Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: modnet on September 05, 2007, 06:48:59 PM
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We are using ver 1.8? and have a problem.
With multi passes the axis does not return to zero before start the next move.
We thought that it maybe losing steps but this is not the case - as you can still send it home and it will go back to the orignal position ?
We are moving at over 7 metres a minute ..
The problem goes when speed is reduced to 2 M a min
Any ideas - should we upgrade
Cheers
Dominic
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Try and increase your acceleration/decceleration time in the motor tuning menu. My personal opinion, you could be loosing steps, you could also increase the pulse width of the step pulse.
You can also slow down the machine and check if this improves the accuracy. Is this true for all the axis?
Whacko
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We have tryed different speeds and it does effect the behaviour, But we are NOT losing steps, g01 x0 y0 always will go back to the origin,
Just not in the middle of a program - so corners are being cut off at speed, It is as if Mach is starting the next move before the current one is finished.
Does anyone know if there is buffering / queue of the cmds in Mach / or the steps in a Gecko controller ?
Cheers
Dom
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Could it be your license isnt installed properly, and that Mach is stopping at its 1000 lines of code demo mode?
See here http://www.artsoftcontrols.com/forum/index.php?topic=301.0
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Do you mean it is rounding corners? If so, do you have it set in exact stop mode or Constant velocity? Cv Mode can do that if you have low accels.
Brett
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Not a license issue - running over 400k lines of code no prob, but could be the Constanst Velocity setting, will do some testing and update.
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Hi,
Maybe the problem could be in computer. If you set kernell speed to 45K for example, so it can run at G0 10m/min, and if computer for some reason (weakness) drop down to 25K, than happens something similar to your problem.
Cheers
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Read the post on Constant Velocity.
I don't have this problem because my speeds are only 4 inches per minute, and it makes no difference whether I am in constant velocity mode or not - my steppers can accelerate or decelerate almost instantaneously.
If you are in constant velocity mode, at the speeds you are trying to move, the machine will start one move before the last has completed so that it is up to speed for the next move. - hence the rounded corners.
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Why not try the newer version?
Whacko
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Which version would you'ss currently suggest / recommend
Cheers
Dom
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do you have CV on ??? Could you show me a SMALL (5 lines or less) bit of code where you see this problem? I think you are seeing CV rounding and that we need to have a look at some of the CV setings...
I think we can fix this no problem!
thanks
Brian
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Solved ... Thanks All
The problem was / is the CV constant velocity turned on - At high feed rates, this was not just rounding - but chopping a foot off the corner !!!
We have the solution now.
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I think I have the same problem. I tried to add G61 and my corners are not rounded anymore ;D
Just now I am working on a project that has sharp corners and rounded shapes. If I add G61 in the beginning the sharp corners are beautiful, but the rounded shapes take forever to make because the router stops on every coordinate. Is there any way to get sharp corners and speed up the rounded parts?
(My project is designed in ArtCam and contains 50.000 lines)
Terje
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Turn on CV and set your CV angle to 90 deg.. please tell me if that works for you
Thanks
Brian
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Hi Brian
I am pretty new to this world of G-codes.
You must tell me how to set the angle. Is it a prefix or what?
Please show me a line where you have done it
Thanks
Terje
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This is a setting on the "settings" page near the bottom of the page.
Thanks
Brian
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Thanks
Found it.
I`ll experiment with the values
Terje