Linear optical encoders for closed loop



  • I'm working on a design for a macro scale machine which will require linear optical absolute encoders on the x and y axes, such as the Renishaw Resolute :
    https://www.renishaw.com/en/linear-absolute-encoders--10940

    I understand that the Duet 3 will be able to run closed loop hybrid stepper servos using an expansion board. Would this also mean it would be possible to use independent encoders to close the loop?
    Desktop machines can get away with open loop steppers but much larger machines require absolute positioning.


  • administrators

    This is very much on our radar, and is one of the reasons why we don't have an external stepper expansion board for Duet 3 yet. It's not as easy as it sounds, because at 3D printer speeds and resolutions the quadrature signals arrive at quite high frequencies, so it's not practical to use the main microcontroller to capture them using ordinary pin inputs.


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