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GRT Product Support

Tankerpilot75

Well Known Member
I don’t believe in vendor bashing but after two agonizing months of trying to get my new Horizon EX EFIS units to communicate GPSS data to my TruTrac Vizion 385 autopilot it’s time to let the VAF crowd know about my problems.

Upgrading the Horizon WS EFIS with the new EX EFIS requires installation of a separate ARINC module for GPS to autopilot communications. In my case because my old WS units were not wired for GNAV functionality I also had to run two new wires for the ARINC C1/C2 input from my G430 pins 46 & 47 (ARINC 1A/1B out). I talked to the people that originally built my panel (Aerotronics) and they kindly guided me through this process and after I screwed up the DPDT switch on my panel that selects between EFIS autopilot and FMS autopilot inputs they even made me a new pre-wired switch with labels to replace the damaged DPDT switch at no charge.

I live 45 miles from where my RV7A is hangared and it takes approximately one hour to commute to the hanger. In the last two months I’ve put almost 3,000 miles on my vehicle making this commute trying to resolve the EFIS to autopilot communication issue. Aerotronics has spent hours on the phone with me trying to help me with this problem. GRT - has voicemail that says leave a message. They sometimes replied.

Prior to AirVenture I asked if someone from GRT would look at my panel and see if they could figure it out if I brought the airplane to Oshkosh. I also asked Aerotronics and Andrew (now Bendix King formerly TruTrac) if they would look at my panel at AirVenture. Tuesday night at AirVenture both Andrew (TruTrac) and Andre (Aerotronics) came to my airplane and tried to identify the problem. GRT wouldn’t come by.

Both Andrew and Andre both said the autopilot appeared to be working right, the new DPDT switch correctly wired, and the other wiring changes (C1/C2) inputs to the ARINC module were correctly done with continuity checks confirming my work. Andre spent two and a half hours at my plan, checking wiring, swapping EFIS units, doing loop checks, etc. I couldn’t have asked for more expertise than what I received. He finally said it appears to be a possible software issue and would talk to GRT - if he could get a hold of them.

Wednesday morning with the weather threatening havoc that evening I decided to leave AirVenture (like a bunch of other folks) but before leaving I dropped by the GRT booth and told them the results of the previous night and that Andre in particular spent over two and a half hours trying to troubleshoot the problem. I asked them what they were going to do and they “promised” a resolution this week. They wanted me to disappear because potential customers were hearing the conversation.

On Wednesday evening this week I called Jeff DeFouw at GRT (he only works evenings) and also sent an email (another one). His response was “try swapping out the old WS with the new EX and see if that restores EFIS to autopilot communication and we’ll consider making a harness to directly link the ARINC module to the autopilot to see if that will provide GPSS data to the autopilot.”

Another trip to the airport today, swapped out units and now have ARINC 429 communication errors displayed on my G430. Called GRT to get their help and again - only got voicemail!

I called Walt at Experimental Aircraft Services prior to AirVenture and he said he won’t work on panels with GRT Avionics because of their poor to non-existent tech support. A number of other well known avionics shop also won’t install GRT equipment because of poor tech support. Now I’m facing a situation where I have less capability than I had before I decided to “upgrade “ my EFIS units and inadequate help from the vendor that sold me the products.

I hope the moderators allow this post to be seen and comments made because VAF folks need to know the vendors they spend significant sums of money with. I still believe the GRT units are equal in capability to most of the EFIS units out there but without a responsive and dedicated support system it becomes a buyer beware situation when issues arise. I understand GRT has a total of ten staff, including the owner. Definitely a small business. But if they’re going to continue to sell products to the experimental aviation community then customer support becomes paramount.

I will report back to the VAF community if GRT steps up and resolves my problem.
 
If you have a DPDT switch wired to the autopilot so the 430 can communicate directly to the Trutrak which bypasses the GRT altogether...? Wouldnt this eliminate the efis?
 
If you have a DPDT switch wired to the autopilot so the 430 can communicate directly to the Trutrak which bypasses the GRT altogether...? Wouldnt this eliminate the efis?

It eliminates the EFIS on the FMS side. On the EFIS side everything is sent through through the ARINC and EFIS. As I said above. All wiring has been confirmed by a avionics expert (Andre from Aerotronics) and the autopilot confirmed to be working properly by Andrew Barker of nowBendix King.
 
Just got off the phone with Eric at GRT. They said they are going to make some test cables and send them out to collect some data. Again, it’s unfortunate that there appears to be only one “expert” (Jeff DeFouw) at GRT who can truly analyze and trouble shoot “zebra” problems and his workload is obviously high.

I’m sending pictures of the results of the latest approach they had me follow. Maybe that will provide them something new to ponder.
 
I'm sorry you're dealing with this - it sounds very frustrating.

I've been working remotely with Andre for a few months on a new panel design and he's been completely amazing to work with. Glad you had such a good experience with him - the folks at Aerotronics are great.

I had kind of a so-so support experience with GRT. Be that as it may, I cannot see how any company in a technical field can only offer phone support for a few hours a day.
 
Jim,
Sorry for the problems. As Rocket Bob points out, with the toggle switch in one position, your 430 should drive the autopilot independent of the GRT.

Your system should be wired like the diagram found in Legacy Horizon WS Dual Display, GNS 430. You only need the ARINC, Fuel Data Out and GPS In serial connections. Likewise, ARINC module connections and set up is in Miscellaneous Documentation. Set up in this manner it should all work properly.

