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Trutrak Vizion 385R sluggish in capturing Alt

9krpm

Member
Morning from Australia :)

I completed my IFR training in a RV10 that I restored recently; Dynon HDX EFIS, MFD, Avidyne 540, a back up Garmin G5 and a GNS430. I kept and firmware updated the TruTrak Vizion 385R during the restoration of the plane. I'm fairly happy with the Trutrak except the frequent Alt adjustment to match Dynon Efis. I have a back up Garmin G5 and wonder if the Alt can be sent to the Trutrak somehow? It wont sync Alt with the Dynon.

It also banked at around 18 degrees during my training and required a bit of hand flying at times. I was too busy to look into it during the IFR training.

I have adjusted the Lateral activity to Hi and GPSS gain to 30. The plane banks around 24 degrees per the manual, much better for the IFR flying.

I'm not sure what to set for GPSS Max bank.

I now have another problem that was not there before. I may have adjusted another parameter or something in the Mac menu and forgot to returned the original setting, the AP is really sluggish at capturing Alt. It over and undershoot the desired Alt. I dont think I adjusted any vertical parameters though.

Much appreciated for your advice on what else I can tweak.
 

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Congrats on a beautiful refit and getting your IFR. I’ve got an IFR RV-7 in Australia including a Vizion 385. Agree the manual alt setting is a bore. Sounds like VRT ACTIVITY needs to increase, but strange that you’ve had to change it. Maybe the settings were reset to default on the TruTrak firmware upgrade. Where did you get it done (out of interest, mines on an ancient version)
 
I would to call or email MidContinent to have them walk through the settings with you. I don’t recall how everything should be set on the MAC side of the settings.
 
Congrats on a beautiful refit and getting your IFR. I’ve got an IFR RV-7 in Australia including a Vizion 385. Agree the manual alt setting is a bore. Sounds like VRT ACTIVITY needs to increase, but strange that you’ve had to change it. Maybe the settings were reset to default on the TruTrak firmware upgrade. Where did you get it done (out of interest, mines on an ancient version)

I had the unit updated before BK took over. It was done by an Aus representative Jon Johanson.

Yes it is a bit weird that the vertical setting needs tweaking. I only made changes recently. I may have changed something.
Will increase vertical activity increases the capture rate?
 
I would to call or email MidContinent to have them walk through the settings with you. I don’t recall how everything should be set on the MAC side of the settings.

Thanks Andrew. I will.

Is there any other setting I can try as well to increase the altitude capture rate Andrew?
 
I had the unit updated before BK took over. It was done by an Aus representative Jon Johanson.

Yes it is a bit weird that the vertical setting needs tweaking. I only made changes recently. I may have changed something.
Will increase vertical activity increases the capture rate?

I’m by no means an expert, but by the sounds of it the VRT ACTIVITY setting increases the “aggression” with which the autopilot tries to arrest changes.

(Sounds like it tweaks the PID values which is something that’s really interesting to think about if you’re not an engineer, I assume it’s intuitive to them https://www.ni.com/en-au/innovations/white-papers/06/pid-theory-explained.html#section-366714077
 

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I'm curious to know what changes you might have experienced after tweaking the vertical activity setting. If you've had a chance to tweak and fly I would appreciate knowing how this has turned out for you as I suspect I also need to increase the vertical activity setting in our Vizion 385.

Symptoms I'm seeing are altitude over-shoots and under-shoots when in altitude hold mode. As we are coming through the set altitude there may still be +/-200FPM of rate which doesn't get zeroed out until 60-80 feet of overshoot has occurred, then we see the same correction of up to 200FPM being applied in the opposite direction and the a/p once again blasts through the set altitude going in the opposite direction. This constant up and down happens typically on days when there is some convective activity to contend with. On days when the air is relatively smooth the altitude is held rock-solid.

Thanks for any info you are able to share.
 
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