Re: USB ports ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux <lux@d...> wrote:

>
> The original poster stated he was using TCNC, which only does step

and

> direction signaling, as far as I know. (I've got 3 machines running

with

> it.)

Turbo-CNC does not currently support the USB and from a recent
question to the developers, they have not invested much effort into
it. That is understandable as they just released the long awaited
V4 and I assume are in clean-up mode.

>
> I agree that USB would probably work with smart controllers that

aren't

> sensitive to data timing. There is disagreement about using USB
> converters to generate step and direction pulses.
>
> Kim

If you narrow the criteria you can make anything impossible.

He asked two questions.

#1 "Can I run motion control cards from usb ports, "


#2 " and will turbocnc be able to use it?????? "

So, the answer to #1 is deffinatly YES. As Fred posted, been there..
doing it now.


The answer to #2 is not at this time and not in the foreseeable
future.


Limiting the USB connection to step and direction is like requiring a
cable modems to run analog over the wire and a modulator/demodulator
on each end.

As was posted on this list a year ago, stepper motors running at
200,000 hz run smoooooth as silk when you eleminate the horrible
timing signals the PC generates.

It seems the PC timing is so bad that many of the problems we
associate with drivers and friction and power curves may, in part, be
problems with a really poor signal.

Using a smart controller that gets its information from the PC makes
many of those problems go away.

As many of use are painfully aware, the parallel port is marked for
extinction like the 5-1/4 floppy. New machines do not allways have
them and add-on cards are starting to be scarce.

Dave