There also is a GNS430 supplement in Miscellaneous Documentation but it doesn’t show a Tru Track autopilot.

It sounds like you have added the GPS ARINC out from the 430 (pins 46 & 47) to the EX. The toggle switch should toggle the ARINC input to your Tru Track between 430 ARINC output and EX ARINC output.

Be sure there is a GPS RS232 serial output connection from 430 going to both the EX and the Tru Track.

There are lots of these units installed and the basic software is the same for all GRT units, so my bet is you have a wiring or set up problem. Start by trying to get 430 to Tru Track working. Then add the GRT.

Hope this helps.
 
I had a similar issue years ago on the 10, turns out the A/P needed both the ARINC feed and a RS232 serial feed.

I am working through a problem with my GRT and Trig Xpnder right now. Seems the newest EFIS can directly control the Xpnder but the existing manual only shows using the adapter. And they left our the fact you need to ground pin 13 of the Trig to get it to turn on.

Luckily Jeff was able to get me the needed info. But he should not have to deal with issues that should be in the documentation

Life would be a lot simpler if GRT would put out good manuals when they change something.

I sure do miss Carlos...........
 
Jim,
Sorry for the problems. As Rocket Bob points out, with the toggle switch in one position, your 430 should drive the autopilot independent of the GRT.

Your system should be wired like the diagram found in Legacy Horizon WS Dual Display, GNS 430. You only need the ARINC, Fuel Data Out and GPS In serial connections. Likewise, ARINC module connections and set up is in Miscellaneous Documentation. Set up in this manner it should all work properly.

There also is a GNS430 supplement in Miscellaneous Documentation but it doesn’t show a Tru Track autopilot.

It sounds like you have added the GPS ARINC out from the 430 (pins 46 & 47) to the EX. The toggle switch should toggle the ARINC input to your Tru Track between 430 ARINC output and EX ARINC output.

Be sure there is a GPS RS232 serial output connection from 430 going to both the EX and the Tru Track.

There are lots of these units installed and the basic software is the same for all GRT units, so my bet is you have a wiring or set up problem. Start by trying to get 430 to Tru Track working. Then add the GRT.

Hope this helps.

Jim,
As I pointed out above, the G430 to TruTrac (dpdt switch = FMS) works exactly as it should. It’s the (dpdt switch = EFIS) that isn’t working with the result being no A/P control through the EFIS.

Andre from Aerotronics spent 2 1/2 hours at AirVenture confirming my wiring is correct going to the ARINC and from the ARINC to the dpdt switch and then to the autopilot pins 14, 15 & 17. I’m pretty sure it’s NOT a wiring issue.

Mike,
The A/P is getting both serial and ARINC inputs when EFIS is selected. In EFIS mode it gets serial input from serial port output #4 (Autopilot (Aviation)) and ARINC input from ARINC output pins C5/C9.

The phone support is weak at best. It appears there is only one true technical expert at GRT and that’s Jeff DeFouw. His working hours are in the evening. He’s admitted this issue has him stumped. While I never knew Carlos I’ve heard he was quite good. For a company to have only one true technical expert for all the products they sell and limited access to that one person is a sign that their focus is selling product and not supporting what is sold.

I honestly wish I’d never started this upgrade!
 
Jim,


Andre from Aerotronics spent 2 1/2 hours at AirVenture confirming my wiring is correct going to the ARINC and from the ARINC to the dpdt switch and then to the autopilot pins 14, 15 & 17. I’m pretty sure it’s NOT a wiring issue.

Mike,
The A/P is getting both serial and ARINC inputs when EFIS is selected. In EFIS mode it gets serial input from serial port output #4 (Autopilot (Aviation)) and ARINC input from ARINC output pins C5/C9.

e!

Hi Jim,
Sorry for your trouble. A few questions/suggestions:
1. Autopilot pin 17 is an rs232 input. If you have a DPDT switch it should be switching the two arinc lines. So the wire from pin 17 (autopilot) should go directly to efis rs232 out port #4, not thru the DPDT switch. Is that correct?
Make sure you don’t cross any wire pairs, always ‘A’ to ‘A’, ‘B’ to ‘B’.
2. Efis rs232 out port #4 should be configured for NMEA-0183, per the tru trak manual.
3. Make certain the efis port 4 and the tru trak pin 17 (rs232 in) have the same configuration (NMEA) and the same speed (choose 1200, 2400, 4800, or 9600)
4. You mentioned you ‘screwed up’ the dpdt switch wiring. Did you short out or short together the A and B wires with power applied? You may have damaged the arinc box.
First thing I’d try is to re-configure efis port 4 (out) to nmea, and check the speeds (baud rate) match those set in the autopilot.

Bob
 
One more thing: I think my above recommendation will work, but I would suggest following GRT’s recommendation with respect to the RS232 line, namely, run the wire directly from the Vizion pin 17 to an RS232-OUT on the 430. In this case you can choose the format either NMEA or Garmin-Aviation (same format and speed in both the 430 and the Vizion). If wired this way, activating the DPDT switch will let you run the autopilot without the efis. With your wiring, the efis must work or the autopilot will not get any rs232 data.
 
Jim,

You must have a serial connection from your GRT to the ARINC module. In setup you should set ARINC connected and you should see ARINC data counters for both in (from 430) and out (to 430 and autopilot) incrementing (changing).

