Hello Guest it is May 26, 2019, 07:43:23 PM

Author Topic: Pulse width help  (Read 2979 times)

0 Members and 1 Guest are viewing this topic.

Pulse width help
« on: November 24, 2012, 07:00:26 AM »
Hi all,

I have built a cnc 3 axis router that has 4 nema 23  stepper motors. I had my cnc running perfectly for about a month except it had a glitch that would randomly reverse anyone of the axis every now and then. To get rid of the glitch I decided to format my hp computer and reload windows xp according to the windows xp optimization guide supplied by Mach3.

Here's my problem, when I reloaded Mach3 and calibrated it to my old settings none of my motors would work properly. They would only turn slowly and vibrate profusely. The only way I could get them to work properly again was by going into motor tuning and increasing the pulse width from 1 to 15us. Anything below 13us and the motor would turn slowly again.

When the X axis and the slaved A axis move the gantry back and forth they loose there position by a random amount. I have lowered the velocity and acceleration by 50% and it's still loosing it's position. It can loose it's position up to 0.7mm.

Could someone please explain what I have done by increasing the pulse width to get the motors to move?

Also is there a better way to perfectly tune the stepper motors?

Also I need to understand what has changed in my computer before I formatted to after I had formatted it. Because my machine worked perfectly with a pulse width of 1us  before I formatted the computer.

Any help would be unreal!

Regards

Mattk

Offline ger21

*
  • *
  •  6,234 6,234
    • View Profile
    • The CNC Woodworker
Re: Pulse width help
« Reply #1 on: November 24, 2012, 07:47:18 AM »
The first thing, is that you shouldn't need to optimize a fresh copy of Windows. Did you Optimize the previous version of XP? If not, the optimization may be the issue. You should only optimize if you have problems.

Did you make any bios changes? I like to disable in the bios, any hardware devices that aren't being used, like sound, and extra drive channels, and unused ports.
Typically, when you need to increase the pulse width, it's due to a weak signal from the parallel port. There are probably numerous things that can cause this, and I really don't have an answer for you.

Did you install XP in Standard PC mode, or ACPI? What was it before?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

Offline Hood

*
  •  25,828 25,828
  • Carnoustie, Scotland
    • View Profile
Re: Pulse width help
« Reply #2 on: November 24, 2012, 08:48:21 AM »
except it had a glitch that would randomly reverse anyone of the axis every now and then.

That is a common problem when using a pirated licence, not saying that is the case with you, just saying ;)
Hood

Offline Tweakie.CNC

*
  • *
  •  7,765 7,765
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: Pulse width help
« Reply #3 on: November 24, 2012, 09:01:49 AM »
Quote
I had my cnc running perfectly for about a month except it had a glitch that would randomly reverse anyone of the axis every now and then.

As Hood has said this could be a license issue. Best to check that your license is valid before spending too much time looking for a cure. The email address is towards the bottom of this page http://www.machsupport.com/purchase.php

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Pulse width help
« Reply #4 on: November 24, 2012, 05:36:49 PM »
Gerry, Hood and Tweakie,

Thanks for your input guys!

Gerry when formatting the computer I First reinstalled windows xp normally without optimization. It was only after I couldn't get any life from my stepper motors that I formatted the computer again but this time following the standards pc proceedure.

The computer I'm using is an old one given to me by my work. When the machine was running well it had all software still on it from when it was a work pc.

I will check to see whether any other unwanted devices are still enabled within the bios because I have not changed many things. I only had changed my parallel port to running as ECP + EPP. I will also see if there is a chip set driver which can enhance my parallel port output signals.

Hood and Tweakie the only software that is on my computer is only a genuine copy of windows xp and a genuine copy of mach3. Considering the glitch was before I formatted my computer and the software on my computer was from my old work, I couldn't tell you whether the old software was genuine or not. But it's good to know what the old glitch could have been caused from. Thank you.

If you guys think of anything else that could enhance my parallel port signal please let me know.

I feel like I'm chatting to celebrities after reading almost every post on this forum! Haha :)

Your input has been highly appreciated. Cheers!

Mattk
Re: Pulse width help
« Reply #5 on: April 05, 2013, 04:41:57 PM »
I too am experiencing glitches of random reversing axises during running. My copy of Mach3 is genuine, any ideas??



Steve

Offline Hood

*
  •  25,828 25,828
  • Carnoustie, Scotland
    • View Profile
Re: Pulse width help
« Reply #6 on: April 05, 2013, 05:01:13 PM »
Only other thing could be noise or loose connection on Dir signal.
Hood
Re: Pulse width help
« Reply #7 on: April 08, 2013, 10:40:26 AM »
Hello again and thanks for your thoughts! I thought I would do a follow up to my question in case anyone else had this problem.
I checked all wiring connections at the recommendation of this thread and that proved not at fault. I then removed the Cmos battery from the computer and that caused all the settings in Bios to reset to factory. That did the trick and the machine is acting normal again. If your axis is reversing by itself this may help you fix the problem. Steve