What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Example Garmin G3X System Schematic

Strikhedonia

Well Known Member
I did a search and didn't see any recent posts on this topic, if I missed one let me know and I'll delete this post and add to that one.

I just finished up the exhaustive process of creating a schematic for my upcoming panel (3 G3X displays, G5, GMC 507 A/P (roll,pitch, yaw), GTN 650, GSU 11 and GSU 22, GMA 245, pretty much every option available). I'm happy to share this information for those looking to take this on with their build. All the documents are on my blog: http://www.svstrikhedonia.com/garmin-g3x-avionics-schematic-drawing/

I spent a lot of time validating but if anyone finds a mistake I'd love to know before I begin making up connectors in a few weeks...
 
I did a search and didn't see any recent posts on this topic, if I missed one let me know and I'll delete this post and add to that one.

I just finished up the exhaustive process of creating a schematic for my upcoming panel (3 G3X displays, G5, GMC 507 A/P (roll,pitch, yaw), GTN 650, GSU 11 and GSU 22, GMA 245, pretty much every option available). I'm happy to share this information for those looking to take this on with their build. All the documents are on my blog: http://www.svstrikhedonia.com/garmin-g3x-avionics-schematic-drawing/

I spent a lot of time validating but if anyone finds a mistake I'd love to know before I begin making up connectors in a few weeks...

I?d recommend a adding a second ADAHRS... you have a backup magnetometer, so why not ADAHRS?
 
I?d recommend a adding a second ADAHRS... you have a backup magnetometer, so why not ADAHRS?

Initially I had planned to have a second ADAHRS. But in researching about the G5 I learned that its built in ADAHRS, when coupled with the GSU 11 and GAD 13 (temperature), provides redundancy. From g3xpert, "single GSU 25 can be powered off and the PFD will then revert to using the G5 provided attitude data." The G5 can also drive the GMC 507 in a backup situation. So that led me to delete the second GSU 25.
 
Chris, I owe you a beer at OSH. I'm planning out the almost identical layout you are with 3 G3X displays and GTN650xi and was going to spend hours reinventing the wheel, not any more!

I listened to the CAN Bus webinar from Garmin and the presenter recommended doing more of an "L" shape with the layout, starting at the Roll Servo and ending in the rear of the plane (as Leok did in his layout).

I'm going through how much wire to order to get started and will report back. Any body have thoughts on integrating the TCW IBBS into the G3X system? If you wire to the backup power source on the GDU, GSU, GEA not only is it used as a backup, but stabilized power for starting. Correct?
 
From an IFR perspective, is there an advantage to have a GTN750 instead of a GTN650 + G3X MFD?
How about seeing yourself on a geo-referenced plate? Can the G3X do that? Or is in the end an iPad better than a G3X for that?
I see that all advertisements for the G3X are done referring to VFR, not IFR while GTN750 is an IFR instrument.
Thanks
Martin
 
Chris, I owe you a beer at OSH. I'm planning out the almost identical layout you are with 3 G3X displays and GTN650xi and was going to spend hours reinventing the wheel, not any more!

I listened to the CAN Bus webinar from Garmin and the presenter recommended doing more of an "L" shape with the layout, starting at the Roll Servo and ending in the rear of the plane (as Leok did in his layout).

I'm going through how much wire to order to get started and will report back. Any body have thoughts on integrating the TCW IBBS into the G3X system? If you wire to the backup power source on the GDU, GSU, GEA not only is it used as a backup, but stabilized power for starting. Correct?

Happy that I could help! Please be sure to double check everything, I am still working on wiring so I am not able to confirm that everything works yet.

The "L" shape sounds like a good way to go, I did the math and the orientation I have will be easily under the 66 foot maximum so it should be okay for me.
 
From an IFR perspective, is there an advantage to have a GTN750 instead of a GTN650 + G3X MFD?
How about seeing yourself on a geo-referenced plate? Can the G3X do that? Or is in the end an iPad better than a G3X for that?
I see that all advertisements for the G3X are done referring to VFR, not IFR while GTN750 is an IFR instrument.
Thanks
Martin

The only difference is between the 650 and 750 is the size. For IFR the requirements are for the GPS/NAV/COM to be certified, which the 650 (650xi) meet. The 650 shares data with the G3X and the MFD is able to display IFR low enroute and approach plates.
 
