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Slow speed with G0/G1

PeterPeterPeterPeter
in Motor Control
Hello, I alo use the Repetier H & F to move a laser.
I found that there is no different in the lower speed settings under ~20mm/minute.

So
G0 ... F10 and
G0 ... F1 makes no different.

I send the commands by the Repetier Host Scripts.

Any hints ?

- Peter

Comments

  • RepetierRepetier
    The firmware has a minimum speed which depends mainly on acceleration (see update derived parameter routine I think). Reason is timing computation for first step which gets awfully wrong with low speeds and high accelerations due to explicit integration error.
  • PeterPeterPeterPeter
    Hi Repetier, how can I get the slowest speed if i don't need acceleration?

    M201 X0 Y0 Z0 E0

    G1 X100 Y100 Z20 F1

    gives no effect !?

    -Peter
  • RepetierRepetier
    Minimum speed is computed like this

        float accel = RMath::max(maxAccelerationMMPerSquareSecond[X_AXIS], maxTravelAccelerationMMPerSquareSecond[X_AXIS]);
        minimumSpeed = accel * sqrt(2.0f / (axisStepsPerMM[X_AXIS]*accel));

    So acceleration 0 causes a division by zero. Also as you see it depends on print and travel acceleration. You can modify them in eeprom.
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