M201, M203, M566 ?

  • Hello,
    I am finishing the configuration of my CoreXY printer under Duet2 WIFI.

    My printer :

    1 300x300 E3D heated bed in 240v.
    1 Titan E3D and its Slimline engine.
    1 E3D Lite6 HotEnd (all items are genuine).
    4 motors 17HS4401 for the different X / Y / Z axes
    1 12V power supply.

    However, I would like to understand how we calculate M201, M203, M566?
    I currently have values ​​that I put a little at random! Is there a calculation to make, a rule to respect or do we have to fumble and do different tests?

    By the way, do you think that M913 (disabled in my configuration) is a good option (put m / A max engines in M906) or is it better to use only M906 with a percentage (60/80%) m / A max.
    And what is M207 for (disabled in my configuration).
    Thank you...

    ; Drives
    M569 P0 S0 ; Drive 0 goes forwards
    M569 P1 S0 ; Drive 1 goes forwards
    M569 P2 S0 ; Drive 2 goes forwards
    M569 P3 S0 ; Drive 3 goes forwards
    M350 X16 Y16 Z16 E16 I1 ; Configuration des micro-pas (mm/min)
    M92 X80.00 Y80.00 Z1600 E837.00 ; Configuration pas per mm
    M906 X1100 Y1100 Z1100 E1000 I30 ; Régler les courants du moteur (mA) et le facteur de ralenti du moteur en%
    ; M913 X70 Y70 Z70 E70 ; réduire le courant moteur à 70% de la valeur nominale
    M201 X800 Y800 Z40 E300 ; Définir les accélérations (mm/s^2)
    M203 X11639 Y11639 Z200 E600 ; Définir les vitesses maximales (mm/min)
    M566 X600.00 Y600.00 Z50.00 E600.00 ; Définir les changements de vitesse instantanée (mm/min)
    ; M207 S0.8 R0 F8000 T1500 Z0.0 ; Paramètre de rétraction
    M572 D0 S0.2

  • Moderator

    For motor currents I use M906 to set the max rated for the motor, and then I use M913 to set the percentage of that. For printing I use 85% as is recommended, and for homing I use the lowest value that still produces reliable motion.

    For maximum speed and acceleration you can do some calculations based on what your motors can handle.

    See the EMF Calculator at this link: https://www.reprapfirmware.org/

    And acceleration here: https://wilriker.github.io/maximum-acceleration-calculator/

    Those will help define the theoretical maximum for speed and acceleration, but your actual implementation will likely be less based on a number of physical and electrical factors of the machine. So you'll have to do actual testing to find the applicable limits.

    As a best practice you should set the maximum speed for X and Y to be equal to what you would want your maximum travel speed to be, which should be below the theoretical max speed to ensure no loss of steps. That way if you increase print speed using the speed factor slider it won't increase the travel speed beyond the limit you set.

    For the extruder you can use this calculator to find your maximum retraction speed: https://wilriker.github.io/microstep-calculator/

    And your Z axis max speed will depend on your bed weight and lead screw pitch, etc, and will need to be found by testing.

    For jerk and acceleration for actual printing you'll need to do some testing since it will depend a lot on the resonances of the printer frame, belts, etc.

    I think the values you have chosen now are good starting points and are very close to what I use on my CoreXY.

  • @Phaedrux Very interesting all this!

    Thank you, it's thanks to people like you that I gain in technicality !

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