Official Luthiers Forum!

I wasn't ignoring CyborgCNC's warnings, in fact I thought it might be important enough for a new thread.

Ok, I hear the word "breakout" and I think of a breakout box. I made a simple one to debug RS-232 issues in the old days. I was ignoring those in my research because I thought it was something else. A little surfing has proved it's an entirely different thing.

The opto-isolation sounds like a good idea. I'd like to be more than optically isolated from this sucker. If *I* was building a controller from scratch, of course I'd get one of these. But somehow DeepGroove or whomever built this controller didn't feel the same way at the time.

So, just how bad is it to not have a breakout board???

It's not my mill or controller. I don't know whether the actual owner wants to put any money into improving it yet. He got it for free to begin with. I suspect he'll want to see if it can do anything useful for him first. Thankfully I got the laptop for free too from my brother last year. It won't run on the battery for any length of time so I always use it on A/C and I think the bottom of the case is cracked. I don't like to wantonly destroy any computer hardware, but in the grand scheme of things I'd rather gamble with that than say something bad happening to the mill, motors, etc.

Thanks,
...Ath

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-Nothing bad can happen to the mill or motors from the lack of a breakout board, but I wish I could say the same for the computer!

-Let's look at a motor: It is a great device! if you apply some voltage to it, an electromagnetic field in its coils, will make it spin. Great invention! Now, apply the same filed at specific locations, and you can make it move a predefined number of steps! WOW! A stepper is born. Again, a good thing....

-Now for the other side: it can also be a generator! Move the motor by hand, and since internal magnets move, the induce a current around the motor windings...ie, and AC current/voltage differential.

See where I am going with this??

There can be an induced EMF voltage/field (back EMF) that the motors produce, that if you are connecting them directly to a computer, with no isolation, BOOM! it can fry your mother board.

Another reason to use a break out board: After you get this thing going, you will want to have things like limit switches, height control etc....having a breakout board, makes these connections easier...

So is it bad?

I would not run a CNC machine with out one!

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-CyborgCNC
http://www.cncguitar.com
https://www.facebook.com/CncGuitar

Ok, I get it. I took AC circuit analysis about 26 years ago. Never did take DC. But I do vaguely remember a discussion of back EMF.

Now this sounds like more what I expected from the name. Which is why I didn't look into them at first, not wanting to break anything out yet. I'm more at the trying not to break things stage. ;->

I would certainly not build another controller box without one. But I'm still trying to figure out if this is bad as in "Turn the box off and do not turn it on again until you have purchase and installed one"???

This thing doesn't belong to me. I'd get one for my machine. But then I'd wait until I could afford Geckodrives, something with a wider X axis, etc. I'm in low fundage situation right now unfortunately. CNC as always been a lovely dream for the future for me.

I have to tell the owner what's up and see what he says. I don't know if he wants to put any money in it or not. At least not until I prove it can actually do a decent job of say cutting his logo in shell and routing a pocket in rosewood.

Thanks,
...Ath

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First off, I agree with cyborg. But, I'm running a stock Hobby CNC controller package which does not have an opto isolation board. I know of one guy who fried his mother board when he improperly hooked up a test probe circuit. There are at least 10+ other guys I know who have not had any problems with the same set up. That said, at some point I will rebuild my controller and add an isolation breakout board. My advice would be to get a garage sale clunker computer, then upgrade when you know what you need/want. There are plenty of guys using vintage pentium pc's to run mach.

So, get up and running asap, learn on cheap equipment, make some $ and upgrade... I oughta write a how-to book.

Bob

So Athena,
just in case you missed my post in the other thread.



May I suggest that you get these 2 PDF files on Mach3. I think they may help point you in the right direction.
MK

http://www.machsupport.com/docs/Mach3Mi ... Config.pdf


http://www.machsupport.com/docs/Mach3Mill_1.84.pdf

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I'm outside looking in, just farther from the window than most.

Thanks Mike, I've got them.

The plan right now is to continue basic testing as is. On one hand, I'd like the machine to pay for it's upgrades... but I'm looking into selling a couple things so I can fund a new controller with a G540, real power supply, breakout board, nice enclosure, etc sooner than later.

Thanks for all the help guys,
...Ath

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It's not a big mill so if you are looking for a deal on a 3 axis set of steppers, drivers, Breakout and power supply. Probotix.com has a lowerend set for 199.00

Just an FYI.

mk

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I'm outside looking in, just farther from the window than most.

Thanks Mike. I'm going to play with this as it is for now. I'm lighting a big CNC fire under my guitar builder friend. Visions of a nice K2 are dancing in my head.

...Athena

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