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S Bus

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Old 09-17-2017, 06:11 PM
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JollyPopper
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Default S Bus

What is S Bus and how does it work? What does it allow me to do that a traditional receiver does not?
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Old 09-17-2017, 08:09 PM
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Do you know anything about computers? Have you ever looked inside one and seen all the different "cards" plugged into the "Motherboard"? Noticed that all the connections are wired together?

Well "S Bus" basically stands for "serial buss" and is a computer term. Data sent between various components on the same electrical "path". is accomplished by giving each component it's own "address". Data is delivered in "packets" of information and each of those packets have identifiers noting the address of the component they are meant for as well as a starting marker and an ending marker so the component knows if it got the whole package. If not, it will request that the sending component resend that packet which was not received completely.

So like an address on your house and all the others on the same road, the mailman knows where each piece goes and only one road is required for all the houses.

A serial buss is basically the same thing only for data transmission and allows you to "number" each servo and using only one wire, send instructions to each specific servo and not all of them. Sometimes it will be necessary to ad an additional power source at the "hub" where all the servos plug in as the connectors are limited in their ability to carry larger amounts of current.

Your cell phone, cordless phone, home Internet network and even your 2.4GHz RC equipment all work the same way.

Does that help?
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Old 09-18-2017, 04:37 AM
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With an S.bus receiver, the receiver will support as many channels on the S.bus port as the transmitter provides, even though the receiver may only have a few PWM on it, such as the R6303sb that I run with an S.bus capable power expander. Serial bus power expander/flight controllers sre growing in popularity, the X24 from XPS being a good example.
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Old 09-18-2017, 05:53 AM
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Sbus means you have to spend more on Sbus compatible servos.
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Old 09-18-2017, 09:34 AM
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Quote:
Originally Posted by rgburrill View Post
Sbus means you have to spend more on Sbus compatible servos.
LOL.....

Not necessarily.... Conventional servos may be used with a hub installed. That said; the S.Buss2 servos are really nice but as you noted, pretty damn spendy.

Last edited by Zeeb; 09-18-2017 at 09:36 AM.
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Old 09-18-2017, 10:32 AM
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Since Hitec has added S.bus to some of their newer receivers, I wonder if they'll be adding S.bus capability to their newer digital servos?
If the servos already are programmable, how hard would it be to add S.bus?
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Old 09-18-2017, 10:59 AM
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Here is just what my observation is but it seems like most people use the SBus function on SBus receivers for 2 things:

1. Serial receiver redundancy on supported devices
2. Multirotors

1. Systems like PowerBox SRS or the new XPS X24 require serial receivers for control input (these devices handle power distribution/servo matching on large models that require a large number of servos), the main advantage is these devices can allow up to 4 SBus receivers for the input to pretty much ensure that you will never have a problem with reception (more receivers, more antennas, more field of view, per say).

2. Multirotors, some of these models require a serialized input to control various functions on the flight controller, as well as to help cut weight down.
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Old 10-07-2017, 04:42 AM
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What Hitec TX works with s-bus? Only the 9X or will the older A9 work with a software upgrade.
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Old 10-08-2017, 08:10 AM
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Quote:
Originally Posted by JollyPopper View Post
What is S Bus and how does it work? What does it allow me to do that a traditional receiver does not?
It's a Futaba system designed as an attempt to 'lock you in' to buying Futaba's expensive S-Bus servos. And as an 'incentive' for you to do this they now don't make any 'regular' receivers with more than eight channels.

They say it saves you wiring and complication, but in practice it doesn't as for every three servos you have to buy a little box (more expense) that you connect the servos to. And of course you have to find accessible places to put these little boxes.

What it boils down to is that they have, in effect moved the 'addressing' of the servos (previously in the 'hardware' form of the numerous output sockets on the receiver) from the receiver to the servos themselves.

It works fine, but for the modeller rather than Futaba it has no real point. It does allow multiple battery setups, sometime useful in larger planes, but that's dead simple to do yourself on a regular system anyway. But if you have to have this 'bus' gimmick (which is all it is) then go for the Futaba one. Others now do similar stuff but Futaba's is the only one that has gained significant acceptance.

Last edited by Mark Powell; 10-08-2017 at 08:12 AM.
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Old 10-09-2017, 08:58 AM
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Amazing system, once you get used to it you can't go back to anything else. On the SBus you can connect any device that is SBUS enabled, servos, gyros, telemetry sensors anything. You can also use SBUS without Futaba but have to use the 'Powerbus' connections of a PowerBox SRS devise that has this feature (Powerbus).

You assign the servo channel and that is it. You can connect it any point in the system. For an airplane with 10 servos or more with telemetry etc it makes sense obviously it might not make sense for 5-6 servos.

I'm very happy with it - really happy.

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Old 10-09-2017, 12:27 PM
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Quote:
Originally Posted by geneh-RCU View Post
What Hitec TX works with s-bus? Only the 9X or will the older A9 work with a software upgrade.
The original Aurora 9 can use either the Optima SL or Optima D receiver to get s.bus.

Quote:
Originally Posted by Mark Powell View Post
It's a Futaba system designed as an attempt to 'lock you in' to buying Futaba's expensive S-Bus servos. And as an 'incentive' for you to do this they now don't make any 'regular' receivers with more than eight channels.
Hi Mark, they have a 14 channel with s.bus that was just introduced:

https://www.towerhobbies.com/cgi-bin...&I=LXGPHA&P=ML

Not to mention the other receivers can generally be linked in a manner such that you expand the channels available.
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