For me, the vast majority of components are hard metric specified! I do
a lot of fine pitch SMD.

As has been noted before on this forum, if Protel had a hard metric
base unit in the database it could still provide imperial entry for those
that live in backward countries :-) but with the significant advantage
that there would be no conversion error when converting between display
units.

Protel's use of english base units is a fundamental flaw that could easily
have been rectified in the process of writing a major new release (e.g. in
Protel 98 or in DXP), and it would have been easy to specify that version 5
databases are hard metric, while versions below this are english base units.
The fact that it wasn't was, for me, the biggest disappointment with DXP.

John Haddy



-----Original Message-----
From: vincent mail [mailto:[EMAIL PROTECTED]]
Sent: Friday, 2 August 2002 12:04 AM
To: Protel EDA Forum
Subject: Re: [PEDA] DXP comment, but slightly off topic


ok . open any electronics component catalog.  ( digikey , mouser , avnet
, farnell ,newark arrow )and look at parts

you fill find things like 50 mils 25 mils 100 mils for lead pitch and
widths. and then look at the equivalent in millimeters. Which numbers
would you rather key in to create a new footprint ? Sure there are
metric parts but we don't use them ( yet ) . Ribbon cable is still a 100
mil pitch , Smd components ares still 50 mil pitch ( some tqfp and bga's
are in millimeters true )  and i'd rather key in 25 mils when creating a
part then a crazy value like 0.62954 millimeter.

i think we will only be successful in switching to millimeter when there
are no more parts made using imperial pitches. and that is not going to
happen for a long time.

And believe me i know what a pain converting is , I am from belgium and
have grown up with the metric system , after 2 years in the usa using
inches , and feet and pound and gallon that heve no linear relationship
to them is still a nightmare. But for board layout i translates in nice
round numbers.

> In a global economy standardisation is essential, do you really think
> that inches have a future?
> The IPC recognises this, which being American based is very
> surprising, but encouraging.
> Even Britain the bastion of Imperial is slowly but inexorably moving
> towards metrication.
> I was brought up on imperial and pounds and shillings, so I'm fairly
> understanding.
> As far as I'm aware the USA is the only country that doesn't have a
> metrication programme in effect


>
> Chris Mogford.
> ************************************************************************
> * Tracking #: E7E9D6B0EAA28E45B0C48EF8E6F4E50D563153A1
> *
> ************************************************************************
>


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