How to connect to SBUS on G-RX8?

[Stephen Belshaw]

I have put a G-RX8 in my Multiplex Lentus and connected the integral Vario, I also want battery state telemetry and so have bought a FAS40 Current Sensor. The sensor comes with a cable with a JR type plug at each end, which would be ideal in say an XR8 Rx but doesn't suit the Smart Port of the G-RX8. I have a lead with a Smart plug connection so can solder the two together but I'm not sure which wires I need and what goes where:

 

 

 

Edited November 11, 2022 by Stephen Belshaw

[Ron Gray]

The instructions for the GX8R show the S-Port connection details

 

[Mike Blandford]

The G-RX8 should have come with a cable to plug into the small, 4-pin connector of the Rx, mine did. This should have three wires going to a Futaba style connector, which is the SPort, and this then plugs directly into the FAS40.

 

Mike

[Stephen Belshaw]

Thanks for your reply Ron, I seem to have got my proverbial in a twist, it is in fact the Smart Port I need to connect the FAS40 to. Hence the need for the lead with the white plug, so that still leaves me in the dark as to which wires go where ..........

[Stephen Belshaw]

Just now, Mike Blandford said:

The G-RX8 should have come with a cable to plug into the small, 4-pin connector of the Rx, mine did. This should have three wires going to a Futaba style connector, which is the SPort, and this then plugs directly into the FAS40.

 

Mike

Yes Mike, I haven't got that, hence my query as to which wire goes where. I understand it could cause a terminal problem if I get it wrong.

[Ron Gray]

I've got a spare one already wired up, pm me your address and I'll send it to you.

[Stephen Belshaw]

That's very kind of you Ron, but I'm in Hungary! I think it would be quicker if I could just solder the two plugs I have together in the correct configuration ......

[Mike Blandford]

Does the white connector fit in the G-RX8?

If so, no soldering should be necessary. Each of the wires has a small connector crimped to it. These crimps are retained in the connector housing by a small tab.

Using a pin, or similar, gently prise each tab end (part furthest from the wire entry) and you should be able to (gently) pull the wire with crimp out of the housing.

Note which way the crimp was fitted into the housing.

Now just push the crimps back into the housing in the required order. Look at the side of the G-RX8 and the 4 positions are labelled +, -, AIN and a symbol that looks a bit like a 'S'.

Place the wires in so:

Red to +

Black to -

Yellow to the 'S'

White to AIN

 

The yellow wire my already be in the correct position (looking at your picture).

The other end of the cable with the white connector is also not correct, the red and black wires need to be swapped over. Again, these have crimps on them and a small tab holding them in place. Using a pin again, it is possible to pull these out from the black housing and replace them swapped over, you want the wires in the order of yellow, red black.

 

Then just put the white connector in the G-RX8 and the black connector in the FAS40. Check carefully before powering on that the signals do connect in the correct order:

- to -

+ to +

'S' to 'S'

 

Mike

[Stephen Belshaw]

Update on this, following Mike's instructions led to a quick resolution and the FAS40 was safely connected and discovered on my Taranis. Now to decide which battery parameter to monitor and use as an alarm, current, voltage or power consumed as suggested by Richard Mrázek in this video: 

 

 

[Andy Gates]

Steven,

 

Depends on your needs as to which you use or if you use all of them.

 

I fly a Pitts on a 60A speed control, its maximum current draw static on the ground is 120A. I use the higher current sensor that sits around the power cable, and have an alarm which sounds at 60A and a warning at 80A (ESC burst limit).

I also use a separate sensor which plugs into the lipo balance plug to give me voltage info including cell voltages.

 

Horses for courses.

 

Good luck