explain interpolation settings please



  • Im not understanding the effects of these settings.
    What is the difference for example between
    M350 X16 Y16 Z16 E16 I1 and M350 X16 Y16 Z16 E16 I256

    Or is there any difference?



  • @57buick said in explain interpolation settings please:

    M350 X16 Y16 Z16 E16 I1 and M350 X16 Y16 Z16 E16 I256

    the first one is ok the second one does not work.
    see
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M350_Set_microstepping_mode



  • I256 is is not a valid parameter. I = 0 or 1. Interpolation on or off.

    The Duet2 only supports interpolation for x16 microstepping. I believe the Duet3 supports interpolation at all microstepping levels but you'll have to check the documentation.

    Unless you have a very specific reason should go with x16 and interpolation on. So your command should look like this:

    M350 X16 Y16 Z16 E16 I1
    

  • Moderator

    I1 means interpolation on, I0 means interpolation off. When it's on, the drivers will take the incoming step pulses and interpolate between them to produce 256 pulses for the motors.

    Interpolation always changes the incoming rate to 256.

    The Duet Wifi/Ethernet can only interpolate from x16 microstepping. The Maestro (and I think the Duet 3) can interpolate to 256 from any microstepping value.



  • great thanks for the clarification



  • What does interpolation mean in this context? Smoother transition from one microstep to the next?


  • Moderator

    @zapta It means that the Duet generates x16 microstepping and sends that to the driver. The driver then takes that and sends x256 to the motors resulting in smoother, quieter movement.

    The strain on the CPU is less, but you don't get the theoretically better positioning of actual x256 steps, but it's debatable if using actual x256 makes any sense at all. We're talking about microscopic amounts of movement, which would be obliterated by extrusion inaccuracies.


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