Do you see this?

Jim Butcher
 
Here’s an email from GRT after I told Jeff the results of what happened when I reinstalled the old WS unit as he requested and I told him of the G430 error message that said “not receiving input data on 429 channel #1.” However, as I also told him with the new ARINC/EX installed there is “no error message.”


Jeff wrote: “The 430 error is a very bad sign, but the whole point of this test was to find out if GPSS still works from the WS. You said GPSS was working before with the WS in heading mode, so it should still be working. GPSS mode from the EFIS is driven by the C5/C9 connections. Your C5/C9 connections from the EFIS ARINC to the switch shouldn't have changed, therefore, they should still work. If GPSS doesn't work with the WS anymore, then the problem is not the EX or external ARINC.”

My simple response to Jeff was: “So the problem isn’t with the ARINC or Ex. And Andre says the problem isn’t with the wiring. And Andrew says the problem isn’t with the autopilot. Therefore I guess there isn’t a problem!

Just what I need to know. No one wants to say there is a problem! Great technical support!!!
 
Jim,

You must have a serial connection from your GRT to the ARINC module. In setup you should set ARINC connected and you should see ARINC data counters for both in (from 430) and out (to 430 and autopilot) incrementing (changing).

Do you see this?

Jim Butcher

Yes, counters show changing data.
 
Hi Jim,
Sorry for your trouble. A few questions/suggestions:
1. Autopilot pin 17 is an rs232 input. If you have a DPDT switch it should be switching the two arinc lines. So the wire from pin 17 (autopilot) should go directly to efis rs232 out port #4, not thru the DPDT switch. Is that correct?

Answer: yes. Pin 17 switches serial port input data when I go from FMS to EFIS. The dpdt switch also switches autopilot pins 14 and 15 from G430 pins 46 &47 to ARINC pins C5 & C9 when moved from FMS to EFIS. Both Andre and I confirmed this doing continuity checks. We’ve also done continuity checks at the 25 pin d-sub pin connector going to the autopilot.

Make sure you don’t cross any wire pairs, always ‘A’ to ‘A’, ‘B’ to ‘B’.

Answer: Both Andre and I have confirmed all As are only talking to ‘A’ and ‘B’ are only talking to ‘B’with continuity checks on the ARINC C connector and the G430 pins 46, 47, 48 and 49.

2. Efis rs232 out port #4 should be configured for NMEA-0183, per the tru trak manual.

I initially had it configured as Autopilot (Aviation) but today did try Autopilot (NEMA0183) with no change in results.

3. Make certain the efis port 4 and the tru trak pin 17 (rs232 in) have the same configuration (NMEA) and the same speed (choose 1200, 2400, 4800, or 9600)

All are set at a baud rate of 9600.

4. You mentioned you ‘screwed up’ the dpdt switch wiring. Did you short out or short together the A and B wires with power applied? You may have damaged the arinc box.

Response: Bob my screw up was that I cut the old dpdt switch wires too short for working with after making a few bad solder connections. I switched to using d-sub pins after that for connections because I had to do so many continuity checks tracing down the connections. Andre made a new switch for me, labeled the wires and confirmed proper working of the switch when he checked everything at AirVenture.

As far as the ARINC module being shorted, Jeff DeFouw didn’t think that was the case but they sent me a loaner which I tried with no changes. I gave them back the loaner at AirVenture.

:confused:
First thing I’d try is to re-configure efis port 4 (out) to nmea, and check the speeds (baud rate) match those set in the autopilot.

Bob

Unfortunately Bob everything you’ve suggested has been either checked or tried several times. Like I said, Aerotronics gave me a lot of help over the phone as we tried to troubleshoot this issue. GRT frankly has sent confusing emails with a few frustrating phone calls.

However, I still believe there has got to be a simple solution and I honestly think it’s a software or firmware issue at this point.

Jim
 
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If there is any secret to deciphering grt’s lack of current documentation, it’s this: new equipment often uses much of the old.
Jim, you should go to <grtavionics.com>/products. Click on the Hx, click on the photo of the Hx. You should see a page full of useful information, even though it is not for the EX.
Click on the Hx setup manual, go to page 3, near bottom is rs232-out format info, suggesting to use NMEA format for data out to an autopilot.
Back to the previous web page, under ‘wiring diagrams’, click on the one with a 430. Your wiring should look the same. Yes, it’s a different TruTrak, but the ARINC A and B pins, and the rs232-in pin, are the same as yours. Yes, the Hx has arinc built in, but its arinc connections on connector C are the same pin numbers as on the arinc adaptor you have. The only thing missing is the connections from the adaptor to rs232 ports on your EX. To see these, go back to the products page, click on miscellaneous, go down the list and click on arinc adaptor. You’ll see a picture of your adaptor and directions for wiring. Look very carefully at the pin numbers on the d-sub connectors (I use a magnifying glass). It’s very easy to get them wrong - backwards, or mirror imaged. On this same page, right side, there are some simple steps to confirm proper operation.
I would start by wiring the rs232 connection to the autopilot directly to a 430 rs232-out port. You can then use either NMEA or Garmin Aviation format, just use the same at both ends. Run thru the tests suggested on the arinc adaptor web page.

Edit: I see you posted while I was writing. Let me give it some more thought.
 
