Planning out G3X interconnects

The garage has gotten too cold to warm back up for riveting sessions on weeknights. So when I get home from work, I'm starting to turn my attention to electrical and avionics layouts.

Based on the discussions kicked up by the GTN 625 promo, here's my first stab at an interconnect list for a hypothetic system setup. Does anything stick out as glaringly wrong, should be improved, or otherwise? Most interesting is how, in a GTN 625 thread (http://www.vansairforce.com/community/showthread.php?t=123251), Brian @ Garmin says to connect the GTX 23 to the GDU display directly, rather than through the GTN. I'm a bit out of serial ports on the GDU screen it looks, though.

Let me know your thoughts. I'll be designing other variations on this list, with a 2nd GDU display (at which point I won't have serial port shortages. ), maybe a GTN 650 replacing the one GTR 20 & VAL NAV 2000, etc. But this is what I consider my base configuration for now.

Thanks!

(Ignore the connector notes - those are for me to start laying connector schematics out in SchemeIt)

1-Screen G3X Touch 460 w/GTN 625, 2x GTR 20 COMs, VAL NAV 2000 NAV
--

• GDU 460 (9 pin, 50 pin)
  • CAN Bus
  • RS-232 to GSU (P4601): To GSU 25 RS-232 1
  • RS-232 1: To GDL 39R RS-232
  • RS-232 2: To VPX Pro RS-232
  • RS-232 3: To GTN 625 RS-232 4
  • RS-232 4: To VAL NAV 2000 RS-232
  • RS-232 5: To GTN 625 RS-232 3
• GSU 25 ADAHRS (9 pin, 15 pin)
  • CAN Bus
  • RS-485: To GMU 22
  • RS-232 1: To GDU 460 P4601 RS-232
  • RS-232 2: To GMU 22
  • RS-232 3: To GTX 23 ES RS-232 1
• GEA 24 EIS (9 pin, 50 pin, 25 pin, 37 pin)
  • CAN Bus
• GMU 22 Magnetometer (??? pin)
  • RS-485: To GSU 25
  • RS-232: To GSU 25 RS-232 2
• GMC 305 A/P Head (15 pin)
  • RS-232 1: ?
  • RS-232 2: To GSA 28 Roll Servo RS-232 1
• GSA 28 Roll Servo (15 pin)
  • CAN Bus
  • RS-232 1: To GMC 305 RS-232 2
• GSA 28 Pitch Servo (15 pin)
  • CAN Bus
• GAD 29 ARINC (9 pin, 25 pin)
  • CAN Bus
  • ARINC Xmit 1: To GTN 625 ARINC In Air Data
  • ARINC Xmit 2:
  • ARINC Rcv 1: To GTN 625 ARINC GPS
  • ARINC Rcv 2: To GTX 23 ES ARINC-429 Out 2 (Hi-Speed)
  • ARINC Rcv 3:
  • ARINC Rcv 4:
• GTN 625 (78 pin, 26 pin)
  • ARINC Out GPS: To GAD 29 ARINC Rcv 1
  • ARINC In Air Data: To GAD 29 ARINC Xmit 1
  • RS-232 1: To GTX 23 ES RS-232 2
  • RS-232 2:
  • RS-232 3: To GDU 460 RS-232 5
  • RS-232 4: To GDU 460 RS-232 3
• GTR 20 COM 1 (37 pin)
  • CAN Bus
• GTR 20 COM 2 (37 pin)
  • CAN Bus
• VAL NAV 2000 (37 pin)
  • RS-232: To GDU 460 RS-232 4
• GTX 23 ES Transponder / ADSB-Out (60 pin)
  • RS-232 1: To GSU 25 RS-232 3
  • RS-232 2: To GTN 625 RS-232 1
  • ARINC-429 Out 1 (Lo-Speed):
  • ARINC-429 Out 2 (Hi-Speed): To GAD ARINC Rcv 2
• GDL 39R ADSB-In (9 pin)
  • RS-232: To GDU 460 RS-232 1
• Vertical Power VPX Pro:
  • RS-232: To GDU 460 RS-232 2

The GTN cannot control the GTX23ES like it can the GTX330ES.

If you install a GTN, you definitely want it's ADS-B+ output connected directly to the GTX23ES's serial port 2.

The G3X also connects to the GTX23ES's serial port 1 on a dedicated serial port on the AHRS for configuration and control.

Right, I know the GTN can't control the transponder, Brian. And just to be clear, the 23ES is configured/controlled by the serial link to the GSU.

It looks like the only question mark is the serial link between the GSU and GDU. That's noted in the core interconnect diagrams as being an "optional backup" to the CAN Bus link (Figure 21-1.2). Yes, no, reading things upside down, need to drink more coffee?

Thanks!

sbalmos said:

Right, I know the GTN can't control the transponder, Brian. And just to be clear, the 23ES is configured/controlled by the serial link to the GSU.

It looks like the only question mark is the serial link between the GSU and GDU. That's noted in the core interconnect diagrams as being an "optional backup" to the CAN Bus link (Figure 21-1.2). Yes, no, reading things upside down, need to drink more coffee?

Thanks!

Click to expand...

You can use the serial port built into the 9 pin P4601 for the backup AHRS to GDU link. That port is hard coded to be used as the GSU25 backup. This lets you keep your other 5 ports for others stuff.

AH! Okay, missed that serial link. Thanks Brian! I'll update the list in a moment.

Unless I missed it, You're going to need a second 232 line to the GTN if you're going to want to use the connext features.

avionicsr said:

Unless I missed it, You're going to need a second 232 line to the GTN if you're going to want to use the connext features.

Click to expand...

Yep good catch! To free up a port, you can just use the single connection between the roll servo and the GMC 305. You lose redundancy but it will still work just fine.

Close, though it brings up a new point. Connext is on GTN port 4, and GDU port 3. But I thought all Nav data came through the ARINC GAD? I guess a separate MapMX port is still required.

Well... crud... So, Brian, replace GDU Port 5's connection to the GMC with the MapMX GTN Port 3. And thus the GMC's control will come down the CAN Bus, to the roll servo, and then back up the roll servo's serial to GMC? What redundancy is lost there, removing the GDU to GMC link?

sbalmos said:

Close, though it brings up a new point. Connext is on GTN port 4, and GDU port 3. But I thought all Nav data came through the ARINC GAD? I guess a separate MapMX port is still required.

Well... crud... So, Brian, replace GDU Port 5's connection to the GMC with the MapMX GTN Port 3. And thus the GMC's control will come down the CAN Bus, to the roll servo, and then back up the roll servo's serial to GMC? What redundancy is lost there, removing the GDU to GMC link?

Click to expand...

Yep you still need MapMX to get all the nice flight plan graphics on the map and Touch tuning of the GTN in the future (not released yet but be sure to make this link bi-directional and you will be ready).

Yes, the suggested GMC 305 wiring has you connect the GMC 305 both to a GDU and to the roll servo. This provides redundancy on that connection. It operates just fine connected only to the roll servo however you do lose that redundancy.

Okay. No harm no foul if things still run one way or another. Would it help, for the sake of the thread, if I posted up other variations on this base config (2nd screen, 650 instead of 625, etc)?