Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: kencor1 on July 25, 2008, 05:28:39 PM

Title: Motor tuning while rapiding
Post by: kencor1 on July 25, 2008, 05:28:39 PM
I need help with my motor tuning while.  I have a fireball v90 with the probostep breakout board and drivers from probotix.com.  When the motors are running at normal speed 70ipm they run fine I can try to hold on the the axis and the motors will not miss a beat, but when I am rapiding and 150ipm I just barely touch the axis the motors will bind(make the loud whining sound). I have tried tuning different settings but I think that I am beginning to chase my tail.  I have checked the axis's after removing the motors and the move fine. What am I missing here will the motors always have that much less torque and rapid speeds?  I have tried all of the different step modes on the motors from 16th to full, but the problem always seems to be there.  ???
   Does anyone feel that if i add a smooth stepper to the setup that it will help?  If anyone has any other things that I can change in the setup please let me know.

I have read the Manuel still not 100% sure on what changing the step and direction pluse does, or if that will even help

Thanks in advance for any advice,
Tom
Title: Re: Motor tuning while rapiding
Post by: Hood on July 25, 2008, 05:50:07 PM
You need to tune your motors at full rapid speed, thats all there is too it. If you can move your motors at the Velocity and Acelleration you have set when in motor tuning then you are set. When tuning the motors you move the Vel or Acell sliders then use the Up Down arrow keys to see if all is good.
Hood
Title: Re: Motor tuning while rapiding
Post by: kencor1 on July 25, 2008, 05:54:09 PM
What about the step and direction pulse settings what effect will they have?

Tom
Title: Re: Motor tuning while rapiding
Post by: Hood on July 25, 2008, 05:58:16 PM
Some drives require a longer pulse, 5 is max I think you can set on Motor tuning page. If you need longer you can try Sheline mode.

Hood
Title: Re: Motor tuning while rapiding
Post by: kencor1 on July 25, 2008, 06:51:17 PM
Thanks, I will keep plugging away at it. Next questions is to add the g28 to the button of ref all home do I simply put the g28 at the end of the button code already there, or is there a special way it need to be formatted.  It would be great if someone could post an example or even a screen shot othe the button editor text.

Tom
Title: Re: Motor tuning while rapiding
Post by: Hood on July 25, 2008, 07:05:24 PM
You will need to put your G28 positions in the boxes on the Homing and Limits page (from Config menu) and at the bottom of the Ref All code you would put

Code "G28"

Hood
Title: Re: Motor tuning while rapiding
Post by: RICH on July 26, 2008, 07:24:26 AM
kencor1,

"speed 70ipm they run fine I can try to hold on the the axis and the motors will not miss a beat, but when I am rapiding and 150ipm I just barely touch the axis the motors will bind"

Just a general comment on what you said above for info.
In general as a steppers speed increases the torque decreases as shown in the example attached. I couldn't find any info on the V90 site for a motor curve ( gave info on motor wiring but no torque to speed curve). This seems typical these days for a lot of the generic hybred motors which are sold today. Don't get me wrong, great motors at a nice price but you just don't know in advance how they will behave over a range of speeds. All motors have DIFFERENT curves depending how they are wired ( series, parallel, unipolar ) ie; it's a comprimize on how fast you want to go and how much power you will have at that motor speed. Additionaly, if you ask for a motor curve the seller never seems to be able to provide one or gives some
general info which is useless and not meaningfull. Again not knocking the V90, just some general info on steppers which may be of value to you.
RICHÂ