GTX-345 Wx & Traffic over RS-422 to IFD RS-232
Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=1879
Printed Date: 22 May 2025 at 2:52am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: GTX-345 Wx & Traffic over RS-422 to IFD RS-232
Posted By: matthewsjl
Subject: GTX-345 Wx & Traffic over RS-422 to IFD RS-232
Date Posted: 26 Oct 2019 at 12:13pm
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Really looking for @AviSteve to weight in on this one. I've got my GTX-345 hooked up to the IFD using the GTX RS-422 line and going to an IFD RS-232 line (IFD-540 if it matters). The manual states to have wx and traffic connected on different lines but the IFD does have the setting for "Capstone HS Wx & Trfc" and this does work for feeding both wx and traffic to the IFD (same wire). The question I've got is that the IFD seems to not always run in sync with the Aspen units that are being fed by the same GTX-345. The Aspen's will typically show Regional Radar being 0-5 minutes old, while the IFD can be anything from 0-12 minutes old (and the age differs between the Aspen and the IFD with the Aspen being more recent data). Occasionally, I'll get an alert on the IFD that one of the Wx products is out of date (yesterday it was SIGMETS). So, a rudimentary judgement would be that the IFD is missing or not processing weather updates over the wire. Traffic appears to work fine and moves in real-time as you would expect. So, the question for AviSteve is why would the IFD be out of sync? Bandwidth on the wire (unlikely as the Aspen works) or bandwidth on the IFD RS-232 or processing? Thanks, John
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Replies:
Posted By: AviSteve
Date Posted: 28 Oct 2019 at 10:21am
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Sounds like a configuration issue to me - most likely baud rate. Traffic from the GTX345 comes in over 429. Really need to study your aircraft wiring to get a real answer. My suggestion is for your shop to call tech support so they can ring it out together. ------------- Steve Lindsley Avidyne Engineering |
Posted By: matthewsjl
Date Posted: 28 Oct 2019 at 11:31am
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So, Steve - the interesting thing is that the 422 line does appear to have Weather and Traffic on that wire from the GTX-345. I can select any of the following: - Capstone HS Wx - Capstone HS Trfc - Capstone HS Wx & Trfc .... and get the desired products. Plus, my IFD is not connected to the GTX-345 via AIRINC429. The GTX-345 is locked to the format that the Aspen screens need - change that and I lose the data to the Aspens. The real revelation here seems to be that weather and traffic both seem to be on that RS422 line from the GTX-345 (this is how the Aspen gets wx and traffic, no AIRINC between the GTX-345 and Aspen units either). I think logically, this is supported by the "Capstone" protocol being the G* GDL-90 spec and that lists both traffic and weather messages. So, I know I'm not wired per the IFD wiring diagram (as no AIRINC wires between the GTX-345 and IFD). But it appears to work somewhat with the single wire (RS422->RS232).......... Thanks, John PS: As I'm not wired per the IFD install manual, my guess is that support would say that I'm on my own, hence why I'm here to see if any of the above makes sense and if it could be made to work *or* if in that single wire config, the bandwidth is an issue......
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Posted By: Melohn
Date Posted: 28 Oct 2019 at 11:03pm
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it’s not likely that bandwidth is an issue; Garmin uses the RS422 for moving data to a FlightStream 210 for Bluetooth broadcast. Perhaps it is the format used by a Garmin not being supported to non Garmin devices? |
Posted By: matthewsjl
Date Posted: 29 Oct 2019 at 9:56am
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And the Aspen also uses the same feed so again, bandwidth is admittedly unlikely. John
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Posted By: AZ Flyer
Date Posted: 29 Oct 2019 at 10:13am
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I assume you have the IFD RS-232 rate set to high speed. That is what the Aspen uses and so would have to be consistent on the IFD. In other words, the RS-232 port speed on the IFD has to be identical to that of the Aspen.
Stan
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Posted By: matthewsjl
Date Posted: 29 Oct 2019 at 1:54pm
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Is there a specific setting for HS? I thought "Capstone HS Wx & Trfc" covered that one..... and that is what I'm set to. The traffic coming over the link looks good with what looks to be regular updates - it's the weather that seems to get behind. Of course, this seems to be pretty new to have the IFD receiving both wx and traffic over the GTX RS-422 line John
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Posted By: AZ Flyer
Date Posted: 29 Oct 2019 at 4:24pm
| That sounds like the right setting (I can't check mine). This is new with the 10.2.3.1 IFD software update in May. |
Posted By: AviSteve
Date Posted: 29 Oct 2019 at 4:25pm
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Without expending a lot of effort to look at logs or to recreate your configuration here, we're just guessing that perhaps the IFD is filtering some weather products that have expired and the Aspen is not. We don't believe it is a bandwidth issue. ------------- Steve Lindsley Avidyne Engineering |
Posted By: matthewsjl
Date Posted: 29 Oct 2019 at 8:03pm
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Thanks for the input Steve. I do think that thinking through it, there shouldn't be any bandwidth issues on the link. Replication of the configuration should be relatively easy if you have a GTX-345 and IFD connected. On the IFD, simply turn off the AIRINC connection and set the IFD serial input coming from the GTX-345 to "Capstone HS Wx & Trfc". Of course, you'll need another weather display but a tablet should be able to fulfill that role. One last question - there have been multiple wiring configurations and/or serial input settings as the IFD has evolved through the sw versions and installation manuals. Was there a reason that Avidyne settled on the AIRINC connection handling traffic and RS-232 handling weather when connected to a GTX-345? It seems, I have proved that the wx and traffic exists on the same RS-422 line (and the Garmin spec for Capstone seems to support that it carries traffic data) so it would simplify wiring for new installs and free up an AIRINC port on equipment. I'm not sure expiring data is the right answer - given that the Aspen is frequently showing more recent weather (the IFD knows it has a regional radar image, it's just older than the one the Aspen is showing). Cheers, John
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Posted By: AviSteve
Date Posted: 31 Oct 2019 at 9:25am
It's because the GTX345 installation manual (table 3-8) says that's how it is approved to be connected. ------------- Steve Lindsley Avidyne Engineering |
matthewsjl wrote:Posted By: matthewsjl
Date Posted: 31 Oct 2019 at 4:36pm
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OK - sort of makes sense although I didn't know that G* acknowledged Avidyne's IFD existed (a bit tongue in cheek but it's true). It looks like Avidyne went for the "replicate the 430 configuration" which I understand. Anyway, I've got a friend at G* who has more or less validated that the "OPT LGCY ADSB" does seem to be the Capstone protocol - and this does seem to work with the "Capstone HS Wx & Trfc" setting on the IFD to display both ADS-B feeds of weather and traffic. I may well try turning off the traffic (setting: "Capstone HS Wx") and see if the delay/difference in the weather is improved. Thanks, John
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