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GPS175 install questions

N546RV

Well Known Member
Tonight I'm reading through a GPS175 install manual to wrap my head around the wiring requirements, which means...questions. Oh yes indeed.

Brief overview of my intended installation: EFIS will be a dual Skyview HDX system with the ARINC-429 interface box. The GPS will also be providing serial data to the Skyview transponder and an Artex ELT. No other Garmin stuff installed anywhere.

First, regarding the pinouts: it would appear that out of this monster 62-pin connector, I really only need a small handful of connections:

Code:
p#	description
20	ground
21	+12V
41	ground
42	+12V

61	ground (enable auto power on)

9	serial 1 out (to SV-ARINC-429)
8	serial 2 out (skyview xpdr)
7	serial 3 out (ELT)

5	ARINC 429 out 1A (to SV-ARINC-429)
6	ARINC 429 out 1B (to SV-ARINC-429)
27	ARINC 429 in 1A (to SV-ARINC-429)
28	ARINC 429 in 1B (to SV-ARINC-429)

This seems like a comically small usage, but most everything else seems like it'd pertain to driving analog instruments like a CDI. Does this seem right at a glance? Am I missing anything important?

Second, and sort of springing off #1, there are four pins for a "config module." Is this something required for all installations? Is this module included with the unit? As in, do I even have to care about this?

Appreciate any info.
 
Last edited:
The config module is included with the GPS 175. It will be physically located in a special holder that is part of the metal backshell assembly of the large connector for the GPS unit. This module will contain all the uniqueness of the installation that you will program into the module at power- on time.

The Dynon ADHARS module provides altitude info to the Dynon transponder. I believe the Dynon install manule shows an example of the wiring for a Garmin GPS navigator using the a serial line and the -429 interface module.
 
Thanks for the info.

To clarify a bit, the GPS175 will be providing certified GPS data to the transponder for ADS-B Out compliance. This is mainly because I picked up an older SV-250 GPS puck for dirt cheap. Gotta save $$$ somewhere on this build...anyway, that's the reason for having a serial connection to the transponder.
 
Dynon ARINC to Garmin GPS175 Connections, TX needed?

Hello VAF. I am installing a Dynon HDX system in my 7. I have an existing Garmin GNC355 (175 w/com) that was connected to a TT 385 AP via ARINC & serial. I am removing the TT and installing the Dynon AP system.

I am looking at the installation manual for the Dynon ARINC module - it shows the ARINC module both RX and TX from/to the Garmin 430 & GTN 650 series navigators. There are no install figures in the manual for the GPS175. I'm trying to figure out if the TX from the Dynon module to the RX in the GPS175 is needed - and if so, what information is being sent to/consumed by the GPS175? I thought Garmin had "locked out" third parties from sending information to their newest navigators..... Curious minds want to know, and if I don't need that connection, I will not add it.

Also, if anyone has an interconnect diagram and settings for the GPS175 to Dynon ARINC they would share with me - greatly appreciated.
Thank you for your input.
 
Just speaking in generalities - the gps navigator will generally work without any data input from the efis, but you lose some functionality. For example, the navigator needs heading and airspeed data from the efis in order to calculate a wind vector.
As to your software question: yes, Garmin uses proprietary software formats when it thinks it will increase their bottom line. But communication to/from the efis is via ‘open source’ software. The adsb-out data is sent via Garmin’s proprietary ‘ADSB+’ format, but the Trig TT22 (Dynon) transponder can read it.
To the OP: make certain you set up the configuration module correctly. The main function of this device is to prevent you from sharing data cards with anyone else; if you get it wrong you won’t be able to read your own data card.
 
Hello VAF. I am installing a Dynon HDX system in my 7. I have an existing Garmin GNC355 (175 w/com) that was connected to a TT 385 AP via ARINC & serial. I am removing the TT and installing the Dynon AP system.

