Re: Circuit Board Layout Program

The RS-274D spec default is 3,4 meaning 3 leading digits and 4 digits
after the decimal. I normally place my ACAD drawings at the origin to
have the gerber x,y co-ordinates look more meaningful. Not necessary
to do though.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> "Ian W. Wright" wrote:
>
> > HI,
> >
> > I downloaded Autogerb and have tried it on a filoe I already had
in Autocad
> > but I can't understand what it has actually produced - not g-code
as think I
> > know it. Can someone give me a brief explanation of what the
output is
> > please? This is a short bit of it.....
> > G54D12*X-3737532Y38312095D02*X-
3805393Y36392196D01*G54D12*X83262468Y35236985
> > D02*X83194607Y33317085D01*G54D12*X-
3551133Y36508287D02*X82949179Y33450838D01
> > *G54D12*X-3549661Y36549927D02*X-3552605Y36466646D01*X-
3800977Y36517118*X-380
> > 0977Y36517118*X-
3549661Y36549927*G54D12*X82950651Y33492479D02*X82947707Y3340
> >
9198D01*X83199023Y33442007*X83199023Y33442007*X82950651Y33492479*G54D1
3*X390
> > 02903Y35087693D02*X38962734Y35130805D01
>
> OK, this looks like it is halfway between EIA and ASCII versions of
RS-274.
> Most old paper tape machines would take either EIA or ASCII codes on
> the punched paper tape. The format of the blocks was also
different for
> the EIA code version. The asterisks are the 'end of line' codes.
> So, if you break it into lines at every *, you will get something
that
> looks more reasonable.
>
> G54 D12*
> X-3737532 Y38312095 D02*
> X-3805393 Y36392196 D01*
> G54 D12*
> X83262468 Y35236985 D02*
>
> Ahh, now I recognize it! This is an Gerber photoplotter file.
Yes, it IS
> also a defined format of RS-274D, but the dialect is for a
photoplotter to
> put a drawing on photographic film. D12 sets the aperture that
will be
> imaged onto the film. D01 and D02 control whether it is a draw or
flash
> operation. The coordinates are with suppressed decimal point, and
it
> looks like the zeroes have been supressed. I can't tell from the
snippet
> whether it is leading or trailing zeroes that have been suppressed.
>
> But, it IS, in fact, a totally valid form of the RS-274D spec!
> The coordinate values look pretty odd,
> though. Maybe this converter was designed so it could handle
photomask
> files for integrated circuits, too, which have very large plots
with VERY
> small lines.
>
> Anyway, the file is totally useless without knowing what size and
shape
> is supposed to be loaded into each aperture slot. Your snippet
shows
> D12 and D13 are used, but there may be many more in the total file.
> These files are usually accompanied by an aperture list file.
>
> Jon