GTN 650 vs GTN 625 ARINC (Differences???)

**UPDATE w/answers** GTN 650 vs GTN 625 ARINC (Differences???)

This is probably a question for G3Xpert but open to ANY comments.

I have a Garmin GTN 650 connected to a GRT HXr10.4 and on startup, I get the "needles" on the GRT from the GTN test page as expected. The approaches work as expected.

I have a Garmin GTN 625 connected to a GRT 10.1 (Sport + ARINC module) and on startup I get NO NEEDLES. {Flight plan and navigation works as expected.]

The 650 system was done first (by me) and it works.
I attempted to duplicate (as closely as possible) the 650 setup when I did the 635.

I have traced ALL of the wires to insure continuity and that they were connected where I thought they should be.

I have configured the GRT systems in the same manner.

BUT !!!!

At one point in time, I **think** that I was able to put the same ARINC settings on the 635 as on the 650. But after assuming all configurations were correct but it not working, I assumed that it must be my wiring and therefore checked all the wiring. Then, when I tried configure the 635 (ARINC), I did NOT see the same settings as I have seen on the 650.

How can this be?
What have I done wrong?
What am I overlooking?

I have done configurations with the Garmin 400 Series and the GRT as well as the 600 Series and the GRT and they all work! This one is KICKING me. There MUST be something somewhere that I have overlooked.

HELP!!!!

James, it would be helpful if you could explicitly state what ARINC 429 (and for that matter RS232) formats you have configured.

Thanks Matt ... some more info +Update from memory

mburch said:

James, it would be helpful if you could explicitly state what ARINC 429 (and for that matter RS232) formats you have configured.

Click to expand...

Yes, Matt, you are correct and my apologies for not having more details at hand.
I will get the details when I get back to the airport.

WAIT! WAIT! I took a photo.

On the 650

ARINC 429 Out 1: Speed=LOW, Data=GAMA Format 1
ARINC 429 Out 2: Speed=LOW, Data=OFF
SDI, LNAV1

ARINC 429 In 1: Speed=LOW, Data=EFIS Format 2
(**I thought this was on Format 1**)

ARINC 429 In 2: Speed=LOW, Data=OFF
(**Hmmm. Now I am questioning this one since I have ILS on the 650**)

SDI, LNAV1

================
Stuff from memory.

Serial 1: In=FADC1 (GRT side= Fuel/Air Data Z format), OUT= Aviation1?/Aviation MAPCOM? (failed memory but it works)
Serial 2: Not used
Serial 3: Not used
Serial 4: In=?, OUT=ADS-B+, this goes to a TRIG TT30 (On the 635 only the "ADS-B" option works, going to a TRIG TT22)
============

I have gone back to the 650 so many times as I knew that it worked as advertised in the past but I haven't used it in quite some time. I may have inadvertently changed something there if THIS is wrong. If so, TOTALLY my error.

The major point is that it was appearing to me that the (navigation) setup on the 635 MIGHT be different and I was wondering if it was. I think I have 6.72 software on the 635.

BobTurner said:

Since the only real difference is lack of a vor/ils in the 625, is it possible the efis is booting up looking for a vor (which of course isn’t there)?

Click to expand...

Thanks Bob, but ...

The reason I have the 625 instead of the 650 in this case, is that I already had an SL30 that does the VOR/ILS (+additional COMM).

When I select "NAV" (as opposed to "GPS1") on the GRT, and tune in the local localizer, sitting in my hangar, I get the PROPER needle with the proper offset.

So, I *think* that the "NAV" source is properly configured.
Do you know of a way that I might have introduced a conflict? Just wondering.

jclark said:

On the 650

ARINC 429 Out 1: Speed=LOW, Data=GAMA Format 1
ARINC 429 Out 2: Speed=LOW, Data=OFF
SDI, LNAV1

ARINC 429 In 1: Speed=LOW, Data=EFIS Format 2
ARINC 429 In 2: Speed=LOW, Data=OFF

Click to expand...

This looks correct for the GPS portion of either a GTN 650 or GTN 625.

A GTN 650 additionally has a separate VOR/ILS ARINC 429 output, which confusingly is configured on a different page.

I'm unfamiliar with GRT products so unfortunately can't comment there, other than to suggest platform-agnostic troubleshooting steps such as verifying ARINC 429 format, speed, and SDI settings, looking for swapped or shorted pins, etc.

mburch said:

This looks correct for the GPS portion of either a GTN 650 or GTN 625.

