Re: [CAD_CAM_EDM_DRO] Re: Circuit Board Layout Program

"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*G54D13*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