Hello people,

I just got a new computer from my brother in law for my homebuild cnc machine, instead of a slow Pentium AMD 750 thingy I now have a Pentium 4 fast thingy :-)

But when I run the axes there is a strange noise from the steppenmotors.... I am sure it has something to do with the switch of the computers, not with the cnc machine itself.

But what can be wrong and is there a solution?

here a small movie with the strange noise:
http://www.youtube.com/watch?v=g5EmKL6HLPo

Here a movie as a reference how it was before (movie was the first test when the machine was finished)
http://www.youtube.com/watch?v=hZtFQbRiX0E

hope someone can help,

many thanks,
Cor

<edit>inserted correct youtube link </edit>

You posted the "before" link the same as the "after" link. I think the proper "before" link is...
http://www.youtube.com/watch?v=hZtFQbRiX0E&feature=channel

I don't know what your problem is for sure. I can tell you that mine done the same thing, to a lesser degree, but only on one axis. I do believe it started on 2 axis after a short period. How I fixed my problem was....I bought some gecko drivers. They solved the problem. Are your drivers the 3or4 in 1? I'm not saying that the drives are the problem, but if might be worth trying some different ones if possible. Good luck.

@ Sam: youtube link is updated. 

Sam, what dou you mean with the gecko drivers, software drivers or are those the steppenmotor drivers (hardware)?   If that's the case, I think it will be easier to switch back to my old computer ......although I like the extra speed.

I tried different modes on the parallelport:
-SPP
-EPP
-ECP
-ECP +EPP
-normal.

but no succes

:-( Cor

COR,
What make of computer and does it have on-board graphics?

If you can, look at the pulses out of the PP with an oscilloscope. I will bet you have ringing or even multiple spikes on the pulse. What i think happens is, the driver actually sees
two pulses in a hit or miss fashion,  and thus it sounds like a mallet / hammer is hitting the stepper motor.

If you can, try adding a different video card. Some computers allow you to jumper the on
board graphics out. That "may" not cure it. Other then that, i don't believe you can do anything about it.

You can use a Smooth Stepper with that computer and not have any problems.

Just check out the pulse before you get into spending any money on anything.
( BTW, i USE GECKO DRIVES AND THEY WILL NOT CURE A SCREWED UP PULSE, NOR ANY SETTING IN WINDOWS THAT I AM AWARE OF )

RICH

No, they certainly will not, Rich.
If your old computer still runs the motors fine, then that kills the drive theory.

Did you start with a fresh install of Windows and do the optimization for Mach? Did you do a driver test? If so what were the results? Is your parallel port a 5V port?

You have an issue with the pulse stream coming from your parallel port. If could be that due to other things running Windows can't make smooth pulses, it could also be a hardware limitation of the particular PC. If you have a BOB that expects 5V signals and you have a 3V port that will cause problems as well.

For my money I would use a SmoothStepper.

It's most likely (pretty much guaranteed) the service interrupt of the mainboard. It's higher than the NMI and cannot be affected by regular code. Also NVidia cards are known to insert milisecond long interrupts which creates pulses inthe pulse train.  Nothing you can do about. My parallel port driven taig mill does it, my servo driven smooth stepper router does not. My EMC controlled ill does not because the Linux OS allows a real time core which the amateur OS from Microsoft cannot provide. The problem with a windows based machine is that you cannot possibly achieve real time behavior regardless how hard you try. Only the isolation of the critical timing into external hardware (smooth stepper and alike) provides relieve. Anyone who claims otherwise is into cnc vodoo and might try to sprinkle chicken liver onto his stepper drives to persuade the G-Code Deamons.... haha

Rainer
 

hey Guys,

The mainboard is a MSI PM8M-V series:
http://www.msi.com/index.php?func=proddesc&maincat_no=1&prod_no=205
manual:
http://www.msi.com/index.php?func=downloaddetail&type=manual&maincat_no=1&prod_no=205

Installed is a 3ghz intell processor.



@ Rich  & Jeff_birt: it has a oboard graphic card, I will try to replace it with an external one. Hope this helps.
I haven't checked the pulse stream, will do that as soon as I am home again next week.
It was a fresh install of windows XP
What do you mean with the optimization with mach?
No clue what the voltage is of the parallelport


@ Lemo: no clue what you're talking about....... all a mystery for me.... what I understand for you , there is no solution , just to go back to my previous (slow) computer.

Which mode needs the parallel port in (SPP,EPP,ECP,ECP +EPP or normal)?

all thanks for the input, I will let you know the outcome at the end of next week.

Cor

Cor

that noise is a mechanical thump. take a motor loose from the machine and hold it in your hand and spin it.

bill

@ docltf:  and than what?   (As said in the first post, this strange noise came a day after I installed a new computer. and is also on all axis. I am 99.99% sure it has only something to do with the new computer and not a mechanical defect)  Before I put back the old computer together :-( I want first to explore all possibilities to get this new baby to work well with my cnc machine.

Cor