Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: montejw on March 02, 2008, 08:58:40 PM
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First post here. I've had a Taig CNC for a couple years now, never got it working really well. Just started to work with it again hoping to get it running. Been following Mach since Mach1, using Mach3.
Running Mach on a 1.5ghz Pentium 4 machine, 640mb ram. The cpu has been overclocked from 1ghz to 1.5ghz. The Windows XP installation is not very old, though several programs have been installed and uninstalled, etc. If I have to, I suppose I could re-install it, again.
Here's the issue, I wrote a little program that goes
F10
G90
G1 X2 Y1 Z1
G1 X1 Y.5 Z.5
G1 X3 Y1.5 Z1.5
G1 X2 Y1 Z1
.....
G0 X0 Y0 Z0
I took a digital camera video so you could see the movement and hear the steppers. I sounds like they're losing steps, at 10 ipm. I did a FRO 10%, and it sounds the same at 1 ipm. I can see the motors stutter, all 3 axes do it. Mach3 is running at 25,000hz, it did it at 35,000hz too. Step pulse is 1, Dir pulse is 0.
http://www.youtube.com/watch?v=BVW-lYR9Yyg
Does anyone have an idea what I need to do? Is it the computer? Setup/motor tuning?
Thanks,
Monte
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Hello Monte,
Have you verified that you have NO undue mechanical loads on the motors ?
Are the ways free and well lubed ? Screws, nuts and bearings clean, lubed and free ?
You mentioned that it had been idle for some time. (I get gummy when I do that)
You might disconnect the motor couplings or remove the belts and see if the motors miss any steps with no load on them.
Just a possibility.
Good luck,
RC
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>Hello Monte,
>Have you verified that you have NO undue mechanical loads on the motors ?
>Are the ways free and well lubed ? Screws, nuts and bearings clean, lubed and free ?
No, but I think it's fine mechanically. It's lubed and clean.
>You mentioned that it had been idle for some time. (I get gummy when I do that)
>You might disconnect the motor couplings or remove the belts and see if the motors miss any steps with no load on them.
I guess I could try that. It's a hassle, but I'll give it a go.
One thing else, it's inconsistent. It's running at 5 ipm right now. It started out fine, but it's starting to miss steps again as the program runs.
Monte
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Just took all the steppers off and set them on the table, it still does it.
Monte
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It may very well be an electrical issue as all 3 axes are doing it. But I would make absolutely sure that there is nothing wrong mechanically.
But that's just me. I'm more of a mechanic than electrician.
Good luck Monte,
RC
Man, you're QUICK !
Well......that shoots my theory in the arse.
I'm sure there is someone on this forum that can help here.
Regards,
RC
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It may very well be an electrical issue as all 3 axes are doing it. But I would make absolutely sure that there is nothing wrong mechanically.
But that's just me. I'm more of a mechanic than electrician.
Good luck Monte,
RC
Man, you're QUICK !
Well......that shoots my thoery in the arse.
I'm sure there is someone on this forum that can help here.
Regards,
RC
The table and headstock is fine mechanically. Loosed the leadscrews and moved everything around by hand, slides fine.
Monte
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Monte, one thing I've seen numerous times here is the mention of keeping the signal wiring clear of higher voltage wires.
Picking up "noise" can cause problems.
I assume you are aware of this though.
RC
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Monte, one thing I've seen numerous times here is the mention of keeping the signal wiring clear of higher voltage wires.
Picking up "noise" can cause problems.
I assume you are aware of this though.
RC
Yeah, I'm aware of that. I think it's clear in that regard.
If (motors still loose on the table) I turn the motor velocity all the way up and do a continuous jog they'll not run smoothly either. It actually sets up a regular noise pattern, sort of like dit dit ditty ditty dit dit, dit dit ditty ditty dit dit, dit dit ditty ditty dit dit, etc. Sort of hard to describe, but my camera batteries are both dead so I can't post another video. All 3 axes will do it, it's the same pattern for each. They'll all sync if I hit the cursor keys the right way.
