Potentiometer calibration procedure

Potentiometers require calibration when they cannot be fully rotated. It is often the case when they are mounted on control sticks: the hardware usually limits the potentiometer rotation to 90 degrees. Since most potentiometers have a rotation angle of 180 degrees, an uncalibrated potentiometer would deliver only half of the possible values.

To check if a potentiometer requires calibration, enter the Command mode.

If the potentiometer has a mechanical trim, you must adjust it so that, when the stick is centered, the transmitter sends exactly a 50% pulse to the corresponding channel, moving the servo to its neutral position.
Move the trim slider and the potentiometer to their middle position and type ? POT1:

The potentiometer should give 512 when centered, so you must move the trim a little bit to get closer to 512.
Adjust the trim and repeat the ? POT1 command until you get as close as possible to 512.

Now, move the potentiometer to its lowest position and type ? POT1:

Here, 65 is the lowest value returned by this potentiometer. Since the minimum logical value is zero, calibration is required.

Then let's check the highest value returned by this potentiometer: move the potentiometer to its highest position and type ? POT1:

Here, 953 is the highest value returned by this potentiometer. Since the maximum logical value is 1023, we get the confirmation that calibration is required.

Let's enter both values in the transmitter's settings:

Refer to the Model variables page for more about KLx and KHx variables.

From now on, the software will be able to convert the physical values read in the range [65, 953] to the full logical range [0, 1023], for this potentiometer.

See also: Throttle calibration procedure : special calibration for the throttle security check