From an IFR perspective, is there an advantage to have a GTN750 instead of a GTN650 + G3X MFD?
How about seeing yourself on a geo-referenced plate? Can the G3X do that? Or is in the end an iPad better than a G3X for that?
I see that all advertisements for the G3X are done referring to VFR, not IFR while GTN750 is an IFR instrument.
Thanks
Martin

The main advantage to the 750 is the larger screen. I have a 3 screen G3X touch layout, with the GTN 650 IFR navigator. The G3X screens WILL show geo-referenced aircraft position on the approach plates shown on the G3X. Works great:). Many other pilots I've taken up are quite impressed with the capabilities of the system.
 
The main advantage to the 750 is the larger screen. I have a 3 screen G3X touch layout, with the GTN 650 IFR navigator. The G3X screens WILL show geo-referenced aircraft position on the approach plates shown on the G3X. Works great:). Many other pilots I've taken up are quite impressed with the capabilities of the system.

Thanks, great answer. I am used to flying IFR with GNS430/530/GTN650/750 and having my iPad mounted somewhere and was therefore hesitant to plan my RV-10 panel with G3X only. It seems the iPad will just go into the side pocket as backup but doesn't need panel space!
 
XM Radio

You have the XM antenna going right to a GDU 465.

Check me on this, but I'm pretty sure the 465 display is discontinued, and you now need to install a GDL 51R, and run that to a 460.
 
I did a search and didn't see any recent posts on this topic, if I missed one let me know and I'll delete this post and add to that one.

I just finished up the exhaustive process of creating a schematic for my upcoming panel (3 G3X displays, G5, GMC 507 A/P (roll,pitch, yaw), GTN 650, GSU 11 and GSU 22, GMA 245, pretty much every option available). I'm happy to share this information for those looking to take this on with their build. All the documents are on my blog: http://www.svstrikhedonia.com/garmin-g3x-avionics-schematic-drawing/

I spent a lot of time validating but if anyone finds a mistake I'd love to know before I begin making up connectors in a few weeks...

You have put together a great system and you will be very happy with your choices!

A couple of comments:
  1. Unless something has changed that I am not aware of, the GTN can only transmit MapMX over a single RS-232 port, so you can't use 2 GTN serial ports for the G5/PFD like you have shown. Just parallel the MapMX TX output from a single serial port on the GTN to both the G5/PFD.
  2. As others have mentioned, the GDU 465 display with a built-in SXM receiver is no longer being offered, so you would need a GDL 51R (SXM only) or GDL 52R (ADS-B traffic/weather plus SXM weather/radio). I have the GDL 52R in my aircraft, and it allows me to have both ADS-B traffic/weather and SXM weather/music selection on 2 displays (since the GDL 52R supports 2 RS-232 connections). On your 3rd display, you could connect it to only the GTX 45R for ADS-B traffic/weather. Another option is to connect the 3rd display to the GDL 52R using Bluetooth, and install a lower cost GTX 35R instead of the GTX 45R. The only downside of this is that your GTN would no longer have traffic/weather, but that is not a big deal since you have 3 large 10.6" GDU 460 displays providing traffic and 2 kinds of weather.
  3. You should consider only installing one magnetometer, not two. Measuring the earth's magnetic field in small aircraft is fraught with problems and installing 2 magnetometers is asking for heading miscompare errors during maneuvering. If you look at the accuracy requirements of TSO'd magnetometers, you will realize the low accuracy of magnetometers in general. Personally, I always use a GPS track based HSI in my G3X Touch aircraft and use TRK mode on the autopilot instead of HDG mode unless being heading vectored by ATC. I couldn't care less where the nose of the aircraft is pointing (heading), but care a lot about whether or not the aircraft ground track is following the course line (GPS track). Losing the single magnetometer (unlikely) in a G3X Touch aircraft is not a big deal since it does such a good job of integrating GPS TRK with the autopilot and HSI.

Steve
 
Last edited:
You have put together a great system and you will be very happy with your choices!

