Re: [CAD_CAM_EDM_DRO] USB DRO

I would be very wary of USB. I have USB ports on two of my PC's. One is a Toshiba Infinia
which runs W95. The USB port is used only for a Toshiba proprietary device which is interesting,
it provides a volume knob and some push buttons and a message display. Nothing else will work on
the USB ports. Windows 98 might change that.

My other USB machine runs W98 and has nothing on the USB ports. I had a scanner on it, but
returned it. It would stop periodically during the scan for 10 - 15 seconds. I think it may have
been Windows doing this. I purchased the same scanner in the parallel port model, and had no problems.
I don't have anything on the USB ports of this machine at present. The motherboard is less than a year old.
I've also tried my Microsoft Natural keyboard on it...didn't work. A USB mouse.. worked, but I didn't like
it and went to a PS2 trackball.

The neighbors kid has a USB joystick. He whines because it tends to lose all functionality
in the middle of his games.

EDN had a design article on USB a year or two back where they actually designed and built
a board, but I didn't save it.

My suspicions are that the problems I've seen with USB are all due to Windows software.

I think that for CNC to really work with USB, you would need an intelligent controller
that could accept not just velocity and direction commands but distance, etc. In effect,
you would have to reproduce the PC at the remote end, in which case you might as well
se a PC and an ethernet link.

Marshall

----- Original Message -----
From: Eric Keller <eek105@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Wednesday, April 05, 2000 4:28 PM
Subject: Re: [CAD_CAM_EDM_DRO] USB DRO


>
> Jon Elson wrote:
> . I think 8 axes plus digital control is
> reasonable with respect
> to bandwidth of the USB, but I have no idea about latency.
>
> Jon
> I think that the whole idea of USB is dependent on distributed intelligent
> devices really, which is the way of the future for most things.
> However, if like most of us you want to use the pc as the _device_,
> usb is not the way to go.
> eric
>
>
>
>