RE: Interface for CNCPro, etc.

> -----Original Message-----
> From: Bertho Boman [SMTP:boman@...]
> Sent: Monday, February 21, 2000 8:51 PM
> To: CAD_CAM_EDM_DRO@onelist.com
> Subject: Re: [CAD_CAM_EDM_DRO] Interface for CNCPro, etc.
>
> From: Bertho Boman <boman@...>
>
> A couple of quick comments:
>
> 1. Please use a terminal strip connector (screw terminal block) that will
> plug into a mating terminal strip on the board so that
> you do not have to disconnect individual wires if you need to remove the
> board or computer.
>

Good Idea!

> 2. If you are going to have meaning full opto-isolation, you need two
> independent supplies for the opto board, one using the
> computer power side, one using the load power side. I have seen several
> examples were the load side was powered from the
> PC.... I assume that you already know that.
>

I have a source for 5V DC-DC isolators for the load side. The PC 5V
feeds this as well as the computer side.

> 3. I usually connect direct and make sure the computer and the load is
> powered from one common point and are well grounded
> together.
>

The optoisolation is for those of us that tend to make sparks. Also
for industrial applications where we don't always have control of what goes
on the other end.

> Further, I try to keep wires reasonably short and I do not roll up excess
> wires into a coil. I fold it together and
> tape it to avoid the pickup coil effect.
>

Good point. Coil about five wraps of the line running to a NEMA 42
step motor and see how warm it gets.

> Bertho Boman
>

Doug Harrison