Two elevator trims

Dejw

New Member
Joined
Oct 24, 2024
Messages
5
I have two elevator trim servos and I would like to see their position on the HDX display, but it seems I cannot setup it this way (only one trim servo is possible to confirm) - is there any solution/workaround?
 

mikelupo

Member
Joined
Feb 22, 2024
Messages
45
Location
Gilford, NH
Hi Dejw,
I've not encountered a dual elevator trim situation in my own experience with experimental.
Was this something that was part of a kit? I'm not flaming or trying to be confrontational at all here. Just trying to understand.
If it was part of some design, it would be helpful to the user community... point us to that documentation so we can see what the interfaces look like and understand why it was done that way.
The outcome of this thread may be you going back to the drawing board on the trim. It may be that it's not a supported configuration or maybe someone has been down this path before and can guide you to the solution you hoped for.

I hope this sort of helps...
 

Dejw

New Member
Joined
Oct 24, 2024
Messages
5
Hi Dejw,
I've not encountered a dual elevator trim situation in my own experience with experimental.
Was this something that was part of a kit? I'm not flaming or trying to be confrontational at all here. Just trying to understand.
If it was part of some design, it would be helpful to the user community... point us to that documentation so we can see what the interfaces look like and understand why it was done that way.
The outcome of this thread may be you going back to the drawing board on the trim. It may be that it's not a supported configuration or maybe someone has been down this path before and can guide you to the solution you hoped for.

I hope this sort of helps...

Hi Mike,

It’s an official kit - Savannah SR from I.C.P - basically modified zenith 701.

It uses two separate trim tabs on aa elevator and therefore two servos. The POH says you should do a full trim cycle before every flight to make sure they are synchronized. I want to monitor both these trims on my HDX but haven’t found a way to do it :/
 

mikelupo

Member
Joined
Feb 22, 2024
Messages
45
Location
Gilford, NH
I had to think about this. The trim position sensing comes from each servo. Each servo being independent of the other (elevator and roll). That said, I believe it can be done actually...
The install guide has this to say about it; Taking note what I have bolded.

"Position potentiometers may be connected to any general-purpose input pin on the SV-EMS-
220/221’s D37 and must be calibrated according to the instructions found in the EMS Sensor
Calibration Section. The number of position potentiometers in any installation is limited by the
number of unused general purpose input pins on the SV-EMS-220/221’s D37 connector.
The
tables in the Example Engine Sensor and Transducer Installations Section contain
recommended input pins for position potentiometers."

I hope this helps!
 

Dejw

New Member
Joined
Oct 24, 2024
Messages
5
that’s exactly what I also found but honestly after trying it - I have no idea how to achieve that.

See attached pictures - I don’t have any possibility to create my own sensor input - only use already existing ones and ELEV can be used only once - no chance to add it in “a custom way” :/

Not sure if I can create my new sensor and display it alongside these already there ?
 

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mikelupo

Member
Joined
Feb 22, 2024
Messages
45
Location
Gilford, NH
Thanks for the photos. That helps. It seems that you need to create new device names. Like, ELEV-S (S, for Starboard) and ELEV-P for, you guess it, port side. then it won't complain. I think you might have to go into another menu to create new names? I ran into that. I just don't recall how I accomplished it. Also, some pins are dedicated to specific functionality. It seems that since Pin 9 is also a general purpose interface, that it will allow a 0-5v device also. So your pin choices seem okay to me.
So try to make custom names for Pins 9 and 10. Let us know how you make out.
 

Dejw

New Member
Joined
Oct 24, 2024
Messages
5
Ok, I managed to to add another option "ELEV2"

1734886481745.png


- the problem is, when I want to display it, only two styles are available - analog value (between 0 and 5) or FLAPS-like widget (quarter-gauge and needle) but no other styles - so no elevator trim widget (bar with two arrows on each side) is possible to select from styles :/
 
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