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Losing steps on reversal
« on: May 23, 2009, 12:16:15 AM »
I'm using the latest version (3.042.020) with a Mechatronics driver board and a Zenbot tool. I am loosing a step at each direction reversal. The test is to home on a dial indicator, run 10 iterations of X3 Y3, X0 Y0. (Distance does not matter) DROs end at zero but the indicator shows .015" drift. I have tried three different computer systems, each with a minimal WinXP, 2-3Ghz processors, and at least 2GB ram.

Before anyone chimes in with useless suggestions such as belt tension, loose cables, etc... I have read many posts here and on Yahoo about this. I know that the Mechatronics and Zenbot are not at fault because I can run the same test with TurboCNC and all the same motor parameters and the carriage returns home, dead on.

So, is Mach3 really so sensitive to the PC setup that it has to be just right? I know others have felt this pain, how did you resolve it? Most posts I have read did not have a successful resolution. Some of the solutions resulted in blue screens or an unbootable PC for me, or were things I had already done. I know at least one poster here has switched to other software because this could not be resolved.

For those of you who are lucky enough to have a machine working with precision: Has anyone documented their PC hardware setup (Motherboard, BIOS, CPU, video card, memory, peripherals) and a step-by-step installation and stripping of winXP (which version and which service pack, did you get all the latest updates from Microsoft, etc. What additional drivers got loaded?) I know about systems that don't work and would like to know something about the systems that do work.

I have spent a week on this, hijacking servers, buying a new motherboard, re-installing XP for the nth time, etc.  I have to start cutting so I am stuck with TurboCNC for now, doing the diskette shuffle from the design system to the workshop. Had to install a diskette drive on the design system.

I'd appreciate hearing about your successes.

Jurgen

Offline Chip

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Re: Losing steps on reversal
« Reply #1 on: May 23, 2009, 01:58:16 AM »
Hi, Jurgen

This could be causing your Problem.

Some Controls Board's are Sensitive to the "Low Active" setting's in Port's and Pin's "Motor Outputs", Try both  "Checked" or "X".

If the controls board's are all the same, "Low Active" setting's (Dir/Step) should All be Set the Same Ether "Checked" or "X".

Use "Reversed" in Home and Limit's to change an axis direction If Needed.

Hope this Helps, Chip
« Last Edit: May 23, 2009, 02:00:46 AM by Chip »

Offline RICH

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Re: Losing steps on reversal
« Reply #2 on: May 23, 2009, 08:16:31 AM »
Jurgen,

Try what Chip has suggested as that just may be the problem.

"Before anyone chimes in with useless suggestions " & "So, is Mach3 really so sensitive to the PC setup that it has to be just right?"

- Mach is highly configurable.
- If you think in terms of a CNC system (ie; mechanical, electrical, software) it's complex to address all the different makes of computers, driver boards, break out boards, add on boards, possibilities of interface problems as they pertain to mechanical, electrical and software.
- If someone uses "YOUR" system combination and has specific experience then there may be a simple answer as it pertains to your system. If not, someone may take the time for you and try to narrow it down. Some times the suggestion  may seem useless, but you don't know  their thinking / or from what perspective they are coming from.
- There are no "useless suggestions" in my opinion.
- Something works, like Turbocnc / Mechatronics / Zenbot and Mach / Mechantonics / Zenbot does not. An apple is not an orange
and surely looks and  tastes differently but in the end it provides food for the body. Resolution to a problem comes about once the system is understood. Mach produces step and direction signals which can be configured to address different drivers.
I don't use or know anything Mechatronics drivers. It would helpfull if the model, a link to the site, manual was provided to make it easier for others to help you.


"would like to know something about the systems that do work"

-Tough one to answer, so here's a generic answer:
A dedicated optimized computer for CNC, with Windows XP running a lockdown version of  Mach, which provides a clean signal out of the PP, only with
software that  will not interfere with the controlling program. Mach configured to address an appropriate mechanical and electrical system interface used  for CNC. Of course, an operator who knows the above.

RICH
Re: Losing steps on reversal
« Reply #3 on: May 23, 2009, 09:58:21 AM »
Thanks for the replies...

Chip - these suggestions I had not seen before and will try out. This is the kind of information I am looking for. Thanks.

Rich - All good observations, however, I have tried the "generic" configuration with three sets of hardware so far. Yes, Mach3 has many configuration options, I've tried the ones from the vendor and the ones in the video tutorials and Mach3 manual. That's why I was asking for the specifics of working configurations.

Back to the shop...
Re: Losing steps on reversal
« Reply #4 on: May 23, 2009, 10:42:28 AM »
Chip - I tried all four combinations of active low/high. Had high hopes but it did not make a difference.

All - Here is the link to the Mechatronics board information and manual: http://www.easy-cnc.com/3axisdriver.html
« Last Edit: May 23, 2009, 10:50:00 AM by jgschmidt »

Offline Chip

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Re: Losing steps on reversal
« Reply #5 on: May 23, 2009, 02:56:00 PM »
Hi, Jurgen

Post your (Mach3Mill.xml) profile file, Use the REPLY button then "Attach" option, You'll find it in C:\Mach3 folder.

There are only 2 combination's, First 2 pic's.

You should try pic 3 ( 5 & 5 ) in Motor Tuning and also Srerline Mode 1/2 step mode in Ports & Pins pic 4.

Chip
Re: Losing steps on reversal
« Reply #6 on: May 23, 2009, 05:04:04 PM »
Thanks, Chip, for your continued interest.

My original xml file from Zenbot had DirLowActive checked and StepLowActive X'd. That is why I thought there were 4 possibilites. So is it correct that they should be the same? Either both checked or unchecked?

 :) Anyway, turning on the Sherline 1/2 pulse seems to have fixed the drift I was experiencing in my little test.  Active high or low did not matter once I checked this. Actuall cutting will be the final confirmation.  :)

Would be interesting to know what that actually does to the signals. The manual does not give any insight into why this might or might not be checked. The tutorials just say that beginners show ignore these settings!

Unfortunately all this testing seems to have fried one of my channels. I can test the reversals on one axis but can't do any cuts until I get some replacement ICs. I can at least test with one axis on the other systems and see if they fare better as well.

Is it possible to fry a driver board with badly chosen parmeters in Mach3?


Thanks again.
« Last Edit: May 23, 2009, 05:06:19 PM by jgschmidt »

Offline Chip

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Re: Losing steps on reversal
« Reply #7 on: May 23, 2009, 05:32:47 PM »
Hi, Jurgen

Sherline 1/2 step mode increases the pulse width to a greater value than 5 in motor tuning, Giving your stepper control
more Time to see the Pulses.

"Is it possible to fry a driver board with badly chosen parmeters in Mach3?", It shouldn't cause any problems like that with what you've done.

Chip

Re: Losing steps on reversal
« Reply #8 on: May 23, 2009, 10:07:36 PM »
Thanks. That seems to imply that the max value I can set for pulse length on the motor tuning panel is 5. Even though it allows me to enter and save larger numbers. One suggestion I tried a few days ago was to enter a "15" for the pulse lengths. Of course it did not solve my problem which is no surprise if it maxed out at 5.

So, does the Sherline setting add or multiply by a certain amount?

I can look at the spec sheets to see how motor driver chips work. It would be nice to have a better understanding of what signals result from the settings on the Mach3 configuration panels so I can make a correlation. Is such information available?

Offline Chip

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Re: Losing steps on reversal
« Reply #9 on: May 23, 2009, 10:48:08 PM »
Hi, Jurgen

"Art" posted this some time back, " Sherline switches to 40us pulse width, so its a good test of pulse
width issues."

Chip