[Mr.Chips]

OK I'm Ashamed.

I am one of those that started a machine and never finished it. I started it over three years ago, here’s the link to the build thread http://www.cnczone.com/forums/showthread.php?t=2695. I’m biting the bullet and finally getting back into it.

Forgot all I know about the electronics, which was my weak link to start with. And the reason I stopped. My CNC is mechanically complete, but I have been procrastinating because of my fear of the electrical system, and putting something in backwards and blowing the whole thig up.

Here is my electrical configuration: (Antiques now)
Controllers (3) XS-3525/8S-1 from Xylotex …………………………………………$120
Stepper Motors 116 oz/in from Xylotex ……………………………………………... $60

A friend of mine gave me a 25.6 VDC 8A power supply that should work with my system. The PS is made up of a transformer, 4 diodes 2 capacitors and 1 resistor, he says it is unregulated. It’s a heavyweight at 19.5 lbs.

My current problem is that I need a parallel interface, between the PC and stepper control boards. Is an optically isolated one the way to go or just a universal one? Could someone recommend some of each? Also could this interface be used with Servos?

Thanks :rainfro:
Hager

[Mr.Chips]

My current problem is that I need a parallel interface, between the PC and stepper control boards.
Is an optically isolated one the way to go or just a universal one?
Could someone recommend some of each?
Also could this interface be used with Servos?

Here is my electrical configuration: (Antiques now)
Controllers (3) XS-3525/8S-1 from Xylotex
Stepper Motors (3) 116 oz/in from Xylotex
25.6 VDC 8A power supply 19.5 lbs.

Thanks
Hager

[NC Cams]

There is a whole lot of techno-babble involving ground currents and the like but, in the fewest, simplest terms, you DEFINITELY want an isolated one, especially if you are "electronically challenged"..

I had some BTR interfaces that weren't isolated and they worked - until the fateful day when something in the wiring in the building went wrong and "ground" at the PC wasn't the same as "ground" at the CNC controller I was using.

Result: a current surge developed in the GROUND line between the devices. The $200 PC survived but the NC controllerS (yes multiple ones), got fried.

As they are legacy devices and made by Fanuc, it cost a small fortune of at least 10 times that of the PC to repair them. I"d have gladly toasted a 3-4 PC's but life isn't that easy at times.

Guys will write in with all sorts of qualifiers and this's and that's on how NOT to need an optoisolated interface but, from my experience, BUY AN INTERFACE THAT IS ISOLATED.

I wish mine had been!!!!

[Mr.Chips]

I agree NC. Penny wise and Pound foolish. And Murphy is out there, just waiting.

I'm not having any luck in searching for these, what is the exact terms I should be using?

[NC Cams]

Try "LPT break out board" perhaps then add "optoisolate"

[Al_The_Man]

Maybe something like this. http://www.campbelldesigns.com/breakout-board.php
I believe you are commited to steppers with the Xylotex board.
BTW what is the status of your Acroloop M/C?
If you were to use that system from the mill it would provide true servo closed loop.
Al.

[Mr.Chips]

Maybe something like this. http://www.campbelldesigns.com/breakout-board.php
I believe you are commited to steppers with the Xylotex board.
BTW what is the status of your Acroloop M/C?
If you were to use that system from the mill it would provide true servo closed loop.
Al.

Yep I know I will have to go to Gecko on Servos, that is the next machine. I was just thinking of reusing the isolation module on the second CNC which will be a Servo CNC for more accurate feedback and control.

"BTW what is the status of your Acroloop M/C?" HUH Lost in translation Al. Give me the long hand version, i've been out away from the CNC jargon for 3 years.

Thanks

[Al_The_Man]

"BTW what is the status of your Acroloop M/C?" HUH Lost in translation Al.
Thanks

Sorry, I got you mixed up with another member, he uses Mr also.
Al.

[Mr.Chips]

No problem Al, glad to see there are a lot of the experts still around.

[ger21]

Hagar, there are many breakout boards available. Here are the most common manufacturers.

www.cnc4pc.com
www.campbelldesigns.com
www.pmdx.com
www.candcnc.com

[Mr.Chips]

Thanks Gerry,

In the description of the optical isolation some manufactures just list a few connections while the one Campbell describes as:

"The break-out board provides total optical isolation of the parallel port from the power supply and the equipment being controlled."

Is it correct to assume that all output connections aren't necessary to isolate?
And the wording from Campbell is saying the same as the other manufactures and only isolating the necessary ones?

Thanks
Hager

[pminmo]

All outputs need to be isolated to prevent ground loop problems. It's the inputs that aren't technically necessay if you're just using switches. When usings swtiches for inputs you utilize the isolated 5V required by the optoisolators and it's return. I'm fairly sure there are some DB25 modules that would be ideal for your setup.