Re: Pico VS IMService???

Jon,
Please let me know if I am understanding correctly. With your USC
board you can create a "pseudo-servo" system if you install encoders
on the steppers? The USC board has onboard rate generators to
eliminate any possible host computer timing "bugs"?(takes the host
out of the equation?) You mentioned using a 4th axis "channel" to
generate PWM for spindle speed control. Could you elaborate on this.
Is it possible with EMC,could you use say 5th 6th or 7th and still
retain the 4th axis for rotary motion? Can I use drives other than
Gecko or Rutex (say Xylotex) and still utilize the encoder feedback?
I Thank You For Your Time!!
Ken

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>
> turbulatordude wrote:
>
> >>the USC board was delivering 45,000 steps/second per axis. This,
> >>
> >>
> > of course, is not the limit, it can go to about 300,000
steps/second.
> >
> >
> >That is impressive
> >
> >
> >
> Well, this is what you can do in dedicated hardware, and Field
Programmable
> Gata Arrays make custom hardware very affordable.
>
> >
> >
> >>It allows you to connect encoders from the motors to the board,
> >>
> >>
> > which then relays the position information back to the CNC
computer.
> > One of the greatest advantages of this is that you can switch
back
> > and forth between CNC and manual operation, and use the
computer as a
> > DRO when in manual.
> >
> >
> >Another great feature, I assume the computer required encoders and
> >does not 'see' the steps as the DRO ?
> >
> >
> >
> Well, if you are using Gecko or Rutex servo drives, you already
need
> encoders
> for that.
>
> I'm not sure what you mean by "not 'see' the steps as the DRO".
>
> >
> >
> >
> >>The USC board also has 14 opto-isolated inputs for limit and home
> >>
> >>
> > switches, so you can have separate indications of - and +
limits for
> > each axis.
> >
> >The site
> >
> >http://pico-systems.com/univstep.html
> >
> >that shows the board, lists one parallel port. is that all that
> >connects the PC to the board ? it seems like you have found a way
to
> >exceed the normal 5 inputs of a simple breakout board.
> >
> >
> >
> Yes, it only requires one parallel port. The parallel port does
not
> have dedicated
> pins, as it does for the traditional step/direction output. It
becomes
> a communications
> channel between the computer and a peripheral device, so registers
are
> addressed,
> read out and written to, to accomplish the functions needed. With
EMC, the
> way we are running it now, 1000 times a second the position is read
in,
> a new
> velocity computed for each axis, and the new velocity is sent to
the rate
> generators. Also, the sense switches are read in, and solid state
relay
> outputs
> are sent out at the same time.
>
> The IEEE-1284 protocol makes it possible to access 256 registers on
devices
> on the (parallel port) bus, and so it can support up to FOUR of
these boards
> on one parallel port!
>
> Jon