A couple of comments:
  1. Unless something has changed that I am not aware of, the GTN can only transmit MapMX over a single RS-232 port, so you can't use 2 GTN serial ports for the G5/PFD like you have shown. Just parallel the MapMX TX output from a single serial port on the GTN to both the G5/PFD.
  2. As others have mentioned, the GDU 465 display with a built-in SXM receiver is no longer being offered, so you would need a GDL 51R (SXM only) or GDL 52R (ADS-B traffic/weather plus SXM weather/radio). I have the GDL 52R in my aircraft, and it allows me to have both ADS-B traffic/weather and SXM weather/music selection on 2 displays (since the GDL 52R supports 2 RS-232 connections). On your 3rd display, you could connect it to only the GTX 45R for ADS-B traffic/weather. Another option is to connect the 3rd display to the GDL 52R using Bluetooth, and install a lower cost GTX 35R instead of the GTX 45R. The only downside of this is that your GTN would no longer have traffic/weather, but that is not a big deal since you have 3 large 10.6" GDU 460 displays providing traffic and 2 kinds of weather.
  3. You should consider only installing one magnetometer, not two. Measuring the earth's magnetic field in small aircraft is fraught with problems and installing 2 magnetometers is asking for heading miscompare errors during maneuvering. If you look at the accuracy requirements of TSO'd magnetometers, you will realize the low accuracy of magnetometers in general. Personally, I always use a GPS track based HSI in my G3X Touch aircraft and use TRK mode on the autopilot instead of HDG mode unless being heading vectored by ATC. I couldn't care less where the nose of the aircraft is pointing (heading), but care a lot about whether or not the aircraft ground track is following the course line (GPS track). Losing the single magnetometer (unlikely) in a G3X Touch aircraft is not a big deal since it does such a good job of integrating GPS TRK with the autopilot and HSI.

Steve

Steve,

I really appreciate the feedback, thank you!
1. See attached image, I believe I am wiring to match this document. Do you see any mistakes (I did change which serial port for the G5 but I don't believe that is an issue).
2. I was bummed to find out that from when I started the design until I got to the point of ordering components the 465 was discontinued. For now I am holding off on adding the XM receiver.
3. That is a great point about the magnetometer. I still plan to install both as as I would like a redundant system for my G5 should the Adhrs fail (and I have already purchased them). But I will keep the GMU11 powered down unless it is needed.

GTN650_G5_GAD29.jpg
 
Steve,

I really appreciate the feedback, thank you!
1. See attached image, I believe I am wiring to match this document. Do you see any mistakes (I did change which serial port for the G5 but I don't believe that is an issue).

Hello Chris,

You might have missed my point on item 1. The image you attached above shows the MapMX interface from the GTN to a single device (the G5), but doesn't cover your design which also requires GTN MapMX data be supplied to the PFD.

The point I was making is that you need to use a single RS-232 port (not 2) on the GTN to supply MapMX data to both the G5 and the PFD. As shown here, your block diagram shows 2 GTN RS-232 ports (ports 2 and 3) being used to output MapMX when the GTN only allows you to configure a single MapMX port.

MapMXConnections.png

If you wire it up the way you plan with 2 GTN RS-232 ports, you would find out when it comes time to configure the GTN that it doesn't support that wiring.

Steve
 
Steve,

I really appreciate the feedback, thank you!
1. See attached image, I believe I am wiring to match this document. Do you see any mistakes (I did change which serial port for the G5 but I don't believe that is an issue).
2. I was bummed to find out that from when I started the design until I got to the point of ordering components the 465 was discontinued. For now I am holding off on adding the XM receiver.
3. That is a great point about the magnetometer. I still plan to install both as as I would like a redundant system for my G5 should the Adhrs fail (and I have already purchased them). But I will keep the GMU11 powered down unless it is needed.

GTN650_G5_GAD29.jpg

To echo Steve's point on the dual magnetometer installation, you will need to reconsider how you plan on going about this part of the install. The only way to support dual magnetometers is to install two GSU 25 ADAHRS within the system, a G5/GSU25 installation does not support the installation of 2 magnetometers.

With a single GMU 11 on the CAN bus, you can lose either your GSU 25 or G5, and the remaining ADAHRS will still have access to the magnetometer data, as the GMU 11 exists as its own CAN bus LRU and is not reliant on either ADAHRS source to provide its data to the system. The GMU 22 is connected directly to the GSU 25 (not connected directly to the CAN bus), so if you lose the GSU 25, you would also lose the GMU 22. You could always install a 2nd GSU 25 to make use of the 2 magnetometers that you currently have, but a G5 and GSU 25 with a single GMU 11 should be sufficient.

