TinyG home/limit problem

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  • June 29, 2016 at 12:23 am #9823
    Mightygrom
    Member

    I built an OX based router and I am driving it with a TinyG controller. I have it pretty much nailed down, but I am having a problem with homing the machine. I am using chillipeppr to drive it.

    I have 6 switches, 3 are set to home/limit (1 per axis) and the other 3 are set to limit. All are wired to be NC

    If I just manually put the machine in about the home position and run the chillipeppr demo gcode, it performs correctly (well, it moves in the right directions, I have not installed the spindle in the mount yet) but if I home the machine, it homes Z and then it stops and blinks red furiously. I checked my wiring to the switches on X and Y and it is right… and my meter says that they are functioning correctly (getting correct continuity at the contacts on the TinyG)

    Any thoughts?

    June 30, 2016 at 9:01 am #9826
    cmcgrath5035
    Moderator

    Homing Z first is correct.
    The “stops and blinks red furiously.” indicates you exceeded a limit switch, likely caused by the Zmin and Zmax settings, which show as exceeded when Zmax gets reset to 0.0 (‘home’).
    A copy of your parameters ($$ command) posted to a cloud drive with URL would help

    July 2, 2016 at 1:44 am #9828
    Mightygrom
    Member

    Your response put me on the right path 🙂 thank you. GrOX now homes all the way.

    If you have a moment though, I am still Z-baffled… My Z travel is such that when the tool is 0mm from the machine, Z reads 70mm, and flying all the way up is at 0mm… I could draw my files so that I am cutting from 0 to 70mm but I would really like the machine to home to 70mm (all the way up) and know that 0mm is tool to bed. can you give me another hint as to how to do this?

    https://drive.google.com/file/d/0Bxha8mdWWzsPdTBKcWRzLUtyTlk/view?usp=sharing

    July 2, 2016 at 6:58 am #9829
    cmcgrath5035
    Moderator

    I think you have Z axis reversed in you head and in parameters.
    Parameters should look like
    $ztn = -70
    $ztm = 0
    If you want to home Z axis,
    $zsx = 1 (or perhaps 3)
    $zsn = 0 (do you really have a Zmin switch?)

    Make sure to review

    and

    Keep in mind the following:
    1. Z homing is primarily to move the gantry and bit as far away from the work surface as possible before moving in X and Y
    2. Z homing is not really useful for setting a starting point for a milling job, since it is not based on the actual bit position, in general.
    3. Most folks seem to adopted a work flow that follows a Z homing to top with a secondary probe operation to find the work surface with the bit tip, then resetting the Zero to be the top of work.

    Hope that helps –

    July 4, 2016 at 10:57 pm #9832
    Mightygrom
    Member

    Thank you for all of the assistance. GrOX is dancing happily now.

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