I am looking at the installation manual for the Dynon ARINC module - it shows the ARINC module both RX and TX from/to the Garmin 430 & GTN 650 series navigators. There are no install figures in the manual for the GPS175. I'm trying to figure out if the TX from the Dynon module to the RX in the GPS175 is needed - and if so, what information is being sent to/consumed by the GPS175? I thought Garmin had "locked out" third parties from sending information to their newest navigators..... Curious minds want to know, and if I don't need that connection, I will not add it.

Also, if anyone has an interconnect diagram and settings for the GPS175 to Dynon ARINC they would share with me - greatly appreciated.
Thank you for your input.

Check the Dynon forum for help on the connectivity and settings.
 
Hello VAF. I am installing a Dynon HDX system in my 7. I have an existing Garmin GNC355 (175 w/com) that was connected to a TT 385 AP via ARINC & serial. I am removing the TT and installing the Dynon AP system.

I am looking at the installation manual for the Dynon ARINC module - it shows the ARINC module both RX and TX from/to the Garmin 430 & GTN 650 series navigators. There are no install figures in the manual for the GPS175. I'm trying to figure out if the TX from the Dynon module to the RX in the GPS175 is needed - and if so, what information is being sent to/consumed by the GPS175? I thought Garmin had "locked out" third parties from sending information to their newest navigators..... Curious minds want to know, and if I don't need that connection, I will not add it.

Also, if anyone has an interconnect diagram and settings for the GPS175 to Dynon ARINC they would share with me - greatly appreciated.
Thank you for your input.

I just finished installing a GPS 175 this past week. I also have the Dynon HDX and ARINC modules and am using the Dynon A/P. There is no need for the TX out of the ARINC-429 module to the GPS, just the RX. Air data is sent to the GPS through the ARINC module - you set the ARINC RX mode on the 175 to EFIS/ADC. I can't say for sure that this works from the Dynon equipment, I did see some messages saying that I was missing the air data - but I don't recall if that is still happening.

There are only a few connections involved.

GPS175 <--> ARINC-429
  • ARINC TX-A
  • ARINC TX-B
  • ARINC RX1 A
  • ARINC RX1 B
  • RS232 #2 TX
GPS175 --> SV-XPNDR-261
  • RS232 #1 TX - with inline 1.21K resistor
 
Thank you

Thank you, all for the responses.
Brian - great documentation in the pdf you posted.
The information you all provided is greatly appreciated.
 
Pinout and RS232 wiring question

Reviewed the comments here and also on the Dynon support site and have two questions about the GPS 175 wiring for a Dynon EFIS system.

1) Looking at the TSO installation manual, is it correct to assume that all the grey shaded pins on figure 5-2 pinout are grounded thru the GPS' internal circuitry to ground? I'm asking because I think I can simply connect pin 61 and pin 62 with a short loop wire inside the back shell to achieve the 'auto on' feature. Or, do I have to run a long wire from pin 61 to the ground block?

2) Can I connect RS232 Tx #2 (Pin 8) to the Dynon XPNDR with an unshielded wire or do I have to use a single conductor shielded wire here?

Thanks!
Logan
 
Reviewed the comments here and also on the Dynon support site and have two questions about the GPS 175 wiring for a Dynon EFIS system.

1) Looking at the TSO installation manual, is it correct to assume that all the grey shaded pins on figure 5-2 pinout are grounded thru the GPS' internal circuitry to ground? I'm asking because I think I can simply connect pin 61 and pin 62 with a short loop wire inside the back shell to achieve the 'auto on' feature. Or, do I have to run a long wire from pin 61 to the ground block?

2) Can I connect RS232 Tx #2 (Pin 8) to the Dynon XPNDR with an unshielded wire or do I have to use a single conductor shielded wire here?

Thanks!
Logan

1) Yes - this is exactly how I wired up the auto-on for my 175.
2) I think opinions may vary on this one, but I'm using the 175 for my XPDR source, and I simply used a single 22AWG wire to do the job. This has worked just fine for testing in the hangar, though I'm still a ways from flying. My way of thinking is there are plenty of serial connections in the airplane using unshielded wires, and this seems to be perfectly acceptable.
 
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