A GTN 650 additionally has a separate VOR/ILS ARINC 429 output, which confusingly is configured on a different page.

I'm unfamiliar with GRT products so unfortunately can't comment there, other than to suggest platform-agnostic troubleshooting steps such as verifying ARINC 429 format, speed, and SDI settings, looking for swapped or shorted pins, etc.

Click to expand...

Again, thanks Matt for such quick response.

I will sort out the GRT side but my question, put another way is this:


?????
Is the "GPS" side (not VOR/ILS) of setup on the 650 and the 635 be expected to be IDENTICAL (I am assuming yes).

And **IF** you see a difference in the setup menu (on the GTNs) what MIGHT cause that???
?????


By the way, on the GRT side, I can see that there is data flowing from the 650 ARINC channels. When I do the same for the 635, I get ZERO bits flowing.

AND, making the assumption that maybe I had a BAD GRT ARINC module connected to the 635, I got another and connected it. Same, no data.

jclark said:

?????
Is the "GPS" side (not VOR/ILS) of setup on the 650 and the 635 be expected to be IDENTICAL (I am assuming yes).

And **IF** you see a difference in the setup menu (on the GTNs) what MIGHT cause that???
?????

Click to expand...

I haven't compared side by side, but I would expect the options on the Main (i.e. GPS) ARINC 429 configuration page to be more or less identical between a GTN 650 and a GTN 625 if they both have the same software version.

Newer GTN software versions support additional ARINC 429 formats, but with a non-Garmin display you won't be concerned with those.

jclark said:

By the way, on the GRT side, I can see that there is data flowing from the 650 ARINC channels. When I do the same for the 635, I get ZERO bits flowing.

AND, making the assumption that maybe I had a BAD GRT ARINC module connected to the 635, I got another and connected it. Same, no data.

Click to expand...

Can you clarify, are these two different aircraft, or a single panel with two GTNs?

And, do you have a GTN 625 or a GTN 635? It should make no difference for this discussion, but I notice you mentioned three different types of GTN so I want to make sure I understand what equipment you have...

mburch said:

I haven't compared side by side, but I would expect the options on the Main (i.e. GPS) ARINC 429 configuration page to be more or less identical between a GTN 650 and a GTN 625 if they both have the same software version.

Newer GTN software versions support additional ARINC 429 formats, but with a non-Garmin display you won't be concerned with those.



Can you clarify, are these two different aircraft, or a single panel with two GTNs?

And, do you have a GTN 625 or a GTN 635? It should make no difference for this discussion, but I notice you mentioned three different types of GTN so I want to make sure I understand what equipment you have...

Click to expand...

My mistake. (650 and 625 ...NO 635, that was a typo)

I have two planes with two setups.
They are as follows:
RV8, Garmin GTN 650, GRT HXr 10.4, Trig TT30
RV6, Garmin GTN 625, GRT 10.1 (Sport + external ARINC module), Trig TT22
[Trying now to finish a 3rd, so I need to get this RIGHT! ]

By they way, just before hitting submit, I noticed that I had done the typo of 635 vs 625 again! Caught it this time.

Okay... since you have determined that your GRT ARINC 429 module is good, that would indicate either a problem with the GTN 625 itself (unlikely but who knows), a problem with the GTN configuration, or a problem with the wiring between the GTN and the GRT ARINC 429 module.

The first thing I would do is look at the GTN Diagnostics --> ARINC Inputs page in config mode on your GTN. This will tell you if the GTN is receiving data from the GRT ARINC 429 module, which would be good to know.

If the GTN is receiving, but your GRT equipment is not - and you are sure your configuration is correct - then I would start looking for wiring issues. Wrong pins, pins swapped, A/B wires shorted together or to ground, etc.

James,

Use the GNS430 Supplement manual on the GRT website to configure your GTN650 in theRV8.

There is a supplement document Jeff wrote for GPS175 which will work for your GTN625. Here is the link:
https://grtavionics.com/forum/viewtopic.php?t=3215

Hope this helps.

Jim Butcher

mburch said:

Okay... since you have determined that your GRT ARINC 429 module is good, that would indicate either a problem with the GTN 625 itself (unlikely but who knows), a problem with the GTN configuration, or a problem with the wiring between the GTN and the GRT ARINC 429 module.

