PFC Electric Trim

[dfournie]

Pete,

I just received my PFC Modular Flight Deck w/electric trim. I'm trying to understand the operation of the electric trim mechanism and how the trim wheel and it's associated trim indication stays 'synched' with the trim position in FS2004. I'm starting to find some situations when the trim rate and position supplied to FS2004 does not appear to match the rate at which the electric trim motor trims the flight controls on the modular flight deck. After a while either 1) the trim inside FS2004 reaches it's maximum up/down limit, or 2) the electric trim on the MFD reaches it mechanical limits and then no longer matches the trim position inside FS2004. It appears to me that the trim switch on the yoke sends both a command to FS2004 to run the trim (as it would in a PFC yoke with no electric trim), but also sends the command to drive the electric trim motor in the flight deck. These two operations don't always seem to occur together at the same rate. I did notice a pitch trim reset that is available in the PFC.DLL user interface. It appears to reset the trim in FS2004, but has no effect on the MFD trim motor/wheel.

[Pete Dowson]

I just received my PFC Modular Flight Deck w/electric trim.

I don't know about that. Does it have motor drive for the trim? Is it fitted with the latest firmware which includes the facility for my PFC.DLL to tell the trim motor where to go? (You may need to ask PFC about that).

I'm trying to understand the operation of the electric trim mechanism and how the trim wheel and it's associated trim indication stays 'synched' with the trim position in FS2004don't always seem to occur together at the same rate.

Can you ask PFC what it is all about then let me know, or get them to let me know please? I have only one device of theirs with trim motors, and that is the 737NG cockpit with motor driven trim wheels. The electric trim drives that and the pot associated with that drives FS. In the latest PFC.DLL I disconnect the electric trim buttons on the yoke from FS and allow the trim axis to operate instead, and this is defaulted for the 737 cockpit.

If your trim system is sending both trim axis commands and trim controls, you need to go into the yoke button options in PFC.DLL and reassign those buttons to do something innocuous. But also check the latest PFC.DLL (see top announcement in this Forum). There have been lots of changes in this area.

You'd also need to calibrate the trim axis in PFC.DLL, and probably enable the motor drive if you expect the A/P to be able to operate the electric trim too -- but this latter action really depends how it is all connected and operated. As I said, I don't know the device at all.

In any future questions, on ANY of my modules, please always state the version number. It is very difficult to help blindfolded both as to the hardware and the software! ;-)

I did notice a pitch trim reset that is available in the PFC.DLL user interface. It appears to reset the trim in FS2004, but has no effect on the MFD trim motor/wheel.

It won't. Don't use it. It is for the system using increments/decrements. A trim axis system, once calibrated, has its own (calibrated) centre.

Regards,

Pete

[dfournie]

The unit just came last week. 1000 lb crate. Egad.

I don't know about the firmware. From your description it acts like it may not be updated. Good question. I will find out. The electric trim sometimes seems to have a mind of it's own.

After reading your reply I believe it is sending both trim axis commands and trim controls. It looks like it's getting into some sort of a feedback loop where the trim switch is controlling both the FS2004 trim and the electric trim until they get out of sync. Makes sense. This would probably explain why the trim moves on it's own sometimes. It's fighting to get itself back in line with the trim in FS2004. Way cool. I will try that. Didn't dawn on me before.

FSUIPC is 3.50, PFC.DLL is 1.92.

[Pete Dowson]

The unit just came last week. 1000 lb crate. Egad.

The 737NG cockpit came in a 6'x7'x7' crate and the gross weight was about 2000 lbs I think -- a lot of that (about 400 lbs or so) being the crate itself! Egad indeed! ;-)

FSUIPC is 3.50, PFC.DLL is 1.92.

Check the topmost announcement in this Forum. The PFC.DLL has been going through lots of changes since 1.92 -- it's now 1.989. It's only not on general release because (a) I've not had time to update the documentation, and (b) most of the changes are only applicable to the 737NG cockpit and then only to recent versions -- though there are many other improvements along the way. It certainly isn't withheld from general release because it is unreliable in any way, far from it!

You might as well get FSUIPC 3.507 too whilst you are there. ;-)

Regards,

Pete