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erratic pulse train fix?
« on: June 10, 2013, 03:17:26 AM »
I have MACH3 hooked up to a Gecko 540 but the power and fault (charge pump) lights both rapidly flash and the steppers vibrate. I suspect the timing pulses are erratic.

I've read the MACH3 manual entry that describes running the DriverTest program:

You can ignore all the boxes with the exception of the Pulses Per Second. It should be fairly steady
around your chosen kernel pulse frequency (25,000 Hz, 35,000 Hz, etc.). Your pulse rate may vary,
however, even quite wildly. This is because Mach3 uses the Windows clock to calibrate its pulse timer
and, over a short time scale, the Windows clock can be affected by other processes loading the com-
puter. So you may actually be using an “unreliable” clock (the Windows one) to check Mach3 and so
get the false impression that Mach3's timer is unsteady.

DriverTest evaluates the pulse stream and displays a Pulse Rating below the Timer Variations graph.
In Figure 2-4, the pulse rating is Excellent. If your system has more variation, the pulse rating may be
good, fair, or poor. If you see a screen similar to Figure 2-4, with only small spikes on the Timer Vari-
ations graph, a steady number of pulses per second, and a good or excellent rating, everything is work-
ing well. Close the DriverTest program and proceed to Section 2.3 describing Mach3 Profiles, below.
If you have problems with the installation, refer to Section 2.4, Installation Problems.



But section 2.4 doesn't explain what to do if the pulse rate is poor. How bad does it have to be? The DriverTest shows me results that sometimes say "Excellent" but at other times "Too Slow" or "Too fast". Is this the normal variation simply caused by the Windows clock measuring approach? I have a 1.6GHz Athlon processor on an old motherboard. The parallel port is fine. I've set the Bios to EPP for bidirectional signals etc. I have a 'fresh' installation of XP and nothing else running. What should I do? Switch to another junky computer? Is there a list of computers that have been tested with MACH3? Is there a list of BAD computers?

What set of computers are used by ArtSoft for their regression tests?


« Last Edit: June 10, 2013, 03:19:18 AM by Clive McCarthy »

Offline Hood

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Re: erratic pulse train fix?
« Reply #1 on: June 10, 2013, 04:45:00 AM »
If you are getting these warnings then you have problems.
Best scenario is that the line in the driver test window is perfectly flat with no disturbances. If it is a bit raggedy it may be fine, If it has lots of big spikes and is very erratic then you will almost certainly have issues.

You can sometimes do things that will help, there is a document that details them on the downloads page of the Mach site, its called Win XP Optimisation but can help for other operating systems.
You will find it here
http://www.machsupport.com/downloads/XP_Optimization.txt

Hood
Re: erratic pulse train fix?
« Reply #2 on: June 10, 2013, 07:06:38 AM »
dell computers are pretty stable.

Offline RICH

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Re: erratic pulse train fix?
« Reply #3 on: June 10, 2013, 08:03:18 AM »
Quote
dell computers are pretty stable.

Just a comment and your experiences may be different ................. :)
 
Not my experience and that goes for about 6 different models that we have tried using.
The on-board graphics may cause problems thus providing a very poor output signal.
I would not recommend using a Dell unless you use an extenal motion device.

RICH
Re: erratic pulse train fix?
« Reply #4 on: June 10, 2013, 08:23:26 AM »
thanks for your input on the dell machines Rich, i've not come across these problems on any dell machines that I've used, but i'll keep an eye out for it. I have used approximately 50+ dell machines to this date.

Machines I have had problems with are mainly ibm and ibm clones.
Re: erratic pulse train fix?
« Reply #5 on: June 10, 2013, 08:49:12 AM »
Thanks for your inputs.

I'm quite dismayed to discover how sensitive MACH3 is to the type of computer system. I was hoping to just assemble a PC from junk parts in my store room -- which I have done. The motherboard is an old Foxconn 400 series with a very inexpensive AMD Athlon processor -- it's about ten years old. I cased the thing up, slapped a copy of XP on a 40GB HDD and fired the thing up.

I shall follow some of the suggestions in http://www.machsupport.com/downloads/XP_Optimization.txt to see if I can shut down any other drivers, processes etc.

Your comments so far, suggest that Dell is both good and that Dell is bad! Hmm. I have an old Dell box which I might be able to resurrect.

Offline Hood

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Re: erratic pulse train fix?
« Reply #6 on: June 10, 2013, 09:01:07 AM »
Motherboards with onboard graphics are usually problematic when wanting to use the parallel port. Even if you use a PCI or AGP graphics card things can still be affected. Some mobos you can disable onboard graphics, some you cant but even ones that you can sometimes still show issues.

I use external controllers now but previously when I used the parallel port I only ever had issues with one computer, it was a PC Chips cheapo with onboard graphics, all the rest of the mobos were fine and all computers were built from parts by me and not bought in systems from big name brands.


Hood
Re: erratic pulse train fix?
« Reply #7 on: June 10, 2013, 09:28:47 AM »
Thanks.

If the on-board graphics is a problem then there is almost no board that doesn't have this. I'd have to find a VERY, VERY old board -- most machines have an Intel chipset with basic graphics. I have used this board with an AGP graphics card but I'm guessing this might only make things worse. It is possible to disable the on-board graphics in the BIOS of this board.

I'm going to disable the networking, power saving, etc. to see if these processes are stealing cycles and messing with the interrupt latency.




Re: erratic pulse train fix?
« Reply #8 on: June 10, 2013, 11:29:50 AM »
The big problem with on board graphics IIRC is the use of shared memory. If the onboard graphics has its own memory you are less likely to have problems. If you have a computer and the driver test is so so then  I would consider trying it out on the machine to see if it works.

I have had good luck using dells.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.
Re: erratic pulse train fix?
« Reply #9 on: June 10, 2013, 12:06:58 PM »
First off I must say that I omly use Pentium 4 level computers.

I have 7 novatech desktop machines that have "bad" parallel ports, 3 ibm lenova desktop computers that have "bad" parallel ports, and a few others that have been gutted for parts over the years. I've converted a lot of denford and boxford  and conect machines over a lot of years and I actively seek computers that I know work. I've just purchased a load of viglen desktops that work, but I normally go for dell.
With the greatest respect, i'm not a Mach3 guru like Rich or Hood so the inner workings of mach are a mystery to me, all I can comment on are the computers I use.