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Re: Tutorial about IPC-7531A


On Wed, 1 Sep 2010, Brian F. G. Bidulock wrote:

Do you know of any place where the V2009 (*.plb09) or earlier V6
(*.plb) file formats are documented?  Or, anybody willing to
reverse-engineer the format?

No, it's not public. It seems that it's simply a csv with the ipc
parameters encoded in a 'base64-ish' way, nothing else.

I converted some by hand that I got from gEDA's library.
Someone did the work to recalculate the lands using the
IPC-7351 equations with an m4 script.  I hand converted a bunch
of chip capacitors and resistors to pcbnew modules (pcbnew's
library chip capacitors were wayyyyy wrong).

I have a lot of discretes in my libs if you want them, all done with ipc
(except SOT23, which our assembly people said preferred with bigger

their own *.plb09 files.  (Which begs the question: where did
they get the format?  Or do they just use LP Wizard or

LP Librarian or the LP Calculator itself can generate the plb files. LP
Wizard directly creates a CAD package (only for your licensed CAD, of

manufacturer's recommended land pattern anyway.  Some do not
provide IPC-7351 values on their datasheets.

Manufacturers which don't say how big a pin is? Some of the information
the calculator ask are only for library purpose or for trigger some

Do you thing that purchasing the standard would shed some light
on this library format?  Or are the fields in the file just the
(some of the) parameters that get stuffed into the equations?
It seems that there are a lot of non-IPC things too (like silk
screen clearance).

No, they only say how to use the calculator, otherwise you wouldn't buy
the LP Wizard :D Heck, they doesn't even let you download the calculator
because otherwise people didn't buy the standard!

But I think that some experimentation with the calculator would give
insight on the encoding. If they aren't so sick to actually encrypt the

Maybe all we need is a kind-of-a module-editor wizard that
uses the calculations from IPC-7[23]51, A, B to guide the
user and generate (and name) the module under module editor
which can then be customized from there.  It would still be
nice for that wizard to read directly a vendor-supplied PLB

What are your thoughts?

My doc should give all the info needed for doing such a thing. Oh, and
it's only up to the A revision (sorry, we aren't so rich to buy each
update:D). As of the plb file I'll see if I can reverse engineer some of

Lorenzo Marcantonio
Logos Srl

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