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Maverick972
12-17-2019, 07:37 AM
I upgraded to the vision 385 this year and it is wired up to the Garmin 430 and the GRT HXr.

I also have a switch that is GPS or EFIS.

According to the drawing. RS232 data drives the auto pilot when the switch is in GPS position.

I am assuming that it uses ARING data when in EFIS position as it is wired up that way.

My question is why cannot I control my auto pilot from the HXr or the unit go into GPSS mode when the switch is in EFIS mode. What am I missing? Settings? User error? (More than likely)

Thanks for the help. Sean

Canadian_JOY
12-17-2019, 11:24 AM
Check the GRT-provided wiring diagram again. Look hard at it.
You'll see the EFIS/GPS switch actually is a source control switch. It allows you to control which ARINC429 source feeds the autopilot.

When the switch is in the EFIS position, the HX is acting as the source for ARINC429 data going to the autopilot.

This is where things get a bit confusing for many users.

It doesn't matter which unit is driving the autopilot, GPS or EFIS, you MUST manipulate the buttons on the autopilot directly to select its modes of operation. To repeat and clarify, hitting buttons on the EFIS only controls what the EFIS sends out over the ARINC429 data bus. You have to then tell the autopilot what you want it to do with that data. You have to tell the autopilot what mode you want to use.

Set up the HX so that it is supplying valid data to the autopilot. Hit the MODE button on the autopilot to see GPSS (that's the first mode option that appears if the autopilot detects data on its ARINC 429 input). Hit the ALT button to select your altitude mode. Dial in the desired altitude with the rotary knob. Press the knob to select the altitude. Dial in the desired rate of climb or descent, press the knob again and you're now navigating in 3D using data from the EFIS.

(Hmmm, I think that's how it works... I find the autopilot knob-ology has become a reflex so when I'm not sitting in the airplane I kind of forget the button press sequence!)

ALagonia
12-17-2019, 01:16 PM
Check the GRT-provided wiring diagram again. Look hard at it.
You'll see the EFIS/GPS switch actually is a source control switch. It allows you to control which ARINC429 source feeds the autopilot.

When the switch is in the EFIS position, the HX is acting as the source for ARINC429 data going to the autopilot.

This is where things get a bit confusing for many users.

It doesn't matter which unit is driving the autopilot, GPS or EFIS, you MUST manipulate the buttons on the autopilot directly to select its modes of operation. To repeat and clarify, hitting buttons on the EFIS only controls what the EFIS sends out over the ARINC429 data bus. You have to then tell the autopilot what you want it to do with that data. You have to tell the autopilot what mode you want to use.

Set up the HX so that it is supplying valid data to the autopilot. Hit the MODE button on the autopilot to see GPSS (that's the first mode option that appears if the autopilot detects data on its ARINC 429 input). Hit the ALT button to select your altitude mode. Dial in the desired altitude with the rotary knob. Press the knob to select the altitude. Dial in the desired rate of climb or descent, press the knob again and you're now navigating in 3D using data from the EFIS.

(Hmmm, I think that's how it works... I find the autopilot knob-ology has become a reflex so when I'm not sitting in the airplane I kind of forget the button press sequence!)
That?s interesting because that is NOT how my system functions.
I have dual AFS 4500 screens, Garmin GPS 175, ARINC module and a TruTrak Vizion 385. When my select switch is set to EFIS I do not have to touch any of the controls on the TruTrak. As a matter of fact, the only thing I do with the TruTrak is sync the altimeter before takeoff. After that I never touch the autopilot. All input is through the AFS EFIS.

Canadian_JOY
12-17-2019, 02:24 PM
Interesting... Now I have a good excuse to go out and burn some more avgas!

BTW altimeter sync in ours comes across from the EFIS automatically so the altitude readout on the 385 always matches the EFIS altimeter.

ALagonia
12-17-2019, 03:43 PM
Interesting... Now I have a good excuse to go out and burn some more avgas!

BTW altimeter sync in ours comes across from the EFIS automatically so the altitude readout on the 385 always matches the EFIS altimeter.
Wow, I wish mine did that. Not that it?s a big deal to sync them.

Maverick972
12-17-2019, 04:00 PM
That?s interesting because that is NOT how my system functions.
I have dual AFS 4500 screens, Garmin GPS 175, ARINC module and a TruTrak Vizion 385. When my select switch is set to EFIS I do not have to touch any of the controls on the TruTrak. As a matter of fact, the only thing I do with the TruTrak is sync the altimeter before takeoff. After that I never touch the autopilot. All input is through the AFS EFIS.


That is how I was told my system should function. The altimeter does not sync.

The 365 man states that if ARINC data is present then GPSS will be automatic select. When I press MODE only GPS nav is available. I can see on the drawing the ARINC is going to auto pilot.

