RE: [CAD_CAM_EDM_DRO] Things to check? Crispy Fried Geckos? No motion...

Jim,

He has an open circuit. The +5V is from a power supply that is not
common to the laptop as he described it. The common pin (+5V in this
case) on the Gecko is only tied to the optos on the drive and not to
anything else. The step & direction pins on the Gecko are also only tied
to the optos.

So, we have the laptop parallel port pins connected to the Gecko step
and direction. We have an isolated power supply connected to the Gecko
+5V common. That is an open circuit as there is no connection between
the isolated supply and the laptop. Of course he may have a second
problem in that the laptop may not put out the full required voltage,
but the main problem now is the open circuit. If he was using the laptop
for the +5V you would be correct.

Tim
[Denver, CO]
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> -----Original Message-----
>
>
> Tim the current flows through the drive chip in the laptop
> through the led in the optoisolator to the 5v in the laptop.
> circuit complete. In other words it is an active low that is
> required in the Geckos. I think his problem is the drive
> capability of a laptop may not be enough to drive the
> optoisolators. I us a 74hct541 driver between the PC and the
> Geckos. Jim
>