Re: DRO meaning in the Artofcnc world

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Art <fenerty@a...> wrote:

> Hi:
>
> BTW: Sorry for all the confusion about DRO, but my background
> is in electronics where DRO stands for D igitalR eadO ut , at
> the time I didn't realize it also stood for "Da numerical
> Readout indicating position stored from counting encoder
> pOsitioning data". ;)

LOL!

It does literally stand for Digital ReadOut, but in the machining
world is understood to mean <D>igital readout of <R>eal p<O>sition.

DROs were first applied to _manual_ machines. The DRO eliminates
the drugery (and errors) when counting turns of the handwheels.
It also accounts for backlash, wear of leadscrews, etc. Of
course to do this the DRO must directly read table position, and
all _real_ DROs do exactly that - usually using a linear scale
connected directly to the table and completely independent of the
leadscrew.

I believe words that have specific meanings to end users should
be used correctly, or not at all, to avoid confusion. I don't
think for a second that Art is trying to imply that his displays
are a "real" DRO. However, a machinist could easily draw the
wrong conclusion.

And to be fair, I must admit that EMC's displays are not real
DROs either, IMHO, because they show the position of the leadscrew,
not the table or tool.

To summarize:

Art's "DRO" = display of commanded position

EMC's "DRO" = display of commanded position (stepper or
step/servo machine)

EMC's "DRO" = display of actual leadscrew position (real
servo machine)

Real DRO = display of actual table (or tool) position,
independent of the leadscrew or other actuator


Regards,

John Kasunich