Monte
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Here's a video of one motor on the table. Listen to the audio pattern that gets going. I'm doing a continuous jog with the keyboard. You can hear when I started up the other 2 motors for a short time in the middle of the video. I can feel the motor make a little jerk that matches the sound pattern. Missing steps? Computer problem?
http://www.youtube.com/watch?v=DZUrAlST1kA
Thanks,
Monte
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While you are running a NC program, bring up the task manager and see if the cpu usage increases at the same time as the motors change tone, it could be background tasks grabbing the cpu.
Graham.
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While you are running a NC program, bring up the task manager and see if the cpu usage increases at the same time as the motors change tone, it could be background tasks grabbing the cpu.
Graham.
I did that once, it didn't seem to be linked to the cpu usage.
Thanks,
Monte
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just a thought but what does your driver test look like with ref to what Art says in the vid?
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Monte,
Just for the heck of it, you might try it in Sherline 1/2 Step mode ?
Regards,
RC
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just a thought but what does your driver test look like with ref to what Art says in the vid?
It looks fine compared to the one in the video and the one in the manual.
Monte
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I take it Sherline Mode did not help.
Did you try setting the pulse step incrementally up to 5 in motor tuning ?
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I take it Sherline Mode did not help.
Did you try setting the pulse step incrementally up to 5 in motor tuning ?
Sherline Mode didn't help. Either did stepping up the step pulse.
Monte
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Monte,
Did you try changing the active high/low for the step pulse ?
RC
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Monte,
Did you try changing the active high/low for the step pulse ?
RC
Yes, no help.
Monte
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Monte, Another two cents worth. I am running basically the same setup you have (different controller though). Watched your utube demo and the miss sounds more mechanical to me (but it could just be my ears - selective hearing and all that). My Taig runs very true, excellent repeatability, etc. I was having a problem before that turned out to be misadjusted gibs (too tight). I would lose steps while cutting circles and get ovals. The bind would generally rear its head when cutting arcs. Once I adjusted the gibs it wasn't a problem any longer. Just something else to check. One more item - how about the couplings between the motors and your screws? Some slop there would definitely cause problems.
If you Like, I can send you copies of my configs, motor tunings, etc.
Good luck. Taigs are great, but can be a little (lot!!) frustrating at times. But, the good pieces I have made have compensated for all the headaches. If you haven't already done so, look up Nick Carter's Taig site. There is a lot of information regarding tuning Taigs that I have found really helpful.
Bob@BobsShop- Time to go cut some more.
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Monte, Another two cents worth. I am running basically the same setup you have (different controller though). Watched your utube demo and the miss sounds more mechanical to me (but it could just be my ears - selective hearing and all that). My Taig runs very true, excellent repeatability, etc. I was having a problem before that turned out to be misadjusted gibs (too tight). I would lose steps while cutting circles and get ovals. The bind would generally rear its head when cutting arcs. Once I adjusted the gibs it wasn't a problem any longer. Just something else to check. One more item - how about the couplings between the motors and your screws? Some slop there would definitely cause problems.
If you Like, I can send you copies of my configs, motor tunings, etc.
Good luck. Taigs are great, but can be a little (lot!!) frustrating at times. But, the good pieces I have made have compensated for all the headaches. If you haven't already done so, look up Nick Carter's Taig site. There is a lot of information regarding tuning Taigs that I have found really helpful.
Bob@BobsShop- Time to go cut some more.
Bob,
The gibs seem fine to me. I'll look at them again. I've been all over Nick's site, lot's of good information to go through, just haven't made it all the way through.
Yes, I would like to see your configs, motor tunings and such, thanks.
Monte
montejw:earthlink:net
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Monte, sent you a pm with all my (or most of it anyway) settings. Reread your posts and it seems like you have covered pretty much everything. Scratching my head and trying to remember problems I have had. At one point I had a short in one of the motor cables. Did not happen all the time, but every now and then my motors would stutter and suddenly reverse course. Took me a while to sort that one out.
