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Garmin meets GRT, questions result

Dugaru

Well Known Member
Okay, so for reasons that are unimportant, and at the risk of mixing matter and anti-matter: I've ended up with a combination GRT and Garmin panel. Relevant to my questions, I've got:

Garmin 430W
connected to a
Garmin G5
with a Garmin GAD29, and running a
Garmin GSA 28 autopilot with GMC 307 controller
The Garmin G5 acts as my nav indicator for ILSs, LPVs, etc. etc.
I do not have the Garmin magnetometer, so the "heading" bug on the 307/G5 sets ground track.

AND MEANWHILE

my main EFIS is a GRT Horizon EX
with GRT's adaptive AHRS and digital magnetometer

I'm actually very happy with this setup. The EX is a great box, talks to my existing GRT EIS 4000 perfectly, and was a (relatively....) simple upgrade from the old WS. The G5 is an absolutely terrific gadget. Price/performance is off the charts and the redundancy with the battery backup is awesome. The 430W user interface is showing its age, but I have been reasonably fluent in 430 for a long time now, and given the price of new GPS navigators, I am TOTALLY happy with it.

But there are still a few quirks.

First, the current GRT Horizon EX recently replaced an old Horizon WS. The old Horizon WS had an ARINC box bolted to the back (D-dub connector "C", for those of you who speak old GRT), and played just fine with the 430W. But when I replaced the WS with the EX, I didn't purchase the (now entirely separate) GRT ARINC box that would go with the new EX. This means that although I get GPS waypoints from the 430W displayed on the EX (via a serial connection, I believe), I no longer get any of the CDI-type stuff.

On startup, the 430W also complains that it's not seeing the ARINC data it was previously getting from the WS. Not surprising, since it's no longer connected across an ARINC box.

None of this is a major problem, because as noted above, my 430W/G5 combo is my "official" IFR solution.

But I think I'd like to cross the Ts and dot the Is, and make everything happy. For one thing, it would be nice to have a real CDI on the EX screen. I'd also like to have compass data on the G5.

So, after that too-lengthy lead-up:

1. Can my current GAD29 act in place of the GRT ARINC box, while simultaneously feeding my G5? Or will i need to buy and wire in the separate GRT ARINC box?

2. Can my current GRT digital magnetometer give the G5 what it needs for compass data?

3. I almost never use VORs for any real-world purpose. But the G5 is all I have right now for an OBS. Assuming I solve 1 and 2 above, am I right that I'll get back to having a cool HSI available on the EX screen?

Thanks!
DMG
 
I would for sure check with GRT, but I suspect the answer will end up being:

1. Can my current GAD29 act in place of the GRT ARINC box, while simultaneously feeding my G5? Or will i need to buy and wire in the separate GRT ARINC box?

ARINC is it's own bus/protocol which needs to be converted to a serial protocol or canbus before it can be consumed by the GRT or G5. Each platform has it's own converter which on the front side speaks ARINC429 but on the back side, from what I understand, it's proprietary Garmin or GRT. So, you will need the GRT arinc 429 interface.

You should be able to split the nav and gps and airdata arinc signals from the 430 to both converters, but I'm much less certain on this.

2. Can my current GRT digital magnetometer give the G5 what it needs for compass data?

No, same issue, the GRT magnetometer speaks GRT not Garmin, so I think you will need to buy the Garmin magnetometer as well.

3. I almost never use VORs for any real-world purpose. But the G5 is all I have right now for an OBS. Assuming I solve 1 and 2 above, am I right that I'll get back to having a cool HSI available on the EX screen?

You should. If the 430 spits out HSI data to the GRT arinc interface, then I would expect it to show up just like it did on the old box when it got arinc data.

Matt
 
I'll take an initial crack at this.

1. Can my current GAD29 act in place of the GRT ARINC box, while simultaneously feeding my G5? Or will i need to buy and wire in the separate GRT ARINC box?
NO - the GRT ARINC box and the GAD29 both convert ARINC data to RS232 data via proprietary formats. The probability of both boxes speaking exactly the same RS232 language is just about zero.

