----- Oorspronkelijk bericht -----
Van: Kim Lester <[EMAIL PROTECTED]>
Aan: Multiple recipients of list proteledausers
Verzonden: zondag 25 februari 2001 5:14
Onderwerp: RE: [PROTEL EDA USERS]: Library Management

> Brian And everyone,
> I was just about to post a very similar message.
> I'm currently very irritated because I just found a library problem in a
> production run of boards....

How can you have problems in a production run, if your prototype
board was okay ? (hint -> *always* have protypes made). Okay, i'll
admit that a very minor change on a board that already has been
in production not always requires a new set of prototypes to be

> Gripe 2: The schematic symbol for a pot has pin 3 as the tap/wiper.
> I never saw this because my pin names were off...
> I converted from sch to PCB and applied the generic footprint
> VRn - to avoid wiring problems (hah!). That what the whole point of this
> technology is for isn't it!
> I checked my transistors for pin problems and found some (but
> I guess I had kind of expected a transistor problem. I didn't
> expect a problem in something so basic as a VR and time was short).
> The PCB component was correct  - pad 2 is (and as far as I know is
> ALWAYS) the wiper. So as far as I'm concerned the schematic
> library component is wrong in a dangerous and dumb way.
> I can see that it is an extension of resistor but surely everyone
> would get caught by this.
> Question:  Take the RETSISTOR TAPPED sch library part for eg.
> It does not have any hidden pins (according to library params)
> yet I have to use display hidden pins to see the pin nums etc...
> Why is this so ?

In the library, 'show pin names' & 'show pin numbers' are turned
of. Place checkmarks to make them visible in the schematic. This
is not desirable for small components - it messes up the schematic.

> Question:  What is the correct way of assiging schematic pins so they
> match PCB pins (how do I make the change and ensure correctness)

Newly designed schematic symbols and newly designed footprints
only require thoroughly checking. Any errors that slip through
are caught when the prototype boards are made. I never make
changes to supplied libraries, but copy the components/footprints
to my own library. After the copy, I change them if need be.
This is a lot of work, when you just have started to use Protel,
but after a while, your own personal library gets better and better.

> Question: Do I have to create my own compatible sch and PCB libs which
> seems really stupid in as "professional" a product as PCB.
> I seem to remember that others have had to make libs too. Do we have a
> shared library pool (schematic compatible). I currently don't feel like
> trusting protel libs. ISA9000 or not.
> Ok so am I being really stupid/naive or is it a serious problem ?

You are not stupid, it has happened to us all. Holes too small,
pins mixed, wrong dimensions in footprints etc. There are perhaps
a dozen or so different types of 'common' pots, what would be
a correct 'default' footprint for a pot ? Protel can not give
you an answer on that, and has left the footprint fields empty.
You simply choose an incorrect footprint, without checking it
it was actually correct.

You will certainly have more luck with your next project ;-)


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