Thanks,

Justin
 
Hello Chris,

You might have missed my point on item 1. The image you attached above shows the MapMX interface from the GTN to a single device (the G5), but doesn't cover your design which also requires GTN MapMX data be supplied to the PFD.

The point I was making is that you need to use a single RS-232 port (not 2) on the GTN to supply MapMX data to both the G5 and the PFD. As shown here, your block diagram shows 2 GTN RS-232 ports (ports 2 and 3) being used to output MapMX when the GTN only allows you to configure a single MapMX port.

View attachment 1401

If you wire it up the way you plan with 2 GTN RS-232 ports, you would find out when it comes time to configure the GTN that it doesn't support that wiring.

Steve

Steve,
I checked with g3xpert and this was Michael's response:
"The GTN will send MAPMX to the G5. The wiring diagram is correct. This connection provide GPS data to the G5 and allow you to not install a antenna on the G5."

But I'm still thankful you asked the question because it stopped me from potentially needing to redo some wiring if it had been wrong.
-Chris
 
To echo Steve's point on the dual magnetometer installation, you will need to reconsider how you plan on going about this part of the install. The only way to support dual magnetometers is to install two GSU 25 ADAHRS within the system, a G5/GSU25 installation does not support the installation of 2 magnetometers.

With a single GMU 11 on the CAN bus, you can lose either your GSU 25 or G5, and the remaining ADAHRS will still have access to the magnetometer data, as the GMU 11 exists as its own CAN bus LRU and is not reliant on either ADAHRS source to provide its data to the system. The GMU 22 is connected directly to the GSU 25 (not connected directly to the CAN bus), so if you lose the GSU 25, you would also lose the GMU 22. You could always install a 2nd GSU 25 to make use of the 2 magnetometers that you currently have, but a G5 and GSU 25 with a single GMU 11 should be sufficient.

Thanks,

Justin

Justin,
My design is with one GSU25/GMU22 and as a backup a GMU11/GAD13. The GSU25/GMU22 would be the primary and normally only powered magnetometer. If by some bad luck the GSU25/GMU22 failed, my thought was to power down the GSU25/GMU22 and power up the GMU11/GAD13. Is that a bad idea?

Thank you for the help!
-Chris
 
Steve,
I checked with g3xpert and this was Michael's response:
"The GTN will send MAPMX to the G5. The wiring diagram is correct. This connection provide GPS data to the G5 and allow you to not install a antenna on the G5."

But I'm still thankful you asked the question because it stopped me from potentially needing to redo some wiring if it had been wrong.
-Chris

In case you guys are unaware, Longeze Steve is the G3X guru and you would do yourself a big favor to listen to him above all else (he used to be G3Xpert in a past life).
 
In case you guys are unaware, Longeze Steve is the G3X guru and you would do yourself a big favor to listen to him above all else (he used to be G3Xpert in a past life).

Walt, thank you for sharing that!

Steve, the G3X install manual (Page 27-36) shows the MapMX to the GDU460 with both RS-232 Rx and Tx connected. Should the G5 get the Signal ground and the Tx (from the GTN 650) and skip the Rx (to the GTN 650)?
 
Walt, thank you for sharing that!

Steve, the G3X install manual (Page 27-36) shows the MapMX to the GDU460 with both RS-232 Rx and Tx connected. Should the G5 get the Signal ground and the Tx (from the GTN 650) and skip the Rx (to the GTN 650)?

Hello Chris,

Yes, wire the bi-directional GTN 650 to GDU 4XX MapMX interface with Tx/Rx/Gnd as shown on page 27-40 of the current Rev. AM G3X Touch installation manual.

The MapMX interface from the GTN to the G5 is a 2 wire interface with data only flowing from the GTN (Tx) to the G5 (Rx).

Steve
 
Hello Chris,

Yes, wire the bi-directional GTN 650 to GDU 4XX MapMX interface with Tx/Rx/Gnd as shown on page 27-40 of the current Rev. AM G3X Touch installation manual.

The MapMX interface from the GTN to the G5 is a 2 wire interface with data only flowing from the GTN (Tx) to the G5 (Rx).

Steve

Steve, Another big thank you! I have updated my blog post with revised schematics and the block diagram (removal of the second magnetometer and the corrected G5 MapMX). Your help is very much appreciated.
 
Back
Top