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Stuff like this makes us all frustrated. Sorry, it just must be your turn.

I am really hesitant to jump in here, but I did a very small upgrade to my panel. After the upgrade, the autopilot would not talk to the grt efis. That or the grt wouldn't listen. After double checking ALL the wiring, I sent the autopilot to Trutrak. They sent it back and said nothing was wrong. Next I got out the manual and found that some how some where along the line I had screwed up the settings, which is easy to do if you hold one of the Trutrak buttons a little too long. Maybe double check the settings???


Good luck.
 
As others have posted this can be a frustrating situation, I went through it as well. When I added my GRT EFIS I had the exact same issue. I tried everything, all the settings, copious amount of time on the phone with GRT support etc. GRT kept telling me it was a wiring issue yet I couldn’t find an issue. I was really getting PO’d.

During the various testing I found that the TT would function properly when the switch was set to the 430 but not when the switch was set to EFIS. I was sure I had done all the wiring correctly, my next step was to drop the airplane at my avionics shop.

Before I took the airplane to the avionics shop I gave it one more attempt, I traced every single wire from end to end with a meter. I found that two wires on the switch were flipped, yet I was positive everything was correct.

I moved the wires to the proper location and the system worked as advertised.
Boy did I feel stupid.
 
As others have posted this can be a frustrating situation, I went through it as well. When I added my GRT EFIS I had the exact same issue. I tried everything, all the settings, copious amount of time on the phone with GRT support etc. GRT kept telling me it was a wiring issue yet I couldn’t find an issue. I was really getting PO’d.

During the various testing I found that the TT would function properly when the switch was set to the 430 but not when the switch was set to EFIS. I was sure I had done all the wiring correctly, my next step was to drop the airplane at my avionics shop.

Before I took the airplane to the avionics shop I gave it one more attempt, I traced every single wire from end to end with a meter. I found that two wires on the switch were flipped, yet I was positive everything was correct.

I moved the wires to the proper location and the system worked as advertised.
Boy did I feel stupid.

Skid,
I’ve done what you’ve suggested at least two dozen times because I realize my electrical expertise is next to nil and felt the likelihood of a wiring error on my part was high. However, after Andre confirmed with his efforts at AirVenture that what he’d checked was okay my confidence in my own work increased. Having said this, I will next week once again do a series of detailed continuity checks to confirm there isn’t a wire crossed that I’ve missed. The issue with the swap out of the old WS with the G430 indicates there may still be something wired incorrectly.

One thing is very apparent to me after this experience and that is GRT’s documentation and experienced technical support staff is extremely poor and very limited for a business that sells products to the experimental community.

As I said at the very beginning I don’t like to vendor bash because let’s face it, they’re mostly small businesses on the leading edge of aviation technology leading us into a new and exciting future. But, if they only focus on selling product and ignore good documentation and the training of talented support staff then people are just wasting their money dealing with them. As is obvious from other posts to this issue my problem is not unique and their experiences similar to mine.

I’m sure by now my ability to have GRT continue to work with me is gone. I just ask that before others spend their savings they think not only of product but the service and documentation behind the product.

Bob Turner, when you read this please give me a call at (405) 761-three three seven four. I would really like to discuss this with you. I know first hand your expertise and hopefully you can guide me through this to a positive solution. GRT needs to take you on as a technical consultant. I agree will Mel in that their products seem to equal or exceed the competition at a competitive price. But people are buying more than a piece of technology - they’re buying the company behind it.

All I can say is thank you Delta Romeo for creating and sustaining this forum. Thanks to Aerotronics for going the extra, extra mile to help a second owner of a panel you built. You guys are the gold standard in customer support. Thanks to Andrew for not only designing a great autopilot but recognizing that if customer support is important then sometimes you have to partner with a larger company to continue that support.
 
I had four (yes 4!) 1st gen GRT screens (WS), Tru-Track A/P an IFD440-B and uAvionics ADS.

Very recently, I upgraded one screen to the HX and I'm using the original WS integrated AIRINC module (mounted on back of WS EFIS above the new HX). I just finished the HX install as a plug and play deal and I'm checking now the A/P functionality off the much higher resolution HX box. It seems to be working...errr...mostly anyway but there are issue (ADS-B WX and traffic on new HX unit which is a software setting perhaps, since my ADS-B works with other WS boxes).

I also have noticed some peculiarities with simple "direct-to" using GPS-2 and the new HX (like it does not work!). Befuddling to me. The setup menu is very complex and confusing...even counter-intuitive. I just wish there was a template for proper software settings for my avionics, which are fairly typical. I did back up and copy to all settings from the WS original but to no avail (lots of issues). Right now I'd never attempt IFR flight with the set up. Must do way more testing and validation. It is a bit of a sh*t show however due to poor product documentation and lack of solid tutorials from the GRT avionics folks. Support has been okay but I'll be calling multiple times as I sort it all out. God help me if I have to do 'pin surgery'... ugh. Complicating this process is that I'm not familiar with the logic of the system (2 GPS's internal and external, SAP redundancy, etc.) but I'm a quick study so that will come soon (thanks Jerry the "Widget"!!)..

I guess the bottom line is: it ain't easy and you will be thrown into the deep end of the pool. GRT support can be a lifesaver or an anchor depending on the complexity of the problem(s). Compounding the problem is my plane was professionally built (not by me!) and avionics wiring details are lacking and enigmatic.
 
