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From: john larkin <jl@glen--canyon.com>
Newsgroups: sci.electronics.design
Subject: Re: PCB version control
Date: Mon, 24 Mar 2025 13:16:53 -0700
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On Mon, 24 Mar 2025 14:51:11 -0400, bitrex <user@example.net> wrote:

>On 3/24/2025 2:46 PM, john larkin wrote:
>> On Mon, 24 Mar 2025 14:14:38 -0400, bitrex <user@example.net> wrote:
>> 
>>> How do you version control your PCBs these days?
>>>
>>> I'm at the point I need to implement a more consistent schema for
>>> hardware versions, prototype, and production boards.
>>>
>>> E.g. PCB-12345-R-B where 12345 is the PCB/product identifier and B is
>>> the manufacturing revision. Would you letter designate prototypes that
>>> are manufactured as well, or just revisions intended for public
>>> consumption?
>>>
>> 
>> For a V375 VME module, our schematic drawing number is 22S375A, where
>> 22 means the VME product line and S means schematic and A is the rev
>> letter.
>> 
>> 22D375A is the PCB fab (drill) drawing and pcb design file name.
>> 
>> 22A375A is the pcb assembly drawing.
>> 
>> 22M37501B might be a mechanical part drawing, like a front panel.
>> 
>> 22A375.1A is the BOM file for the sellable -1 version.
>> 
>> During development, we iterate the schematic and PCB together, as
>> 22S375A4 and 22D375A4, for example.
>> 
>> We have a formal procedure about all this. FPGAs, uP code, test sets
>> and procedures and software have to be coordinated too.
>> 
>> Times hundreds of products with rev letters and dash number versions,
>> this gets serious.
>> 
>> Prototypes are 99 series, with informal project files on a server.
>> These are essentially little breadboards. We don't prototype entire
>> products; we just release the full rev A document set to manufacturing
>> and expect it to work.
>> 
>
>
>I see, that makes sense. Some designs I'm working on now are modest 
>enough that can do that with the entire product relatively cheaply, so I 
>guess, y'know, existentially speaking, if "A" ended up needing major 
>revisions, but _if_ it had worked first time it could've been sell-able, 
>that should count that as a letter-revision.
>
>That is to say I guess it makes sense to be consistent and give any full 
>board that gets manufactured in whatever quantity a letter revision, and 
>I like the idea of giving "little breadboards" that aren't a full thing 
>their own project/test series designation

We roll the rev letter if there is any change to the schematic or the
PCB. Dash numbers identify versions, like parts values or stuffing
options. A new BOM can create a dash number without revving the PCB.

This is a quasi-military drawing number system which is in fact
acceptable to the US military and NASA.

It's important to note that only physical things have dash numbers.
Drawings don't.

We have one big customer that assigns the next available 12-digit
number (their 12NC) to the next thing that needs a number. A
schematic, a forklift, a building, an employee. You need a
cross-reference to tell which schematic corresponds to which PCB.