the radio I set rudder stick to channel 9. I tested one decoder at the time with a one servo.

- State 1. All was normal. Leds was solid green and servo responded normally.

- State 2. Leds was blinking at high rate but servo responded stick movement. Although it seemed to move little bit slower and it was also quieter than normally.

- State 3. Leds was blinking at high rate and servo danced rumba (jittered) on the table.

- State 4. No leds at all first but then casually led number 1 blinked and servo jittered. And when stick was touched it begun to jitter and blinking even more.

Also I noticed that they started up on state 2 more often than any other.

So, to question is if I wanna get these replaced do I contact directly to FrSky, because we know that HK is not so willing to replace the goods or lets say it's hard to deal with HK?

Also, could I trust these faulty ones if they are started up as they should?

-Spoogy

[Tomkfly]

Mine behave exactly the same. Fr'Sky say once they sync they are OKay., but I am a little nervous of trusting them in a large model.

Tom

[Spoogy]

Yeah, me too. I might use these for controlling the leds or something else not so critical on the plane, but it might be frustrating for trying to start-up the electrics for the plane so, that decoders boot-up correctly on the field.

I just send a message to FrSky what to do and see what they answers. I might trash these and get a new ones. Just thinking that where I could get a new ones which are up to-date. Maybe HK has good stock? I don't know. Any good (trusted) source in a Europe?

-Spoogy

[Tomkfly]

Giant Shark have some in stock.
http://www.giantshark.co.uk/product/172 ... wm-decoder

Tom

[Spoogy]

Could anyone say if I could use those Futaba decoders (those custom made which I mentioned above) on X8R. Mainly the question is that, is that S.BUS protocol same on both brands?

The servo center seems to be 1520ms on those decoders (according to manual) and in Taranis that is 1500ms by default, but it can be changed (as far as I know). How about the ending points. Those are 880ms and 2160 on decoders. Does that make them incompatible or... ?

Those I could get in a couple days and they are not expensive.

edit: Thanks Tomkfly for the tip.

-Spoogy

[Kilrah]

S-bus is s-bus, it should work. No idea about the end points, you'll probably have to adjust the limits...

[Spoogy]

Just thinkering here that the Taranis PWM pulse is 1500us by default when servo is centered and it should then send SBUS value 991 which converts throug decoder as 1520+(991-1023)*0.625=1500us so, the servo should be in a same position with decoder or without it (direct connection to receiver). If FrSky SBUS doesn't work as Futaba has made the specs. then if it outputs SBUS value 1023 for 1500us pulse then there will be 20us offset by the decoder compared direct connection to receiver.

Futaba SBUS resolution is 625ns for each digistep and I've been told that for example Powerbox converts that as 500ns/digistep which causes servo resolution to drop and the movement of servo is limited compared to directly receiver connected servo.

Just thinking that, how it might be. I don't know about Taranis SBUS... but I talked with the maker of those decoders and requested one already for testing.

-Spoogy

[Kilrah]

The X8R puts out 992 on Sbus for a 1500us center.

[Spoogy]

Hmm...starting from 1 not zero? Odd.... Okay, but difference is minor. But it's not following specs.

Thanx for the info!

-Spoogy

[thomasf]

Hello,

I bought two decoder end of December. They have the following date codes.

date code 15JUN13
date code 17/09/13

The older one (15JUN13) has the same faulty behaviour as Spoogy described.
The newer one seams to work ok (Leds were solid green, Servos worked normally)
Test was identical for both with Taranis+X8R on channels 9-12 with 3 futaba and one savox servo.

I made some sbus modification to multiwii code, so I know that there are the following values on
X8R sbus.

// TARANIS % <> SBUS RAW <> RCVALUE (us)
//X8R SBUS Mid-Point at 1500 -100..+100 <> 172..992..1811 <> 1090..1500..1909
//X8R SBUS Mid-Point at 1500 -120..+120 <> 009..992..1974 <> 1008..1500..1991

I will contact the seller to get the wrong exchanged.

Thomas

[Kilrah]

Hmm...starting from 1 not zero? Odd.... Okay, but difference is minor. But it's not following specs.

Hmm I checked that with channels that actually had the sticks mixed on. 1 unit is pretty much equivalent to the noise on the stick reading, so probably if I had just looked at the stick it would have gone to 991. The us display rounds to single us, so it could have been at least +/-1 sbus count off. So completely irrelevant.

And it can't follow non-existant specs S-bus has been reverse engineered, it's never been given away by Futaba.

[thomasf]

Hello ,

I found this at

http://www.frsky-rc.com/BBS/viewtopic.php?t=107

“
The Decoder sprayed date code show the middle (20th) of SEP is new upgraded version. We are most suggesting contact your seller or Frsky dealer for replacement if necessary for save the delivery cost. (this decoder is not support customer own upgrade.)
“

Thomas

[Spoogy]

Why it is 992?

Eleven bits = 2047 / 2 = 1023 .... how many digital steps there might be then on Taranis SBUS?

edit: okay Kilrah answered meanwhile I was writing here. Yes, that's totally irrelevant. So forgot my above thinkering.

-Spoogy