I had four (yes 4!) 1st gen GRT screens (WS), Tru-Track A/P an IFD440-B and uAvionics ADS.

Mark - your problem very clearly is that pesky IFD-440. Just yank it out and ship it to me, I'll make that little problem go away. Heck, I'll even pay the shipping so you can easily get rid of this headache! :D:eek::p
 
In another review of the vast and scattered documentation I may have discovered the problem. The ARINC has two sets of ARINC inputs. One is G430 GPS ARINC output P4001 pins 46 & 47 (46 = GPS ARINC 429 A OUTPUT and 47 = GPS ARINC 429 B OUTPUT). Notice the numerical sequence! In my setup pin 46 plugs into ARINC C1 and pin 47 plugs into ARINC C2.

The ARINC also has a VOR/ILS ARINC input and those come from the G430 P4006 pins 23 & 24. However pins 23 & 24 have a reversed numerical A/B logic (23 = VOR/ILS ARINC 429 “B” Output and 24 = VOR/ILS 429 “A” output). They provide the input for the C connector C3/C4 pins.

Since I’ve (and everyone else) have been focusing on the GPS side of the equation (because the autopilot wasn’t getting a GPS Steering (GPSS) signal if there is an A/B conflict on the ARINC VOR/ILS then that could account for a signal conflict downstream of the ARINC module (ie autopilot). Remember ALL “A”s have to only talk to As and ALL “B”s can only talk to Bs.

I won’t be able to confirm this error on my part until Tuesday but if it is what I think it might be then I’ll just confirm I’m stupid! However, this again illustrates that because tech support didn’t point out this potential GNS A/B numerical change up between GPS and VOR/ILS A/B signal then maybe I’m not totally to blame.

I’ll let you guys know if this is an installation error I’ve made. Again a better ARINC installation guide (more than the one page picture on their website) would have highlighted this potential installation error.
 
In another review of the vast and scattered documentation I may have discovered the problem. The ARINC has two sets of ARINC inputs. One is G430 GPS ARINC output P4001 pins 46 & 47 (46 = GPS ARINC 429 A OUTPUT and 47 = GPS ARINC 429 B OUTPUT). Notice the numerical sequence! In my setup pin 46 plugs into ARINC C1 and pin 47 plugs into ARINC C2.

The ARINC also has a VOR/ILS ARINC input and those come from the G430 P4006 pins 23 & 24. However pins 23 & 24 have a reversed numerical A/B logic (23 = VOR/ILS ARINC 429 “B” Output and 24 = VOR/ILS 429 “A” output). They provide the input for the C connector C3/C4 pins.

Since I’ve (and everyone else) have been focusing on the GPS side of the equation (because the autopilot wasn’t getting a GPS Steering (GPSS) signal if there is an A/B conflict on the ARINC VOR/ILS then that could account for a signal conflict downstream of the ARINC module (ie autopilot). Remember ALL “A”s have to only talk to As and ALL “B”s can only talk to Bs.

……...

I’ll let you guys know if this is an installation error I’ve made. Again a better ARINC installation guide (more than the one page picture on their website) would have highlighted this potential installation error.

I said I’d let people know if this was the error I made. We’ll, it wasn’t!!! Once again I checked all my wiring and confirmed all “As” and Ann “Bs” are only talking to their correct ARINC inputs and outputs.

It really seems like there isn’t any ARINC output coming across the “C” connector C5/C9 wires to the autopilot. However EFIS channel 1 &2 ARINC counters are showing inputs.

I’m out of ideas and thinking about bypassing the ARINC output to the autopilot.
 
Jim

Bummer!

Looking at my setup, there are 3 ARINC settings in General Setup that aren’t described.

ARINC: Send Selected Course: Yes
ARINC: Sel Crs Mode Filter: ON
ARINC: Send Baroset: No

Probably won’t make any difference but worth checking.

I know you have 2 GNS430. Are both connected to your GRT EFIS? If so, how, meaning is there wiring between them?

Jim Butcher
 
Skid,
I’ve done what you’ve suggested at least two dozen times because I realize my electrical expertise is next to nil and felt the likelihood of a wiring error on my part was high.

Given that by your own admission your electrical expertise is "next to nil", and you are attempting a complex upgrade of an IFR panel originally built by Aerotronics, maybe it's time for you to dust the cobwebs out of your wallet and seek paid professional assistance rather than getting frustrated and bashing GRT.
 
Jim

Bummer!

Looking at my setup, there are 3 ARINC settings in General Setup that aren’t described.

ARINC: Send Selected Course: Yes
ARINC: Sel Crs Mode Filter: ON
ARINC: Send Baroset: No

Probably won’t make any difference but worth checking.

I know you have 2 GNS430. Are both connected to your GRT EFIS? If so, how, meaning is there wiring between them?

Jim Butcher

Jim
The bottom G430 just feeds the CDI and is not connected to this EFIS, A/P setup.
 
Given that by your own admission your electrical expertise is "next to nil", and you are attempting a complex upgrade of an IFR panel originally built by Aerotronics, maybe it's time for you to dust the cobwebs out of your wallet and seek paid professional assistance rather than getting frustrated and bashing GRT.

