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Re: gEDA-user: Master Parts List
On 2/27/07, Bob Paddock <bob.paddock@xxxxxxxxx> wrote:
On Monday 26 February 2007 17:17, John Luciani wrote:
On Monday 26 February 2007 17:17, John Luciani wrote:
I am putting together a master parts list table for my component
database.
The categories CAP, RES, IND, DIO, LED, BAT, etc. would work.
Don't try to force inventory into a category system. It makes sense
in the beginning when you only have a few parts,
but has your system/business grows it rapidly falls apart. May Heaven
help you if there is a buy out/acquisition, where two category based
systems collide.
Consider an multifunction widget. What category do
you put it in? You end up with a "Misc" category, which rapidly grows.
Assign non-significant part numbers to each part, such as 00001 for the first
part, or perhaps related to date&time. That part number
appears in BOM. That part number is the referenced throughout
to print the fields of interest, at the point of interest. The purchasing
department has vastly different interests in some fields than,
do the people in the warehouse, or the engineering department.
I agree that it is impractacle to embed all of the fields of interest
for all of the departments into the part number. I was hoping to embed
some of the fields related to electrical engineering. At the last
company I worked for they had a two or three digit component group
prefix followed by a series of digits. Sometimes the series of digits
related to component attributes and other times it was just an ordinal.
For example a 330pf 1% X7R ceramic cap in an 0805 package could be
CAP_X7R-331-102-0805
Playing devils advocate here: Does the above part number tell you
if you can substituted a part of "form/fit/function"? Has that part
been used in a regulator drawings; think FDA? If it has you can't
change substitute it even if it meets "form/fit/function" etc.
To make matters worse has it been used in more than one regulatory
environment like both FDA and MSHA? Did some bureaucrat just
come up with some new regulation that cuts across all categories;
think Lead Free?
It is unlikely that any part number scheme is going to allow you to
make "form/fit/function" substitution decisions. For that you will
need to lookup component specifications. My plan is to have a table
that relates CAP_X7R.... or part number 000001 to various manufacturers
parts that meet the specification. Regulatory information would
require additional tables.
A few other caps --- CAP_NPO, CAP_AE (aluminum electrolytic)
Cap arrays --- CAPCAV, CAPCAX, CAPCAF
For ICs maybe IC_AMP, IC_LDO, IC_74LVC138, etc. Some sort of package
suffix convention is needed.
I think your already seeing why the category system fails as it expands.
I agree that these categories are getting close to the infamous
"misc". Assigning ordinals to the part numbers makes everything
"misc" from the start;-) I was hoping there was something between an
infinite number of categories and one category with an infinite number
of parts ;-)
There are several Open Source ERP systems these days, take a look
at them. I'm still doing that myself.
From the Been There Done That "Category" with 175,000+ parts,
at my former place of employment.
Have you seen any documentation for part numbering schemes in any of
these Open Source ERP systems? Could you post the URLs ERP systems
that you have found?
Thanks.
(* jcl *)
--
http://www.luciani.org
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