I am building an RV10 I have 2 HDX1100 screens (one in front of each pilot, my wife was a Pro pilot also) and a HXD800 in the middle for engine instruments. I also have a Vertical Power Pro for switching and circuit protection. The Pitch and Roll trims are wired through the Vertical Power Pro and the Vertical Power Pro interfaces with all 3 EFIS via a serial port. Roll trim works perfectly. Pitch trim works perfectly except the Pitch trim indicator is running backwards. When I When I trim nose up the indicator tracks to the top of the scale instead of the bottom. I have tried several wiring configurations suggested by Dynon and Vertical Power and nothing fixes this problem.
Pirch Trim Indicator running in reverse
- Thread starter rjones560
- Start date
I believe the pitch trim indication direction determined during the calibration for that widget, which I believe is still done when you have a Vertical Power. So I *think* that you should be able to fix this by re-doing the widget cal.
DBRV10
Active Member
My 20c worth.....always wire the trim indicators directly to the EMS module. There is a time delay that annoys me off the VPX.
You could swap the 5V and GND to the servo potentiometer and trick it ;-)
Otherwise refer the Dynon post above.
You could swap the 5V and GND to the servo potentiometer and trick it ;-)
Otherwise refer the Dynon post above.
XPRSAV8R
Member
So the instructions on the calibration screen are a bit ambiguous, with directions to demonstrate "full up" and "full down". But it doesn't specify whether that means note up or trim tab up. We may have in fact worded it that way so that installers could interpret it in the way that they prefer. I was in the room for those discussions, but I honestly don't remember the reasoning at the time.
If you interpret it as "full nose up", for example, the trim indication will move up on the screen as the nose goes up. This is how some electric trim indications display (such as the Ray Allen indictor, which is widely used in experimental aircraft), but indeed the opposite of the convention of other aircraft trim displays, which likely originally gained their indication because of how they're mechanically rigged (think of how the wheel in a C172 is tied to the indicator - you roll the wheel forward to trim nose down, which winds a thing inside forward, which then causes the indication to travel UP the view window even though the aircraft is being trimmed nose down).
All of that said, there are two ways to reverse it if you don't like the direction it's moving. One is to redo the calibration. The other is to go into the calibration screen and instead of doing a whole new one, just swap the two voltage numbers in the table. Either will be the work of a few minutes.
If you interpret it as "full nose up", for example, the trim indication will move up on the screen as the nose goes up. This is how some electric trim indications display (such as the Ray Allen indictor, which is widely used in experimental aircraft), but indeed the opposite of the convention of other aircraft trim displays, which likely originally gained their indication because of how they're mechanically rigged (think of how the wheel in a C172 is tied to the indicator - you roll the wheel forward to trim nose down, which winds a thing inside forward, which then causes the indication to travel UP the view window even though the aircraft is being trimmed nose down).
All of that said, there are two ways to reverse it if you don't like the direction it's moving. One is to redo the calibration. The other is to go into the calibration screen and instead of doing a whole new one, just swap the two voltage numbers in the table. Either will be the work of a few minutes.