Common button for rotaries and elevator trim with autopilot

[Steku]

Hi Pete

I hope your eyes are getting better!

I have question about programming phase shifted rotaries. In you doc you wrote:

“One last thing. If you are using several rotaries of this type (that is, with the two signals in different phase rela-tionships to indicate direction of turning), you can save button connections by making one of them (on each one) common. If you do this you can only turn one of them at a time, but this is probably a worthwhile restriction if you are getting short of button connections.”

I don’t understand this. How you can have one connection common on all rotaries? This way if on one of this rotaries this connection is “on” (parallel connection) it will stay “on” even if you turn another rotary and on this rotary the connection goes through “on” – “off” states. When you have parallel connection – it will always be in “on” state if it’s “on” on only one of rotaries…

For use of this method should I look for rotaries with detents forcing rotary to stay in such position that contact is always "off" when roatary is left free?

And another question:

I have elevator trim wheel implemented by analogue pot on gameport interface and connected to FS as an ana-logue axis. I have problem with autopilot which is trying to control altitude hold by using elevator trim. Because signal from analogue pot is jittery autopilot is “fighting” with trim set by analogue axis. I know I can control trim by up-down presses but I really like this analogue feel of my trim wheel where wheel position can be used as trim indicator without the need to look at screen.

Is there any way to turn signal from axis on-off by push of a button by FSUIPC programming? Any other suggestions?

[Pete Dowson]

I don’t understand this.

Actually, nor do I. Sorry, I'l have to study it. I'm sure it was all clear to me when I put it in, but it was derived from a contribution from someone else. It dates back so long now I've forgotten all the logic.

You are probably correct in any case. I shall delete that paragraph just in case and only reinsert it if I can think it through and it works! :wink:

Is there any way to turn signal from axis on-off by push of a button by FSUIPC programming? Any other suggestions?

No at present, no. Sorry. I could probably add another bit to offset 310A to disconnect the trim -- maybe two bits, one to disconnect it totally and the other to disconnect it when the A/P is active. Then it could be controlled by the Offset Byte ToggleSetBits control, or I could add an option in the A/P operated case.

You'd think that FS would do this anyway, as it effectively does for the main controls. Strange.

I'll see if it can be added quickly enough to go into the impending 3.30 version, otherwise I'm afraid it'll be a few weeks.

Regards,

Pete

[Erups]

About the rotaries:

it is possible to think of a system in which the phased outputs of the encoders are common.

In such a system you have only one direction/pulse decoder, but you have to check the grounds of all the encoders...

You are simply shifting the problem from the output to the input.

I mean: usually encoders have ground in common, and the phased outputs are read for each encoder.

It is possible (in theory) to make a device in which the outputs are in common, and you check the grounds, but it requires a very complicated circuitry. Better to use the standard system...

About the axis control: sadly FS itself only disables the throttle, all the other axis remain active while in autoflight.

[kevindarling]

“One last thing. If you are using several rotaries of this type (that is, with the two signals in different phase rela-tionships to indicate direction of turning), you can save button connections by making one of them (on each one) common. If you do this you can only turn one of them at a time, but this is probably a worthwhile restriction if you are getting short of button connections.”

For use of this method should I look for rotaries with detents forcing rotary to stay in such position that contact is always "off" when roatary is left free?

The answer to the last question is Yes.

The idea is that you could use phase-shifted rotaries that turn on A, then B in one direction... B, then A in the other direction... but are off in the detent.

However, you could connect all the B outputs in common, while A is individual per switch. When you see the A change, you simply also check the common B input... if it's off then you're turning one direction, else if it's on then you're turning the other direction. A is the trigger, B is the direction.

That's why the doc says you can only turn one of these common switches at a time. Turning more than one simultaneously could give a false directions.

Best, Kev

[Pete Dowson]

For use of this method should I look for rotaries with detents forcing rotary to stay in such position that contact is always "off" when roatary is left free?

The answer to the last question is Yes.

The idea is that you could use phase-shifted rotaries that turn on A, then B in one direction... B, then A in the other direction... but are off in the detent.

Ah, yes, it is clearer now. Thanks! I will add this clarification about the rotary detent condition to the doc.

Best regards,

Pete