Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Fred_evans on May 11, 2012, 04:29:26 AM
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Hello Chaps- Please tell me is this is an acceptable way to correct a stepper motor
that is not measuring correctly
Select this page
Config->motor tuning
Example setting Z axis on lathe machine in millimetres
after setting the zero position on the Axix dro to Zero and pressing enter
I give the instruction G0 Z-100
Then I measure the distance actually moved and find that it has moved 110 mm
My current setting in steps per is 250
I do the followimg sum 250 divide 110 multiply 100 = 227.27
enter 227.27 into the steps per-- window in motor tuning screen
regards
fred evans
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Hi Fred - re-inventing the wheel again? ;D
You're on the right lines but there is a procedure built into Mach to do this all for you.
goto the "settings" screen and bottom left hit the "set steps per unit" button. If you're using a screenset that doesn't have this screen or button then just temporarily load the standard 1024.set via the "view" menu button - do the biz and then reload your original screenset. Voila!
Ian
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Thanks ian--
I will try it immediately
By the way they still havent invented anything better than the wheel----
regards
fred
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Got some of it --
Its asking how far I want to move the axis--
what does it mean by "how far" ?
How far from where?
sorry
fred
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sorry Ian _ I am confused
I loaded the screen that is called 1024.set. (I see it should have been 1024.lset
is this a problem--)
Now this 1024.set has become my default screen when I start up.
I want to get back to the original lathe screen.
What is the filename for the original lathe screen and where should that file be
in the mach3 folder?
regards fred
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1024.set is the one with the calibration button on.
1024.lset is the standard lathe screen - all .set and .lset files are in c:\mach3
re: how far from where? - from where it is.
Ian
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Fred,
Position the axis so you can make a move as long as possible .....a move you can measure. Remove any backlash, you move one way and then a small distance the other way.
You will asked how far to move, lets say 10", the axis will move 10" based on the current steps per unit settings, it will then will ask you how far you
moved....you measure and find it to be 9.950" and that's what you input for the value. The steps per will be recalculated and you will be asked if you want to change them, you reply ok, if you go to motor tuning you will find that the steps per have been changed. Save settings if you want to keep the revised settings.
You can use the mill screen for the tuning, but, make note of the values and use them in the turn screen.
Once you have the steps per correct then you want to try a a few intermediate steps and see how linear the axis is in movement.
With the steps per unit correct then you want to check for backlash.
RICH
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You can use the mill screen for the tuning, but, make note of the values and use them in the turn screen.
RICH - do you NEED to do this? i.e. note the values. The values are surely stored in the xml NOT the screen. We're only using the mill screen for the button. The xml will still be the lathe xml. Yes/no?
Ian
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The xml will still be the lathe xml. Yes/no?
Ian
Correct Ian, personally I prefer to calculate the steps per, but maybe I am unusual that way ;D
Hood
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Correct Ian, personally I prefer to calculate the steps per, but maybe I am unusual that way ;D
Nope - me too - never actually used the calibration thing.
Ian
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Thank you Rich-- I just couldnt figure how the procedure was supposed to work
Are these and similar instructions available anywhere- I cant recall seeing them anywhere in
the manual--
But you guys are a great help
thanks
fred
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Fred,
Not sure what the manuals say about using the axis calibration. To lazy to have a look at them. ;D
There is a nice axis calculator in the Members Docs which one can use to do caclulations and comes in handy if one wants to compare
different parameters. Here is the link:
http://www.machsupport.com/forum/index.php/topic,16315.msg110286.html#msg110286
I also like to calculate the steps per unit , use that value and then check the axis movement to extremes ie; profile the axis for record keeping.
The profiling is done opticaly but note that i have the tools to do it that way and may be a little wierd........ :D
RICH