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Author Topic: Motors stalling, losing steps  (Read 21340 times)

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Offline Zaae

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Re: Motors stalling, losing steps
« Reply #20 on: February 07, 2009, 02:24:33 PM »
I have 3, though the guy at gecko wasn't concerned with that, apparently the drive is supposed to limit the current. That aside, we had the same problem with the 10 amp 29 volt power supply.

Offline Hood

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Re: Motors stalling, losing steps
« Reply #21 on: February 07, 2009, 02:55:05 PM »
Ok well thats what I was getting at, you have 3 motors so the most they will ever draw is 3 x your motors current but more likely 2/3. So your capacitance would be worked out on the motors current rather than what the power supply is capable of, however more shouldnt do any harm :)
Hood

Offline Zaae

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Re: Motors stalling, losing steps
« Reply #22 on: February 07, 2009, 03:13:36 PM »
Ok, I hooked up 3 6300uf caps, which are functioning, but it didn't help the problem   :-\

They run SO NICE and so smooth for 30-60 seconds, then there's just a blip where they're apparently losing signal, or something. I've removed everything possible from the pc startup, and stopped every process that didn't cause the pc to have problems, and it just won't go away. Also for kicks I tried a new parallel cable too. I've tried the wire wiggle test too, no tell tale signs there either.

EDIT:
I don't know if I mentioned it, or if it helps, but if I lower the speed of the motor down to say, 300rpm(ish), it will actually stall, instead of just the usual little twitch I've been describing.
« Last Edit: February 07, 2009, 03:33:40 PM by Zaaephod »

Offline Hood

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Re: Motors stalling, losing steps
« Reply #23 on: February 07, 2009, 03:37:19 PM »
Do you have a scope? would be interesting to see the pulse.
Hood

Offline Zaae

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Re: Motors stalling, losing steps
« Reply #24 on: February 07, 2009, 03:45:42 PM »
I do, though it's an old green screen, so I couldn't really share the results. I had two quick ideas to try, if they don't work I'll dig out the scope.

Offline Zaae

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Re: Motors stalling, losing steps
« Reply #25 on: February 08, 2009, 01:18:59 AM »
I was unable to see any spikes or drops using the scope.

For lack of anything better to do, I (temporarily) took my wife's pc, which is one of few remaining here with parallel ports, and installed mach3 on that. After 30 minutes of testing, the motors hadn't skipped a beat.

I'm not sure how three completely different computers can cause the same issue, but some unknown, mysterious thing about them is causing it for sure. Unfortunately, I don't think I can steal my wife's computer, but it at least gives me a direction to run in.

Offline Hood

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Re: Motors stalling, losing steps
« Reply #26 on: February 08, 2009, 04:09:48 AM »
Have you tried the optomisation steps?
Hood

Offline simpson36

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Re: Motors stalling, losing steps
« Reply #27 on: February 08, 2009, 06:20:44 AM »
Unless you are mis-typing, or I am missing something, you still are off by a factor of 1,000 on your set resistor.

For the 540, your set resistor should match your motor's draw amps times 1,000.  So if I remember right your motors in series draw something like 2 amps, which would call for a 2K (two thousand) ohm resistor.

I'm no expert in electronics, but it seems to me that a 3.3ohm resistor in this application is equivalent to not having a resistor on there at all. I can tell you from my experience with my Gecko 203v drivers that they are very sensitive to having the correct resistor. Bumping and stalling is the symptom of the wrong resistor.

As to your computers, you might check that there is no software polling the parallel port as that could cause the rhythmic bumping that you are getting.

Look for things like printer drivers, antivirus, spoolers, etc. that talk to the parallel port. Make sure your parallel port is set to the highest communication level in the computer's BIOS. If it is set for a printer, it will likely cause trouble.

Other things to watch out for: wireless anything, network, keyboard, Xbox360 controller, phones nearby.

Again, not being a electronics whiz, I would still have to second Hood's comment that the caps may be more effective on the drivers rather than the power supply. I have them in both places, calculated, again as Hood suggested, based on the motor draw.





« Last Edit: February 08, 2009, 06:24:14 AM by simpson36 »

Offline RICH

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Re: Motors stalling, losing steps
« Reply #28 on: February 08, 2009, 10:03:33 AM »
The capacitor formula in reply#16 is a standard powere supply formula you will find in most electronic books.
The capcitor size found from the formula is a value, which if used, should provide you with DC ripple
to less than 10%. So less cap maybe more ripple in the DC and likewise more cap less ripple. So it acts
as a fiiter.

As far as steppers running hot....I don't like mine running above 120F ( my preference only )
80C  and above you can burn yourself and they should be guarded from a safety point of view.
Yes you can run them hotter. Motor winding insulation is one limit on how hot you can get them.
I know that if the temp gets to high they will start acting strangely.
Then if they are only warm, the motor isn't working to it's available potential.

The "ticking sound" ........you realy need to take a look at the generated pulse signal out of the
PP port and see what it looks like. If you have ringing or whatever on the signal out of the PP it can
create all kinds of problems. The only way to clean up a pulse signal is deal wiith the source of it.
If you can't find that source and cure it.......nothing downstream will clean it up......from trying homemade
clean up circuits / break out boards / different PP card , if it's generated by the computer before the PP,
they will probably not work ( my experience and what other knowledgable people have told me).

One solution is to have the pulse provided by using the SmoothStepper.

Just some info for your consideration as i think your not having much fun!,
RICH




Offline Zaae

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Re: Motors stalling, losing steps
« Reply #29 on: February 08, 2009, 11:39:11 AM »
@ Hood ~
Yep, that was one of my first attempts was following the optimization guide.


@ Simpson & Rich

I've got you guys a bit confused about where I'm at in the troubleshooting procedure, and I apologize for that :) At this point I'm confident that the motors, driver, power supply, etc. are working correctly now. It's something about the signal coming from the pc.

I've done a lot of stuff over the last couple days, some of which I have, or haven't mentioned here, though all of it really isn't the problem. Since all of my efforts to remove / uninstall / stop whatever is causing the interruption haven't helped yet, I've started from scratch with a fresh format and reinstall of XP.

I noticed while digging around in the bios that this computer appears to have been used as a server for some business, as there's lots of stuff in there about security, backups, and all sorts of things you don't see in a normal desktop bios. It's entirely possible that the format and reinstall may not work, even though I've disabled all of the 'extras' in the bios, and anything that sounded like it might have an effect several days ago.

At this point, I'd respectfully suggest that you don't think too hard about my problem until I come back with more information, because I think we've found the problem.

:) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :)