Pm-940m-cnc (pre-assembled)

So you are running a larger buffer and that solved it. Good to know....

Mine was automagically set, probably the default. I'm using a computer running widows XP, btw , which may have less overhead / more efficient. And coupled with a possibly faster computer I can get away with the default settings.

Yeah, I tried it with the same buffer that you have and it still had the same problem. I wonder if this has more to do with the speed of my computer. The computer I have on the mill right now is pretty weak, even as far as XP machines go. I have another one that I can get setup to run XP, I'll probably start that process over the weekend, along with transferring all of the settings.

PZ
 
Jake,
I can't thank you enough for sharing how you relocated the electrical enclosure. I'm expecting my 940 cnc in about 4-5 weeks and will likely do the same as you.

Rod in San Francisco

No problem, let me know if you need any more detail and I'll try to help.

Jake
 
Yeah, I tried it with the same buffer that you have and it still had the same problem. I wonder if this has more to do with the speed of my computer. The computer I have on the mill right now is pretty weak, even as far as XP machines go. I have another one that I can get setup to run XP, I'll probably start that process over the weekend, along with transferring all of the settings.

PZ
EDIT : Retraction ! The hiccups were actually bad G-Code from FUSION 360 !

Well, I just experienced the same thing you had happen , "hiccups" while running G code. Adding to the buffer didn't get rid of it completely. It has only shown up during short segments with a lot of small lines of code with quick changes of direction. When it happens the spindle speed also increases and then backs down until the next "hiccup". Even if this is easily curable I'll be accelerating my move away from Mach 3+usb to LinuxCNC via ethernet or PCI interface.

Jake
 
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Now I have a new problem. If I set x0y0 at somewhere, then jog atleast an inch away from that in both x and y, then run a G0X0Y0... it never returns to quite the same spot. It's usually .05-.4" off on the DRO. This doesn't make any sense to me, even if it is missing steps the DRO should still go to zero correct?

Could you do a little test of the above Jake and let me know what yours does?

PZ
 
Now I have a new problem. If I set x0y0 at somewhere, then jog atleast an inch away from that in both x and y, then run a G0X0Y0... it never returns to quite the same spot. It's usually .05-.4" off on the DRO. This doesn't make any sense to me, even if it is missing steps the DRO should still go to zero correct?

Could you do a little test of the above Jake and let me know what yours does?

PZ

I tested mine 6 times exactly as you asked. When instructed via the G0x0y0 command Mach3's DRO returned back to 0.0000 most times and a few times the DRO would show .0001 of true "Zero". Yeah, I agree, since it is an open system, I would think Mach3 should "think" it moved back to exact ZERO every time.

Jake
 
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Thanks Jake!

Well, I'm uninstalling and reinstalling Mach 3 for round 3... I really am at a loss to what I am doing wrong here, unless running the demo version is my problem, though I have not ready anything that would suggest it would.

PZ
 
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I think that the .0001 may be mach trying to hit the best possible mark with what it has to work with.
Basically something like this....maybe?
1.8 degree steppers at half step is 400 steps per revolution. Coupled to a 5mm pitch ball screw which travels .19685" per revolution or .000492125 per half step. so if your asking it to make .001" it can never really move the .001" so it comes as close as it can????
 
Yeah, mine is possibly due to an acceptable "rounding" type error , but PhazerTwo's is far beyond a rounding error, right !!?
 
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I think that the .0001 may be mach trying to hit the best possible mark with what it has to work with.
Basically something like this....maybe?
1.8 degree steppers at half step is 400 steps per revolution. Coupled to a 5mm pitch ball screw which travels .19685" per revolution or .000492125 per half step. so if your asking it to make .001" it can never really move the .001" so it comes as close as it can????

Yes, this is correct. With 8000 Steps/in I should be able to get a resolution of 0.000125.

Yeah, mine is possibly due to an acceptable "rounding" type error , but PhazerTwo's is far beyond a rounding error, right ?

FAR beyond. When I am 0.050 off that is 400x the rounding error I should be getting... Not acceptable.

Last night I re-installed Mach 3 and started playing with the buffer time. If I set the buffer time high then my error goes up, and my "jumping" goes away. If I set the buffer low my error goes down but the "jumping" shows back up. Hopefully I can find an acceptable balance of no jumping and accurate enough. All and all, I am very unimpressed with the nMotion controller which is super unfortunate because it seems to be a capable unit short of its few issues.

PZ
 
Yes, this is correct. With 8000 Steps/in I should be able to get a resolution of 0.000125.



FAR beyond. When I am 0.050 off that is 400x the rounding error I should be getting... Not acceptable.

Last night I re-installed Mach 3 and started playing with the buffer time. If I set the buffer time high then my error goes up, and my "jumping" goes away. If I set the buffer low my error goes down but the "jumping" shows back up. Hopefully I can find an acceptable balance of no jumping and accurate enough. All and all, I am very unimpressed with the nMotion controller which is super unfortunate because it seems to be a capable unit short of its few issues.

PZ

And this is repeatable on all 3 axis??
 
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