G3X Setup Questions

Hey G3X Guys,

The above is what I am looking at...

The GSU25 has a green light on it, so I know it is getting power.

The GMC305 also has power on both pins.

Both roll and pitch servos are energized.

I am running version 8.5 and have reloaded it twice with all devices powered up.

The GMU22 is connected.

The CANBus adapter is installed at the GEA24 and the shunt is installed on the pitch servo.

The roll servo is not installed.

I have not calibrated the GMU22.

It seems that I cannot test the autopilot functions.

What am I doing wrong?

CJ

Do you have your CAN wired to be terminated at the Roll Servo then? If not, did you either try plugging in the roll servo or putting in the can adapter there? I can't give you a detailed idea until I know where you wire the CAN termination to be in the system/loop verses where you have actually placed the adapters, etc..

Did you try sending a note directly to the Garmin folks? They usually answer those support emails within minutes and it you might get a quicker response. Just a suggestion!

Cheers,
Stein

Stein, No the CAN Termination is on the pitch servo and that IS installed. The roll servo is not, as the wings are not mounted onto the fuse.

I haven't talked to Garmin yet because I am familiar with this forum and thought I would try here first.

I know that Matt and Steve check in here often.

CJ

CAN wires reversed on the GSU25? I assume the GDUs are not at one end of the CAN bus, and you did not connect pin 28 to 45 on either of the GDUs Could you post the schematic of the bus?

Hello CJ,

This forum is great, but it is actually pretty hard to provide support at times without being able to copy and paste information.

If we had received this over [email protected], we would have pretty quickly asked you to highlight the GSU25 and magnetometer and provide screen shots of the lower window with those devices highlighted.

A red-x in that upper window doesn't always mean no communication, but since you didn't report that the green status LED on the GSU25 is flashing, it is probably not communicating properly and there is a CAN bus wiring or termination problem.

There is also a display of CAN ERROR RATE at the bottom of the lower window for each device which we always ask about. A good CAN connection will always show a 0% error rate.

Fortunately CAN bus problems are usually very easy to fix. As suggested above, we could benefit from knowing where the CAN bus starts and ends and knowing that the termination is only at those devices. Since you state that termination is at the GEA24 and the pitch servo, those two devices must be located at the extreme ends of the twisted pair CAN bus.

Contact us and I am sure we will get you going in no time.

Thanks,
Steve

Steve,

Email sent!

Thank you in advance!

CJ

CAN Bus wiring

Can someone please provide an example of how to wire a node on the can bus? I fully understand the wiring diagram. The bus has a beginning and ends with a terminator on the end. Then there is a node that tee off. The shields are tied together per the g3x install manual. My question is how do you physically make that connection; tee connectors, wire splices and heat shrink? Pictures if you got'em.

Thanks in advance.

Refer to the g3X installation manual revision L, page 16-16, figure 16-12. Each node is formed at the connector using the method shown. In the case of the CAN bus, two wires are connected verses the single wire splice shown in the aforementioned figure. A termination is used at either end of the bus. This is accomplished by either using the termination adapter, or connecting the termination pin as shown for the specific LRU.
Hope this helps

I was kind of thinking that was it.
Thanks for the reply.