Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: CUTMORE on April 23, 2009, 09:14:48 AM
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Hi,
I have a practical cnc router that originally came with Wincnc. I wanted to try Mach on this machine as I use mach on my lathe. The set up is,
Pc Dell desktop, dual core processor, 1 g ram.
Stepper drives IMS 483's running 48v.
Motors Pacsci 270 oz/in motors.
Mach v3.042
Steps per- 2038 on the x and Y (rack / pinion), 10000 on the Z (Ball screw)
Accel 100, Velocity x,y (400) z (100)
The weird thing is that in the motor tuning, These settings work smooth as silk. As soon as I save the changes and go back to the program, Mdi screens the machine runs like crap! However, If I am manually jogging and move the mouse, the motors smooth out! At least while I am moving the mouse.
In Wincnc i can run these motors @ 600"/min rapid. In Mach only about 450"/min before the motors are stalling.
Any help appreciated,
Cutmore
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Try the pulse width at 5 and see if that helps.
Hood
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Thanks Hood,
Sorry I forgot to mention,
I tried the puse width at from 1-5, the Kernel speeed at 25Khz- 100khz, Re-tuned the motors each time. Cv on, Cv off, Step, direction Active low checked, un-checked.
Also I had initially set the machine up with Mach running on a laptop (2ghz processor 2 gig ram) With the same results, which made me think it was worth trying on a desktop system.
the thing that baffles me is that, I was testing a program on the laptop, and when I had Mach on the Program run screen the motors were running 1/2 decent, i switched to the diagnostics screen and the motors were smooth. Every time I moved the mouse the motors would smooth out while moving the mouse,both the laptop and the desktop. i even un-plugged the mouse but the motors were still rough.
???
Cutmore
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Do you have any sort of CPU power saving mode? Sounds like it could be that is causing a problem, windows thinks the computer is doing nothing due to Mach not working like normal software, you move the mouse and windows sees activity so ramps the CPU a bit. Well its a good theory anyway ;D
Hood
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I did try shutting the screen saver off as well as dis-abling the hibernation mode. Even set the configuration to desktop.
I am stumped! It does sound like some sort of Windoze >:D sleepy thing though!
Cutmore
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Looked in the BIOS, maybe some sort of sleepmode there?
Hood
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Thanks Hood,
i didn't think of the Bios settings.
I want to run a test of Mach vs Wincnc on my router with a 3d file I recently ran. The run time with Wincnc was 6.5 hours.
Hopefully the bios setting idea will help,
Cutmore
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Have you done the mach driver test? That is a good way to see how smooth the output wave form will be. You can also turn on 'Sherline' mode. This really stretches the step pulse out. I had to do this one one machine to get good results. Also be sure that you have the step/directions signals set up to the correct state. Some driver switch on the rising edge of the signal (Active Hi) some on falling edge (Active Low). If you get it backwards the drive won't work properly. You can see anything from lost steps to rough running.
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Thanks for the tips Jeff,
I did do the driver test and it came up probably the smoothest of any of my Mach pc's yet!
I did try the signals for both step/direction in the active hi, and active low. I changed 1 at a time. man lots of combo's you can test!
I did not however try the sherline mode as i didn't know what that did.
Cool. More things to test!
Thanks,
Cutmore
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Check the docs for your drivers to what edge they trigger on and set Mach accordingly. If that is not set properly than any other changes you make won't produce meaningful results.
Also keep in mind that WinCNC uses dedicated external HW to generate the stepper pulses where as Mach uses the parallel port. As great as the Mach LPT driver is it can't match having a dedicated HW built for the purpose. Also, some motherboards just can't actually drive the LPT that fast. The driver test will come out great but the actual LPT hardware is lacking. Sometimes an add-on PCI parallel port card will make all the difference, sometimes not. Take a look at this thread as it may have a few other ideas that you can try. For a more realistic comparison you would need to use something like a SmoothStepper: http://soigeneris.com/shop/Warp9_97624.aspx or other motion control card.
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And now for the rest of the story...
Last night I tried the suggestions, Hibernate, Bios settings, Sherline mode. all with the same results, Motors ran smooth in the drive tuning but as soon as I saved the settings and went back to any main screen, the motors ran rough and periodically stalled. the motors would smooth out if I moved the mouse.
O.K. time to try something different I thought. Disconnected the lathe computer, Hooked it up to the Router. Put all the same step resolutions, Accels, Velocities in. Voilla! Smooth as silk! I was able to actually increase the rapid a bit from what I could run with Wincnc.
Lathe computer, 1.8ghz P4 IBM Netvista able to run @ 199khz. XP service pack2
Computer I WAS going to use for the router, Dual core 3ghz IBM Netvista, XP service pack2
I have to conclude that either Windows, or Mach do not utilise the dual core processor properly, at least in my case.
Hope that helps someone else,
Cutmore
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Sometimes it is just the parallel port or South-Bridge chip-set that prevents the driver from driving the parallel port properly. The link I gave a few posts above this one had that very problem.
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Thanks jeff,
I thnk i have a parallel port card somewhere, Maybe I will try that.
BTW,
I did click the link you had posted but I didn't find a thread just your link to the Smoothstepper. Did I not get the right link?
Thanks,
Cutmore
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Sorry, I thought I had included it on this thread? Anyhow here is the link: http://www.machsupport.com/forum/index.php/topic,11108.0.html , basically with the motherboard that Rusty had not even another PCI card would work although the driver test looked great. Something in the chip-set that handles the PCI bus (perhipials) did not like being driven that fast. He had tried several things to try and make it work though so I thought some of them might apply in your case as well. If you have a PCI parallel port card I would try that first to see if it helps.
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Thanks again Jeff,
i just read that whole thread. I think My system has that same processor. I will have to look at the Mobo though to see if that's the same as well. if so maybe that combo is the problem.
I will try a pci parallel card as well, just to see.
Cutmore
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I'm a noob, but, had the same rough running on my Dynacnc mach. at first. I set lookahead to 200 lines, CV mode on, CV options off, make sure "plasma mode" is off. I did that and the machine smoothed right out, 3D cutting speeds went from 25IPM to 110 IPM max. In 2d cutting I have it set a 300IPM and it has no troubles, I don't what it can do 2D maxed out. I'm using a Dell 530 dual core with add-on cards for the ports. The computer complains(splash screen) that Mach won't let it go into standby mode on long cuts, but it doesn't seem to cause problems. Just my 2cents worth.
Good luck
Mike