Hello Guest it is April 18, 2019, 11:12:11 AM

Author Topic: best supported controller?  (Read 14082 times)

0 Members and 1 Guest are viewing this topic.

Offline Hood

*
  •  25,779 25,779
  • Carnoustie, Scotland
    • View Profile
Re: best supported controller?
« Reply #30 on: December 30, 2010, 05:38:29 PM »
Thats just a straight connector, no buffering, no isolation but it would make it easier than connecting by soldering.
Hood
Re: best supported controller?
« Reply #31 on: December 30, 2010, 06:35:16 PM »
Hmm... that's an expensive way to avoid soldering, then. Is there a good enough cheap BOB available from UK? I'm guessing cheap and buffered are mutually exclusive... how important is this in comparison to isolation? or do Bob's generally have both, rather than just one of these features?

RB

Offline Hood

*
  •  25,779 25,779
  • Carnoustie, Scotland
    • View Profile
Re: best supported controller?
« Reply #32 on: December 30, 2010, 06:43:56 PM »
Afraid I have no idea what boards are available from the UK :(

Hood

Offline Hood

*
  •  25,779 25,779
  • Carnoustie, Scotland
    • View Profile
Re: best supported controller?
« Reply #33 on: December 30, 2010, 06:47:15 PM »
Quick google brought up this, how good or bad it is I have no idea. http://www.slidesandballscrews.com/uniport-breakout-board-p-179.html?cPath=54
Hood
Re: best supported controller?
« Reply #34 on: December 30, 2010, 07:37:19 PM »
Looks quite interesting, good documentation, too. Still not as cheap as chips, though.

Saw this on Ebay, CNC DB25 Breakout Board Adapter Stepper Motor Driver.

http://cgi.ebay.co.uk/CNC-DB25-Breakout-Board-Adapter-Stepper-Motor-Driver-/150540689910?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item230ceca1f6#ht_4039wt_912

About half the price... maybe worth a try; what could go wrong?!

Anyone recognise this product?

Offline Hood

*
  •  25,779 25,779
  • Carnoustie, Scotland
    • View Profile
Re: best supported controller?
« Reply #35 on: December 30, 2010, 07:49:29 PM »
Its from Hong Kong but otherwise looks ok.
 I made the mistake of buying cheap with my drives and BOB when I first started out and it ended up meaning I had to go buy stuff that worked properly, so I wont do that again. At £25 suppose you dont have much to lose.
Only other thing is it says its opto isolated but doesnt give specs and doesnt say whether step/dir outputs are,  sometimes having double isolated step/dir can cause issues and I think you said your drives did have isolation.

Hood
Re: best supported controller?
« Reply #36 on: December 30, 2010, 07:56:37 PM »
I could short across the step dir optos? Obviously whatrever wraranrt ther was goes out the window.

I like how you said "Its from Hong Kong but otherwise looks ok." Damning with faint praise?!

What can go wrong with cheap Bob's, and what went wrong with yours?

Offline Hood

*
  •  25,779 25,779
  • Carnoustie, Scotland
    • View Profile
Re: best supported controller?
« Reply #37 on: December 30, 2010, 08:12:40 PM »
Quote
and no VAT or duty or long wait, etc.
Was why I mentioned Hong Kong, not anything to do with its origin in respect of quality or anything else.

What went wrong with mine was they were crap, the BOB sucked up noise from anywhere and everywhere, even soldering caps all over it failed to cure it. The drives had lovely alu heatsinks on them but if I touched them to anything metalic the steppers would start rotating all on their own. I isolated the drives from the cabinet and got things going eventually but if it hadnt been for the great advice and help I recieved from John Prentice I would have thrown in the towel.
 John sent me up a Gecko to try and from a max of 400mm/min withthe drives I had it instantly allowed me to get 4000mm/min and that was without anything else being changed, so as soon as I could afford it I bought some Geckos, I had already swapped out the crap BOB for the first PMDX122 that I have had.

Hood
Re: best supported controller?
« Reply #38 on: December 30, 2010, 08:19:58 PM »
See what you mean; I noticed the delivery time for these is about a month... not so great.

Maybe I could make my own? is it doable with veroboard, and a gang of opamps with a gain of, say 1.5 to act as buffers? Opto couplers on all lines except step/ dir... I can solder okay, what spec amps and optocouplers might be okay? Or am I heading towards noise problems, too? Could noise be negated by mounting the Bob(s) as separate boards, each very close to my drivers? Loath to spent more on electronicky stuff than I have to. Maybe shooting myself in the foot, of course.

Offline Hood

*
  •  25,779 25,779
  • Carnoustie, Scotland
    • View Profile
Re: best supported controller?
« Reply #39 on: December 30, 2010, 08:24:58 PM »
I dont know enough about electronics to be anything other than dangerous ;)

Hood