Auto steps/mm correction

edited December 2017 in Feature Requests
I guess that this would be easy function for you. To add a g code command where it would go from min to max Endstop and compare the length it think it is to the real length written in EEPROM. Then it could automatically fill in the right steps per mm or write them for user to type in.


  • Not so easy as you think and most printers do not have both endstops or know the distance.

    Better solution is to print 2 blocks 5 and 10cm. Take the difference in length which equals 50mm planned. Correct stepsnew = stepsOld * 50/distanceMeasured and store it in eeprom using eeprom editor.

    Difference because settings can make objects slightly bigger but both blocks should have the same error so you subtract error of same size and get real width.
  • edited December 2017
    I know solution with calibration cubes, but I think that many people would invest a few dollars into max endstops if this would be a thing. And it could help to get these calibrations less time consuming and less material consuming, beacuse of bigger calibration cubes like 10 or 15 which takes at least a few meters of filament. And the distance would be known by just first calibrating it with a cube method and trying.
  • The problem is you do not know distance between endstops. So how to measure that? I mean it must be 0.1mm correct or even better. And that is something you do not know. If you could measure that you could also measure resolution directly.
  • edited December 2017
    Well you could send it from min to max and let it measure distance, but that would need a new command since it only stops, but continues counting when hit max end. And if you would do this after you calibrate it the conventional way, you would get the exact measurement of distance and it wouldn't change until you move endstops, so after that you could use that g code I was talking about to "restore" calibration (instead of doing it over again) , whenever you have to tension the belts or change the threaded rods.
  • So you want to first calibrate the normal way so you can calibrate the length between endstops and then use this later again to calibrate in case steps have changed.

    That is a feature nearly no one would even notice exists and use. So it would be very low in my priority list. So do not expect to see it.
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