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Hard Limits

Discussion in 'Controller Boards' started by dfox1787, Nov 16, 2019.

  1. dfox1787

    dfox1787 New
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    Hi

    I have set hard limits up on my black box but it still lets me move out of my machine work area?

    Soft limts work however they seem to round up to the nearest 10.

    does anyone have any suggestions?
     

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  2. sharmstr

    sharmstr OpenBuilds Team
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    Hard limits are limit switches. So you're saying your limit switches aren't working? Have you gone into the troubleshooting tab to test them?
     
  3. dfox1787

    dfox1787 New
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    Im using limtit switches and they work fine. I can home all axis but when i travel the machine its able to exceed those travel limits. I have enabled hard limits.
     
  4. Alex Chambers

    Alex Chambers Master
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    Hard limits relies on having switches at both ends of each axis. If you want to stop your machine travelling outside its limits without switches at both ends you need to use soft limits.
    Alex.
     
  5. dfox1787

    dfox1787 New
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    ah thank you i didnt realize you needed them on ends.

    Do you why when i set soft limits it rounds up to the nearest 10? my machine is set to 775mm but alarms at 770?
     
  6. Alex Chambers

    Alex Chambers Master
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    That's one for the blackbox/grbl specialists - I use the Duet controller which runs the rep-rap flavour of g-code.
    Alex.
     
  7. dfox1787

    dfox1787 New
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    Thank you.

    So its the nearest 100 it rounds up to. anyone have any ideas?

     
  8. sharmstr

    sharmstr OpenBuilds Team
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    Hard to tell in the video, but is your homing switch on the right side of your X gantry? If so, you need to take pull off distance into consideration. You have your limit set to 810. You're trying to jog 800+10+your pull off distance.

    Do the same exact test but instead of jogging 10mm at the end, jog 1mm and see if you get an error.
     
  9. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    False, you only need them on one end of travel, correctly programmed soft limits take care of the other side. Switches on both ends are supported of course, but optional. Not "relies on having switches at both ends" (you may want to get Grbl sometime to play with (; or ignore the Grbl questions hehe)

    I think Sharmstr is onto it, as you jog 10mm it feels to you like it rounds off, but Grbl definitely honors the configured Maximum Travel distance down value to one step pulse!
     
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  10. dfox1787

    dfox1787 New
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    thanks guys think i got this sorted.
     
    Peter Van Der Walt and sharmstr like this.
  11. Alex Chambers

    Alex Chambers Master
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    To avoid making this mistake again could someone please tell me how to set up HARD LIMITS without using a switch (or other sensor) at both ends of each axis.
    Thanks, Alex.
     
  12. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Hard limits on one end, soft limits takes care of the other
     

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