What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Trim Position through VP-X or G3X?

grayforge

Well Known Member
I know that one can route the Trim Position wires to either the VP-X or straight to the G3X and trim positions will be displayed on the G3X for either method...

Is there a preference for which way to go when one has both the VP-X and G3X?

Thanks!
Russ
 
If your aircraft has a reflex flap position.... If you connect the pot to the VPX you will not see a negative position displayed on the G3X. When the pot is hooked directly to the G3X you will see a negative position graphically displayed on your G3X.
 
I put mine through the VPX because that is where the trims get mixed anyways. I felt it to be the most logical place.

Not sure there would be any benefit wiring it through the G3X?

I can tell you that it works fine my way though!

:cool: CJ
 
I know that one can route the Trim Position wires to either the VP-X or straight to the G3X and trim positions will be displayed on the G3X for either method...

Is there a preference for which way to go when one has both the VP-X and G3X?

Thanks!
Russ

Hello Russ,

Not sure if you have rudder trim, but the G3X system supports 3 axis of trim position sensing/display while the other system only supports 2.

It is best to not connect some of the position sensors to one system and one to the other, so if you ever think you will want 3 axis of trim position sensing, by all means connect the roll and pitch trim position sensors to the G3X system.

Thanks,
Steve
 
Steve has a valid point about the 3 axis trim. Although I rarely touch my rudder trim. It's set for cruise and left alone for long periods of time.

I don't have a Garmin EFIS, so I can't specifically comment, but I can provide a question to ask to help you make a decision.

I have AFS and the flaps, elevator and aileron trim are controlled by the VPX. The position of all of them are passed through to the EFIS and displayed.

Does the G3X VPX software interface have the same feature in which is can get the position information from the VPX and display it?
 
Mine is connected to the VP-X, works great there on my 7.

The VP-X Manual actually states:

"IMPORTANT: Do not use the trim position inputs on
the EFIS. The EFIS gets trim position information from
the VP-X over the serial data line."


and

"6.4 Configuring the Garmin G3X EFIS
Turn on the master switch and verify the VP-X is turned on by looking
for the blinking orange lights on the Ethernet jacks.
Follow these steps within the EFIS setup pages:
1. Under COMM page in the setup, set the MFD serial port that is
connected to the VP-X Pro or Sport to “Vertical Power”.
a. A green check mark in the left column indicates it is
receiving data from the VP-X.
2. The trim and flaps are automatically configured to read their
position from the VP-X. If you have a third trim axis wired into
the G3X analog position input, you can configure it in the trim
and flap setup as described in the Garmin manual.

3. You can configure the Amps gauge to display amps from the
VP-X instead of from an external shunt."


The G3X Touch Install Manual states:

"Vertical Power: When using a Vertical Power unit, trim and flap positions will automatically be displayed.
Connecting, configuring, and calibrating the POS inputs is not required when the position sensors are
connected to a Vertical Power unit."


While I never tried to configure the G3X Touch for using the VP-X and connecting the trim sensors directly to to the G3X itself, it appears that the setup is hard coded to provide pitch, roll and flap indications from the VP-X when you tell the G3X that the VP-X is being used.
I have no idea if you can go back after the fact and reconfigure these sensor inputs to display local connected sensors or not. It would appear that you can based on Steve's comment above but I would double check with him before making those wiring connections.
 
Steve has a valid point about the 3 axis trim. Although I rarely touch my rudder trim. It's set for cruise and left alone for long periods of time.

I don't have a Garmin EFIS, so I can't specifically comment, but I can provide a question to ask to help you make a decision.

I have AFS and the flaps, elevator and aileron trim are controlled by the VPX. The position of all of them are passed through to the EFIS and displayed.

Does the G3X VPX software interface have the same feature in which is can get the position information from the VPX and display it?

Yes the G3X shows the position information from the VPX. I have the GX pilot servos (TruTrack), not the newer garmin ones, so it seemed obvious at the time to send them through the VPX. Now the choice is not so obvious in either direction.
 
I only have 2 Axis Trim, so no need for rudder trim position display.

So I wonder if the display of trim position on the G3X screen is the same whether the data is coming in directly or it's coming through the VP-X.

Sounds like the VP-X is the way to go since it's auto configured.

Thanks!
Russ
 
I only have 2 Axis Trim, so no need for rudder trim position display.

So I wonder if the display of trim position on the G3X screen is the same whether the data is coming in directly or it's coming through the VP-X.

Sounds like the VP-X is the way to go since it's auto configured.

Thanks!
Russ

Displayed the same, yes I think so although the position displayed will depend on the calibration for each unit. You still have to calibrate the sensor to the box it is connected to...
 
The G3X autopilot servos have built in auto-trim. If you or some future owner wish to use this feature it might be best to wire the trim through the G3X.
 
The G3X autopilot servos have built in auto-trim. If you or some future owner wish to use this feature it might be best to wire the trim through the G3X.

The G3X will still auto trim if you run the wires through the VPX. It does on mine!

:cool: CJ
 
Like CJ says, the VP-X works fine controlling the trim servos along with the G3X's ability to auto trim the plane.
 
As these guys said. I'm setting my plane up with Auto-Trim. The Servos do the trimming since they are inline with the VP-X trim lines. The position outputs going to either the VP-X or G3X don't have any bearing on auto trim.
 
Back
Top