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Offline RICH

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Re: getting no motion
« Reply #40 on: September 05, 2011, 07:06:21 PM »
Quote
The machine didn't have backlash issues with the anilam controller

Did you test to see how much backlash you have? You do have backlash it's just a matter of how much.

RICH

farmertwingolf

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Re: getting no motion
« Reply #41 on: September 05, 2011, 07:10:59 PM »
The anilam just didn't have issues with the backlash. I'm sure it was corrected electronically. I turned backlash on and tried adjusting the numerals in the Y axis but didn't seem to correct the issue. Frustrating to be so close and not be able to make parts. The help here has been great.

Offline RICH

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Re: getting no motion
« Reply #42 on: September 05, 2011, 07:20:41 PM »
You need to measure the backlash. That is done by moving in one direction and then moving in the other to see how much lost motion there is.
I use use steppers and thus rather servo tuning stupid so I leave that to those with experience on it.

RICH

farmertwingolf

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Re: getting no motion
« Reply #43 on: September 05, 2011, 07:26:02 PM »
Will that be the value I put in for the backlash value once backlash is enabled? And if I move .200 each direction and get a .010 difference, would it be that number or how far off per inch that would come out to be?

Offline RICH

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Re: getting no motion
« Reply #44 on: September 05, 2011, 08:11:04 PM »
It would be the distance / .010". You moved one direction say .2", actualy you should move twice in the first direction just to make sure that all play is taken out.
When you  move the opposite direction your off  by say .010" and that is due no linear axis movement. The motor will be tuning but the axis movement is just taking up
the slack in the system.

You can also just move in one direction and then jog in say .001" increments the other way and you will see that it took 10 jogs @.001"  to get movement.

There are some controllers that required the backlash be set in pulses but that is not the case in Mach.

My 50-50-50 rule which you may want to consider.
50% - The max velocity is 50% of where your steppers will start to skip
50% - Set the shuttle Wheel setting in configuration to .0050  to .050 ( .5 too slow )
50% - Backlash speed
Not sure how the above works for servos.

RICH
« Last Edit: September 05, 2011, 08:16:25 PM by RICH »

farmertwingolf

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Re: getting no motion
« Reply #45 on: September 05, 2011, 08:16:56 PM »
Ok. Thanks rich. When I go from + to - it goes the correct distance. But when I go - then + it is off. I'm not sure how to compensate for only one direction. Another thing I have noticed is that I don't see where mach is reading my encoders. They plug into the dugong drive so I don't see where I would assign the pins.

Offline RICH

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Re: getting no motion
« Reply #46 on: September 05, 2011, 08:24:37 PM »
Backlash only provides compensation on change of direction.

No experience with the drives you have but there a numerous folks in here that are. There also are numerous posts about using them so try a search.

RICH

farmertwingolf

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Re: getting no motion
« Reply #47 on: September 05, 2011, 08:26:56 PM »
Ok thanks again rich.