Hello Guest it is April 12, 2021, 12:08:46 PM

Author Topic: Motor tuning question  (Read 7780 times)

0 Members and 1 Guest are viewing this topic.

Offline MarkR

*
  •  25 25
    • View Profile
Motor tuning question
« on: May 22, 2006, 10:25:18 PM »
I am using a 3 axis driver board from HobbyCNC.com. I have set the jumpers on the board to 1/4 step microstepping.

I am confused by the 'steps per' setting in the Motor tuning setup. I am using 1.8 degree 200 step motors with 200 oz/in torque. I am using lead screws of 5 turns per inch for X and Y, and 16 tpi for the Z axis. I have the same motors on all 3 axis.

So, in order to set up the software properly, do I use the 2000 'steps per' setting? I have watched the video and read the manual, and am just a bit confused if I have done this properly. I set the value to 2000 'steps per' and I am calibrating in inches in the system.

(My initial thought is that I am set for 1/4 step micro stepping, so that would be 4 steps per turn, times 5 turns per inch, so it would be 20 steps per inch, but since that is SO far off from what I see in the manual, I am confused.)

Thanks for the help!

Mark
Re: Motor tuning question
« Reply #1 on: May 22, 2006, 10:47:13 PM »
Actually "steps per" means steps per unit, if you are calibrating in inches, then you need 5 complete motor turns (assuming direct dive), if you were not using microsteping this would translate into 200steps*5turns=1000 steps per inch, since you are using 4 microsteps per step, then that would yield 4000 steps per inch.
Same thing with the 16 tpi screw, 200*16*4=12800 steps per inch on that axis.
Hope that helps

Offline MarkR

*
  •  25 25
    • View Profile
Re: Motor tuning question
« Reply #2 on: May 23, 2006, 12:35:55 AM »
Thank You! That makes sense, and I will adjust my settings accordingly.

Whew! And I thought BASKET WEAVING was technical :)

Mark

Offline MarkR

*
  •  25 25
    • View Profile
Re: Motor tuning question
« Reply #3 on: May 23, 2006, 12:44:55 AM »
WOW! What a difference that makes in the cut speed! I KNEW something was wrong, as the speed was SO slow. Thanks again!

Offline MarkR

*
  •  25 25
    • View Profile
Re: Motor tuning question
« Reply #4 on: May 23, 2006, 12:08:03 PM »
Uh Oh! The last post was based on testing the settings in Mach 3 without connecting it to the driver board. When I do connect it, and run the axis with the arrow keys, I get a VERY erratic jumping of the motors and NO torque. So, I know I am over stepping them with this setting. I have tried the slowest settings on both vel and acc and had the same thing happen.

When I set the motors at '20' steps pe, I get slow travel and rock hard torque.

Setting at 2000 per gets similar jumpiness and loss of torque. My driver board micro stepping is set for 1/4 step.

Any ideas as to what is happening?

Thanks again!

mark
Re: Motor tuning question
« Reply #5 on: May 23, 2006, 12:14:20 PM »
Try running a gcode program, or an mdi line

something like:
F20 (or some other number you think you should be able to get it to run at)
G01 x10

and see how that behaves
Another thing might be the voltage you are running the board and motors at
Re: Motor tuning question
« Reply #6 on: May 23, 2006, 03:19:22 PM »
Move the sliders for the Accel and Max vel. That should get you up and running :)
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline MarkR

*
  •  25 25
    • View Profile
Re: Motor tuning question
« Reply #7 on: May 24, 2006, 11:06:38 AM »
I spent quite a bit of time in the motor tuning section today, and what I see happening is this:

If I set my 'Steps per' to the 4000 setting (1/4 step setting on the driver board = 4 microsteps per step*200steps = 800 per turn*5 lead screw turns per inch = 4000 "Steps per'), then tough the sliders as instructed, I get jumpiness. I then move the sliders to lower settings and I get better movement, but much slower travel.

I am guessing I need more voltage (only 12 volt supply @ 60 amps for a 3 motor @ 3 volts each set up).

More tinkering to come, but I think you guys have given me the right direction. What I wish I knew was what speed I should be satisfied with using this set up...
Re: Motor tuning question
« Reply #8 on: May 24, 2006, 12:01:00 PM »
Take the voltage up to about 60V and I think it will help you with you rapids :)
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: Motor tuning question
« Reply #9 on: May 24, 2006, 12:05:24 PM »
I'm not sure the hobycnc board will be able to take 60V, check with them.