Could it be a setting in the 430 or the HXr

BobTurner
12-17-2019, 04:28 PM
1. The selector switch should be switching the ARINC lines, not the RS232 line. So you need at least a double pole, double throw switch there. (Actually TT says to switch the arinc lines. Trio says to switch arinc and rs232).
2. Make sure the efis and 430 are using arinc out, the TT ports are arinc in.
3. Arinc set to low speed, all units
4. ‘A’ goes to ‘A’, B to B.
5. Some TT models require switching to a particular mode to accept arinc data, others don’t. I have a Trio which defaults to arinc. Other than turning it on and setting the altitude, I never touch it again when controlling thru the HX.
6. I’m assuming you meant 430W. I don’t know what the non-WAAS does.
7 To feed GPSS data thru to the autopilot the HXr must be in GNAV mode.

Maverick972
12-17-2019, 09:25 PM
1. The selector switch should be switching the ARINC lines, not the RS232 line. So you need at least a double pole, double throw switch there. (Actually TT says to switch the arinc lines. Trio says to switch arinc and rs232).
2. Make sure the efis and 430 are using arinc out, the TT ports are arinc in.
3. Arinc set to low speed, all units
4. ?A? goes to ?A?, B to B.
5. Some TT models require switching to a particular mode to accept arinc data, others don?t. I have a Trio which defaults to arinc. Other than turning it on and setting the altitude, I never touch it again when controlling thru the HX.
6. I?m assuming you meant 430W. I don?t know what the non-WAAS does.
7 To feed GPSS data thru to the autopilot the HXr must be in GNAV mode.

Thanks Bob, yes it?s a 430W. Look forward to getting this working

Skid
12-18-2019, 01:53 PM
I upgraded to the vision 385 this year and it is wired up to the Garmin 430 and the GRT HXr.

I also have a switch that is GPS or EFIS.

According to the drawing. RS232 data drives the auto pilot when the switch is in GPS position.

I am assuming that it uses ARING data when in EFIS position as it is wired up that way.

My question is why cannot I control my auto pilot from the HXr or the unit go into GPSS mode when the switch is in EFIS mode. What am I missing? Settings? User error? (More than likely)

Thanks for the help. Sean

I also upgraded to a Vizion 385 from an older TruTrak A/P after Oshkosh. My setup was a GRT Sport SX EFIS (with external ARINC), TruTrak 385 A/P, Garmin 430 (non WAAS), and a switch for EFIS or 430 to drive the A/P. I also had to add the A/P software to the SX as I did not have that installed, I believe the HXr has it as standard.
I had an issue when I first installed the EFIS where I could not get the GPSS on my old A/P, it turned out to be two wires installed on the wrong pins on the switch.

In learning the new A/P I was told other than engaging the A/P I was to control it through the EFIS, which it did, sort of.

I am nearing a point where I have the process down.

One very important step is to not move the aircraft until the A/P is powered up and ready. The A/P does sync the altimeter with the EFIS so I do not have to set that, with the switch in the EFIS position.
I set the desired altitude on the EFIS by accessing the A/P commands, set desired climb speed, and descent rate, turn on the flight director, select source (heading, ENAV, or GNAV), and arm the approach if necessary. The A/P must be engaged by pressing the large knob, there is no way to engage the A/P from the EFIS, I wish there was. I engage the A/P after takeoff, the EFIS drives the A/P based on the altitude set and the GPS navigation from the 430, assuming the nav source is set to the 430.
The unit worked fine with the 430 except it would climb through the altitude set on the EFIS. Since it was a non WAAS unit I did not get any vertical GPS approach commands from it, I decided to upgrade to an Avidyne IFD440.

I am still working on a process to get the A/P to not climb through the altitude set on the EFIS. As of now I have to disengage the A/P and re-engage it while level, this is not desirable and I am working on why it behaves this way. I have contacted GRT, Trutak, and Avidyne but am still working on the issue.

As of now I believe the issue is not the EFIS or the IFD440, it is the behavior of the A/P. I have spoken to TruTrak/BendixKing twice but have gotten no where with them, each time I get another person at BendixKing support with no record of my previous call.

Once re-engaged while level the A/P works flawlessly with the EFIS and IFD440.

catmandu
12-18-2019, 05:13 PM
I agree it would be nice to have the Vizion capture altitude right off the bat.

My current technique is to set the initial altitude in the EFIS and control initial rate of climb with the Vizion (typically 800fpm). 200 feet shy of your initial target altitude set in the EFIS, roll the rate of climb to zero on the Vizion. It then captures and holds the target altitude. After that, all changes can be made solely with the EFIS.

Canadian_JOY
12-18-2019, 05:33 PM
I agree it would be nice to have the Vizion capture altitude right off the bat.

My current technique is to set the initial altitude in the EFIS and control initial rate of climb with the Vizion (typically 800fpm). 200 feet shy of your initial target altitude set in the EFIS, roll the rate of climb to zero on the Vizion. It then captures and holds the target altitude. After that, all changes can be made solely with the EFIS.

