Example Garmin G3X System Schematic

[MCA]

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.

[Longez]

Originally Posted by Strikhedonia

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...matic-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

[Strikhedonia]

Originally Posted by Longez

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.

[Longez]

Originally Posted by Strikhedonia

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.



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

[g3xpert]

Originally Posted by Strikhedonia

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.

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

[Strikhedonia]

Originally Posted by Longez

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.

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

[Strikhedonia]

Originally Posted by g3xpert

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

[Walt]

Originally Posted by Strikhedonia

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).

[Strikhedonia]

Originally Posted by Walt

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)?

[Longez]

Originally Posted by Strikhedonia

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