I’m more than willing to pay for some professional help but the avionics shops I’ve talked to either don’t have the time right now or in several cases have said they won’t touch GRT stuff because of poor technical documentation and them not having readily available technicians to contact for questions. BTW, GRT hypes this upgrade as “plug and play” with the a previously installed WS system. It’s definitely not plug and play!

My “venting” just reflects the issues I’ve dealt with trying to get help with this situation captain avgas! That’s why I kept silent and tried working with them and a few other experts for two months before my venting began!

As I said in the beginning they market some good, competitively priced equipment but if you run into problems and need serious technical support then you’re basically on your own because of poor documentation and very limited staffing (like three people - one sales, one software expert and one very limited avionics support person) at GRT. It is a very small company!
 
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Jim

Bummer!

Looking at my setup, there are 3 ARINC settings in General Setup that aren’t described.

ARINC: Send Selected Course: Yes
ARINC: Sel Crs Mode Filter: ON
ARINC: Send Baroset: No

Probably won’t make any difference but worth checking.

I know you have 2 GNS430. Are both connected to your GRT EFIS? If so, how, meaning is there wiring between them?

Jim Butcher

Jim,
I checked the ARINC settings you described above. Mine are exactly the same except for:

ARINC: Send Baroset. Mine is set to “yes”. Shouldn’t make any difference in this instance but I appreciate you sharing these settings.
 
Bob Turner suggested a G430/ARINC/EFIS interface test where I insure good satellite coverage and then set the PDF screen to display the Primary Flight Display and the HSI display side by side. With a two point flight plan set in the G430 I then select GPS with the CDI button and OBS. Rotate the EFIS right hand knob and confirm the G430 screen tracks the course change into the FP fix. Repeat this exercise for the VOR by selecting VLOC on the G430 CDI button.

I just completed this test and it appears the G430/EFIS and ARINC are talking to each other - at least through the serial port one connections. Now the question is what’s being transmitted to the autopilot through the C5/C9 pins? Is there some type of communication compatibility issue between the autopilot and the ARINC?
 
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Jim,
Did you get it working?

Like you I have a real concern about GRT support and whether Greg is heading out the door. I have complained twice now about their website with no response from anyone. I have been looking at upgrading two WSs to Horizon EXs but their website that discusses this says it's basically a plug and play yet when you select the Horizon EX you get one screen about the Horizon EX then the next eight or ten screen all discuss the Sport EX which is not anything like the Horizon EX. You can spend hours trying to figure out what is different.

I finally ordered two Horizon EXs and then began plotting out the wiring changes and found it to be extensive. I guess if you had a basic VFR set up it may be a plug and play but I have two WSs, a GNS-480, GTX-330ES, TruTrac auto pilot with VS. The 480 has a bunch of analog outputs to the EFIS CDI and the WS has inputs for them but the EXs doesn't so all those wires have to be removed as well as several other changes (Remote ARINC on the EX verses a built in one on the back of the WS). I called back a couples of days later an cancelled my order. It didn't seem to bother them at all!

I'm really sick about GRT because their support used to be excellent and now I'm looking at just staying with the WSs until they die then rewiring the whole panel for Garmin which really don't want to do!
 
My experience ....

Just a question, lots of discussion and lots of wiring but I don't see a wiring diagram published anywhere (maybe I missed it). In my 7a, I had 2 WS screens with ARINC, TPX330 with squitter, GNS430 and a TT Horizon with VS and preselect. My AP is wired to work through the HX and/or direct from the GNS430. I rewired using the diagram that was published on the GRT site, and still is I think. I did it wire by wire to upgrade from the dual WS to the a dual HX upgrade. Once the setting were correct everything worked as promised although I still find the AP coupling to be less than intuitive.

I find it very difficult to be certain anything is wired right unless I use a diagram and go wire by wire.

My experience in the past with GRT support has been very good as long as I was fully prepared to have the discussion.

Bottom line, if it's not too much trouble, I would be interested in seeing your original wiring diagram and then what changes you made to get to this point.
 
Danny,
I understand your frustration. And I agree the documentation is poor.

But Horizon EX are pretty much a drop in replacement for Horizon WS. They have analog ports built in. And actually, you can omit all the analog wiring and just use ARINC and two serial ports.

You have to dig thru the website, but there is documentation there.

Jim Butcher
 
GRT

Well, my experience is not that bad with GRT. Frankly, although documentation might be better, I doubt you get much hand holding from Garmin. I had no GRT equipment in the plane except an EIS and I had such a time trying to sort out how that thing in the air, with all the pages and strange indications that I looked for and found a Sport SX and put that in so it could display all the engine information. It was a slave only unit, so not a full EFIS. No harness, only the website info. It worked fine, but took some time to get set up properly. I had some questions on setup, which GRT helped with, although it did take some time to get a call back, they DID call back. Or answered by Email questions within a day or two.

I liked the unit and decided to get another Sport SX, this one a full EFIS to run the Autopilot and give me PFD and MFD as a primary instrument. Again, no harness, used, I followed the directions, installed the remote magnetometer, etc. all wiring checked, and again had to go through all the setup steps, again some questions requiring support from GRT, but they answered all of them. Bottom line it all works and plays together and runs the autopilot (TruTrak Vision).

The equipment worked fine and support is all I could expect, frankly.

I regret you are having problems...
Ed
 
Just answering the question whether I got my EX talking correctly to the autopilot and the answer is NO! GRT said they’d send me a test cable to run between my ARINC and autopilot but they never did. I suspect it’s because of this thread.

