Minimum and maximum M208 coordinates during homing cycle?



  • I have a question about the M208 axis limits and if it's possible to choose whether the minimum or maximum is referenced. At the moment mine are setup as following:

    M208 X0 Y0 Z-190 U0 S1 ; set axis min
    M208 X510 Y740 Z0 U740 S0 ; set axis max

    I home to the back, right and top of the machine – which sets the Z to zero and the X and Y to the maximum stated above. But this set up increases movement and therefore time taken between those travelling between locations. It's not a big issue, but coming from GRBL and not seeing the G53 coordinates in the GUI I was use to wherever the homing limits are being set to zero on all axes.

    I tried to change this by re-positioning the homing limits, and re-writing the homing cycle so the carriage moved leftwards and forwards. But I can't seem to edit the M208 accordingly - and the X and Y set to the maximum limits preventing me form moving after homing.

    Is there a way of selecting between the minimum and maximum M208 coordinates as the reference during the homing cycle?

    Thanks again in advanced!



  • You change the limit switch to be min or max and leave the overall travel the same regardless of where the limit switches are.

    M574 X2 S1 P"io0.in"    ; pnp no x max
    M574 Y1 S1 P"io1.in"    ; pnp no y min
    M574 Z2 S1 P"io2.in"    ; pnp no z max
    

    You would want both X and Y to be X1 and Y1 (i broke my Xmin switch so switched over to using the Xmax by just changing to X2 in the M574 command)



  • @bearer said in Minimum and maximum M208 coordinates during homing cycle?:

    M574 X2 S1 P"io0.in" ; pnp no x max
    M574 Y1 S1 P"io1.in" ; pnp no y min
    M574 Z2 S1 P"io2.in" ; pnp no z max

    Ahh thanks! On my firmware that was commented as "set active high endstops" and I assumed that was referring to the pin. I'll re-write that in case I forget again. I guess it's safer to home moving away from the front of the machine - which is where I'll be eagerly standing.



  • The S parameter sets active high or active low, the number behind the axis min/max. Could probably be clearer.



  • @bearer I just don't read things properly - not a good trait to have while learning to Duet. Lol.


 

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