Re: Gecko 5V supply

Hi,

Top 7 reasons why it's best to use the PC power supply:

1) It's free and it's there.
2) It's voltage tracks the outputs.
3) There's no potential noise problems as with an external supply.
4) Introduced noise isn't a problem; there are a million capacitors
across the PC +5VDC inside to bypass any noise.
5) Fuse the output if you're concerned about shorting it.
6) Your mouse, keyboard and USB cables carry +5VDC as well without
worries about noise or shorts.
7) Virtually no load. Only 32 mA required per drive.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Doug Fortune <pentam@h...> wrote:
> Terry Toddy <tltoddy@c...> wrote:
>
> > I appreciate your assurance that the pc power supply will work
just
> > fine, but I have a switching power supply with +5 right in the
control
> > panel with my Gecko G201s. It would be easier to connect them to
the
> > +5v from the switcher than to bring +5 out from the pc.
>
> Easier yes, but if you connect the ground you've defeated the
isolation.
>
> > Can this be done
> > by simply connecting the Gecko +5 to the +5 on the swithcher and
connect
> > the parallel port ground to the common on the switcher?
>
> This is the tricky part (that complicates things):
>
> - The POWER ground and the LOGIC ground are completely separate
> inside the Gecko. This is good (LOGIC & POWER are isolated).
>
> - Keep in mind the LOGIC ground has to go back to the computer
>
> - But if you connect +5 and GND from the switcher (ie POWER)
> to the logic, the Gecko 201's are no longer isolated from the
PC
> (because the GNDs are now connected).
>
> Maybe thats ok, better ask Mariss. But I prefer to avoid the
complication
> by just taking the LOGIC +5V from the PC, because the 201 was
designed
> that way (ie isolated LOGIC & POWER). And its not too much of a
> coincidence I designed my breakout board to supply the +5V from the
> PC (conveniently down the parallel cable) to handle this exact
situation!
>
> Doug Fortune
> http://www.cncKITS.com