Mach3 strange behavior

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GEdward
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Mach3 strange behavior

Post by GEdward »

I'm hoping someone here has heard of this or knows who to ask. I built a new control system for my machine using a UCCNC C94 motion controller. Got it all put together and it plays nice with Mach3 until I load G code. Up until the point that I load a program into Mach movements are as expected with both the wireless pendant and the GUI pendant. That is to say, if I ask for 0.001, I get 0.001. Then after I load a program, the movements become approximately 100 to 1. As you can imagine, that does not work out very well :shock: Even when I close the program the behavior continues until I close Mach and reboot it. I reset Mach3 to an earlier time when all was well but the problem persists. I have been around CNC machines since the late 80's and have seen some strange things but this kind of takes the cake. Anyone?
Ed

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martin54
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Re: Mach3 strange behavior

Post by martin54 »

What units have you got mach3 set up in & which post processor are you using?
I don't think the C94 is a UCCNC board but that doesn't make any difference :lol: :lol:

GEdward
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Re: Mach3 strange behavior

Post by GEdward »

My apologies. I am using a UC300ETH mounted on a C94 board from CNC4PC. I am using the Mach 3/4 Arcs (inch) post which is what I have been using for about 9 years now. I have made no changes to Mach and the motor tuning units seem to be close enough, ask for 0.100 and a dial indicator shows 0.100, to run a couple of simple programs to verify accuracy and do a final tune, pulses per unit tweak if necessary.

Ed

GEdward
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Re: Mach3 strange behavior

Post by GEdward »

I did a little experimenting in MDI and the problem is apparent in MDI as well. After I confirmed that the movements in MDI were about 100 times the requested amount, I brought up the GUI pendant and the movements were correct; ask for 0.001 and get 0.001 inches. Tomorrow I will mount a dial indicator on the spindle and perform the same experiment in MDI to verify the exact amount of movement when commanding a 0.001 inch move. Maybe there will be a clue as to whats going on when I have an accurate measurement. Not expecting any revelation though.

Ed

ger21
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Re: Mach3 strange behavior

Post by ger21 »

Your native units in Mach3 are different from your g-code units.
In Mach3, set your native units to inches. Then do your motor tuning.
Then, make sure your g-code has a G20 in it, and not a G21.

(I'd also recommend switching to UCCNC) :D
Gerry - http://www.thecncwoodworker.com

GEdward
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Re: Mach3 strange behavior

Post by GEdward »

Thanks ger21. I figured it out just before I logged in to make this post. You were spot on. I have created two other profiles with this copy of Mach and did not run into this issue. My next move was going to be to switch to UCCNC so again, spot on. At least I bought some time before making the switch so there will be no downtime in between.

Ed

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martin54
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Re: Mach3 strange behavior

Post by martin54 »

GEdward wrote:
Mon Mar 06, 2023 1:18 am
Thanks ger21. I figured it out just before I logged in to make this post. You were spot on. I have created two other profiles with this copy of Mach and did not run into this issue. My next move was going to be to switch to UCCNC so again, spot on. At least I bought some time before making the switch so there will be no downtime in between.

Ed
Good to hear you are sorted & back up & running ok :lol: :lol:

That's why I asked what units mach3 was running :lol: :lol:
Been a while since I used mach3 but I think the default units are mm so when you created a new profile for mach3 you probably forgot to change the native units this time :lol: :lol:

If you are going to make the change from mach3 to UCCNC then you might also want to check out ger21's 2022 screenset for it. it has a nice layout (well I like it) & some extra features that aren't (or weren't) in the standard screenset that comes with UCCNC :lol: :lol:

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