The first thing I would do is look at the GTN Diagnostics --> ARINC Inputs page in config mode on your GTN. This will tell you if the GTN is receiving data from the GRT ARINC 429 module, which would be good to know.

If the GTN is receiving, but your GRT equipment is not - and you are sure your configuration is correct - then I would start looking for wiring issues. Wrong pins, pins swapped, A/B wires shorted together or to ground, etc.

Click to expand...

Will do.

For the benefit of those following this ...
I actually took everything apart and "buzzed out" ALL of the relevant wires. Yes, I got to that point of assuming that I had wired something incorrectly or had a broken wire. It is nice how the 4 relevant high density pins are on a "slant'.

Regarding ARINC diagnostics, on the GTN side, I will check that again as I haven't recently. Only looked on the GRT side and was getting nothing.

The GOOD NEWS here is that I have a plane right next to it that shows me what I think I should be expecting to see.

jclark said:

Will do.

For the benefit of those following this ...
I actually took everything apart and "buzzed out" ALL of the relevant wires. Yes, I got to that point of assuming that I had wired something incorrectly or had a broken wire. It is nice how the 4 relevant high density pins are on a "slant'.

Regarding ARINC diagnostics, on the GTN side, I will check that again as I haven't recently. Only looked on the GRT side and was getting nothing.

The GOOD NEWS here is that I have a plane right next to it that shows me what I think I should be expecting to see.

Click to expand...

I can’t offer you much other than morale support, since I went through something similar many years ago.

I have a GTN650 and was an early adopter of the Trutrak Vizion. It wouldn’t go I to GPSS mode. Trutrak support wasn’t helpful and insisted that it was a wiring issue since they hadn’t any failures of the Vizion yet.

Thanks to the assistance of Rob and his team at AFS, I was able to correctly diagnose the issue. AFS shared with me (I didn’t t write them down and have since forgotten them) what each of the ARInC labels represent. Using the ARINC diagnostics page, I was able to determine what wasn’t working. You can test most of them in the hangar and watch the data change. Although the label for glide slope can’t be tested on the ground. Labels with all zeros will indicate what isn’t communicating.

It took several weeks to final solve, but in my case the ARINC receiver in the Vizion was faulty. With the data from the GTN650 gave me the data to prove it.

The Vizion needed to see a specific combinations of ARINC labels live to go into gpss mode, since it didn’t didn’t see that combination, it didn’t engage. You may be having similar issues with GRT, but I don’t any any experience there. You may want to ask GRT if they have any methods of logging ARINC data.

The other obvious issue is that you referenced slant pins. I had problems with the high density pins during that upgrade. With my fat fingers, it seems that I always bent one when make changes to that connector. Any of those pins the ARINC ones?

rleffler said:

I can’t offer you much other than morale support, since I went through something similar many years ago.

<<SNIP>>

The Vizion needed to see a specific combinations of ARINC labels live to go into gpss mode, since it didn’t didn’t see that combination, it didn’t engage. You may be having similar issues with GRT, but I don’t any any experience there. You may want to ask GRT if they have any methods of logging ARINC data.

Click to expand...

I can see the ARINC diagnostics in the GRT. I can see the data flowing on my WORKING (GRT 10.4+GARMIN 650), but get all zeros on the non-working system (GRT 10.1+GARMIN 635)

rleffler said:

The other obvious issue is that you referenced slant pins. I had problems with the high density pins during that upgrade. With my fat fingers, it seems that I always bent one when make changes to that connector. Any of those pins the ARINC ones?

Click to expand...

My reference to "slant" was to say "yes, I tested continuity and as evidence, I can tell you that the ARINC pins happen to line up on a diagonal (slant). Hopefully I have NOT bent any pins!!!

And thanks for the moral support!!!

jclark said:

I can see the ARINC diagnostics in the GRT. I can see the data flowing on my WORKING (GRT 10.4+GARMIN 650), but get all zeros on the non-working system (GRT 10.1+GARMIN 635)



My reference to "slant" was to say "yes, I tested continuity and as evidence, I can tell you that the ARINC pins happen to line up on a diagonal (slant). Hopefully I have NOT bent any pins!!!

And thanks for the moral support!!!

Click to expand...

If you’ve tested all the cabling, you have continuity, no shorts, and wired to the proper pins, my assumption is that you got a hardware problem. The question is which end of the circuit?

