Re: cable from PC to stepper drivers?????

Hi Kayla,

I'll reiterate what Tim has said. You WANT your machine as close as
possible to the mill! I put my Sherline mill in a big Plexiglas box.
OR, you could put your PC display and keyboard in a box. Best would be
to have the monitor ABOVE the mill, or off to one side on a mount. You
want to be able to watch both, NOT run back and forth between mill and
monitor! Think about jogging from the keyboard. How 'ya gonna reach
the keyboard and "feel" the tool touch the part?

I'd also recommend using a DB25 male connector on your "driver/PS box",
and a STANDARD cable ("1284", i.e., best printer cable you can buy).
You should be able to get 50' with one. Normally, 6-10' is recommended
as the max length for a parallel printer cable (and switch boxes can
also make matters worse).

Although not really necessary (Gecko's have optical isolators), I use a
"cable extender" with my driver/PS (I have a few, about $45). They are
good INSURANCE when one is *TESTING* hardware! Lengthening the stepper
pulses might help on a long cable. The problem with a long cable is
that the pulses can "slew" in time relation to each other. This may or
may not be a problem for a particular CNC implementation. The signal
voltage swings can also drop. This IS a problem, as we loose noise
immunity.

HTH

Alan KM6VV


Kayla Sanders wrote:

>
> well would it be possible then to make my own cables and hook them
> up to a parellel port connector ,and then run them to the drivers as
> long as each wire was insulated well against any external
> interference?
> I ask this, because i am going to have to cut one end of the printer
> cable off anyway, in order to connect it to the 3 geckos. i was
> thinking why not make my own cable that is longer and more insulated
> to begin with. id like to be able to run about 18-20 feet from the
> drivers in order to accomadate the healthy and long lifespan of my
> spare computer.
> also, is it going to hurt the geckos if i use a 24Vdc/12A power
> supply? am igoing to have to use a current limiting resister from
> power to the drivers or does the gecko do this for me??
> thanks
>
> - In CAD_CAM_EDM_DRO@y..., "Tim Goldstein" <timg@k...> wrote:
> > I can understand wanting to protect your computer, but you need to
> have the
> > monitor, keyboard, and mouse located right at the machine so you
> can operate
> > it. If you put extender cables on these you can start getting
> interference
> > that causes problems. I had my keyboard cable running over the
> power line
> > from a VFT to my spindle and it made entering anything difficult
> when the
> > spindle was running. Rather than trying to locate the computer far
> away you
> > would be better off putting it into a cabinet to protect it.
> >
> > Tim
> > [Denver, CO]
> >
> > ----- Original Message -----
> >
> > > --- In CAD_CAM_EDM_DRO@y..., "Kayla Sanders" <tattoos4unme@y...>
> > > wrote:
> > > > what is the maximum length i can go from the PC printer port
> to the
> > > > driver? as i want to keep my other PC as far away from flying
> chips
> > > > as possible and its not exactly a cheapo pentium 166.
> > > > thanks
> > >
> > > If you use one of the buffer cards from Bob Campbell
> > > (www.campbelldesigns.com) then you can run probably 20 or 30
> feet. I
> > > don't think I would try that with a conventional straight
> parallel
> > > port. There are also printer port "booster" circuits for running
> > > parallel printers up to 50 feet away that could be used if you
> have
> > > some way to break it out at the drive end.