Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: desutt on February 27, 2011, 08:13:10 PM
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I am trying to learn how to use my new machine. I am having a great deal of difficulty getting any repeatability in the movement of axis'. I have set my homing position to z=0, y=23, z=3/6 on a 24 x 24 inch by 3. 6 inch platform and saved the configuration. If I home my machine and close mach 3 and then reopen it my DRO's do not reflect the home position that I left the machine in. I have done nothing other than close mach3 mill. When I reopen mach3 mill my DRO's read all zero. It seems to me that they should show the home position since I have done nothing except close and reopen mach3 mill. What am I missing? Another problem I have is that when I insert a g20 into my program the measure unit go haywire. In a simple program that works fine the first two lines are;
g0 f80
g1 z2 x8.5 y16
This program works fine. If I make the first line
g0 f80 g20
the the x and y axis movement (per the DRO's) is scaled by ~1/28 and the z by ~ 1/22. I have changed nothing except to edit the g code in Mach3 saved it and regenerated the tool path.
Image 1 is the DRO's prior to adding the g20, image 2 is the DRO's after the g20 is inserted and the x and y axis are manually moved (tab) 1 inch and the z axis 3.5 inches.
Any Help will be appreciated.
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Your homing position should always be 0.000 in Z, Y and Z
Go to General confing and check persistent DRO (I think)
Jeff
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I checked persistent DRO, did not help. Thanks anyway
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Config, General Config, Lower Right corner you will see Copy G54 from G59.253 on Startup, make sure that is unchecked.
For your other problem can you attach your xml and I will have a look.
Hood
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Ok thanks for the help. Is anyone having a problem with G20/G21 operating backwards. I have my machine set up in inches, but when I load a program that contains a G20 it my coordinates swithc to mm, if I replace the G20 with a G21 it goes back to inches.
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Did you close Mach3 after setting unit, you must
Jeff
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I can't find where to set the unit. Must have set to inches when I got it.
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Go to Menu config and the first item is Select Native Unit
Don't forget to close Mach and re start
Jeff
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This is for setting up motor tuning not units for g code. I am afraid to change this as I fear screwing up the motor steps.
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I don't know if I understand your question or you want to do something else but look at the image.
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When I click on "select native units" I get the attached screen. This screen indicates to me that it has nothing to do with my problem.
Am I wrong?
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Please attach your xml.
Hood
Edit
I see you attached it in another post, I have also answered in that post.
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I also get this message but if I hit OK, I have another message box like the one on the second image.
Jeff
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When I do that everything is screwed up.
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From reading all your postings on this it appears you have Mach set up in metric units not imperial.
May be a good idea to save your .xml and settings so you can always go back but start afresh re-install Mach and set it up in imperial units right from the start.
Tweakie.
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I am sure I am setup in inches. I wrote a program to do a 2 inch square at 1/8 inch deep. The resulting square is 2 inches by 2 inches and 1.8 inch deep. I only have a problem if I include the command g20 in my code. When I do this the units change to something other than inches.
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Your xml showed you were set up in metric units.
Hood
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If you are trying to learn how to use your new machine and you wish to use imperial units then Mach should really be set-up in imperial units.
Yes you may have to redo your motor steps but this is not rocket science and getting everything right now will save you lots of grief and configuration problems in the future not to mention possible problems with imported GCode from other programs.
Tweakie.