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  1. #1
    Join Date
    Sep 2003
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    Question Homing and Limits Setup

    Homing and Limits have been set and when I press Reference all Home everything goes home just fine in the picture on the machine. It is a fixed gantry so I wanted home to be in the X-, and Y+ and Z+, this way it would be the easiest to load and remove work.

    When the machine has been homed and Soft Limits is activated I can drive the X in the plus direction and the Z in the minus direction, however I cannot move the Y in the minus direction. The only way I can move the Y in the minus direction is to disable the Soft Limits.

    I have attached a screen shot of the Homing and Limits setup screen showing the settings; hopefully this will show where the problem is.
    Attached Thumbnails Attached Thumbnails DSCN2770.jpg   DSCN2771.jpg   DSCN2773.jpg  

  2. #2
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    Quote Originally Posted by Mr.Chips View Post
    Homing and Limits have been set and when I press Reference all Home everything goes home just fine in the picture on the machine. It is a fixed gantry so I wanted home to be in the X-, and Y+ and Z+, this way it would be the easiest to load and remove work.

    When the machine has been homed and Soft Limits is activated I can drive the X in the plus direction and the Z in the minus direction, however I cannot move the Y in the minus direction. The only way I can move the Y in the minus direction is to disable the Soft Limits.

    I have attached a screen shot of the Homing and Limits setup screen showing the settings; hopefully this will show where the problem is.
    What happen if you chance "Y-axis Home Off -27.5" to positive +27.5 ? (second picture)

    Juka

  3. #3
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    Quote Originally Posted by Juka View Post
    What happen if you chance "Home Off -27.5" to positive +27.5 ? (second picture)

    Juka
    I changed the Home Off to positive +27.5, and the Reference all Home still works but I can no longer activate the "Soft Limits" button. So I switched it back to -27.5.

    Thanks anyway.

  4. #4
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    Curious why you have it set up so that all the coordinates are negative?

    The reason you can't jog in the Y- direction is because you're home position is already at the limit of your soft limits, at -27.5. How far do you want to be able to move (from home) in the Y- direction? If you want to move 10", then change the softlimits to -37.5.

    It's hard to tell in the pic, but it looks like if the router mover right along the gantry, that would be X+. Do you have Y- moving towards me in the pic?
    Gerry

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    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  5. #5
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    Quote Originally Posted by ger21 View Post
    Curious why you have it set up so that all the coordinates are negative?

    The reason you can't jog in the Y- direction is because you're home position is already at the limit of your soft limits, at -27.5. How far do you want to be able to move (from home) in the Y- direction? If you want to move 10", then change the softlimits to -37.5.

    It's hard to tell in the pic, but it looks like if the router mover right along the gantry, that would be X+. Do you have Y- moving towards me in the pic?
    The table is in the XYZ home position now.
    The cut area in the Y axis is 27.5". So I want the table to move 27.5" in the - direction.
    I added the Axis and direction on the photo. Possibly this will help you.
    Attached Thumbnails Attached Thumbnails CNC XYZ Home Position.jpg  

  6. #6
    Join Date
    May 2006
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    1469
    It is perfectly reasonable to have the machine hit home switches in the position shown but you have your Y axis pos and neg around the wrong way.

    Change that by reversing the Y in "homing and limits"

    Then set the "home off" amounts to, X 0 and Y 27.5

    Get that right and get your head around it before progressing to setting up soft limits.

    Which will be something like X 0-19 and Y 0- 27.5

    Greg

    EDIT: Oh yeah you also must set the Y to seek home in the positive direction

  7. #7
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    Yep, what Greg said. I had a feeling the Y was backwards.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  8. #8
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    Sep 2003
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    Question

    Quote Originally Posted by Greolt View Post
    It is perfectly reasonable to have the machine hit home switches in the position shown but you have your Y axis pos and neg around the wrong way.

    Change that by reversing the Y in "homing and limits"

    Then set the "home off" amounts to, X 0 and Y 27.5

    Get that right and get your head around it before progressing to setting up soft limits.

    Which will be something like X 0-19 and Y 0- 27.5

    Greg

    EDIT: Oh yeah you also must set the Y to seek home in the positive direction
    I think I changed it like you suggested see photos, shut Mach down and restarted and with it set like that the Reference all Home still works but I can no longer activate the "Soft Limits" button.

    My head hurts, wrapping too much I guess.

    Most people use a movable gantry and I have a movable table, like a milling machine, this may be the confusion???
    Attached Thumbnails Attached Thumbnails HOME-LIMIT2.jpg   DRO2.jpg  

  9. #9
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    Mar 2003
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    Oops. Moving table means you had it right the first time. Well, almost.


