Recalibrating the ProtoThrottle Horn and Brake Handles

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…

  1. 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.
  2. 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.
  3. Hit the upper left (MENU) button again. You should now see “BRAKE” and a number.
  4. 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.
  5. Hit the upper left (MENU) button again. You should now see “BRAKE LOW” and a number.
  6. 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.
  7. Hit the upper left (MENU) button again. You should now see “BRAKE HIGH” and a number.
  8. 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).
  9. 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.

Comments

  1. Will recalibrating the horn make it more sensitive? I pull the lever and there’s a short delay before the horn sound plays. Will going through these steps fix that or make any difference? Don’t want to screw anything up – esp. since in step 2 you say to “hit the upper right button” but at the bottom you say “Avoid touching that upper right button and you’ll be fine” %^)

    1. The calibration only affects the point at which the horn lever turns the function on, not the overall latency through the system from trigger event to getting the function on the rails to the decoder actually doing something. If you want it to turn on with less of a pull, then recal can adjust that. If your issue is the time between pulling it and the engine responding, that won’t help. How fast the function gets to the rails depends on a lot of factors. The primary one is just how busy the DCC system is sending other commands. Things that send lots of commands, like pulsed variable brakes or rapidly changing the throttle, will slow things down. Plus, some interfaces (LNWI+ESU-BRIDGE) are just slower than others (NCE/Lenz) because of all the translations needing to happen.

      1. Ah! Ok that makes total sense. I’d ventured into this calibration setting before without really knowing what I was doing (rookie mistake) and was afraid I’d screwed something – or would. But before I left, I made sure the setting was what it was when I got there. So no harm done, hopefully %^)

        Thanks much for your reply and thanks for the chance to give you a HUGE THANK YOU personally for developing such a fantastic product! Like so many others, I’m super happy with it and it’s really taken my ops to a whole new, more realistic level. Thanks!!

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