Another time I had electrical interference from a small shop vac. Resulted in motors suddenly taking off at a right angle to the programmed path. That was fun also.
Good Luck
Bob@BobsShop
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They'll all sync if I hit the cursor keys the right way.
Sorry - I'm not clear on this: If you run all three (or at least two) motors (on the bench) at the SAME RATE and at the SAME TIME - something like g1 x10000 y10000, are the interference patterns perfectly in synch or not?
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They'll all sync if I hit the cursor keys the right way.
Sorry - I'm not clear on this: If you run all three (or at least two) motors (on the bench) at the SAME RATE and at the SAME TIME - something like g1 x10000 y10000, are the interference patterns perfectly in synch or not?
I didn't try that. But when running them with the cursor key independently they seemed to have the same rhythm to the interference.
I started out thinking all this was something to do with Mach3 and my computer, but I'm thinking it something to do with my controller and the mill.
Monte
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do you have a scope? if so have a look at the step pulse and see if its smooth or jumping like your motors, that will tell you whether the problem is from Port in to Mach or out to the hardware.
Hood
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do you have a scope? if so have a look at the step pulse and see if its smooth or jumping like your motors, that will tell you whether the problem is from Port in to Mach or out to the hardware.
Hood
No scope.
Monte
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I started out thinking all this was something to do with Mach3 and my computer, but I'm thinking it something to do with my controller and the mill.
I'd be surprised if it has anything to do with your mill seeing as how it does it when the motors are sitting on your bench - course I may be wrong :).
Seriously, I'd try to establish if they all do it and if they do, do they do it in perfect sync or not.
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HELLO MONTE
i am going to take a shot at this for you.first unclock your cpu.you can wind it back later.next take that motor that you had laying on the table in the video.leave it loose on the table like the video.
now go to ports and pins and set that motor as spindle.then go to motor tuning and set your spindle steps to make 1 revolution.now play with your speeds ,accell,and pulse width -
see if you can get it to run smooth and sweet .if you do get it smooth you will see what the true pulse width of your system is .
bill
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Hi, Monte
How many wires on your stepper motors, 4, 5, 6, or 8.
The sound your stepper is making sounds like one with one coil backwards
4 wire hook up without much problem 1 coil A, 1 coil B, Changing ether a or b wires around just change direction.
If it's 4 wire stepper disregard following.
5 wire steppers won't work bi-poler.
6 wire motors will work full coil ct not used or 1/2 coils only, ct and 1/2 half of coil for A, B, if you get one 1/2 coil wrong side of Center tap, It will sound funny.
8 wire motors, If you get a coil backwards, It will sound funny.
Mark the end of your stepper and Single step in one dir, See if it's back stepping on one of the step's.
Hope this Helps, Chip
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I think some of the suggestions on here are superb, that's why it is such a good forum.
I'm going to throw my hat in the ring.
The problem is the computer !! I don't know what you mean when you say the machine is over running etc etc.
Any chance of borrowing another computer, loading Mach3 and plugging in the LPT! socket !!. You might as well start eliminating something, because all you are doing at the moment is altering things and getting nowhere.
Change the computer. If the problem is still with us, at least then, we know where to look.
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I'm going with global warming. 8)
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try and borrow a scope or even get one cheap on eBay, you dont need anything special so should get it cheap enough.
Hood
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Hey all,
Thanks for the tips. Been tied up with other stuff (this is a hobby). I've since changed stepper drivers, now I'm not losing the steps. I think it was a resonance issue. But the motors still have a slight tick in them. The buzz they makes a slight repetitive pause on long straight runs, all three axes do it when they're all moving at the same time. Seems like there's something in the pulse stream from the computer to me.
I have a computer with an AMD cpu in it that I can try, but that's it for other computers except the one I have with 64 bit XP on it which doesn't load the Mach driver.
