Re: [CAD_CAM_EDM_DRO] DeskNC Windows version

Hi Larry, Art,

Thanks for the reply! Trying to run one of the current DOS programs in
a DOS window certainly chops up the pulses to the steppers! So does
windoz hate the parallel port, or would it treat any three ports that
way (it's the time slices that kill us, isn't it)? Or is it that windoz
"traps" the port writes, and makes them virtual? Seems the old Chips &
Technologies F8680 did that! But we could turn IT off! Not so in
windoz! ;>(

Well, I did a few OS/2 DLL's about 8 years ago, are VXD's or WDM's or
whatever they're called similar? What do you call yours Art? I think
you said that the module might be "released" (as a standard?), then
several different programs could use it (OK, sell it!).

A thread of several months ago suggested USB, which might also be an
idea.

Hardware wise, I like what I've seen of FlashCut (except the price). And
8051's, or PIC's! If DeskWinNC's "black box" ketches on, we could have
a STANDARD all could use! I'd like to see TWO standards, a VXD
(software) and a "black box".

Alan KM6VV

Larry Edington wrote:

>
> High speed I/O on the parallel port under Windows is not impossible. But it
> is difficult to do a lot of calculations, timing and pump the data out under
> Windows. The parallel port is just 3, 8 bit ports. You have hundreds of
> other 8 bit ports in your PC screaming along at very high speeds under
> Windows software control all the time.
>
> The best way I know of to do this in Windows is by using a .vxd ( or wdm or
> whatever it'll be called in the next versions of Windows ). The application
> program reads the G codes and calculates the step commands. These commands
> are handed off to the .vxd which runs at Ring 0 and has access to all ports
> of the system without the usual restrictions of Windows. The .vxd handles
> the timing and step / dir outputs.
>
> Still, you are using the same processor to handle the .vxd as the control
> program. A better approach is of course a dual processor system. One
> processor handles the I/O .vxd and the other the control program.
>
> Where the external box really shines, is the timing can be done on a
> seperate microcontroller. This takes a big load off your control program.
> This is the same reason the Ahha Artisian board has the timing circuits on
> it's I/O board. It's like using the dual processor machine but the second
> processor is out there at the end of your serial port.
>
> The biggest limitation of this approach is the amount of data you can pump
> out to the microcontroller due to the typical memory limitations of the
> device.
>
> While I've not built any CNC controllers from scratch in the last 8 years,
> I've used this same approach to a lot of industrial control problems.
>
> Flashcut does this with an 8051 family micontroller. They have a good
> product but it's just too darn expensive. A VB program and an 8051 in a nice
> plastic box for a grand! ( or is it more now ? )
>
> Hopefully DeskNC Windows will be more reasonable.
>
> later,
> Larry E.
>
> ----- Original Message -----
> From: "Alan Marconett KM6VV" <KM6VV@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Wednesday, April 18, 2001 3:49 PM
> Subject: Re: [CAD_CAM_EDM_DRO] DeskNC Windows version
>
> > Hi Art,
> >
> > Thanks for the reply. I'd heard that parallel was impossible, and
> > serial possible under windows. Is there any EPP/ECP support under
> > windows? Might that work better, similar to serial? But then, it
> > wouldn't be a "simple" parallel port, I guess!
> >
> > By 8000 PPS, are assuming a 133Mhz Pentium class machine on Windoz? I
> > thought I'd heard higher numbers, must be for Linux or DOS.
> >
> > I'd also like to hear about the P6 instruction(s) that aid in
> > timing/step generation.
> >
> > Alan KM6VV
> >
> >
> > Art Fenerty wrote:
> > >
> > > Alan:
> > >
> > > When sending to a serial port from windows, you don't hang the
> system
> > > as much. You simply send a series
> > > of commands and let the intelligent box do the rest. Most windows
> software
> > > suffers greatly when sending to the parrallel port due to the time
> involved.
> > >
> > > ""Sounds like a FlashCut!"" -- It is, thats just how flashcut does it
> for
> > > the most part. It tends to make it very smooth and is a good solution
> for
> > > the money.Without a black box, you really can't get higher than 8000
> > > Pulses/Sec.
> > >
> > > Getting Master5 to be smooth under windows was a real challenge and
> it's
> > > easy to see why Black box idea's are starting to proliferate. You just
> can't
> > > go faster than 8000 pulses per second without such a black box, although
> > > that may change under the P6 series chips. My experiments show that
> variable
> > > asynchronous velocities are possible with P6 processors at quite a
> speed. I
> > > may try to implement such a system in a year or so. But it will take
> awhile
> > > for most peoples computers to catch up with the latest motherboards. I
> have
> > > enough problems with the number of people out there using 133's.
> > >
> > > Art