Re: [CAD_CAM_EDM_DRO] more Re: tool comp

At 11:34 AM 4/13/02 -0000, you wrote:

>compensation you need to look ahead at least TWO blocks. Many of the
>old controls looked ahead five blocks in case there were "non-XY
>motion" blocks interspersed, which would have otherwise broken the
>cutcomp calcs.

Thanks for the tip.

>P.S. Looking for IJK to discern arc when you have a "2" or "3" (from
>G02, or G03 seems like backtracking to me.

The way I'm handling the 2/3 thing is to use it to set the direction by
writing a word with CW or CCW in it. This word is added to the rest of the
data to form the output command. The 2/3 stops existing in that variable as
soon as that word is formed. That's because I'm parsing a line of code as
%c%f, repeatedly. So the variable that carries the 2/3 is used again for
data immediately. IE G3X2.3Y2.3I2.1J2.4 is read in as G and 3, then X and
2.3, then Y and 2.3 etc til line is parsed thru. You get it.

>array should allow for these modals to be "kept" until replaced. IMO,
>this is a good place for a UDT. This UDT can then be used in an array
>of sufficient depth to accomodate any lookahead needed.

I don't have any problem setting up arrays and can do so for this problem
as soon as I see what's needed in it. For ex, I have block-retrace working
by keeping an array of all coords to 75 lines back. And one element in the
array is also the file pointer for the line that made those coords. So to
retrace a number of blocks, one gives it a look-back number and the
software rewinds file to right place and computes a move to that location
in three-space. Then it goes on running file. Cute, no?



Regards, Hoyt

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