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Machine Zero vs Work Zero (offset)

Discussion in 'Control Software' started by cmwwebfx, Sep 4, 2021.

  1. cmwwebfx

    cmwwebfx New
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    Hi there, how do I set the machine Zero on Openbuilds Control software? I can set the work Zero on the GUI of the software, but would like to set the work Zero. Where can I set this on the software GUI?

    My CNC is a QBee running Openbuilds Blackbox and Interface.
     
    #1 cmwwebfx, Sep 4, 2021
    Last edited: Sep 6, 2021
  2. David the swarfer

    David the swarfer OpenBuilds Team
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    You cannot set it yourself. GRBL, the software in the blackbox, sets it to 0,0,0 when it boots or is reset. It resets everytime something makes a serial connection to it.
    If there are limit switches and homing is set up, then the homing cycle sets machine 0,0,0 .

    The correct way to do it is to 'fake the home' which simply means always turning on or resetting with the machine in the same place.
    Industry standard for this is +x +y and +Z, but you cna put X and Y anywhere, but Z is critical it MUST be at the top of Z travel for Gcode generated by a wide variety of software to work safely and correctly.
    Read more here
     
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  3. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Or even easier. Install homing switches and remember to Home. Homing sets machine zero
     
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  4. cmwwebfx

    cmwwebfx New
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    Thank you for that info. So I understand from your reply that home is basically an absolute point fir working from.

    When setting the work Zero,would this be regarded as an offset from my home position?
     
  5. cmwwebfx

    cmwwebfx New
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    Thank you for your reply. I do have the mechanicsl filtered switches from openbuilds. However I am thinking that if I want more precise repeatability, I would be better off with proximity switches?

    I'm guessing the normally closed is the way to go? Is there anything I need to be aware of when buying some proximity switches?
     
  6. David the swarfer

    David the swarfer OpenBuilds Team
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    yes and yes. Machine home or 0,0,0 is absolute, everything else is relative to it.
    When you use the 'setzero' buttons in the CONTROL software, you are sending Gcode that tells the controller to store the current position as the offset and regard 'here' as Work 0,0,0.
    There are 6 sets of offsets that you can use, G54 to G59 set them as 'currently in use', you do have to set the offsets for each one before use though. The default is G54. One might use the others if one had a multipart fixture or special needs.

     
    #6 David the swarfer, Sep 6, 2021
    Last edited: Sep 6, 2021
  7. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    You can run Proximity sensors, SN-04 NPN types work well. But they are less repeatable than a lever microswitch :)
     
  8. cmwwebfx

    cmwwebfx New
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    I have done a search for these sensors you mention, but they are 6v-36v.the blackbox shows i need 5v.

    I would have thought that these proximity sensors are more accurate than switches? Is there a way to mount the normal switches so that they don't move?
     
  9. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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