Is the 650 and 625 pin/tray compatible? If so swap the 625 into the working aircraft to see if it works there. That will eliminate or confirm one end of the circuit. I wouldn’t put the 650 in the non working aircraft.

UPDATE ... With some ANSWERS

jclark said:

This is probably a question for G3Xpert but open to ANY comments.

I have a Garmin GTN 650 connected to a GRT HXr10.4 and on startup, I get the "needles" on the GRT from the GTN test page as expected. The approaches work as expected.

I have a Garmin GTN 625 connected to a GRT 10.1 (Sport + ARINC module) and on startup I get NO NEEDLES. {Flight plan and navigation works as expected.]

The 650 system was done first (by me) and it works.
I attempted to duplicate (as closely as possible) the 650 setup when I did the 635.

I have traced ALL of the wires to insure continuity and that they were connected where I thought they should be.

I have configured the GRT systems in the same manner.

BUT !!!!

At one point in time, I **think** that I was able to put the same ARINC settings on the 635 as on the 650. But after assuming all configurations were correct but it not working, I assumed that it must be my wiring and therefore checked all the wiring. Then, when I tried configure the 635 (ARINC), I did NOT see the same settings as I have seen on the 650.

How can this be?
What have I done wrong?
What am I overlooking?

I have done configurations with the Garmin 400 Series and the GRT as well as the 600 Series and the GRT and they all work! This one is KICKING me. There MUST be something somewhere that I have overlooked.

HELP!!!!

Click to expand...

jclark said:

Will do.

For the benefit of those following this ...
I actually took everything apart and "buzzed out" ALL of the relevant wires. Yes, I got to that point of assuming that I had wired something incorrectly or had a broken wire. It is nice how the 4 relevant high density pins are on a "slant'.

Regarding ARINC diagnostics, on the GTN side, I will check that again as I haven't recently. Only looked on the GRT side and was getting nothing.

The GOOD NEWS here is that I have a plane right next to it that shows me what I think I should be expecting to see.

Click to expand...

I will give the "answers" here and if anyone wants more detail, contact me offline.

0. There were matters discovered in the area of Garmin, GRT, and ME!

1. Garmin: When configuring the GTN, the ORDER (Serial Ports vs ARINC 429) of the configuring will affect the OPTIONS that get displayed. Thanks to the people at Garmin (multiple) in making me aware of this. (Sorry Matt, when I called they said that you were "offline" at the time.). Some guy in the inner bowels of Garmin support said "hummm ... that could only happen if he happened to configure xyz before he configured abc". AHA!!!! (sez me )

This resulted in me seeing options when I did it the "correct way" on the GTN 650 that were "grayed out" when I did it in the other order on the GTN 625. As I recall, I went back and turn OFF all serial configs, did the ARINC 429 configs and then went back did the correct serial configs. Now that I am able to get the configs done, it still is not working ... sooooo .

2. GRT: The ARINC module on the 10.4 HXr is INTERNAL and gets powered up when the EFIS is powered up. The 10.1 has an EXTERNAL module and I powered it up when I powered up the GTN 625. The EFIS was already powered up and did not see the ARINC module and thus did not "configure it". (I don't power up the GTN until after the engine is running etc.) The default config of the OLDER ARINC modules (what I have) is not what is typically used these days so the EFIS tells it what to act like at boot up. The newer modules have the typical config that we use (per Jeff) in the firmware.
Sooo ... the answer was to either rewire the power so it was there when the EFIS came alive, or get a "new" (current) module, OR get some update software from GRT to update the firmware in the older module to the newer config. The latter was easiest for me so I loaded and tested it yesterday and now, I have "needles"!!

3. ME: Wiring. I **probably** should have used the Aux Power Output (12V 0.5 Amp max) on pin B14 of the 10.1 EFIS to power the ARINC 429 module. "My bad". I simply was not thinking about the power sequencing of the module when I wired it and had a convenient source of power. Also, you don't normally want to power anything but the magnetometers from the EFIS family.

SUMMARY: Sometimes there is no single "smoking gun". Often several "little things" that add up to the problem. Also, sometimes even though the manifestation of the problem implies otherwise, these little things may not be related yet each must be tackled to get to the final solution.

A big THANKS to Matt and Katie at Garmin along with Greg and Jeff at GRT for sharing in the head scratching on this one.

I know that this ha s been a bit long-winded but I hope that this helps someone down the line.