Re: missed keystrokes problem, back with a vengeance.
On Monday 30 January 2017 09:48:10 Lennart Sorensen wrote:
> On Sun, Jan 29, 2017 at 01:48:50PM -0500, Gene Heskett wrote:
> > Alan, ALL of the motor drivers are switchmode, with the current
> > regulation running at or above 20 KHz. And these noise spikes are
> > ringing at nominally 100 MHz. I have managed to get the xy motor
> > noise under control by takeing out the switchmode psu's, and putting
> > in tordoid transformers, bridge rectifiers, and the biggest
> > electrolytic I had in the drawers that had sufficient withstand
> > voltage. Its a star ground system, and the output cables to the
> > motors are shielded, and the shield grounded as it goes by this
> > single bolt ground on its way out of the box. The shielding extends
> > both ways from that point but is not connected either at the motor,
> > or at the driver, just at the bolt. This is std in such noisy
> > machinery.
>
> Well the USB would probably be at either 12MHz (USB 1.x) or 480MHz
> (for USB 2), but most likely USB1 for your keyboard. That certainly
> is a potential place to hit with noise if you are getting spikes into
> the 100MHz range. And USB cables don't appear to be that well
> shielded in general (they seem to aim for cheap).
Another understatement. You folks are getting good at that. :)
Cheers, Gene Heskett
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Genes Web page <http://geneslinuxbox.net:6309/gene>
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