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Unstable stepper pulse
« on: November 28, 2009, 12:25:43 PM »
Hi All
I hope someone can help with this problem, I am at my wits end with it.

I am bench testing my drives and motors.

When I run / Jog the motor it's as if there is a pulse or more missing. The motor has a sort of small hick-up, this must mean it would loose a step or more when on the machine.
I have tried the diagnostics which say timing / system excellent in all frequencies.
Different motor and drive combos all have the same problem.
I have tried the different settings in motor tuning and pulse timing to no effect.

I have tried running "EMC2" on a Linux boot up and everything appears perfect and smooth. So there shouldn't be any drive / motor issues.

Please Help
John
Mad rush on a treadmill gets nowere

Offline Hood

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Re: Unstable stepper pulse
« Reply #1 on: November 28, 2009, 02:43:35 PM »
A few people had a ticking problem, it was with Dell computers if I recall. I think at least one went the SmoothStepper route after much trying to get rid of the problem.
 Hood

Offline Jeff_Birt

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Re: Unstable stepper pulse
« Reply #2 on: November 28, 2009, 11:50:00 PM »
The hiccup or tick sound comes from variations (jitter) in the output pulse stream from your parallel port. When using Mach it is best to start out with a fresh install of Windows and then delve into the Mach optimization steps as needed (see mach download page for optimization document.) Use the built in mach driver test (drivertest.exe in c:/mach) to see how your system is responding. Typically that will do the trick. There is also a 'special' Mach driver for those systems that don't like the standard driver.

My preference is to use a SmoothStepper: http://soigeneris.com/Warp9.aspx
Happy machining , Jeff Birt
 
Re: Unstable stepper pulse
« Reply #3 on: November 29, 2009, 04:35:31 AM »
Thanks for those replies
The driver test as I said says system excellent in all frequencies
I have tried the special driver, it will not work at all, even with a reboot

I have looked at the smooth step and it's a bit too expensive for now with shipping and tax to the UK

I will have a hunt for the optimisation document.

I don't quite understand why in another programme, EMC2 with a Linux boot on the same machine works smooth as silk.

Thanks John
Mad rush on a treadmill gets nowere

Offline Hood

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Re: Unstable stepper pulse
« Reply #4 on: November 29, 2009, 05:02:13 AM »
Because EMC is not having to take control over windows I would presume.
You will find the optimisation steps at the bottom of the downloads page.
Hood
Re: Unstable stepper pulse
« Reply #5 on: November 29, 2009, 06:31:56 AM »
Fond the optimisation page.
It's odd that a search of the forum does not bring it up !
John
Mad rush on a treadmill gets nowere

Offline Hood

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Re: Unstable stepper pulse
« Reply #6 on: November 29, 2009, 06:44:49 AM »
probably because Americans spell it with a Z or should I say a Zee ;D

Hood

Offline RICH

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Re: Unstable stepper pulse
« Reply #7 on: November 29, 2009, 07:38:53 AM »
John,

I'll assume that you have everything wired up correctly. The sound of the steppers may not be very scientific but it is a good indicator of how the stepper is reacting to the provided signal.

1.What does the driver test look like? Are there a lot of spikes along the horizontal line?

2. In motor tuning, set the  velocity to something slow like 10 ipm / 2 accel and jog the axis.
    If they run.... Can you hear a tick-tick-tick sound or maybe thump-thump-thump ( sort of like a somebody hitting the
    motors with a small mallet / hammer constantly)?
   Can you give a better description of the sound thay make as "HICKUP doesn't help.

3.  What drive and motor are you using? ( in your first post you have a variety of things that you were considering )
4. What kind of computer is it? Does it have onboard graphics? Laptop?

There are a number of things that can be creating the problem,but,I tend to agree with Hood and Jeff that's it's a signal quality problem / computer related. The pulse signal out of the PP should be a nice square wave. You need an osciliscope to see the signal and a decent scope at that. You also need to know what you are looking at when viewing the signal.

I have a Dell Optiplex GX520, fine for everything / good pc, but for running Mach it just plain sucks! Same goes for the Dell Latitude Laptop. Sometimes a change in the PP card or even a different graphics card will do the trick. Sometimes you can do everything  you can think of  and still no joy ( like optimization, removing installed software, modifying every setting know to man!,  etc. So if the computer can't start off with a clean signal there is basicaly nothing you can do about it, and that includes trying to clean the signal up.

Option becomes using an external device like the SmoothStepper or get a different PC. I have done both!

So don't want to to drive you crazy and just suggest you start with the generated signal from the pc.

BTW, been there, done that, and it isn't fun!,
RICH



 

Offline Jeff_Birt

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Re: Unstable stepper pulse
« Reply #8 on: November 29, 2009, 08:08:00 AM »
Quote
probably because Americans spell it with a Z or should I say a Zee

LOL. Reminds me of a movie I was watching recently where one of the characters was musing about Brits adding a 'u' to all sorts of words like 'colour'. (I think the movie was "Three men and a baby".)

You have to love it though. We get all sort of international students at the university who learn 'British' English and then have to learn 'American' English when they get here to the states. Bad enough that they have to converse in a foreign tongue but then we have to throw in all the different 'versions' of English as well. It could be worse, Indians have it tough with hundreds of different languages and dialects in one country, some of them with an obnoxious number of alphabet letters.
Happy machining , Jeff Birt
 

Offline Hood

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Re: Unstable stepper pulse
« Reply #9 on: November 29, 2009, 11:30:56 AM »
Quote
probably because Americans spell it with a Z or should I say a Zee

LOL. Reminds me of a movie I was watching recently where one of the characters was musing about Brits adding a 'u' to all sorts of words like 'colour'. (I think the movie was "Three men and a baby".)

But in reality its not us thats added it, its the Americans that have subtracted it as you originally came from here ;D

Hood