    Hold on while I double check this
    Gerry

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    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  10. #10
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    Set Softlimits Y min to 0 and Y max to 27.5, and Y Home Offset to 27.5

    That should work.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  11. #11
    Join Date
    May 2006
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    1469
    Ok well it is confusing because I read the red arrows on your picture to represent the relative spindle movement and not the actual table movement.

    That is the way you must think about it. Imagine the tool moving instead of the table.

    Greg

    EDIT: and what Gerry said is correct. (which is also what I said) at least that's what I meant

  12. #12
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    Question

    Quote Originally Posted by ger21 View Post
    Set Softlimits Y min to 0 and Y max to 27.5, and Y Home Offset to 27.5

    That should work.
    See configuration pictures.

    After changes it still homes OK
    And the "Soft Limit" button will light when moused.
    The Y will now move off of home with the soft limit light on.
    However the X will not move off of home in the + direction, but it will move to the - dir until it hits the limit. I het reset toclear that, and I can move X in the + direction only slightly then it starts singing the soft limit song and stops.

    Hmmmm I tried to set these soft switches months ago and gave up, wonder if that wouldn't be the easiest.

    Confused in the southern Arizona Desert.
    Attached Thumbnails Attached Thumbnails DRO 4.jpg   HOME-LIMIT 4.jpg  

  13. #13
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    Mar 2003
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    Softlimit X min = 0, max = 19.5

    That should do it for ya.
    Gerry

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    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  14. #14
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    Quote Originally Posted by ger21 View Post
    Softlimit X min = 0, max = 19.5

    That should do it for ya.
    EUREKA!

    Thank You.

    That was the trick. Now after all axis are homed, and the Soft Limit is active, I am able to move all axis away from home.

    Now to understand what just happened.

    Let’s take X for instance:
    Home* is actually where it has contacted the X – limit switch and backed off a little bit. This is called X 0.000. What controls the amount that is backed off? Or is this a big can of worms I don’t want to know about?

    Home* for X is 0.000, and that is also the soft axis Min. that you stated in your last post. Correct?

    The maximum travel for X is 19.5” and that is the soft limit for X max. Correct?

    Both the X Min and X Max soft limits are very close to contacting the limit switches. Is this normal? Or am I peering into that can of worms again.

  15. #15
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    The machine only backs off the switch enough for the switch to open. This is your home position. What you might want to do is set the Home offsets to maybe -0.5. Then after homing, do a goto zero and you'll move 1/2" off the switches, and that will be your zero position. Then change the softlimits to -.5, and 19 and 27.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  16. #16
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    Quote Originally Posted by ger21 View Post
    The machine only backs off the switch enough for the switch to open. This is your home position. What you might want to do is set the Home offsets to maybe -0.5. Then after homing, do a goto zero and you'll move 1/2" off the switches, and that will be your zero position. Then change the softlimits to -.5, and 19 and 27.
    Yes, that is a good idea moving -0.5 further away. You say "do a Goto Zero" is that the "GO TO" button below the DRO readings? Or how do I do that. Remember you are working with a guy that just got working and I think understand soft limits less than 12 hours ago.

    Thanks
    Attached Thumbnails Attached Thumbnails DRO ORIGINAL.jpg  

  17. #17
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    Yes, it actually says "GOTO Z", with Z for zero.

    You might want to change the max soflimits to 18.5 and 26.5, to give you 1/2" from all 4 switches.

    You can also modify the Ref All Home button to automatically move away from the switches when you home. Let me know if you want to try it. It's not that hard.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  18. #18
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    Quote Originally Posted by ger21 View Post
    Yes, it actually says "GOTO Z", with Z for zero.

    You might want to change the max soflimits to 18.5 and 26.5, to give you 1/2" from all 4 switches.

    You can also modify the Ref All Home button to automatically move away from the switches when you home. Let me know if you want to try it. It's not that hard.
    The Auto move away from home sounds like a needed function. I'll give it at try so go ahead and give me some step by step directions.

    Thanks
    Hager

  19. #19
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    Under the operator menu, click Edit Button script. The Ref All button should start flashing. Click on it, and a window will open. Copy the code in the window and paste it here so I can see what it says. Close the Code window and Don't save. Then I'll give you code to replace it.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  20. #20
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    Quote Originally Posted by ger21 View Post
    Under the operator menu, click Edit Button script. The Ref All button should start flashing. Click on it, and a window will open. Copy the code in the window and paste it here so I can see what it says. Close the Code window and Don't save. Then I'll give you code to replace it.
    Here it is:
    DoButton( 24 )
    DoButton( 23 )
    DoButton( 22 )
    DoButton( 25 )

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