Author Topic: accel and velocity  (Read 13069 times)

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Offline prototype

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Re: accel and velocity
« Reply #50 on: March 05, 2012, 07:11:05 PM »
I have been trying to calibrate steps per unit using mach 3 settings and checking with digital readout.  Not consistent.  It will be off. 018 going in positive direction and. 786 in negative direction.

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Offline prototype

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Re: accel and velocity
« Reply #51 on: March 05, 2012, 07:11:39 PM »
Those numbers are off using 10 inches of travel

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Offline Hood

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Re: accel and velocity
« Reply #52 on: March 06, 2012, 01:54:35 AM »
Calculate the steps per unit from your hardware specs.
Hood

Offline prototype

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Re: accel and velocity
« Reply #53 on: March 06, 2012, 10:11:27 PM »
I will set x and y to 20000 and z to 22222.2222 . Then hopefully adjust settings until its accurate.  This will fix the problem of traveling different in positive and negative directions?

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Offline prototype

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Re: accel and velocity
« Reply #54 on: March 12, 2012, 08:54:51 PM »
It is set at 20000 steps per unit. It is consistently travelling .990 in one direction and 1.06 in the other.

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Offline alenz

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Re: accel and velocity
« Reply #55 on: March 12, 2012, 10:21:09 PM »
As Hood stated your hardware specs determine the correct step/unit, other methods are approximations subject to the accuracy of your measurements. You might want to take a look at a stepper calculator http://www.machsupport.com/forum/index.php/topic,16315.0.html
 to verify/confirm your calcs.
Also are you allowing for backlash in your measurements? Backlash could account for what you are seeing.
al

Offline prototype

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Re: accel and velocity
« Reply #56 on: March 13, 2012, 08:33:29 AM »
Im using a digital readout for the travel measurements

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Offline prototype

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Re: accel and velocity
« Reply #57 on: March 14, 2012, 08:31:00 PM »
I got the steps per unit correct in the settings. I entered 3 inch moves and it was correct with the digital readout. But when I went to mdi and entered a motion it over traveled again. Feeling like its never going to be right to be honest.

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Offline prototype

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Re: accel and velocity
« Reply #58 on: March 15, 2012, 09:37:25 PM »
Now its moving correct with straight cuts but not angles or arcs. I need help PLEASE. I have to get this fixed and im learning as I go.

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Offline Fastest1

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accel and velocity
« Reply #59 on: September 16, 2012, 09:49:11 AM »
You never answered in regards to backlash. After you got your distances traveled correct did you measure for backlash? Do you have it entered and enabled? What % is your arc slow down set to? Do you have CV or Exact Stop selected?
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)