Re: Thoughts on Gcode interpreters and CNC controls....

Matt,

Yes, but most don't look ahead very far. And that look ahead'ing is
using computing power on the slower contols. Don't you agree that
some controls run slower with cutter comp? How many times have you
had a program that ran just fine, and then you changed a cutter
diameter slightly and you get half way through the program and it
errors out because of cutter radius/contour problems?

Maybe, it's because I'm using 1990 "state of the art" controls that I
see these problems?

Speaking of controllers and speed, my Dynapath Delta 20 uses an
Intel 186 processor. That's a nice control with some great
features. Just goes to show what a dedicated CNC specific control
can do with limited processor horsepower.

thanks,

Doug







--- In CAD_CAM_EDM_DRO@egroups.com, "Matt Shaver" <mshaver@e...>
wrote:

> > From: dougrasmussen@c...
> > My question is, why don't controls have an option to pre-scan a
> > program and by accessing the tool and part offset tables pre-

calulate

> > all the cutter paths so that when actually cutting all the

controller

> > has to do is deal with interrupts and motion control? Or do some
> > controls have that ability?
>
> They do, it's called "look ahead", and the number of blocks the

control looks

> ahead is usually part of the specification. The EMC software starts
> interpreting the g-code as soon as you start running a program and

usually

> has most of my programs fully interpreted by the time the first

tool is

> loaded. I don't know how big the look ahead buffer is, but it must

be huge.

>
> Matt