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View Full Version : How to run the trim wheels actuated by the A/P ?


Brian
06-28-2007, 01:05 PM
Hello,
I am using the NG trim wheels just for running making any input with the trim switches locating on the control wheels.
So, if the PM/FS A/P makes any changes in pitch during autoflight the FS stab trim moves.
How can I make this trim motors run during any A/P input...
Nose up input = ...?
Nose dn input = ...?
I am not using any trim axis, just the bottons configured by FSUIPC.
I only need one relay input for nose down and one for nose up to make the DC motor run in the right direction as long as there is any change in trim during auto trim...
Thanks
Brian
Peter Dowson
06-28-2007, 03:26 PM
How can I make this trim motors run during any A/P input...
Nose up input = ...?
Nose dn input = ...?

They are not separate things. You have to watch the trim indicator value (FSUIPC offset 0BC2) and turn the wheels according to whether that increases or decreases.

Pete
CocnutAir
06-29-2007, 02:30 AM
Brian,

What interface are you planning on using for relay that is controlling motor ?

Regards,
Alan.
Westozy
06-29-2007, 05:35 AM
Hi guys, I made this work using a double throw rocker switches. The trim indicators operate the trim potentiometers. Easy mechanical solution!

http://www.mycockpit.org/photopost/showphoto.php?photo=177&ppuser=305

Gwyn
mauriceb
06-29-2007, 04:36 PM
Here is how I did it so that the trim wheels turn when either the autopilot commands pitch up or pitch down, or when the trim is changed manually with a switch in the yoke (I am using the Phidgets 8/8/8 interface card ). The DC motors must be of the type that reverses direction when the supply voltage changes polarity.

Maurice

http://i32.photobucket.com/albums/d38/mau_ben/Trimcontrol.jpg
Brian
07-01-2007, 09:45 AM
Hello,
many thanks for help. Now I solved the problem using PM Offsets...
5528 2 (Boeing MCP Trim Movement Write)
To insert for phidgets card:
5528 .4 TrimValueDecrease
5528 .5 TrimValueStable
5528 .6 TrimValueincrease
Now it works together with the 16/16 phidgets card running PM-System directly.
I am using two relays switching the right movement direction.
Thanks Maurice
Brian