Homebrew PCBs

Thanks for the input, Harvey. This little vinyl cutter uses very 
small steppers (1.7" dia x .6" thick) that draw about 500ma at 24 
volts. The original  board uses BD6395 driver ICs which are rated to 
1.2 A at 28 volts; The board I bought will do at least 2.5 amps, so 
it shouldn't be a problem.

Mark

At 06:46 PM 3/3/2013, you wrote:
>On Sun, 03 Mar 2013 16:35:04 -0500, you wrote:
>
> >No, but it isn't that expensive, either. Another (free) alternative,
> >as has been mentioned before is Linux and linuxcnc. You would have to
> >become familiar with Linux if you haven't used it (I haven't), but it
> >should be pretty easy if you are only using it for one program.
> >
> >I just ordered a 3 axis controller on ebay ($42 USD including
> >shipping), though I think I could use the parts from the on-board
> >controller to make my own controller, especially if I use the parallel port.
>
>As a note culled from the CAD/CAM group.  Please be aware that the
>chip/chipset used in the boards can be a limiting factor.  Some chips
>cannot be pushed all that close to their limits.  Almost all (if not
>every one) of the chips/chipsets do NOT tolerate removing the load
>(stepper) from the chip with power on.  It generally blows the output
>in the chip (requiring either replacement of the entire chip or the
>driver for that channel, if separate).
>
>You need to be aware that connectors used to run the board to the
>stepper need to be as robust (read: lock in place) as possible, and
>the wires need to be reasonably flexible (wiring from the connection
>to the stepper will flex, so you don't want that to break).
>
>That said, I think, (without any kind of data to the contrary), that
>these boards will work well within their limits (NO overvoltage, NO
>overcurrent, NO disconnects).  The only boards/drivers that I know
>about that are as rugged as possible are made by gecko, and are the V
>series (vampire.... Mariss has a sense of humor).  Even then, the
>warranty is outstanding.
>
>What I use (because I'm thoroughly cheap and had the chips) is an
>L297/L298 chipset with jumper settings for parameters and optical
>isolators for step and direction.  I haven't blown any of them, *but*
>I have been very careful with what I've been doing.  Roughly 35 volts
>and about 2.5 amps maximum, no behavior compensation, so not the best
>in the design.
>
>I'm doing a parallel port if I mess with a controlling PC, a custom
>program (to be written) using an XMEGA otherwise, and for a full blown
>solution, an FPGA hardware pulse generator (it works, but I need to
>see how good it is, implemented in the simulator).
>
>
>Harvey
>
>
> >
> >Mark
> >
>
>
>
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>
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