Re: [CAD_CAM_EDM_DRO] Re: not working!

JanRwl@... wrote:

> In a message dated 8/3/00 10:02:26 PM Central Daylight Time,
> mr.c@... writes:
>
> << You need a ground
> connection to the parallel port. To the metal part of the plug should
> work. >>
>
> Not always! Often, that "metal shield" is not even connected to the
> braid,
> if any, and often, only ONE of the 8 "ground pins" actually
> connects! Use a
> LOUD continuity-checker (or a DVM, etc., in bright light!) to check,
> FIRST!
> Better: Make your OWN LPT-1 cable!!

All PCs I've ever worked on have a solid ground in the power supply,
and often a mounting hole connected to the motherboard's ground plane,
as well. So, any connection to the PC's case, metal-shell connectors
on plug-in cards, etc., will have a fairly decent ground to the logical
ground voltage. For stepper driving purposes, this should work
fine. The grounding and shielding of the cable is totally up in the
air. High quailty, US made cables generally have a good shield braid
connected to the cable shells at both ends. No-name Taiwan
cables could have anything.

Jon