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Author Topic: Am I loosing steps?  (Read 3091 times)

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Offline sn96

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Am I loosing steps?
« on: March 13, 2011, 10:26:47 PM »
Hey guys,

I have a sherline 5400 inch mill with sherline stepper motors and driver. The pc I am using is an IBM ThinkPad T43 with 2ghz processor and 512mb ram running Windows XP with no extras. I did a complete format of the hard drive and installed a watered down version of XP. I did install the following drivers: Audio, Touch pad, wi-fi, and Oprera web browser so that I can check the forums, check documentation or anything else I may need. I went into the bios and turned off power management and processor throttling which fixed my jogging problem. After starting mach3 the motors would jog fast then slow down before editing the bios.

I do have a question with the stepper motors: x,y and z seem to thump once or twice when jogged the full lenght of travel but I don't notice any difference in accuracy. how much is one lossed step equal to in distance? when I grip the motors when jogging, you can feel as well as hear a bump/thump. what is it? is that what happens when a step is lost?

I am still learning. Thanks in advance.
________________
Mike

Sherline 5400 with Sherline steppers
Visual Mill 6.0 Standard
Mach3
Windows XP

Offline Tweakie.CNC

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Re: Am I loosing steps?
« Reply #1 on: March 14, 2011, 03:18:25 AM »
That odd tick from a stepper is the symptom of lost (or additional) steps. On my machine one lost step would equal 0.003mm and you would be hard pushed to notice a few of those as an inaccuracy.
It is not recommended to use laptops with Mach unless a separate motion controller (such as Smooth Stepper) is used. There are many reasons why laptops cause problems and you could be lucky and locate the problem early on or you could be chasing this forever.
I would suggest you either get a SS or use a machine dedicated PC then use your IBM for internet / programming etc.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline RICH

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Re: Am I loosing steps?
« Reply #2 on: March 14, 2011, 06:29:57 AM »
You should not be hearing any "thumps" when running. You need to look at the pulse signal  generated by the pc with an oscilisscope. You may be getting additional
pulses and not actualy loosing steps.
RICH

Offline sn96

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Re: Am I loosing steps?
« Reply #3 on: March 14, 2011, 08:52:22 AM »
That odd tick from a stepper is the symptom of lost (or additional) steps. On my machine one lost step would equal 0.003mm and you would be hard pushed to notice a few of those as an inaccuracy.
It is not recommended to use laptops with Mach unless a separate motion controller (such as Smooth Stepper) is used. There are many reasons why laptops cause problems and you could be lucky and locate the problem early on or you could be chasing this forever.
I would suggest you either get a SS or use a machine dedicated PC then use your IBM for internet / programming etc.

Tweakie.


Thanks Tweakie. Before I decided to blow the dust off the laptop to use for cnc, I did use my primary desktop PC  which uses an AMD Athlon 64 2.4ghz 2gigs memory with a 256mb video card and that computer worked flawlessly, in fact, I was able to jog faster with that machine without the motors going ZZzzzzzzzzzz! due to a stall. I will take your word and use the Desktop as my production PC.

Thanks for the help.
________________
Mike

Sherline 5400 with Sherline steppers
Visual Mill 6.0 Standard
Mach3
Windows XP

Offline Tweakie.CNC

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Re: Am I loosing steps?
« Reply #4 on: March 14, 2011, 09:04:47 AM »
I don't think you need to use your best (or favourite) PC - A second user one would perhaps do.

Having said all this I have an old Dell Inspiron which works just great, but perhaps this is the exception.  ;D

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline sn96

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Re: Am I loosing steps?
« Reply #5 on: March 14, 2011, 11:11:11 AM »
I don't think you need to use your best (or favourite) PC - A second user one would perhaps do.

Having said all this I have an old Dell Inspiron which works just great, but perhaps this is the exception.  ;D

Tweakie.

Well my main plan was to use the desktop when I got a new PC but was tired of unhooking it from inside the house, hooking it up in the garage only to unhook - re-hook when I was done using it. The laptop I had sitting in the closet unused and I figure it was worth formatting and trying XP on it so that I can use it while I wait for the time to get a new PC.

What I will end up doing is getting a new laptop, take the old desktop for out in the garage, and give the IBM Thinkpad to my daughter so that she can play her games on it. In the mean time, I will use the laptop for learning the ropes and experimenting with.
________________
Mike

Sherline 5400 with Sherline steppers
Visual Mill 6.0 Standard
Mach3
Windows XP