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Author Topic: Missing steps at 10 ipm? Taig, Mach3, Xylotex  (Read 29906 times)

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Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #40 on: May 15, 2008, 08:47:01 AM »
Hi Monte,

Do you still have your step and dir pulse timing set to 1 and 0 respectively?  That is as wrong as it gets because your direction pulse is shorter than your step pulse (not trying to be rude, I know that the proper settings are not made obvious in the setup video), so you may not be just missing steps;  those loud clicks may be your machine stepping randomly in the wrong direction. Probably bad for it, but a little leadscrew backlash probably gives some slack! This is from the Xylotex manual:



Note that they suggest at least 2 microseconds for the step pulse width, so set your Step Pulse should be set to 2 microseconds or longer (I suggest just 2) in the Mach3 Motor Tuning page.
Also note that when they say "Miniumum Command Active Time Before/After Step Pulse" they're talking about the pulse on the direction pin (as well as others). Note that you need 1/5th of a microsecond lead and lag of the direction pulse before/after the step pulse, so making it a microsecond longer should cover it.  So, I suggest that you set your Mach3 Dir Pulse to 3 microseconds.

If this does not fix your problem, there is another setting which may help you. You may need to go to the Ports and Pins Config screen, and set the Dir LowActive to be enabled. In my mind, this should only change the direction, but since the direction can be explicitely reversed in the homing/limits config screen, I think there is more  going on with this setting than meets the eye.  It may affect the timing relationsihp between the step and dir pulses, so try changing one of them to enabled and jog your machine around. This will reverse the direction of your movements, but you can fix that, as I already said, in the homing/limits config screen with the "reversed" setting.

We should suggest to ArtSoft that for the initial configuration, Mach4 supplies a list of commonly used stepper drivers, and then automatically sets all this. Or maybe someone can make a wizard that does the config, because most newbies (including me) have to learn all this for the first time although it's not necessary knowledge for machining.

Best of luck, I hope this helps,
Anthony
« Last Edit: May 15, 2008, 08:56:03 AM by wongstein »
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #41 on: May 15, 2008, 03:18:31 PM »
Have you set your computer to "standard PC", this reduced the ticking I had on my motors.

Jim.
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #42 on: May 16, 2008, 07:21:08 AM »
Jim, are you talking about the Windows power settings, or something in the Mach3 setup? You're right, it's a good idea to make sure your CNC controller is not set up as a notebook or for "minimal power management" or else it will try to save a few watts of power by lowering the CPU clock speed when it can, and that's not good for performance. I don't think that's causing Monte's terrible motor performance, however. It sounds like his machine won't even make a straight line. I just found a P4 2.5 Ghz computer in the garbage, by the way, so if CPU performance is the problem, the good news is that it's now the cheapest thing to upgrade.

Monte, if you want to use your oscilliscope to see what's going on, here's what you do.  Take one channel and put the positive on Pin 1 of your parallel port, which is the step pin for your X axis. Put the negative on the ground pin. Put the positive of the second channel onto Pin 2, which shows your direction signal, and put channel 2's negative on the ground pin as well.  I don't know your scope, but it probably has knobs for each channel for the time and voltage scales. Basically you want to zoom in on 5volts, and about 10,000 Hz.  You can probably just turn the knobs until you see stuff. Don't worry, it's impossible to hurt an oscilloscope with a parallel port. Just turn off soft limits in Mach3 and (without the machine connected, of course) use "g0 x10000" to keep the signal coming while you watch. What you want to see is two wave forms like the one in the graph I posted from from the Xylotex manual. The reason they put it in the manual is because it's essential for the operation. I wouldn't bother with the scope until trying the values I suggested above, however, but it would be fun to change the pulse timings and see what it looks like. I'd love to see what it looks like.

Cheers,
Anthony
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #43 on: May 16, 2008, 02:10:51 PM »
No, most computers when loaded with Windows are configured as a "ACPI PC"or"ACPIx86 PC", and I found on a 2gig AMD machine that I have, when running the motors they had a "tick" every few seconds. I thought it was dirt in the ballscrew but all three steppers did it. It sounded like a square ball going round, and it was loudest on max feed which is about 2 meters a min. Anyhow I came to the conclusion it came from the clock in the computer as no setting changes in Mach made any difference and I had shut everything down in the computer I could think of.

So I decided to configure the computer in "Standard PC mode", the information is in the "optimisation XP" file, but as usual I can't find it now. Anyhow what you do is :-

1, right click My Computer and select properties
2, click hardware tab
3, click Device Manager
4, double click "computer"
5, right click on standard ACPI Computer and choose Update Driver
6, choose "install the software from a specific location (advanced)"
7, click "next"
8, choose "don't search, I will choose driver to install"
9, click "next"
10, choose "Standard PC" from the listing
11, click "next"
12, click OK.

Then reinstall any drivers it asks for on reboot.

This should clean up the pulse output from the computer. Could be worth a try.

Jim.
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #44 on: May 18, 2008, 08:48:36 AM »
Thanks all for the help, I've moved on to Gecko drivers and a Smooth Stepper, problem gone.  Not solved, but gone.  I suspect I had resonance issues, but it could have been something else too, I never figured it out.  The Gecko drivers and Smooth Stepper have smoothed it out.

Monte
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #45 on: May 18, 2008, 11:15:24 AM »
Monte,
Happy you reposted.
The PC and how it relates with the MACH engine is the problem, a real bitchy one at that....

Sorry for taking so long to post back, some of the replies (good ones too!) were after I made the changes.

Besides the random lost steps which I think was resonance, I was getting a regular rhythmic sort of beat in the motors.  Don't know if you saw my video with a motor on the table you can hear what I was getting http://youtube.com/watch?v=DZUrAlST1kA It made me think there was something going on with the pulse stream from the PC.

Anyway, it's way smoother now, just don't have the time to work with it, low priority hobby right now.

Monte
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #46 on: May 21, 2008, 01:07:03 AM »
Hi Monte,

From the video it sounds like there is something running on the PC that is interfering with the Mach3 engine.  Do you have anything like Quicktime installed on the PC? Even if you don't have the application running, it has a service running in the background that could be interfering with Mach. The alternative is that there is electrical noise getting into the Xylotex driver.

Cheers,

Peter.
----------------------------------------------------
Homann Designs
http://www.homanndesigns.com
email: peter at homanndesigns.com
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #47 on: May 21, 2008, 08:14:14 AM »
Hi Monte,

From the video it sounds like there is something running on the PC that is interfering with the Mach3 engine.  Do you have anything like Quicktime installed on the PC? Even if you don't have the application running, it has a service running in the background that could be interfering with Mach. The alternative is that there is electrical noise getting into the Xylotex driver.

Cheers,

Peter.

I'm fairly certain I didn't have anything like Quicktime running, XP was done on a clean install, then Mach, and maybe Firefox web browser.  Now it's running a Smooth Stepper, all seems good.

Monte