Re: [CAD_CAM_EDM_DRO] Re: CNC edgefinding/touch probe update

For whatever reason, TurboCNC/some parallel ports have problems getting
signals into all the available pins on the ports. I've got problems
getting input signals into pins 14 and 15 on some ports. I think it has
to do with the PP mode. I think I'm using SPP+ECP for the setting in
the bios. I'm feeding the probe input into pin #11 on TCNC.

We are using a 5V supply with a 2Kohm pull up resistor.

Kim

On Mon, 2004-02-09 at 18:44, kdoney_63021 wrote:
> This is the setup I'm trying to do with a mitutoyo touch signal
> probe. Do you have the setup information. I tried to set it up
> through pin 10 with a pullup transistor but was unable to get any
> response. How are you feeding the signal to turbocnc?
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux <lux@d...> wrote:
> > I ordered and received the edgefinding touch probe that I spoke of
> last
> > week. Specifically, we purchased an Acu-rite 38-80-00-155, which
> is an
> > electrical contact type probe (ie between the probe stylus and the
> > workpiece). The probe is self centering, with a 0.5" shank (ie
> works
> > with R8 collet mills...) and a 0.2" diameter tip. The stylus has
> about
> > 1/2" of movement in each direction in case of over run. THe probe
> cost
> > $250, plus shipping. I have no affiliation with Acu-rite.
> >
> > There are less expensive touch probes on the market, but:
> >
> > a) they are usually battery powered and visual, ie they light an
> LED.
> > b) they don't readily tie into a CNC controller, although they
> could be
> > made to...
> > c) most have a 1" shank, ie they won't fit an R8 mill.
> > d) most have a 0.4" sensing ball, which is too large for a lot of
> holes.
> > e) most don't do Z axis touches. The Acu-rite does.
> > f) most have limited over travel capability.
> >
> > We mounted the the touch probe in our CNC mill, which is running
> > TurboCNC as the controller. TurboCNC had a G50 command for center
> > finding a hole. The G50 routine had a few bugs, which I fixed. I
> also
> > added a G51 routine for center finding on a protruding shaft and a
> G52
> > routine for edge finding on an ... edge !
> >
> > I've got mixed feelings about the performance of this setup.
> First, the
> > Acu-rite touch probe itself works well, ie it centers itself well,
> has
> > good over travel capabilities, etc. No problems there.
> >
> > The issue I have with this setup is that it utilizes an electrical
> > connection between the workpiece and the probe to sense when the
> edge is
> > "touched". In my (limited) experience, one must have perfectly
> clean
> > parts in order to get repeatable results. One can get Total
> Indicated
> > Runout measurements of 0.0004" on a hole, but it might also take 3
> or 4
> > centering efforts to achieve that.
> >
> > I'll continue to refine our edge finding efforts. If anyone has any
> > advice, I'm all ears.
> >
> > --
> > Kim Lux <lux@d...>
>
>
>
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--
Kim Lux <lux@...>