G540 debug problem

[gotfdirtball]

Let me start by saying I'm new to this stuff and just getting my first project together. It's an X - Y table with the following:

KL23H284-35-4B Motors
KL-350-48 48V/7.3A Power Supply
G540 Drive
Mach3 Software


I'm having trouble with getting my table to move correctly. The problem is sometimes the X & Y move and sometimes they don't. They never fail to jog or home correctly - only when I'm running a program. For example, if I try to cut a square, it may start out cutting in the X direction fine, then when it gets to the Y move, it sometimes moves, sometimes don't, and sometimes after it's supposed to be halfway through the cut it will start to move. Then the same behavior on the X. All the while, the digits on Mach's DRO are clicking off as if it should be moving. I've tried feed rates of 2 -6 inches per minute and this happens even if cutting air. I added 2 micro seconds to the step with no appreciable improvement. I don't think it's cable connections otherwise it wouldn't jog and home correctly as it does.

I'm not real tech savy so only thing I know to try is maybe a different parallel cable connecting the G540 to the computer. Any other suggestions GREATLY appreciated.

[gotfdirtball]

Oh two other things. I tried changing the X output pins and run it on the Z driver and got the same results. And I also noticed the G540 was warm. Am I doing something to over heat it?

[gotfdirtball]

Thought of something else. Computer:

Dell 2350 with 1.8 GHz Processor and 512 Ram. I installed a separate video card last weekend and turned off the onboard driver.

[LaserImage]

Are the steppers making any noises when they should be turning? If so, you may need to reduce the acceleration or speed in Mach. Unless you have a binding issue you should be able to get at least 100ipm out of those motors, if not more. I get over 120 out of mine and I am using a 24v psu.

What are the settings in motor tuning? Speed and acceleration.

Gary

[gotfdirtball]

No, I don't recall any noise when they should be moving.

Just went out and checked settings. Speed 75 in/min Acceleration 5 in/min. It seems to jog, home, and maybe even rapid fine. It's just flaky when I'm trying to run G code.

[gotfdirtball]

I may have made an important observation today when trying out a new cable. Whenever I ran a program at 6 ipm it seemed to run and repeat fine. When I slowed it down to 2 ipm, the problem came back. Does this sound more like a Mach problem or G540 problem?

[ger21]

Originally Posted by gotfdirtball Does this sound more like a Mach problem or G540 problem?

More like a PC problem. Is the port set to EPP in the bios? You have the pulse with set to 2 in the motor tuning? Try setting the pulse width to 30 or 40. It's worked for others who've had similar problems.

[gotfdirtball]

Thanks Ger21. That just may have fixed it!!!!!!! I also noticed I didn't have the problem until I actually turned the mill on. It must be some noise feeding back from the 220V motor on the bridgeport and the added step pulse width seems to have cured it. I actually worked up the courage to cut a part and it came out perfect!!!

I may also put a UPS on the computer and power supply to try to ward off noise.

Thanks again,

Jerry S.

[ger21]

The long step pulse is not a fix, it's a hack to work around an electrical issue. If it doesn't hinder you're speeds, then you probably don't need to worry about it.

Originally Posted by gotfdirtball Thanks Ger21. That just may have fixed it!!!!!!! I also noticed I didn't have the problem until I actually turned the mill on. It must be some noise feeding back from the 220V motor on the bridgeport and the added step pulse width seems to have cured it. I actually worked up the courage to cut a part and it came out perfect!!! I may also put a UPS on the computer and power supply to try to ward off noise. Thanks again, Jerry S.

[jsheerin]

I have this exact same problem, but with my Z axis. See my post in the mach3 forum for more details:
http://www.cnczone.com/forums/showthread.php?t=76084

Gerry, I have not gotten to try your suggestion yet but I will once I get my Y axis thrust bearing working again, hopefully tonight. I was just surfing around for a few minutes looking for other things to try when I get the time and found this.

Similarly, in the move I noticed the Z axis not moving, the Z was supposed to be moving very slowly. However, the X and A (slaved) were also moving very slowly and seemed to be doing fine. The Y was moving quickly - traversing 4 feet at ~ 150ipm. Also, the Z would randomly miss steps - it was not a consistent amount of motion that would be lost.

One piece of information I can add is that my machine has this problem even when my router (spindle) is not running. Does anyone have an idea as to what could be causing noise problems or where to look? Would this be noise on the power input to the computer that makes it to the parallel port outputs or something like that? Could noise be making it in to the system from something connected to the G540? I'd rather understand it and fix the source.

[jsheerin]

I tried this (25us step pulse) this weekend and it seemed to fix the problem. It's hard to say for sure since it was intermittent, but I haven't had problems with the things I've been cutting.

[jsheerin]

So my Z-axis problem has reared it's head again after about 6 months of no problems. It failed to move up after a cut and destroyed all the parts I'd just been cutting for 2 hours by slicing through them at full depth. Then it plunged the bit through my spoil board into an aluminum rail on my machine because it thought it was above the material. That's when the router tripped the fuse in my power strip and everything shut down. Of course that part's my fault for not have a limit switch at the bottom of my z travel. I checked my code and it was fine.

So the longer step pulse was not a permanent fix. Does anyone know what the root problem is here? Is it the the parallel port not putting out good pulses? I have a scope and can look at this stuff. I just don't really know what to look at or for. It seems odd to me that it would be the computer - I would think I would have been having random errors on all my axes before. The Z axis cable is the longest, so I would think it might be noise pick up (although the cable is shielded) or something in the G540 since it's only on the one axis. So I will try shortening my step pulse again tonight, try to duplicate the error, then try swapping to a different driver in the G540 for the Z axis to see if I still only have z axis errors. That should at least eliminate the cabling to the motor.

Any thoughts appreciated. This is shutting down my production (even though it's just a part time thing), so I'm really anxious to figure this out.