[Diy_efi] Project/temperature ranges

[Steven P. Donegan]

Well, the key things I see here are:

1) All automotive ECU's I've looked at have had Commercial grade
components - and failure of these is very rare.

2) Most components I have selected (thus far) have Commercial and
occaisionally Industrial temperature ranges - can I select different
parts - perhaps. I have not found any which support Military grade - and
my read through Digi-Key and Jameco don't show any Military grade parts
(I haven't read both entire catalogs - but of what I have read - not a
single part).

3) Least important to me is any additional cost - and from what I've
seen thus far the difference between cost for Commercial to Industrial
is fairly trivial.

So, unless someone can point me to obtainable in qty 1 Mil spec parts I
will use Industrial where available and Commercial where I must...

On Tue, 2007-02-27 at 22:17 -0800, Dave Harvey wrote:
> I agree with Adam.  The cost of military-grade parts is small compared 
> to the time and expense troubleshooting a thermal or design margin 
> problem.   Unless you are GM, making electronics by the millions, a few 
> extra bucks for parts is no big deal.  I work at the other end of the 
> scale; designing electronics for space applications where we build a few 
> (or one).  In that case, reliability and design margin are everything.  
> I always use the best parts I can get because I've had some bad 
> experiences when I didn't.  As a wise engineer once told me when I 
> remarked on the extra size, weight and cost of additional design margin: 
> "The only thing margin saves is your ass."
> 
> -- Dave
> 
> Adam Wade wrote:
> > --- "Steven P. Donegan" <steve at donegan.org> wrote:
> >
> >   
> >> For the moment I am working more on function and
> >> less on boundary conditions - ie I am working with
> >> commercial temp range parts and 'reasonable' power
> >> supply fluctuations. Once the system works in those
> >> conditions I will indeed go to automotive/military
> >> temperature range components and expect zero
> >> goodness from vehicle power :-)
> >>     
> >
> > I am probably late making the comment, but you
> > probably stand a significant chance of having a bug
> > crop up during development that will eventually be
> > traced back to NOT having done something like spec'ing
> > for wider limits in temp, noise tolerance and/or power
> > supply issues.  If this happens, the time spent
> > debugging in the testing the design phase will likely
> > exceed the time (and effort) required to just spec out
> > parts to handle much larger environmental limits than
> > the basic "standard" you're using to get the thing off
> > the ground.
> >
> > Of course, you might NOT run into a problem, and in
> > that case, you'd end up spending only a little more
> > time and effort to up-rate the design after basic
> > development.  But to me, it doesn't seem like the
> > initial effort would do anything but potentially speed
> > up development, and could potentially save you some
> > serious headaches...
> >
> > | Kawasaki Zephyr 615 (Daphne)       Kawasaki Zephyr 550 (Velma)|
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> >
> >
> >  
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