Right now I’m in California visiting my son and his wife and their new baby daughter. I hope to sandwich another rewiring between some minor eye surgery and other home repairs when I get back next week.

It should have been a simpler project than it’s proved to be. If GRT’s documentation, particularly that dealing with the ARINC module was better, and had the installation documentation gone into greater detail regarding settings than maybe the learning curve could have gone faster. As far as technical support staff, I still have serious issues regarding availability and communication skills.

It’s my opinion that GRT needs either an angel investor or to be sold to a larger company so that adequate resources can be applied to correct their deficiencies. Their products seem to be competitively priced and of reasonably good quality but without a better support system their days are numbered.
 
This may or may not have any bearing on your difficulties with the GRT EX and the external ARINC module but is still something to consider for your installation and for anyone using the external GRT ARINC module.

I had a GRT Sport HS and Garmin GNC-420 GPS/COM and had the external GRT ARINC module for input of ARINC data from the Garmin to the GRT EFIS. My AP is a Tru-Trak Vizion.

Initially, I could get GNAV mode to work on ground just fine but not inflight. The problem turned out to be very subtle.
The GRT EFIS sends configuration data to the ARINC module at initial power on. My GRT EFIS had battery backup power so that it would continue to operate when the battery voltage dropped below 10 or 11 volts during engine start but the ARINC module did not. During engine start when the battery voltage dropped, the ARINC module was losing its inialization. As a result, communication between EFIS and ARINC module was not functioning after engine start.

A simple way to test to see if this is causing your problem is to remove power (primary and backup) from the EFIS after engine start. Since your problem is AP related it would make sense to do this in-flight because its easier to check AP operation in flight rather than on ground.

The problem was solved by incorporating battery backup power to the ARINC module same as the EFIS. The version ARINC module I had only has a single power input. This required using external diode 'OR'ing of the primary power and battery backup to the single power input pin on the ARINC module.

Update: One other observation. Just because you have continuity between each connection and each point to point connection is correct doesn't tell the whole story. You need to also check/insure with your ohm meter that none of your connections are shorted to ground. A pinched wire that is shorted to ground will kill serial data even though it ohms correctly from point A to point B.
 
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James, I believe the GRT Arinc box is working correctly, because of the test reported a few comments back, where the 430 was put in OBS mode, and the GRT hsi knob was rotated. As the HSI course was changed, the magenta course line on the 430 also rotated, as it should. This particular data is transmitted from the EFIS to the 430 via ARINC, leaving me to believe that the arinc out is behaving as designed. This leaves:
1. A wiring error from wherever the arinc-out lines from the efis are spliced, and a split-off pair go to the autopilot.
2. Autopilot software and grt software are not compatible. Jim needs to get the exact software versions from both manufacturers and confirm they are compatible. Of course there will be denials and finger pointing.
3. TruTrak is not in a mode to accept external arinc commands. I don’t have a TT autopilot, but I recall flying with someone else, with an older TT, that he had to rotate the knob on his TT, and maybe push a button or the knob in, before it would correctly accept external (arinc) nav data.
Edit added: Jim, it looks like you need to push the mode button until you see ‘GPSS’ and, I think, ‘VS’, on the TT screen. Have you been doing this?
 
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RE:Tru-Trak GPSS

Bob,

I currently have a GRT Hx with its ARINC Tx output connected directly to a Tru-Trak AP. I did not install the GRT suggested DPDT switch to allow selecting the Tru-Trak ARINC source to be either the GRT Hx or the GNC-420 GPS. So in my installation it is always the GRT Hx driving the TruTrak.

If the ARINC data output from the GRT Hx is valid (in my case it always is unless the breaker on the GNC-420 is pulled) I get GPSS and VS when the the Mode button is pressed on the Tru-Trak. To use the Tru-Trak in basic AP I press the round rotating knob on the Tru-Trak which engages the AP in GPS track mode and its basic vertical modes (VS, ALT Select, and Alt Hold)

For GPSS and VS mode(s) the Tru-Trak requires both valid GPS RS-232 data and valid ARINC data. There is one other caveat to the Tru-Trak gps VS mode. To go into gps VS mode the Tru-Trak must be in ALT Hold or the vertical speed must be zero.

James
 
Jim, it looks like you need to push the mode button until you see ‘GPSS’ and, I think, ‘VS’, on the TT screen. Have you been doing this?

Bob,
I’ve pushed the mode button several times inflight to try to force it to enter GPSS mode to no avail.

Issac,
EFIS/ARINC power are wired together so that when I turn on the EFIS system switch both the EFIS and ARINC are energized at the same time.

My next attempt
I’ve bought 100’ of 22 awg mil spec wire, a new shrink tube label maker, and two colors of shrink tubing for labeling new C connector wiring (ARINC A - white and B - yellow) to hopefully ensure I don’t accidentally cross A/B connections.

Next week, if my eyes allow it after a minor lens corrective PRK procedure, I plan to once again make a new wiring harnesses (C1/C2/G430 P56) and (C5/C9/EFIS A5) to the panel DPMT switch and then new wiring from the switch to the autopilot (P14/P15/P17).

After the new harnesses are installed and checked I’ll fly another check flight (#16) to evaluate my efforts. My fall back position if this fails will be to get an October appointment at an avionics shop (who have agreed to look at it then but have the same experiences and opinion towards GRT as I’ve expressed).

