The handles on the ProtoThrottle come pre-calibrated and should not require any additional adjustments. However, there may be times when you want to adjust the point at which the horn or on/off brake activates. The threshold menu is for doing just that. It allows you to calibrate the horn and brake levers to suit your preferences, or to adjust for mechanical tolerances when assembling the throttles, as no two will be exactly alike.
As the manual notes, normally you will not need to do this. But, the option is available if somebody wants to customize the throttle, or in the rare case needs to disassemble the throttle or adjust for drift over time.
Here’s the basic process for calibrating the throttle…
- Go to THRSHOLD CAL menu, hit the lower left button to enter the calibration process. Note: In firmware version 1.1 and later, you will first need to enable Advanced Functions in the SYSTEM menu before you can see the THRSHOLD CAL menu.
- You should see a menu that says “HORN” and has some value at the bottom. Pull the horn lever roughly a third of the way down, and while holding it there hit the upper right button. This sets the threshold at which the horn goes from off to on.
- Hit the upper left (MENU) button again. You should now see “BRAKE” and a number.
- Set the brake lever to center and hit the upper right button. This sets the threshold at which the on/off brake activates. It does not affect any of the variable brake options.
- Hit the upper left (MENU) button again. You should now see “BRAKE LOW” and a number.
- Set the brake lever all the way to the left and hit the upper right button again. This sets the lower limit for the brake lever and also the point where the emergency brake releases.
- Hit the upper right (MENU) button again. You should now see “BRAKE HIGH” and a number.
- Set the brake lever all the way to the right and hit the upper right button again. This sets the upper limit for the brake lever. This also sets the point where the emergency brake activates (if enabled).
- Hit the lower left button. This will save the calibration constants.
If you find yourself in the calibration menu by accident, just hit the lower left button and it will preserve the existing constants. Avoid touching that upper right button and you’ll be fine.