I think it's this last bit that makes me prefer flying with the EFIS/GPS switch in the GPS position. Setting altitude / climb rate through the autopilot's own buttons results in perfect altitude capture.

Toobuilder
12-18-2019, 07:16 PM
The last few posts have me confused. The 430, GRT WS and Digiflight II I've been flying for years provided flawless altitude capture from the EFIS. Once the AP was engaged, all commands were from the legacy WS screen. Is the need to drive vertical guidance from the AP head a Vision 385 specific issue? Seems like a step back if so.

davevon
12-18-2019, 08:51 PM
The last few posts have me confused. The 430, GRT WS and Digiflight II I've been flying for years provided flawless altitude capture from the EFIS. Once the AP was engaged, all commands were from the legacy WS screen. Is the need to drive vertical guidance from the AP head a Vision 385 specific issue? Seems like a step back if so.

Micheal, Does your Digiflight II have vertical steering? The one I had didn't. If I remember correctly it was an option.

My initial setup was the same as yours, my AP had altitude hold and vertical rate, but no altitude input or capture from the EFIS that I remember. At the time it was easier to just fly off the AP head with guidance from the non-WAAS 430.

The airplane has returned after 12 years and I've upgraded the AP to the TruTrak Vizion with altitude steering. All else is the same for the time being, upgrade coming soon. Now I use the EFIS to control the AP and I can vertically steer the AP through the EFIS, but only after it captures the altitude in level flight. Like in the other posts, if the AP is engaged during a climb I have to disengage at the programmed altitude, level off and re-engage the AP. Once vertically captured I can dial in altitudes or have it follow a synthetic approach.

I engage the AP by pushing the left "Mode" button. It comes up GPSS and the vertical side will display the vertical speed if engaged in a climb or VS if I'm level. At SnF I asked about not capturing the preset altitude and the guy at TT said you just push this and that and it works. Sounded easy and I should have wrote it down... I tried it and so many other combinations that I don't remember what the original one was.

I just checked and the AP does gather baro info from the EFIS. Although it takes more than a few seconds scroll to the new elevation. The EFIS preset altitude does not show up in the Sel Alt window. Maybe that is supposed to happen and that's why my AP isn't capturing the EFIS preset altitude from a climb engagement.

Regards,

Dave

Bavafa
12-19-2019, 10:14 AM
The last few posts have me confused. The 430, GRT WS and Digiflight II I've been flying for years provided flawless altitude capture from the EFIS. Once the AP was engaged, all commands were from the legacy WS screen. Is the need to drive vertical guidance from the AP head a Vision 385 specific issue? Seems like a step back if so.
The same for me, though it was a 430, HX/HS and TT on GPSS mode. I always left the switch to the EIFS and the GPS was just in case my EIFS had died which was never the case. The altitude capture was always flawless and exact.

catmandu
12-19-2019, 01:51 PM
From the Vizion Operating Manual, and why I use the procedure I do:

6.4.5. GPSV Mode (Vizion 385 ONLY)

The vertical GPS Steering mode or GPSV mode is engaged automatically with GPSS mode if the vertical steering signal is present. This mode is displayed with the addition of VS to the GPSS that appears in the lower left of the autopilot display bar. If the autopilot is engaged during a climb or descent, the vertical speed must be zeroed (see section 6.4.1) or ALT HOLD (see section 6.4.2) engaged to engage GPSV. The only exception is if the autopilot is engaged remotely from an EFIS.


I don't know how to engage the autopilot remotely from the HXr.

Skid
12-19-2019, 05:37 PM
From the Vizion Operating Manual, and why I use the procedure I do:

6.4.5. GPSV Mode (Vizion 385 ONLY)

The vertical GPS Steering mode or GPSV mode is engaged automatically with GPSS mode if the vertical steering signal is present. This mode is displayed with the addition of VS to the GPSS that appears in the lower left of the autopilot display bar. If the autopilot is engaged during a climb or descent, the vertical speed must be zeroed (see section 6.4.1) or ALT HOLD (see section 6.4.2) engaged to engage GPSV. The only exception is if the autopilot is engaged remotely from an EFIS.


I don't know how to engage the autopilot remotely from the HXr.

Yep. That?s what it states, but it still stinks. Had I known that I likely would not have upgraded from my old A/P.
My process is: engage the A/P after T/O and let it climb to altitude, disengage it, level off and engage the A/P again, after that it works great.
I was told by GRT support there is no way to engage a TruTrak from the EFIS.

Deweyclawson
12-19-2019, 10:34 PM
I put a GRT auto pilot in my RV6. Now have a 10 with a TT. The GRT servos will be here with the new GRT screens by Christmas. Replacing 3, 6in Hx asreens with 2 10in..