Excellon coordinates DIFFERENT than Gerber?

Coordinates look like the x offset and Y offset are different, and the scales are different for the Excellon.

Please explain.

Same holes.. Excellon file (test_DrillsHoles.XLN): % M48 M72 T01C0.0197 T02C0.0236 % T01 X5056Y13424 X5056Y13424 X826Y13824 X826Y13824 T02 X1526Y624 X4526Y624 M30

Gerber file (test_DrillsHoles.GRB): G75* %MOIN*% %OFA0B0*% %FSLAX24Y24*% %IPPOS*% %LPD*% %AMOC8*

5,1,8,0,0,1.08239X$1,22.5* % %ADD10C,0.0000*% %ADD11C,0.0010*% D10* X000526Y000124D02* X000526Y014124D01* X005526Y014124D01* X005526Y000124D01* X000526Y000124D01* X001408Y000624D02* X001410Y000645D01* X001416Y000665D01* X001425Y000685D01* X001437Y000702D01* X001452Y000716D01* X001470Y000728D01* X001490Y000736D01* X001510Y000741D01* X001531Y000742D01* X001552Y000739D01* X001572Y000733D01* X001591Y000722D01* X001608Y000709D01* X001621Y000693D01* X001632Y000675D01* X001640Y000655D01* X001644Y000635D01* X001644Y000613D01* X001640Y000593D01* X001632Y000573D01* X001621Y000555D01* X001608Y000539D01* X001591Y000526D01* X001572Y000515D01* X001552Y000509D01* X001531Y000506D01* X001510Y000507D01* X001490Y000512D01* X001470Y000520D01* X001452Y000532D01* X001437Y000546D01* X001425Y000563D01* X001416Y000583D01* X001410Y000603D01* X001408Y000624D01* X004408Y000624D02* X004410Y000645D01* X004416Y000665D01* X004425Y000685D01* X004437Y000702D01* X004452Y000716D01* X004470Y000728D01* X004490Y000736D01* X004510Y000741D01* X004531Y000742D01* X004552Y000739D01* X004572Y000733D01* X004591Y000722D01* X004608Y000709D01* X004621Y000693D01* X004632Y000675D01* X004640Y000655D01* X004644Y000635D01* X004644Y000613D01* X004640Y000593D01* X004632Y000573D01* X004621Y000555D01* X004608Y000539D01* X004591Y000526D01* X004572Y000515D01* X004552Y000509D01* X004531Y000506D01* X004510Y000507D01* X004490Y000512D01* X004470Y000520D01* X004452Y000532D01* X004437Y000546D01* X004425Y000563D01* X004416Y000583D01* X004410Y000603D01* X004408Y000624D01* X005526Y014123D02* X000526Y014124D01* X000526Y014124D01* D11* X000426Y013824D02* X001226Y013824D01* X000826Y013424D02* X000826Y014224D01* X000426Y013824D02* X001226Y013824D01* X000826Y013424D02* X000826Y014224D01* X004656Y013424D02* X005456Y013424D01* X005056Y013024D02* X005056Y013824D01* X004656Y013424D02* X005456Y013424D01* X005056Y013024D02* X005056Y013824D01* X004126Y001024D02* X004926Y000224D01* X004126Y000224D02* X004926Y001024D01* X001926Y000224D02* X001126Y001024D01* X001126Y000224D02* X001926Y001024D01* M02*

Thanks.

Reply to
Robert Baer
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excellon places holes at coordinates, gerber draws lines and circles (using lines)

Reply to
Lasse Langwadt Christensen

I'm not sure they are so different. Not sure what you are looking at exact ly and I don't have the details of the Excellon format memorized, but the E xcellon file where the number of digits vary may be leading zero suppressed , or trailing zero suppressed. The Gerber file seems to have the leading z eros so both X and Y are six digits. My guess is both files are in thousan dths of an inch, e.g. mils.

It would help a lot if you explained what the file is, what generated it an d what the settings where when it was generated.

One thing that bothers me is I see coordinates repeated in the drill file. The other is that there are very few holes drilled for what seems like a l ot of traces. It also bothers me that the drill holes don't seem to have a ny pads in the Gerber file, in fact there seem to be no pads at all.

Why do you say the two have different offsets?

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  Rick C. 

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Reply to
Rick C

Not an explanation, just a general statement. Please retry.

Reply to
Robert Baer

Am not bothered by preceding zeros or precision of values.

The files were created by EAGLE. You say "drill holes don't seem to have any pads" - - the x,y offsets between actual Gerber pads and the Excellon drill is exactly what i am talking about. Excellon X5056Y13424 means x=50.56 mils, y=134.24 mils. Gerber: X000526Y000124D02* | X000526Y014124D01* | x=52.6 mils, y=1412.4 mils X005526Y014124D01* | X005526Y000124D01* | x=552.6 mils, y=12.4 mils X000526Y000124D01* |

And Eagle has a bad habit (for well over 5 years) of creating TWO holes for every pad; one from the top down and one from the bottom up; distance indeterminate. Have heard one could break drills if these two holes are too far apart. I no longer use (round) pads, i use vias; safer and look/act same in final PCB. There are 2 (round pad) vias at the top and 2 holes (with rectangles as pads) at the bottom. One actual hole on the PCB is at 0.100, 0.050 (bottom left of

0.500x1.500 board), and a via is at 0.030, 0.1370 (top left).

