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News: Precision Simulator update 10.85 (23 July 2019) is now available

Author Topic: How to calibrate USB sliders and axes  (Read 2579 times)

Hardy Heinlin

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How to calibrate USB sliders and axes
« on: Wed, 11 Jul 2018 00:46 »

PSX update 10.36 provides additional calibration features. They are easy to use and self-explanatory, but I want to add some notes anyway to avoid misunderstandings:

There is a special pop-up window for self-centering axes, and another special window for sliders. The window pops up when the respective "Calibrate" button is clicked. Clicking the button a second time will close the window. Only one window can be shown at a time.

Note that all buttons and edit fields can be accessed with the keyboard as well. Use the TAB key to move the focus from one button to the next (SHIFT+TAB moves the focus backwards). Press the SPACE key to click the focussed button.

Example of an aileron calibration:

The procedure goes like this:

1. While holding the hardware aileron fully left, click "Copy to full left".

2. While the hardware aileron is self-centered, click "Copy to center".

3. While holding the hardware aileron fully right, click "Copy to full right".

4. Move the hardware aileron to the center.

5. Click "Detect tolerance". This will automatically set a center tolerance. (The center tolerance is necessary to suppress random out-of-center-signals in the simulator while the hardware is actually centered; when the hardware is centered, the USB may still send random signals due to electrical noise or vibrations.)

6. If the current USB value (magenta) disagrees with the entered center value, the detector will ask you to center the hardware. Check that the values agree by centering the hardware or by correcting the entered center value.

7. When centered, the detector will start recording the greatest deviation from the entered center value.
Now do not deflect the hardware axis, just shake it gently. The purpose is to make the smallest possible neutral zone around the center position. The tolerance should just eliminate electrical noise and vibrations (good hardware with hall sensors is usually so stable that the center tolerance can be set to "0").

8. Click "Stop detector".

9. Click "Close".

Example of a slider calibration:

Sliders don't self-center. Therefore they don't require a center tolerance. But there is a center point. Normally, the center point is in the middle between the two outer extremes. However, in lower quality products the control range may be not quite linear. This point is especially important when multiple USB sliders of the same kind don't provide equal linearity, e.g. when using a pair of unequal toe brake pedals, or a group of unequal throttle levers. While the individual full forward and full aft points equalize the slider positions in a group when they all approach the outer extremes, the center point adds a third reference in the mid range. So in the mid range too the slider positions will be better equalized. (The center point setting may also be used to intentionally make the output non-linear.)

The procedure goes like this:

1. While holding the hardware slider fully forward, click "Copy to full forward".

2. While holding the hardware slider fully aft, click "Copy to full aft".

3. Click "Center at 50%" (this sets the center to 50% between the entered forward and aft values).

4. Click "Close".

If you have multiple throttles, calibrate those in the same way. When done, add further mid range equalization to your throttle group:

1. Move all hardware throttles to the center. Check that all hardware lever knobs are visually at the same center position on the hardware console. Ignore the lines on the EICAS; their positions may be unequal. The EICAS lines will be equal when the next four steps are done.

2. Click "Calibrate" on throttle 1, click "Copy to center", then click "Close".

3. Click "Calibrate" on throttle 2, click "Copy to center", then click "Close".

4. Click "Calibrate" on throttle 3, click "Copy to center", then click "Close".

5. Click "Calibrate" on throttle 4, click "Copy to center", then click "Close".

Note that minor misalignments across multiple thrust levers are not relevant as the final commanded thrust will be equalized by the 744 systems; the electronic engine control (EEC) modulates the fuel valves directly to a certain degree.

Example of a toe brake pedal calibration:

The procedure is the same as that for other sliders.

General note:

Values can also be entered manually. The quickest method, however, is to use the copy buttons.

Axis reversal is automatic as the entered reference points already provide all data required. Any reference point can be anywhere between -1000 and 1000, so all kinds of constellations can be created, even absurde ones.

When you launch PSX update 10.36 for the first time after using older versions, you should recalibrate your USB hardware with these new features. Save the settings as usual on Instructor > Preferences > Save in the pref file that you are using.


« Last edit: Fri, 8 Mar 2019 15:49 by Hardy Heinlin »


  • Join date: Mar 2015
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Re: How to calibrate USB sliders and axes
« Reply #1 on: Sun, 6 Jan 2019 18:08 »
Thanks Capt Hardy, I managed to calibrate the thing now I must get used to flying using a yoke.