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Trim with SV-AP-PANEL vs VP-X sanity check

riseric

Well Known Member
Patron
Hi, this is also posted on the Dynon Forum.
I thought to post here also to get a wider audiance and opinions.



Hi all, I'm almost finished wiring a RV-8.
Skyview HDX, pitch and roll servos, Ray Allen Pitch Trim.
Sanity check for me concerning Trim wiring.

Not having at that time received the Dynon Skyview goodies, I initially connected the Ray Allen Pitch Trim 5 wires and the trim switches to VP-X as per their instructions.
I now realise that I will need to re-wire the Trim motor and the Trim switches if I want to enjoy the Auto-Trim along with the Auto-Pilot through the SV-AP-PANEL.

If I understand correctly, it would be necessary to entirely un-plug the Trim motor and Trim switches from the VP-X, then connect to the SV-AP-PANEL D15:
the 2 white wires of the Trim motor to #7 & 8,
a 12V 4A (from VP-X) to #9,
a ground to #2,
the pilot's and copilot's Trim switches to #3-4-5-6 as per instructions?

Also the Pitch Trim motor's 2.5V, ground and position input to the EMS?

I believe I'm understanding this out correctly, but before I start to un-do stuff, I'd like to confirm with people that have the same set-up.
Thanks !!!
 
Hi, this is also posted on the Dynon Forum.
I thought to post here also to get a wider audiance and opinions.



Hi all, I'm almost finished wiring a RV-8.
Skyview HDX, pitch and roll servos, Ray Allen Pitch Trim.
Sanity check for me concerning Trim wiring.

Not having at that time received the Dynon Skyview goodies, I initially connected the Ray Allen Pitch Trim 5 wires and the trim switches to VP-X as per their instructions.
I now realise that I will need to re-wire the Trim motor and the Trim switches if I want to enjoy the Auto-Trim along with the Auto-Pilot through the SV-AP-PANEL.

If I understand correctly, it would be necessary to entirely un-plug the Trim motor and Trim switches from the VP-X, then connect to the SV-AP-PANEL D15:
the 2 white wires of the Trim motor to #7 & 8,
a 12V 4A (from VP-X) to #9,
a ground to #2,
the pilot's and copilot's Trim switches to #3-4-5-6 as per instructions?

Also the Pitch Trim motor's 2.5V, ground and position input to the EMS?

I believe I'm understanding this out correctly, but before I start to un-do stuff, I'd like to confirm with people that have the same set-up.
Thanks !!!

Hey,

I'm curious. What did you ever find out about this? How did you wire your trim system? I'm in the same boat now.
 
I had my trim working until I removed from vpx to follow the Dynon guidance. Now nothing works. Still figuring through it.
 
Exactly as in post #1

Hi Ken,
I unplugged the trim wires from the VP-X and re-wired as per Dynon.
Just what I posted in the #1 post above.
All works well !!

Hope this helps
 
Check VP-x Trim Power

I had my trim working until I removed from vpx to follow the Dynon guidance. Now nothing works. Still figuring through it.

I had the same issue with nothing working after connecting the trim to the Dynon from the VP-x. Solution is to remove circuit fault monitoring on the VP-x circuit you use for the trim power to the Dynon AP panel D15 connector.
 
… Solution is to remove circuit fault monitoring on the VP-x circuit you use for the trim power to the Dynon AP panel D15 connector.

Please help me understand what protections you still have. Does that circuit still have normal over-amp CB protection?
 
Yes, I believe so. Even still, the trim power is very low amperage to the Ray Allen servos and according to the Vertical Power installation guide, low amperage devices do not need the current fault detection:

Current Fault: The pin can be configured to detect a “current fault” or open circuit. When a circuit with this feature enabled
is turned on and does not draw any current for 3 seconds, the circuit is faulted. You can use this to detect burned out lights, faulty boost pump, failed avionics fan, or inop heated pitot tube for example. The minimum detectable current is about 100ma, so this should be used on devices like lights, strobes and loads that draw at least 100ma of current.

Since the trim motors connected to the Skyview A/P they require an always on circuit, but if current fault detection is turned on for its power circuit, it will not allow current to flow after the 3 seconds since your trim button or hat switch is not activated.

I should note that for VP-x "switched" circuits, the current fault detection doesn't shut the circuit off after 3 seconds per the above. But for "always" on circuits like you would want for the trim power, the current fault detection operates per above.
 
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I confirm what is said above.
Disable the current fault monitoring on the VP-X trim power pin.
VP-X will protect the circuit normally to the value you entered in its setup.
On my setup, the trim will function only when power is applied to the SV-AP-PANEL.
If only the displays are powered, the trim does not operate.
 
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VPX Trim Control

I wired my trim servos and stick hat trim switch through the VPX Pro. I understand that the Dynon autopilot will therefor NOT automatically trim pitch and roll. Trim works flawlessly with my thumb. If I understand correctly, the Dynon EFIS will enunciate trim up/down/left/right alerts if trim adjustments are needed. I would think the pitch and roll servos would sense the need for trim regardless of whether trim is controlled by the VPX or the Dynon AP. Am I correct? RV-9A still being built... expect another year before flight.
 
I wired my trim servos and stick hat trim switch through the VPX Pro. I understand that the Dynon autopilot will therefor NOT automatically trim pitch and roll. Trim works flawlessly with my thumb. If I understand correctly, the Dynon EFIS will enunciate trim up/down/left/right alerts if trim adjustments are needed. I would think the pitch and roll servos would sense the need for trim regardless of whether trim is controlled by the VPX or the Dynon AP. Am I correct? RV-9A still being built... expect another year before flight.

Short answer - no.

The SkyView integrated autopilot module does all the trim functions, including switching and auto trim when the autopilot is engaged. Using the VPX pro for this degrades the operation of the SkyView autopilot system.

Carl
 
You can use the VP-X for trim switches and trim motor power, or move those over to the Skyview AP control head. I have been flying my RV-9A with the VP-X trim controls and it works just fine. If the Skyview wants more pitch up or down, it will annunciate ("TRIM UP" or "TRIM DOWN") and you just need to bump the hat switch to adjust the trim to quiet the voice.

With the Skyview AP head, it is my understanding that if the AP servos detect too much pressure and if wired to the trim system, it will make the trim adjustments automatically. I don't have the AP control head, so I don't know if it will annunciate what is is doing or not. (I'm assuming it does any auto trimming silently).

I'm getting ready to add the AP control unit for the Skyview, and I did notice that on the VP-X, both the pilot and co-pilot trim switches are connected together, so there is no distinguishing in the electronics as to which stick is manipulating the trim switches. On the Skyview AP control unit, the pilot/co-pilot inputs are separate and the pilot's inputs override the co-pilot's.
This is going to involve a fair bit of rewiring and running 4 new wires from the co-pilot stick up to the AP control unit. I'm wondering if this "feature" is really needed or not. 99% of the time when I'm flying, the co-pilot stick is stowed and isn't even connected. If I leave the stick wiring alone, then I'm basically staying with what I currently have with the VP-X, and either trim control for pilot/copilot will move the trim and there is no override by the pilot.

Any downsides to leaving the copilot trim control wires disconnected on the Skyview AP control head? Instead the copilot trim switches will still all be tied to the pilot inputs.
 
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