2. Can my current GRT digital magnetometer give the G5 what it needs for compass data?
NO - see 1) above - data formats are proprietary

3. I almost never use VORs for any real-world purpose. But the G5 is all I have right now for an OBS. Assuming I solve 1 and 2 above, am I right that I'll get back to having a cool HSI available on the EX screen?
YES, and no... I strongly suspect you will end up with that HSI display on one or the other but not both EFIS devices. In short, if you have the 430's A429 lines wired to the HX, it will do all the singing and dancing. If you have the 430's A429 lines wired to the G5, it will do all the singing and dancing. It will end up being an either/or situation. You could do some fancy toggle switch-ology to allow switching between the 430 and the two EFIS devices to give you control over which one is active.
 
Buying more gadgets is always the answer

Thanks to you both for the incredibly helpful responses. Really appreciate it.

How did anyone do this stuff before the internet.

Additional question for Canadian_JOY:

YES, and no... I strongly suspect you will end up with that HSI display on one or the other but not both EFIS devices. In short, if you have the 430's A429 lines wired to the HX, it will do all the singing and dancing. If you have the 430's A429 lines wired to the G5, it will do all the singing and dancing. It will end up being an either/or situation. You could do some fancy toggle switch-ology to allow switching between the 430 and the two EFIS devices to give you control over which one is active.

Ah, this is extremely interesting. This leads me to conclude that because my GAD29/G5/GMC307 are driving my Garmin autopilot, the G5 will need to be the one doing the ARINC singing and dancing on a full-time basis.

Am I correct that the wiring constraints would permit me to add a second G5 to solve my OBS problem? Surprisingly a new G5 seems like it would be quite a bit more cost effective than a used HSI or even a used old-school indicator.

And then I would have THREE artificial horizons available. Not counting the iPad. LOL, as the kids say. :)
 
Pretty sure that the 430 will provide everything needed for the horizontal portion necessary for CDI display on the GRT. Vertical requires Arinc, as does VOR indications. I have GRT mini-x with no Arinc and it receives horizontal CDI from the 430W on a bridged RS-232 connection. Pushing air data from the GRT to the 430 also requires Arinc I think. But I would research further, as this may be possible on RS-232 aviation format. Pushing the data, including heading, to the 430 would allow it to essentially be daisy chained to the G5, though not sure if the G5 would display heading data coming from the 430.
 
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I've been working on pretty much the opposite configuration, G3x and Mini-AP. This means I've been digging through all of these interfaces trying to figure it out. To get the full functionality I need a GAD29 and the GRT ARINC adapter. You will need the same.

Now to the part I'm only about 90% sure of. I think you need the ARINC adapter to provide air data to the GNS430W. It has 2 ARINC inputs and I believe you could hook up one input to your G5 and one input to your GRT ARINC adapter. Then you can configure the GNS430W inputs to select the input source. I'm considering having a source selection switch and feeding into one interface. I haven't decided if I want that complication or not. Real time selection via the configuration menu doesn't seem like such a good idea though. The GNS430W might even automatically switch sources if one goes away but I have no real information that it does that.

GRT has some supplemental documentation on wiring up the GNS430W so you should refer to that too.
 
GRT used to be able to convert your old ARINC by putting it in a case of it's own. You might ask GRT if you haven't already.
 
Too late!

I did not know that! I sold the old Horizon WS with ARINC still attached.:)

Many thanks to everyone for the advice. Seems like I need to do a bit of homework to figure how best to wire things together.

GRT used to be able to convert your old ARINC by putting it in a case of it's own. You might ask GRT if you haven't already.
 
I hope you guys dont mind me posing a question or two of my own, Im thinking of something similar, with a Sport 10.1 as my EFIS and a G5 as the backup and also driving a 507 autopilot. What Im curious about is if I can link the heading/altitude bugs (preferably the baro too) up on the EFIS and G5 so that I dont have to constantly set both independently. Looking at the G5 installation manual, the ARINC-429 output has "selected heading" and "selected altitude" as outputs...Im wondering if these refer to the heading/altitude bugs, and if so if I can wire that through the GRT ARINC converter and have it accept that from the G5...
 
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