Recently, JR Americas began advertising a protocol converter recently, to change from X-Bus to S-Bus (or vice-versa) called the "SXD Universal Serial Bus Adapter." This is a great device for interfacing with third party electronics manufacturers who have not yet provided X-Bus compatibility!
While I think that this is really intended for those purchasing drones which have S-Bus equipped electronics/gyros, I have been testing one with the Robird FBL unit (I used to fly for Robird USA and have quite a few of them) in my old Atom 550 to see what the result was. Robird development got as far as S-Bus support, but never X-Bus. This was, IMHO, the last thing that was really lacking in it.
The SXD Adapter was connected between between the X-Bus port on the receiver and the Robird. I had to reverse the directions of all of the channels in the FBL unit (from what they were with the PWM setup), and increase the endpoints as well (in PWM mode, the end points were all at about 104% in the 28X, with the Protocol Converter I had to increase them all to roughly 117% in order to maintain 100% travel in the Robird setup program).
Robird has a separate Tail Servo bus (so that the user could run lower voltage to some of the older tail rotor servos). in this particular setup, the Tail Rotor Bus was powered by taking a male-to-male connector, removing the signal (white) lead, then connecting it from an open channel on the receiver to the SRX2/Rud port on the Robird. This takes away a bit from the simplicity of the single X-Bus connection between the receiver and the FBL unit, but was necessary (this could also have been accomplished by removing the FBL unit, disassembling it, and soldering a jumper between the main power bus and the tail servo bus).
With the SXD Adapter, the servos respond a great deal more rapidly to control inputs than with the PWM setup. I assume this is due to the speed of the serial data connection between the DMSS receiver and the Robird.
I did go through the entire Robird setup and did a lot of testing prior to test flying.
I finally got the chance to go out and test fly the machine this morning.
I put five flights on the Atom 550 today with the Robird and the JR Protocol Converter! I had a blast-the machine felt more responsive and more connected than ever. I did have to increase the gains a bit both on cyclic and rudder. I will be adding more JR SXD Adapters to upgrade my existing PWM setups in the future!
I realize that there are not a lot of people flying Robirds these days (there are a great many other, newer FBL units), but the protocol converter should open the door for JR users (especially mulit-rotor types) who want to get the benefits of X-Bus with third party electronics that only support S-Bus.
Team KBDD/Compass Team Manger/Prostar Hobby/Team JR Americas/Gens Ace/WR Field Rep