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Garmin G3X Canbus Wing Connection Question

J

jelliott82

Member
Hello

Second question for me today relating to G3X Canbus! What are you guys doing with running the Canbus out to the aileron servo in the right wing?

I have put ring terminal joiners on the seat floor ribs to connect all the wing wiring to (landing lts, position lts, strobe lts, OAT Probe, CanBus etc) and I have run 2 lengths of Canbus wire into the wing (1 in and 1 out if you like), connected to the Aileron servo as per standard Canbus wiring and then I have effective cut the Canbus (Hi, Lo, and Shield) at the wing root to join them together with the fuselage runs via a ring connector terminal block as per the photo.

So the question ... is this an acceptable way of handling the Canbus for the wing wiring? I am hoping this is what others have done successfully given I have already finished wiring it like this!

0SxCNvVqzSUaRZhsdeytZZfLg


https://share.icloud.com/photos/0SxCNvVqzSUaRZhsdeytZZfLg

Thanks,
Jonathan
 
Last edited:
jelliott82 said:
Hello

Second question for me today relating to G3X Canbus! What are you guys doing with running the Canbus out to the aileron servo in the right wing?

I have put ring terminal joiners on the seat floor ribs to connect all the wing wiring to (landing lts, position lts, strobe lts, OAT Probe, CanBus etc) and I have run 2 lengths of Canbus wire into the wing (1 in and 1 out if you like), connected to the Aileron servo as per standard Canbus wiring and then I have effective cut the Canbus (Hi, Lo, and Shield) at the wing root to join them together with the fuselage runs via a ring connector terminal block as per the photo.

So the question ... is this an acceptable way of handling the Canbus for the wing wiring? I am hoping this is what others have done successfully given I have already finished wiring it like this!

0SxCNvVqzSUaRZhsdeytZZfLg


https://share.icloud.com/photos/0SxCNvVqzSUaRZhsdeytZZfLg

Thanks,
Jonathan
Click to expand...

I will let Garmin answer this.

I would have made a connection with connectors that looks like the Can Bus connection on the back of the units.
 
I like it.

As long as the CANbus Hi, Lo, & Shield wires form a continuous track without any "spurs", and only the far ends are terminated (either with the magic dongle, or with the jumper) you'll be fine.
 
jelliott82 said:
Hello

Second question for me today relating to G3X Canbus! What are you guys doing with running the Canbus out to the aileron servo in the right wing?

I have put ring terminal joiners on the seat floor ribs to connect all the wing wiring to (landing lts, position lts, strobe lts, OAT Probe, CanBus etc) and I have run 2 lengths of Canbus wire into the wing (1 in and 1 out if you like), connected to the Aileron servo as per standard Canbus wiring and then I have effective cut the Canbus (Hi, Lo, and Shield) at the wing root to join them together with the fuselage runs via a ring connector terminal block as per the photo.

So the question ... is this an acceptable way of handling the Canbus for the wing wiring? I am hoping this is what others have done successfully given I have already finished wiring it like this!

0SxCNvVqzSUaRZhsdeytZZfLg


https://share.icloud.com/photos/0SxCNvVqzSUaRZhsdeytZZfLg

Thanks,
Jonathan
Click to expand...
Hello Jonathan,

It is best to not run instrumentation wiring through a terminal block, especially one that mixes these signals with high power signals like strobes. If you have ever seen old terminal blocks in airplanes, you probably know why.

Those zinc/tin connections used in lieu of the gold plated contacts used on all the D-Sub connectors might work ok for a while, but would likely turn in a liability.

The precision RTD in the GTP 59 OAT probe works off of a very small resistance delta from the 500 ohms it reads at zero C. Adding these connections inline between the probe and the GSU 25 is likely to ultimately cause errors in OAT(SAT)/TAS/Winds.

The high speed CAN data bus which supports multiple ADAHRS units outputting attitude data at 50 Hz and simultaneous communications between many devices sharing data on the bus works best with a robust twisted, shielded pair backbone with no inline connectors. The only connections are not inline and are at the various CAN devices which use gold contacts to listen and transmit on the common twisted pair bus.

Paul D. mentioned in this posting that after 4 years of using CPC connectors (better than terminal blocks by a lot) and having corrosion problems, "Next time, I'd realize that the only way I am ever going to pull the wings off is if the airplane is in a field somewhere, so I would just run extra wires out the root and make the connections inside the fuse.".

Thanks,
Steve
 
Hi Steve

Ok interesting, Thank you for the info below. Wish I had asked before finishing the wing wiring!

Also wish I had mounted the OAT probe on the fuse somewhere now too.

Anyway such as life, so what is every body else doing with this? Surely people aren't finishing their RVs and then running the Garmin wiring?

Would it be suitable to order more Garmin DSub connectors and install these under the seat pans for connecting the servo and OAT devices? Or is this not recommended either?

Thanks once again,
Jonathan

g3xpert said:
Hello Jonathan,

It is best to not run instrumentation wiring through a terminal block, especially one that mixes these signals with high power signals like strobes. If you have ever seen old terminal blocks in airplanes, you probably know why.

Those zinc/tin connections used in lieu of the gold plated contacts used on all the D-Sub connectors might work ok for a while, but would likely turn in a liability.

The precision RTD in the GTP 59 OAT probe works off of a very small resistance delta from the 500 ohms it reads at zero C. Adding these connections inline between the probe and the GSU 25 is likely to ultimately cause errors in OAT(SAT)/TAS/Winds.

The high speed CAN data bus which supports multiple ADAHRS units outputting attitude data at 50 Hz and simultaneous communications between many devices sharing data on the bus works best with a robust twisted, shielded pair backbone with no inline connectors. The only connections are not inline and are at the various CAN devices which use gold contacts to listen and transmit on the common twisted pair bus.

Paul D. mentioned in this posting that after 4 years of using CPC connectors (better than terminal blocks by a lot) and having corrosion problems, "Next time, I'd realize that the only way I am ever going to pull the wings off is if the airplane is in a field somewhere, so I would just run extra wires out the root and make the connections inside the fuse.".

Thanks,
Steve
Click to expand...
 
jelliott82 said:
Hi Steve

Ok interesting, Thank you for the info below. Wish I had asked before finishing the wing wiring!

Also wish I had mounted the OAT probe on the fuse somewhere now too.

Anyway such as life, so what is every body else doing with this? Surely people aren't finishing their RVs and then running the Garmin wiring?

Would it be suitable to order more Garmin DSub connectors and install these under the seat pans for connecting the servo and OAT devices? Or is this not recommended either?

Thanks once again,
Jonathan
Click to expand...
Hello Jonathan,

One good option is to just do what Paul recommended which is to run the extra wire you need out of the wing, then after the wing is attached wire the OAT probe to the GSU 25 and the two CAN bus ends to the previous and next CAN bus devices in the daisy-chain.

No extra connectors needed.

Thanks,
Steve
 
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