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Author Topic: Motors are jerky and whine a lot...  (Read 4053 times)

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Offline CHUFF

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Motors are jerky and whine a lot...
« on: August 06, 2008, 03:26:07 AM »
Ok.. Yet another saga in the trouble of setting up a CNC machine. I have a Xylotex board and three steppers, 4 wires, bipolar, 425 oz in.  It's the 'kit' they sell on their web site, XS 3525/8s-3.  I'm running Mach three on a Compaq laptop using windoze XP (I know, laptops aren't recommended, but they don't tell you that until AFTER you get Mach 3!)  Anyway.. my comp is actually pretty stable. I've done all the tweaks in that setup doc on the Artsoft website.

Now the problem. I can get the motors to move, but they only move at VERY low speeds. If I increase the jog rate, they just whine and get really jerky or just stop altogether. I have 5/16 lead screws, and have done the math for my steps per making it 25,600. (8 microsteps*200 steps per revolution*16-screw pitch).

I've played with the Veloc and Accel sliders to try and get 'em smoother, but to no avail. ANY advice?

... as a side note, is there a way to reverse a motor's direction in Mach, or should I just switch the wires around?

Offline Hood

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Re: Motors are jerky and whine a lot...
« Reply #1 on: August 06, 2008, 05:36:57 AM »
First thing to say is it does tell you that Laptops are not recommended, right on the Home Page of Artsoft it says for system requirements "Non-integrated Video Card with 32MB RAM" Dont know of any laptop that does NOT have integrated video ;)

Ok that aside have you tried increasing the pulse width, try it at 5, if that doesnt help then try Sheline mode. Another thing to try is to change the Dir active state, this will reverse your motors as well so it kind of answers your other question. However the reason I am saying to change the active state is because some drives are particular about it being either Hi or Lo. Now if you need to reverse motors further it is best then to go to Homing and limits and reverse there.
 Let us know if anything works and if not maybe someone can help with other suggestions.


Hood

ps have you run the drivertest to see you have a clean pulserate?
« Last Edit: August 06, 2008, 05:38:45 AM by Hood »

Offline Chaoticone

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Re: Motors are jerky and whine a lot...
« Reply #2 on: August 06, 2008, 09:19:48 AM »
Chuff, what size is your machine? What is the vel tuned to in motor tuning? How fast can you get it? In 25KHz mode, you'll only get about 58 IPM at best. If this is the case, I'd look at the Smooth Stepper.

Brett
« Last Edit: August 06, 2008, 09:23:22 AM by Chaoticone »
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Motors are jerky and whine a lot...
« Reply #3 on: August 07, 2008, 02:26:44 PM »
OOOH, I think I'm on the wrong forum. I rear the subject line
and thought this was about my wife.  ;D
Ed VanEss

Offline Hood

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Re: Motors are jerky and whine a lot...
« Reply #4 on: August 07, 2008, 02:32:11 PM »
Thats just wishful thinking :D

Offline CHUFF

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Re: Motors are jerky and whine a lot...
« Reply #5 on: August 07, 2008, 06:40:07 PM »
Now that's just funny! 

Thanks for the advice. Reading through this forum and the Xylotex forums, it seems my computer is the most likely problem. SO.. to that avail, I've found a refurbished desktop on eBay. It has all the system requirements for Mach 3.

The only thing is still the parallel port, but if this machine doesn't have one, I'm gonna invest in the SmoothStepper. Reading through the posts about that thing, it seems like the SmoothStepper is the future of home CNC as parallel ports are becoming a bit rare these days.

I'll keep you all posted!

Offline Hood

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Re: Motors are jerky and whine a lot...
« Reply #6 on: August 07, 2008, 06:42:06 PM »
The SmoothStepper is the Dogs Bo****ks as we say here :)

Hood

Offline Jeff_Birt

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Re: Motors are jerky and whine a lot...
« Reply #7 on: August 08, 2008, 09:07:32 AM »
Chuff, glad you got it sorted. I had a rough time with the first laptop I tired with Mach as well. That system now has a dedicated desktop machine on it. The latest machine I built works great on my work laptop / smoothstepper. Considering all the crapola IT puts on each machine, that is saying something.

Happy machining , Jeff Birt
 

Offline RICH

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Re: Motors are jerky and whine a lot...
« Reply #8 on: August 09, 2008, 07:45:50 AM »
I hope the computer is not a dell latitude or some other one with onboard graphics. Did you try your laptop with the battery removed? Just for kicks do the driver test with it in and out as it does make a difference.
RICH