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Author Topic: Breakout Boards  (Read 16334 times)

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Re: Breakout Boards
« Reply #10 on: November 17, 2007, 07:53:06 PM »
Valuable input...Thanks Greg.
The PCI has a DB25 connector..  correct ?
Do these wires then go directly to the step and dir terminals on the drivers ? No other board necessary. ?
Where can I get a diagram or schematic of a typical hook-up ?
This sounds to me like the way to go.

Thanks again
Re: Breakout Boards
« Reply #11 on: November 17, 2007, 07:56:33 PM »
hi, i am connected thru 2 pci parrallel port cards.one is being used for outputs to larken viper drives and manual pulse generator. . the other pci port is connected thru a sound logic breakout board which has safety charge pump and onboard relays . works for me.the onboard parallel port on the motherboard i have disabled.if your drive has isolation already, why  add another buffer between them?
Re: Breakout Boards
« Reply #12 on: November 17, 2007, 08:00:11 PM »
Sounds reasonable to me.

Any Idea where I can get a diagram or schematic ?

Thanks

Offline Greolt

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Re: Breakout Boards
« Reply #13 on: November 17, 2007, 08:09:41 PM »


........................The PCI has a DB25 connector..  correct ?

Do these wires then go directly to the step and dir terminals on the drivers ? No other board necessary. ?



Sorry you have misunderstood. I was downplaying the need for optoisolation.

I would still use the board we mentioned before from CNC4PC.

Makes hook up easy and buffers low logic voltage which is common on most computers (not just laptops)

Greg
Re: Breakout Boards
« Reply #14 on: November 17, 2007, 09:52:09 PM »
Greg,
I believe I've got it now....duh.
I think what threw me was.... (I'll try to do a quote)
 
 
hi,
 for my two-pence worth, I would not use a break out board,and that's nothing to do with cost cutting.
Tony
 
I guess what Tony meant was he would not use an OPTO ISOLATED  break out board, not no board at all. It's making better sense now.
Sorry to get you tied up in this DEBATE that you warned about earlier.
I'll let it go for now but forgive me if I bring it up later.
You've been a BIG help,
Thanks

Offline comet

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Re: Breakout Boards
« Reply #15 on: November 18, 2007, 05:25:11 AM »
Hi,
  yes I use passive breakout boards.
and good quality shielded data cable(twisted pairs)
be sure to only ground the cable at one end. Not sure why, but
its  apparantly good  practice?
    Tony
Re: Breakout Boards
« Reply #16 on: November 18, 2007, 09:31:22 AM »
Hey Tony,
  I should have realized what you meant initially. Chalk that one up to inexperience on my part.
Which end of the cable shield gets grounded ? Does it matter ?

Also, I searched around the net for PCI cards and am more confused than ever.
$100 to $1000 is all that I saw.
Can you or anyone else provide a link to what is commonly used for "our" applications ?
Thanks one more time.........

Offline comet

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Re: Breakout Boards
« Reply #17 on: November 18, 2007, 10:02:19 AM »
HI,
 if you look on Ebay you should be able to pick one up for about 10-15 £ 0r double that for dollars.
heres one:

http://cgi.ebay.co.uk/High-IEEE-1284-Parallel-Port-PCI-Printer-I-O-Card-UK_W0QQitemZ260183882206QQihZ016QQcategoryZ96880QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

If your not an ebay member join up,as most of us buy the bulk of our gear from there!! Also open yourself a paypal account.
its the best and safest way to transfer monies via the net.
    The shielding is usually grounded at the driver end,I ground every thing ie computer/machine/drivers and the ground is linked to 0volts andI use servo's so there's loads more wiring.
  hope that helps?
   Tony

vmax549

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Re: Breakout Boards
« Reply #18 on: November 18, 2007, 10:13:08 AM »
TONY, if you ground at both ends you have created a loop. The loop can then generate current(bad). If single ended all the stray stuff can do is bleed off to the single grnd point. That is why you also never want to daisy chain the grn. Single point  is the way to go.

Just a thought, (;-) TP

Offline Jeff_Birt

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Re: Breakout Boards
« Reply #19 on: November 18, 2007, 10:17:21 AM »
I guess I'll have to voice the lone pro 'opto-isolation' opinion here. Opto-isolation is useful for far more than protection from getting things hooked up wrong the first time. When properly designed it will electrically isolate the computer from the machine. The primary advantages of this isolation are noise reduction, electrical protection of the host computer and interfacing dissimilar voltages. In some cases this isolation is essential, and in some cases not.

I built an opto-isolated breakout board for a Dyna-2400/Mach III conversion I did. It used all the original drives on the machine. The opto-isolation insured that no noise from the steppers/drivers got fed back to the computer. When I was looking at commercially available boards I was surprised to see some that seemed to have a single onboard transformer to provide power to both sides of the opto-isolation circuitry. That kind of blows the whole point of opto-isolation.

I'm finishing up a Mach III conversion of a Bridgeport Discovery 308 VMC now. It uses a Galil motion control board and ICM-2900 'break out' moudule. The encoders, limits, homes and operator interface buttons are not opto-isolated. They are powered by the ICM-2900/Galil and in shileded cables. The 'extended I/O' which controls both 24VDC and 110VAC. This was done through 'Opto-22' racks, which hold individually opto-isolated SSR's. This completely iso-lates all the higher voltage and 'noisy' signals from the control.
Happy machining , Jeff Birt