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Trio EZ "stand alone" Altitude Hold

DennisRhodes

Well Known Member
Installed a new to me Trio EZ Altitude hold on my RV9 along with the gold standard servo for pitch. My intent is to gain altitude hold to supplement my Trio EZ pilot roll and GPS track wing leveler control which had been in service and worked well since 2008.

The Trio Altitude Hold control device can be installed "blind" and I chose to install ( with correct orientation ) on to the forward side of the panel that's forward of the instrument panel. (that places it about 12 inches forward of the instrument panel) It has both velocity and and static ports to connect to use all the features of this EZ model.

It works as it should BUT it drops out VERY often I believe due to " excessive Gs". That is a electronic feature in the head that provides some protection. My issue is that mild bumps in normal flying will knock the altitude hold off. In perfectly calm air it will remain in and works fine. Most days its off every 5 minutes.

My question is : is it possible that where Ive got the control head mounted is not acceptable due to being to forward of CG. And it's like riding in the back seat of a long school Bus! The G forces are \amplified and it take the hold out on excessive Gs

I see some who have chosen to mount the head to the rear of the baggage bulkhead where the pitch servo is mounted. A location where the ride may be a bit better . Maybe I need to relocate mine??

Interested in hearing comments of users of Trio EZ Altitude hold units , where you mounted the head unit and what experience you have had with that stand alone device. Thanks for any comments you may have.
 
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ALt Hold ideas

I have the same trio set up
RV8 and my "control module" is in the forward baggage compartment so probably a little forward of what you have.
the couple times I had problems
1. for some reason the servo rotation direction setting was wrong (see 6.6 in the manual) once it was correctly calibrated it worked great
2. The Alt hold was identified as a leak during my 24 mo IFR pitot/static check so I sent it in to trio, Trio replaced all the internal tubing which they said gets old an brittle some times.
Its working great now so my recommendation check you servo "rotation direction" and if that doesn't do it call Trio they may have an easy fix or have you send it in for a $200 overhaul which is a pretty decent bargain in todays avionics world.
 
Dennis, the control box must be mounted with a specific orientation. Should be a sticker or something indicating up and forward.

The servo reversal reset happens if the unit is powered on during cranking, i.e. a supply voltage issue.
 
Galin, it s either a EZ 2 or 3. It has both the static and velocity ports on the forward facing surface. And Dan , Forward and left side arrows were there indicating the correct direction for the control module installation. Got all those covered. Was not aware of the servo direction issue but believe that has not been a problem since it works quite well and I have never experienced a servo reversal issue. Thinking that prob,em would be a " what the hello is going on" moment. Some thoughts are: since this box has been inservice before and there maybe some velocity limits set I m not aware of. There is a factory value default in the set up that I am going to try. Also got a email out to Trio. They have always been very responsive.

Thanks for the comments
 
Galin, confirmed it is an EZ-3 from the preselected altitude fx in the programing.
Ok.
The servo reversal reset happens if the unit is powered on during cranking, i.e. a supply voltage issue.
With most installations you use the servo default direction (normal). However in some installations (like mine) you have to use reverse direction. If you get a big enough voltage spike or drop, the servo direction may reset to default (normal) just as DanH noted. So if you have reverse selected, the servo can reset to normal which is opposite of how it is supposed to be for your installation. AFAIK this can only happen on start up. Once it is powered up, the EPROM prevents this from happening.

Don't ask how I know this. :rolleyes:
 
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Ok.
So if you have reverse selected, the servo can reset to normal which is opposite of how it is supposed to be for your installation. AFAIK this can only happen on start up. Once it is powered up, the EPROM prevents this from happening.

Don't ask how I know this. :rolleyes:

I wasn't aware of that issue until now. You're the third person on the responders to mention that , Bet that would be a surprise!! My plan has been to power up after engine start. I used a spare rocker switch and labeled "Altitude Hold" which powers that pitch servo and serves as a back up servo disconnect.

As an update : talked to Jerry at Trio today and he said he didn't think the G force software would be a problem, he suggested to be sure all DB plugs are tight and no corrosion . Also suggested the facrory default Fx and go back and reset everything including servo direction.
 
Dan , Forward and left side arrows were there indicating the correct direction for the control module installation. Got all those covered.

Cool. Just covering the bases.

When it kicks off, does the indicator actually display the legend "Excessive G" or something similar? I ask because just for fun, let's assume there is nothing wrong with the Trio's hardware or software. Instead, perhaps the wire to the disconnect switch is grounding somewhere when you hit a bump.

Was not aware of the servo direction issue but believe that has not been a problem since it works quite well and I have never experienced a servo reversal issue.

Yeah, I only mentioned it to offer an explanation to Mark. Galin explained it better.
 
Cool. Just covering the bases.

When it kicks off, does the indicator actually display the legend "Excessive G" or something similar? I ask because just for fun, let's assume there is nothing wrong with the Trio's hardware or software. Instead, perhaps the wire to the disconnect switch is grounding somewher.


Dan ,that makes sense because there are alarms that are posted on most of the fault modes. I've got to get some more info of what if anything that alarms on the LCD. The other thing that points in that direction is that on the ground it seems to remain latched. Sounds like I need to do some wire wiggling while on the ground.

Thanks for the comments
 
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