![]() |
I'd suggest putting in a "stand alone" switch. If things go really wrong (e.g., dark or IMC and EFIS dies) it might be nice to just be able to fly straight and level.
But to your issue: Do I understand that everything (EFIS, autopilot) worked okay before you installed the ARINC wires? Since you found one wiring error, did you triple check the others? You should have ARINC A OUT from the EFIS to ARINC A IN on the Trutrak, and ARINC B OUT from EFIS to ARINC B IN on the Trutrak. |
Quote:
Quote:
After deciding that it was worth having the ARINC installed, I bought one and plugged it in. I turned the ARINC Installed? option in the General Setup menu of the EFIS to "Y." At that point, the "problems" began. I immediately began getting the ARINC data warnings, AND the A/P would not behave in what to me seemed like a rational way. I'm pretty sure the plugs added to the harness for the ARINC installation are correct with the exception of the one I made correct after the fact. I think I need to absorb some of this for a while. One thing that still bothers me is GRT is really clinging to a need to point the EFIS to the ARINC module on serial port 4. The believe the EFIS software version was old and the option to direct the EFIS to a particular port to look for the ARINC was missing in the old software. But this is not the case though as I have the current software. But they keep bringing this up so it seems significant. I think I have an easier way to test the A/P. That is to unplug the ARINC and turn off the option in the EFIS. In theory, I should be back to a working A/P like I had before I attempted to add the ARINC. |
Andy,
You originally stated you have an early GRT Sport. It likely has a built in GRT GPS, usually connected to Serial port 3. Like Bob, I also didn't understand your set up. There is no GNS 430 or GTN 650 or similar GPS navigator, correct? Your G3X is not one either. You will have to follow your wiring. I would check with Stein if they originally made the panel or Jesse's crew may have made a wiring diagram. The switch may indeed allow you to select either the GRT GPS or G3X GPS to send RS232 GPS information to your autopilot. This will provide horizontal steering only, no vertical steering and no GPSS steering. I have older Sports also and ARINC, but no autopilot. My ARINC is connected to serial port 4 of my primary Sport. However, in General Setup page, serial port 4 in and out are set to OFF since I am not using the serial port 4 provided on the ARINC module. I think GRT tech support may be mistaken here. The ARINC module connects to the Sport over the Sport serial port 4. Since that makes that port unavailable for other uses, GRT added a serial port to the ARINC module to replace the one the module took away from the EFIS. If you use the "extension port", you have to tell (define) it's use to the EFIS just like any other port. But you aren't using it, so your Serial Port 4 in and out should be OFF. This has been standard in the software for years. Bob is the autopilot expert, certainly not me! But, does your autopilot work correctly by itself? Meaning just using it's front panel controls? Then if you connect just the RS232 signal, does the EFIS control it properly? This should be how you have been using it until now. Can you use the switch and control the autopilot with the G3X? GRT Sport EFIS require an upgrade to support vertical autopilot commands. Do you have this? You might want to put your thoughts together and the results of your investigation and post it on the GRT Community Forums. GRT's Jeff, who does all the software programming monitors that forum and provides answers. He is probably the most qualified person to assist. Keep us posted! Jim Butcher |
Hi Jim. Here are some responses. Thanks!
Quote:
|
OK Jim, some of this is sinking in now. I guess by navigator, you me a radio or similar than can fly an approach using the autopilot. No, I do not have anything like that in my plane.
I think I need to go back and start at the A/P end of the chain now to confirm that the A/P is actually working. I presume now that it uses its own gyro and pitot/static input to control the pitch and roll servos. It just can't fly a course line, only a heading. And all vertical commands are simply based on current altitude and rate of change. I'm not sure why it took so long for me to separate the EFIS and the A/P in my head. I'll be back with some info in a few days I hope. |
Andy,
Yes. A navigator like GNS430 not only has a GPS but it has in it's memory all the approaches. So when you select an approach, it "knows" all the points (fixes) and altitudes. It is having all these brains that make them so expensive! Which TruTrack do you have, Gemini AP? Did Jesse do the AP install? If so, he probably knows how things are wired, especially "the switch". I think your explanation of how your autopilot works is correct. The only thing to add is that it probably can follow a flight plan. It just will not have turn anticipation - it will fly to a point in the flight plan and then turn to the next point. Turn anticipation smooths those turns by starting them before you actually get to the point. Why did you decide to add the ARINC capability? Were you looking for vertical autopilot modes? I don't know how to tell if your Sport has the vertical autopilot software. Ask GRT Tech support. I think you're making progress. Welecome to experimental aviation:) Jim |
OK guys, I'm back.
I think everything works now. I appreciate all the patience and help from you guys!! I went to the hangar today to step back, and test each piece of equipment in the chain, beginning with the A/P itself. I removed the three wires from the A/P that were associated with the EFIS (RS232 for the internal GRT GPS, and the 2 ARINC wires). Then I flew the plane and tested the A/P alone. It worked. Then I added back the internal EFIS GPS and flight tested that. It worked. Then I added back the 2 ARINC wires and flight tested that. Fortunately, things worked this time. And to cut to the chase, what I think the problem was, aside from the 1 misplaced wire from before, was a baud rate setting mismatch between the GPS on serial port 3, and the A/P. Hard to believe... To make a long story short, I feel like I learned a ton about the system and how it functions. FAR more than I cared to in the beginning. But looking back now, it seems like I would have been spoiled if it all worked when I plugged the ARINC in the first time. This was some sort of right of passage I guess. Now I have to go and learn how to use the new equipment. Thanks again for all the help!! Andy:) PS. I did my 1st Pilots n Paws trip Saturday. Flew from NJ to NC and back to bring Krypton to a doctor to get him help with a really bad spinal issue. He was a happy dog! I could have used the A/P!!;) ![]() ![]() |
GRT Sport SX Serial Port 4 Setting for ARINC Module
I'm running into similar problems with my GRT Sport SX not controlling the auto pilot.
The system was working fine, but when I sent the Sport back to GRT to fix the screen the unit came back and this feature no longer works. Configuration: - Single GRT Sport SX - GRT ARINC 429 External Module - Garmin GNS-420W - Trutrak Vision 385 Question: In the GRT EFIS Settings and Values, what do I set the the "Serial Port 4 Input" and "Serial Port 4 Output" to? Note: I have "ARINC Module Connected | Yes" Thank you in advance. |
Quote:
Larry |
| All times are GMT -6. The time now is 08:09 AM. |