Hopefully if the problem is a grounding problem as Issac suggested then a different wiring harness should correct it. If not then at least my wiring will be mil spec and labeled!

Great news - my wife and I are proud grand parents of a beautiful baby girl by the name of Naomi ! Our son, a Navy doctor and his wife, an NCIS Agent, are very attentive parents. Hopefully he’ll get to stay here and not get sent to Bahrain in support of the Afghan evacuation but we’ll see. His best friend, a Navy Seal CNA, is there now. Please pray for our military troops!
 
May I suggest another simple test? Based on Issac’s knowledge that the TT will not enter gpss mode unless it has both arinc and RS232 data:
Remove the RS232 line from the efis to multipole switch.
Jumper the RS232 line from the 430 (to that same switch) so that it, and only it, always feeds the autopilot, regardless of switch position. You already know that line works.
Test again, in efis feeds autopilot mode. If the TT now switches into gpss mode you’ve fixed the problem, and isolated the problem to that one rs232 line.
 
May I suggest another simple test? Based on Issac’s knowledge that the TT will not enter gpss mode unless it has both arinc and RS232 data:
Remove the RS232 line from the efis to multipole switch.
Jumper the RS232 line from the 430 (to that same switch) so that it, and only it, always feeds the autopilot, regardless of switch position. You already know that line works.
Test again, in efis feeds autopilot mode. If the TT now switches into gpss mode you’ve fixed the problem, and isolated the problem to that one rs232 line.

Thanks Bob,
I’ll give it a try when I return and let you know.

Question: If it goes into GPSS mode from the EFIS switch position with the G430 pin 56 RS232 wire connected to both sides what does that tell me?
A. The EFIS A5 output is bad?
B. The ARINC serial input input to the EFIS is bad?
c. A ground fault in that wire because the continuity test was okay?
D. Any other possibilities?
 
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If it works with the RS232 ‘by-pass’, then something is wrong in the efis rs232-out to TT connection. Could be pin A5 (serial 4 out) has failed, or is mis-set (wrong format or speed), or that connection failed (bad pin crimp, or loose pin), wiring broken or shorted to ground, multipole switch not working, wire to TT broken (but the wire to the TT rs232-in from the 430 switch must be okay, I assume they are joined together somewhere.
 
RE: GRT to Tru-Trak

Issac,
EFIS/ARINC power are wired together so that when I turn on the EFIS system switch both the EFIS and ARINC are energized at the same time.

Ans: If neither the EFIS or the ARINC module have backup power then your probably ok because they will both sense the same power and if one resets during engine start both will... but, if the EFIS has primary power and secondary power (battery bu) and the ARINC module doesn't then your open to the problem I experienced where the ARINC module lost its initialization from the EFIS.

On the trouble shooting tack that Bob is suggesting, I would propose to just disconnect the ARINC module so Arinc 429 is out of the picture. Then confirm using your existing wiring and switch that the Tru-Trak AP functions with either the GNS-430 RS-232 serial input or the EFIS RS-232 GPS input. Once you confirm that then return to trying to figure out the problem with ARINC and the GPSS VS problem.

It was confirmed previously that the EFIS was responding to VOR/ILS ARINC inputs correctly (P4006-xx). The GPS Arinc output from the GNS-430 is on a different connector (P4001-xx). Are all six pins of the GRT external ARINC module wired?
 
This may or may not apply to the newer GRT Horizon Ex EFIS using the external ARINC module, but while the older GRT Sport HS EFIS could support two GPS inputs, it could only support one external ARINC module. The GPS with ARINC data being input via the external ARINC module had to be 'designated' as GPS #1 in the EFIS "General" setup menus.
 
Need to apologize a little

GRT said they’d send me a test cable to run between my ARINC and autopilot but they never did. I suspect it’s because of this thread.

Right now I’m in California visiting my son and his wife and their new baby daughter. I hope to sandwich another rewiring between some minor eye surgery and other home repairs when I get back next week.
.

Got back from CA this evening. In my mail was a test harness from GRT - no instructions. It looks like the direct connection to the autopilot from the ARINC they mentioned several weeks ago.

Oh well it’s a start. I’ll try to figure it out and see if installing it will determine whether it’s my wiring or a switch problem.
 
It’s a DPDT Switch Problem!

I used the test harness GRT sent me and it appears the problem is the DPDT Switch wiring. The harness they made up and mailed proved there is a problem with my DPDT Switch wiring. The GRT test harness completely bypassed the dpdt switch and by doing so fed ARINC data directly to the autopilot. This allowed the autopilot to enter into GPSS mode and provide vertical steering.

Now that I know what caused the autopilot communication failure I will completely rewire the dpdt switch setup. What I cannot understand is why every previous continuity check, every previous wiring check, and several knowledgeable avionics technicians who closely examined this setup didn’t discover the problem.

I now acknowledge my own failures and thank GRT for creating a test harness that ultimately identified the problem. I’m sure they’re just as frustrated as I am that it’s taken this long and created the dissatisfaction it has.

I still believe a stronger, more accessible tech support system is needed by GRT but at least they followed through on their word to build and mail the test harness.
 
Jim, glad you found the problem.

Thanks for reporting back on this.

Best of luck fixing things.
 
Glad you found it. Do you have a manufacturer and model number for that switch? I’m curious and would like to look it up.
 
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