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Mach 3 acceleration coding change
« on: May 28, 2012, 02:01:39 PM »
Hi All,

I have been using Mach 3 for a couple years for CNC work.  I am trying to use Mach 3 for a special motion control project, here is the situation: The motor I am running (a NEMA 42 4120 OZ/in motor) functions well up to about .4 in/s/s acceleration setting or lower (the min acceleration for 100 in/m max velocity) but I need to run it at 540 in/m (the system accelerates way too fast when I set the max velocity that high and causes a lot of problems).  My question is:  Does anyway know a method (maybe changing the code) so that I can run a a 540 in/m velocity but get to that speed with a low acceleration (.4 in/s/s) or lower?  Right now it looks like mach is designed to reach max velocity about 4 seconds from start.  My best guess at a simple solution would be to extend the ramp up to max time from 4 seconds to something much more gentle at high speeds, like 20 or even 40 seconds.  So my final goal is to have a max velocity of 540 in/min and to get to that speed over a period of time that is 20 seconds or longer with an acceleration of .4 in/s/s or less (.2/s/s would be about ideal)

Thanks for your help,
Tim

Offline Hood

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Re: Mach 3 acceleration coding change
« Reply #1 on: May 28, 2012, 02:36:29 PM »
The Acceleration setting in Machs motor tuning page will set the acceleration to whatever you want but maybe I am misunderstanding what you are asking.
Hood
Re: Mach 3 acceleration coding change
« Reply #2 on: May 29, 2012, 01:42:27 AM »
Unfortunately using the current motor tuning system the minimum acceleration I can input for a 540 unit max velocity is 2.2 unit/s/s acceleration, which is 5 times too fast for my application, hence my question concerning coding.  If I try to put in a lower acceleration value the system forces it back up to what I just described.  I have tried changing kernel speeds and steps and the result is the same.  There is some formula in the coding that defines that acceleration graph and the motor velocity / acceleration parameters, I need help locating that equation in the coding so I can change it to suit my needs.

Offline Hood

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Re: Mach 3 acceleration coding change
« Reply #3 on: May 29, 2012, 03:05:48 AM »
Ok I understand now, unlikely that can be changed by a user and your only hope would be to request Brian  change it.

Hood
Re: Mach 3 acceleration coding change
« Reply #4 on: May 31, 2012, 11:10:26 PM »
The great team at Artsoft hooked me up, for those who are curious:

If you open your XML File in a word editor(IE: Note Pad or Note Pad++) you can manually change the Acceleration to what you would like. Once the XML is open search(CTRL-F) for ACC0 for the X, ACC1 for the Y, and ACC2 for the Z. Save the file run mach3 and you should be good to go.

by XML, he was referring to the XML for the Mach 3 profile I wanted alter.

Happy Hunting!

Offline stirling

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Re: Mach 3 acceleration coding change
« Reply #5 on: June 01, 2012, 03:46:31 AM »
This works for plasma torch vel% too. However I didn't bother replying because the other way that you came accross in http://www.machsupport.com/forum/index.php/topic,3479.msg150754.html#msg150754 seemed an easier and better way to do it.

i.e. just do a SetParam "AccelerationX", 2.2 in the vb editor and job done - it'll wack it into the xml for you.

Ian