grayforge

grayforge

Well Known Member
Hi Folks,

I'm pouring over the G3X (Touch) Install Manual Rev M and ran into a bit of confusion on a couple items.

On page 20-5, the diagram mentions that the CAN Node Length cannot exceed 1 meter. I'm not sure what is meant by this since the distance to the servos is certainly more than a meter. Does it actually mean that the length of the cable between the device and where it connects to the CAN Bus 'trunk' can only be a meter or less?
CAN_BUS_Node_Length.jpg


On page 20-9, the signal ground from the GTU 460 is shown going to pin 'NA' on the GTR 200. Does this mean signal ground is found elsewhere and pin 34 on the GDU 460 does not need to connect to the radio?
GTR_200_Connection.jpg


Thanks!
Russ
 
On the first question, they are talking about stubs off of the main CAN bus trunk line. The trunk line is the longer line with the resistors at both ends. Do not put a resistor on the end of the stubs.

On the second question, you are correct, the ground is elsewhere.
 
Hi Russ,

Brian gave you good advice. You might also re-read this posting about CAN wiring.

You will want to connect your GTR 200 using the CAN bus just like shown on page 22-6 for the GTR 20. This is optional for a GDU 37X system, but really important to a GDU 46X system so you have access to all the touch tuning features if you choose to use them.

Additionally, the GTR 20 and GTR 200 share common software and this is automatically updated over the CAN bus from new G3X software updates when you have these radios connected via CAN on either type of G3X system.

We added CAN bus support for the GTR 200 to GDU 37X based G3X systems in V8.60 that was just recently released.

Thanks,
Steve
 
Awesome info guys.

So there will just be a single shielded wire for RS232-Out on the GDU 460 to RS232-In on the GTR 200.

Thanks!
Russ
 
grayforge said:
Awesome info guys.

So there will just be a single shielded wire for RS232-Out on the GDU 460 to RS232-In on the GTR 200.

Thanks!
Russ
Click to expand...

Hello Russ,

It will not be necessary to connect any RS-232 from your GDU 460 to the GTR 200. Just connect the CAN bus as mentioned above, and you will have full tuning capabilities either from the radio front panel or the GDU 460 touch screen.

On the COM Radio configuration page, your GTR 200 radio will be referred to as a "Network Radio".

Let us know if you have questions.

Thanks,
Steve
 
I looked through the G3X Install Manual (version M) to see if there were other devices that can use the CAN Bus instead of RS232.

Looks like at least 2:
  1. GI 260 AOA Indicator: I see the manual already mentions that it can run CAN only. :)
  2. GSU 25 AHRS: RS232 to the GDU 46X/37X looks to be for backup only.

I love technology.

Thanks,
Russ
 
thres more

what about the GAD 29 and the Autopilot Servos - both also wired into the CAN bus
 
Reading through the manual, it looks like you need both CAN and RS232 on the GSA 28 Roll Servo since it uses RS232 to interface with the GMC 305 (which doesn't have a CAN Bus).

The GAD 29 may talk to the GDU 46x/37x via the CAN Bus and the various radios and avionics via the ARINC interfaces.
 
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