Thanks

Reply to
Robert Baer

just look at the files. Eccellon places four holes, gerber draws an outline , four crosses and two circles

Reply to
Lasse Langwadt Christensen

xactly and I don't have the details of the Excellon format memorized, but t he Excellon file where the number of digits vary may be leading zero suppre ssed, or trailing zero suppressed. The Gerber file seems to have the leadi ng zeros so both X and Y are six digits. My guess is both files are in tho usandths of an inch, e.g. mils.

t and what the settings where when it was generated.

le. The other is that there are very few holes drilled for what seems like a lot of traces. It also bothers me that the drill holes don't seem to ha ve any pads in the Gerber file, in fact there seem to be no pads at all.

.

I don't feel like wading through the Gerber file to figure out what sort of shapes are being drawn. Gerber files typically use a flash command "D03" to draw pads. I see none of these.

I do see an aperture definition command %AMOC8*

5,1,8,0,0,1.08239X$1,22.5* %

This seems to be defining a octagonal aperture rotated so the top and botto m are flat rather than having vertices. I don't know that it is used howev er.

I also see %ADD10C,0.0000*% which is an aperture of zero diameter. Not sur e what that means. I may be showing my limitations in understanding the RS

274X format.

What I don't see is any offset in the RS274X file.

Does any of this make sense to you? What features are you comparing to say there is an offset? Have you looked at the files in a viewing program?

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  Rick C. 

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Reply to
Rick C

  • You forgot, EAGLE does not use those.
  • Not used, again this is EAGLE.
  • Again this is EAGLE.

I use a stupid text editor to look at the files (presented a snippet of them here) and see what i mentioned, compared to what is seen by EAGLE for coordinates of items mentioned.

Reply to
Robert Baer

I know what i get; the TWO vias at the top, via EAGLE produces 4 holes: T01 X5056Y13424

Reply to
Robert Baer

exactly and I don't have the details of the Excellon format memorized, but the Excellon file where the number of digits vary may be leading zero supp ressed, or trailing zero suppressed. The Gerber file seems to have the lea ding zeros so both X and Y are six digits. My guess is both files are in t housandths of an inch, e.g. mils.

it and what the settings where when it was generated.

file. The other is that there are very few holes drilled for what seems li ke a lot of traces. It also bothers me that the drill holes don't seem to have any pads in the Gerber file, in fact there seem to be no pads at all.

ets

part.

in

es

t of shapes are being drawn. Gerber files typically use a flash command "D

03" to draw pads. I see none of these.

No, I didn't forget anything. I don't know Eagle and I don't want to know Eagle. I'm pointing out the facts.

ottom are flat rather than having vertices. I don't know that it is used h owever.

So Eagle customarily clutters the file with pointless commands? Very odd.

sure what that means. I may be showing my limitations in understanding th e RS274X format.

Now we are in Bizarro world. This command defines the D10 aperture which I S used in the rest of the file. In fact. the example lines you referenced for your hole location are, in fact, drawn with the D10 aperture. So if it is not drawing a trace, what is it doing? Why would you worry that it mat ches or doesn't match your holes?

say there is an offset? Have you looked at the files in a viewing program ?

You aren't making anything clear. You refer to invisible traces in the Ger ber file as if they should somehow match the coordinates of the drill file holes. I see no reason why these coordinates should match if the traces ha ve no width and don't result in copper on the PCB.

On the other hand you could view this in a simple viewing program and see w hat it will produce when the board is made. That would be easy and effecti ve. Right now the Eagle produced Gerber file is so full of seemingly point less or not understood commands that it would seem to be difficult to compa re the text.

Do you actually understand the details of each command in your files? If n ot, I suggest you defer to the experts who created the viewer programs.

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  Rick C. 

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Reply to
Rick C

line,

:
Reply to
Rick C

Nothing. The comments are derived from what is seen in EAGLE. On a PCB, place a pad somewhere. Then turn on Top only, move pad and see two and delete one. See what you get for holes only, vias only, drills only (which is where the drills make the pad holes). Make Gerbers, Excellon files and look carefully. If you see a pad on the top only, and a drill place,then would that not mean drill from the top only but zero depth as nothing anywhere sez board thickness.

Reply to
Robert Baer

s

utline,

oles:

?

I think you are saying if you have a pad only on the top layer and none on the bottom you will only get a single drill command. Ok, but so what? I h ave no idea what you are talking about with depth. Unless your design is u sing buried or blind vias the holes go through the board. Even then, I'm p retty sure the vias are all made as through holes on the board layers they need to be on and the resulting panels are stacked after drilling.

Still, none of this explains what you are doing or what is happening in the files that you don't like.

Did you ever use a Gerber viewer to show how the holes line up with the tra ces?

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  Rick C. 

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Reply to
Rick C

YES. Gerbv.exe

Reply to
Robert Baer

Ok, so if the holes don't line up with the traces in a Gerber viewer, it sounds like it's time for a new layout program. I can recommend FreePCB. It's very intuitive and is pretty much bug free.

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  Rick C. 

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Reply to
Rick C

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