Motorized yoke input question

[Kelt760]

Hi Pete,

 

First, thanks for your tremendous work, which allows us to build our home cockpits !

 

I have a question relative to building a motorized yoke for a Baron58 in a FSX/Win 7 sim. I want to get a "real" trim, i.e move the neutral position of the yoke when I use the trim whell (or when the AP moves it). I am using OpenCocpits SIOC language.

 

I currently have a motorized trim wheel with a multi-turn potentiometer ; when piloting manually, to set the trim, I read the pot, and send its "value" to offset x0BC0. Under AP, I read the offset value, and move the motor so that the pot (and thus the wheel) match the trim value ordered by the AP. This works fine.

 

Now, I would like to move the yoke accordingly. I plan to have 2 pots : 1 on the yoke which normally drives the elevator, and the second to drive the motor which determines the neutral (center) of the yoke in similar way as the wheel.

 

The point is, when I will move this center point, the whole yoke will move, thus changing the yoke potentiometer (elevator) value. So I need, before sending the yoke pot value to the elevator,  to substract the center pot value, so that at the new trimmed position, the elevator offset is 0. This way, when I trim the aircraft, I will release the effort on the yoke without moving it, it move the neutral position to match the current yoke position... Under AP, I will use the FS trim value to drive the motor and move the yoke (as I do with the whell), but still with a 0 elevator value)... Hope I am clear !

 

From my readings of your user documents : I understand that I can use joystick calibration in FSUIPC (currently the yoke works from a cannibalized CH yoke), then use the "Send to FSUIPC offset" option to read this value in a SIOC varaible, then substract the center pot value, and then send it to elevator control input at offset x0BB2.

 

Questions : is that idea correct ? If so, in which offset shall I read the calibrated yoke value send by FSUIPC ? I could not find out...

 

The other choice is to read directly both pots in SIOC, loosing calibration facilities. Would that be better/easier ? Do you see drawbacks on either method ? Or is it possible calibrate adding the two pots (to send the resulting value to to calibration), but inthat case data will not come from a joystick but from SIOC (possibly in a unused offset) ?

 

Of course I plan to do something similar with the ailerons, to have the yoke follow the PA orders...

 

Thanks  for the time you will take answering me.

 

Pierre, Saclay, France

[Pete Dowson]

The point is, when I will move this center point, the whole yoke will move, thus changing the yoke potentiometer (elevator) value. So I need, before sending the yoke pot value to the elevator,  to substract the center pot value, so that at the new trimmed position, the elevator offset is 0. This way, when I trim the aircraft, I will release the effort on the yoke without moving it, it move the neutral position to match the current yoke position... Under AP, I will use the FS trim value to drive the motor and move the yoke (as I do with the whell), but still with a 0 elevator value)... Hope I am clear !

 

Yes, perfectly.

 

From my readings of your user documents : I understand that I can use joystick calibration in FSUIPC (currently the yoke works from a cannibalized CH yoke), then use the "Send to FSUIPC offset" option to read this value in a SIOC varaible, then substract the center pot value, and then send it to elevator control input at offset x0BB2.

 

Questions : is that idea correct ? If so, in which offset shall I read the calibrated yoke value send by FSUIPC ? I could not find out...

 

 

 

No, it isn't really correct, because the calibration operates on the Elevator assigned control, not on the raw axis value.  If you send the axis value to an offset then it never gets near the calibration part at all, and you bypass it again by going direct to 0BB2.

 

The way to do it if you want FSUIPC calibration is to disconnect the elevator axis by using bit 0 in offset 310A -- remembering that this needs refreshing every few seconds. Then you can read the calibrated elevator value in offset 3328, which you can then adjust before writing it to 0BB2.

 

That can all be done very easily by, for example, a Lua plug-in. i don't know if SIOC has all the necessary options though.

 

The other choice is to read directly both pots in SIOC, loosing calibration facilities. Would that be better/easier ? Do you see drawbacks on either method ? Or is it possible calibrate adding the two pots (to send the resulting value to to calibration), but inthat case data will not come from a joystick but from SIOC (possibly in a unused offset) ?

 

Sorry, but I don't really understand this bit.

 

Regards

Pete

 

[Kelt760]

Thanks, Pete for this very quick and clear answer.

 

I undestand the method with offsets 310A, 3328 and 0BB2.

 

 

The other choice is to read directly both pots in SIOC, loosing calibration facilities. Would that be better/easier ? Do you see drawbacks on either method ? Or is it possible calibrate adding the two pots (to send the resulting value to to calibration), but inthat case data will not come from a joystick but from SIOC (possibly in a unused offset) ?

 

What I meant here was, would it be possible to add the two pots (elevator and neutral) values, for instance with SIOC, BEFORE sending the resulting value to calibration. That would avoid the 310A disconnect step.

 

In other words, can calibration read its data from something else than a joystick raw data : I could write (with SIOC) the calculated value in an (otherwise unused) offset and have calibration take it from there. More clear ? :-)

 

Thanks again !

Regards

Pierre

[Pete Dowson]

What I meant here was, would it be possible to add the two pots (elevator and neutral) values, for instance with SIOC, BEFORE sending the resulting value to calibration. That would avoid the 310A disconnect step.

 

In other words, can calibration read its data from something else than a joystick raw data : I could write (with SIOC) the calculated value in an (otherwise unused) offset and have calibration take it from there. More clear ? :smile:

 

Oh, I see.

 

Yes. You'd need to use the offset range I added to support my PFC driver -- 3BA8 onwards (please use 3BAA for elevator, as PFC does). Note that you then assign in the axis assignments, as usual except you'll need to select the "RAW" option, otherwise FSUIPC assumes a 0-127 range.

 

Pete

[Kelt760]

Perfect, Pete ! I just "have to", as we say in French. I think it will take a while to build the mecanics, but now I know it will work.

 

Maybe I'll be back with ailerons, which seem a bit more complicated, since under AP I can only read aileron deflexion (2EA8), even though AP uses aileron trim (2EB0 don't move under AP)...

 

Pierre