External drives and extra endstops



  • Hi,
    Just looking for some help to decide how best to have 2 external step drives but also extra end stops.
    I see the "Duet Expansion Header Breakout Bard" gives a lovely interface for external drives but no extra endstops, while the Duex5 or Duex2 give the extra endstops but no outputs for external drives (as far as I can tell).

    Can someone point me in the right direction here?


  • administrators

    Do you intend to use the extra endstops for axis endstop switches, or for some other purpose?



  • For extra endstops


  • administrators

    Please explain what these "extra endstops" are for. Are they for additional axes? If so, how many axes will you have?

    When you use M584 to map the X, Y etc. motors to external drivers, this does not map the corresponding endstops.



  • Thanks for your reply, we have just the standard x,y,z - just looking for ends stops at both ends of each axis.


  • administrators

    @nz_andy said in External drives and extra endstops:

    Thanks for your reply, we have just the standard x,y,z - just looking for ends stops at both ends of each axis.

    RRF uses endstop switches for homing only and applies axis limits in software after homing. So there is no point in having endstop switches at both ends. However, if your intention is to have limit switches that cause an emergency stop when triggered, then you can do that, but it suffices to connect the three extra limit switches in series to just one additional endstop input.



  • Thanks for you input, that makes sense, I have 2 y axis motors on a big printer, the series Z output from the board is not quite enough to do the job. So I guess I could use 2 drives on the board to drive the two y motors simultaneously? Otherwise i'll just keep with the suggestion of wiring the end stop in series (and external driver).


  • administrators

    Are you planning to use a single endstop switch for each of the Y and Z axes, or one for each motor?



  • Just single end stops per axis, we have one motor on the z, 2 on the y and 1 on the x as is a lead screw driven gantry style and the two y motors are also physically linked so they can't get more than a few steps out of sequence when power is off. (so don't need two end stops on the y) The Duet drivers are really nice and do drive one y motor no problem.
    Can I use two duet drivers as simultaneous drivers?

    Got to say I have been real impressed with the duet and ease of use so far.


  • administrators

    @nz_andy said in External drives and extra endstops:

    Just single end stops per axis, we have one motor on the z, 2 on the y and 1 on the x as is a lead screw driven gantry style and the two y motors are also physically linked so they can't get more than a few steps out of sequence when power is off. (so don't need two end stops on the y) The Duet drivers are really nice and do drive one y motor no problem.
    Can I use two duet drivers as simultaneous drivers?

    OK, so you need only use the standard X, Y and Z endstop inputs (or just X and Y if you use a Z probe for Z homing).

    To use multiple drivers for an axis, see the M584 command in the GCodes wiki page.

    Got to say I have been real impressed with the duet and ease of use so far.

    Thanks!


 

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