Monte
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Mine do the same thing on every axis. I just thought it was natural. If were talking about the same little "tick" it will speed up/slow down if you adjust the acceleration.
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Hi, Guy's
Both of you seem to have similar problem's hear, Lets review some.
Have you tried Sherline 1\2 pulss Mode, In Ports Pins first page. (Gives longer pulse's)
Have you tried Changing Dir/Step Low-Active State's, Should be all the same Ether "Check" or "X".
(If an Axis runs backwards use Homing/Limits "Reversed" for the axis)
Are your Steppers 6 or 8 Wire, You may have a Coil winding reversed, Will Cause a Tic Tic Tic sound.
Please Review, Chip
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Never really considered mine a problem. It doesn't affect anything, at least not that I'm aware of. No lost steps or anything of that nature. I will hafta take a sound recording.
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Hi all,
If you can hold the stepper....RICH
Thanks for all that Rich, it's not mechanical. It's from the PC. I had a Xylotex board, now have Gecko drivers and they both sound the same for the most part. Not losing steps like I was, but the weird interruption is still there, but I don't think I'm losing steps. Could Mach be sort of burping, but still know where it is?
Monte
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Hi - this is my first post on this forum. I have converted a SIEG X2 milling machine to CNC and I am using Mach 3 on a decent PC (3GHz 1G ram etc). I am having the same problem as Monte - you sit the motor on the desk and just run it and you can hear it jolting a bit with a fairly repeatable pattern. Seeing his video on YouTube makes me convinced its almost an identical problem to mine.
Luckily I am an electronic engineer so I have looked at the step signals on a scope. The steps were all over the place - i.e. the signals generated by Mach 3 were not evenly spaced but had a *huge* jitter - for example sometimes gaps of a few times the correct spacing, sometime very little time between. Clearly this problem is coming from the software side of things. My guess is some process on the computer taking a higher priority and screwing things up. Anyway I read the text file on the Mach 3 website saying things you can do to improve the performance and I ran the .bat file it mentioned (I think it changes the timing method or something), which improved things. Now, I get regular spacing, and I do get jitter, but it is regular - i.e. its either a certain amount too long or a certain amount too short. There is clearly still something interrupting the low level thread. I cannot figure out what it is, but my bets are on something like the wireless device on the computer (although I have tried disabling it).
Any suggestions would be much appreciated.
On a different issue - on my SIEG X2 there is a thrust bearing on at the opposite end of the x axis to the motor, which was the original bearing, and its not running smooth at all. Does anyone know where I can get a better bearing for this? The original is just a couple of cups and a ball race, not a sealed unit.
Cheers,
Reuben
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http://www.mcmaster.com
http://www.mscdirect.com
Everybody should have these 2 catalogs in there arsenal. If I were Judge Dredd, it would be the law.
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Regarding wireless devices may be causing "jitters." My shop computer is networked with my office computer via a wireless broadband router (linksys wireless -g) and I have a wireless mouse connected to the shop computer. Neither is causing any disruption or creating any "jitters." Previously, a standard 110 cord running in front of the mill was creating a signal that interfered with both the Taig's motors and the wireless mouse. The cord was coiled to reduce its length and the proximity of the coil to the motors and the mouse seemed to be the problem. Once the cord was relocated the problems disappeared and haven't returned.
Bob @BobsShop - not an electronic engineer and I cannot afford to stay in a Holiday Inn
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try and borrow a scope or even get one cheap on eBay, you dont need anything special so should get it cheap enough.
Hood
I wouldn't know what to get, or how to use it. I did buy a TPI Scope Plus 460 a couple years ago, haven't used it. Don't know how, not sure if it would even work for this sort of stuff. Can you give me an idea if it would work and how? 2 Channel, 20mhz.
Thanks,
Monte
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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:
(http://72.0.70.146/~anthony/misc/xylotex_step_timing.jpg)
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
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Have you set your computer to "standard PC", this reduced the ticking I had on my motors.
Jim.
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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
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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.
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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
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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
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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.
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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