Re: A Question to MARISS

Raul,

For best noise immunity, do NOT use an external 5VDC supply. You
should use the PC +5VDC supply. Here's why:

A plasma torch is perhaps the world's most potent RFI (radio
frequency interference) noise source. You are driving the G201s from
your PC. The plasma torch sets up electrical interference (EMF feild)
on its ground line. The PC's +5VDC line will exactly follow every zig
and zag with a +5VDC difference. That is called common-mode noise. If
you use an external +5VDC supply, it will probably zig when the PC
ground zags. That will be a false step pulse to the drive. The PC
won't care because its +5VDC is bypassed internally by a jillion
capacitors; it will never "see" the noise.

Simply sheild the STEP, DIRECTION and +5VDC signals from your PC with
the sheild ground going to your PC ground; do nothing at the drive
end. Everything will be OK then.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Raul Lara <ralaco@y...> wrote:
> Dear Mariss:
>
> I'm in the last steps to run 2 plasma cutters.
> 1.- One with a Gecko drives G 201 / Indexer LPT from
> Ability Systems Combo.
> 2.- The other with Gecko drives G 201A / Indexer
> LPT from Ability Systems Combo.
>
> I'm getting noise in the PC when the plasma is on,
> through step and direction lines.
>
> The PC signal is 4.82 volts, the external power supply
> is 5.03 volts (this is the one it's powering the
> Geckos).
> All the cables are shielded and grounded.
>
> What would your advise be, in order to fix this noise
> problem?
>
> Best regard
> Raul Lara
>
>
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