Re: G90 & G91, best of both worlds....

Doug,

Which controls are these?

I haven't seen this usage before. It appears interesting, BUT...

Control writers beware:

The use of U,V,W in this way can lead to problems in machines with
more than 3 axes. A "W" (second linear axis, parallel to Z) is often
found on cnc machines like ww routers. Secondary linear axes U and V
(parallel to X and Y) are less commonly found, but far from non-
existent.

There are controls which allow slash delete (optional block delete)
in the middle of a line; a very powerful thing, but which would
conflict with your controls' use of the slash...

G90,91 avoids these problems. Having the ability to refer to an axis
departure as abs or rel(incr) WITHIN a block is pretty neat stuff,
but I'd like to see it used with an otherwise "unused" character,
rather than the slash. The dollar sign might be a good candidate,
since its former use for EOB (End Of Block) is waning to near non-
existence... And it is not commonly used in "expression" math

Hope this helps.

Ballendo

--- In CAD_CAM_EDM_DRO@y..., "doug98105" <dougrasmussen@c...> wrote:
> Group,
>
> For those writing control software they might consider what is
> offered on two of my "commercial professional" controls.
>
> The controls wake up in G90, absolute mode, and there is no need
ever
> to invoke the G91, incremental mode. Absolute and incremental
modes
> can be intermixed in the same block. For example, in one of my
> controls the incremental coordinates are specified as U,V,W
referring
> to X,Y,Z, respectively, to indicate an incremental move. "G01 X1.0
> V0.5" means move to absolute X1.0, and 0.5 incremetally from the
> current Y position. My other controller with this option simply
uses
> a "/", as in "Y0.5/" to indicate the move is incremental.
>
> This feature is incredibly powerful for MDI, (shop floor
> programming). Aside from ease of programming it makes the program
> very readable, it's apparent just from looking at a block in
question
> whether a move is absolute or incremental.
>
> Doug