AP VS as an axis

[Jmcmanna]

I have a potentiometer wired to a Bodnar card which I am trying to use to set the autopilot vertical speed.  FSUIPC sees the pot, which I have set to "Send to FS as a normal axis" and then I select "AP VS set" from the drop down.

Under the "joystick calibration" tab, I don't see where I can then calibrate the axis like I was able to do with the throttles, flaps, spoilers, etc....  What I want to do is calibrate it like I did with the flaps: a range of values for different positions (+500fpm, +1000fpm, etc.).  Is this possible, or am I way off on this?

[Pete Dowson]

1 minute ago, Jmcmanna said:

Under the "joystick calibration" tab, I don't see where I can then calibrate the axis like I was able to do with the throttles, flaps, spoilers, etc....  What I want to do is calibrate it like I did with the flaps: a range of values for different positions (+500fpm, +1000fpm, etc.).  Is this possible, or am I way off on this?

No, it is not calibratable. That's only done for normal analog controls. The VS is a digital value, specific numbers..

Analogue axes do not give specific values, and they increment at a rate dependent on the resolution of the medium used -- graphite, wire windings, marks of optical disks, or metal through sensors.  They are thoroughly unsuitable for use in the way you intend.

One way of getting very specific values would be to use the right-hand side of the axis assignments tab to set zones, and assign a different AP VS SET + parameter to each one. That would only give you 10 (I think) values though: maybe --2500 to +2500. If you needed more, and the axis values were predictable enough, you could instead assign the axis to a Lua plug-in you could construct, and have a table in that plug-in which converted smaller ranges of input values to specific VS values for sending using AP VS SET.

For a continuous change of values, the only possible way you might do it is by using the arithmetic scaling options you can add to the axis assignment lines in the FSUIPC4.INI file -- details are in the Advanced Users manual. You can add values and multiply them, to make them behave more like the way you might want them to. but it wouldn't be easy and you'll probably never manage to find the correct values to give all desired inputs. You might also need to set "Raw" mode in the assignment tab to avoid interference in the values from normal Windows pre-processing of the input.

Finally, I'm not sure what units the AP VS SET control uses. Have you tried with some specific values?

Pete

 

 

[Jmcmanna]

Thanks for the information.  It's a real autopilot out of a DC-9, so I was hoping I could just wire it up and go.  From what it sounds like, it might be more trouble than it is worth.  I can probably replace the potentiometer with a rotary encoder and work it out that way.

I hadn't gotten far enough into it to try any specific values yet.

[Pete Dowson]

10 hours ago, Jmcmanna said:

I can probably replace the potentiometer with a rotary encoder

Yes, that's by far the better option. You'd use INCs and DECs to achieve any required valid value.

Pete