27 Aug
2011
27 Aug
'11
4:30 p.m.
On 08/27/2011 01:49 PM, Tony Duell wrote:
Indeed, they're all over the place in industrial control environments.
Yep. It's prevalent in the software world as well.
Clicking-and-drooling while mired in the eye-candy interface of an IDE,
gluing bits of other people's *real* code together and clicking "build
my program", without ever really understanding how anything works.
Google's databases are chock full of archived forum posts containing
unbelievably stupid questions from these sorts of "programmers". Idiots.
-Dave
--
Dave McGuire
Port Charlotte, FL
Never seen a
USB-20mA (for example). Everything seems to be based on
voltage thresholds these days, and the shortcomings of that were brought
Is it? I've seen analogue transducers with a 4-20mA analogue output (i.e.
a current source output) very recently. I assume they still exist. home to me
today in discussion with a building management systems
installer advising that the signaling from a leak detector would not
travel several hundred feet without an (expensive) booster box at each
end. We're not talking about fast baud rates here, just some remote
sensing device with an output consisting of voltage-free relay contacts,
feeding equipment that provides a voltage to distinguish "on" this
morning from "off" this afternoon. The cable resistance has an inherent
voltage drop of course, so they can't guarantee that closing the relay
contacts will cause the voltage to drop sufficiently at the active
equipment end. A current-sensing input could deal with that no problem,
but they'd never come across the concept of current-sensing.
ARGH!. But that's what you get nowadays. So-called 'engineers' who belive
problems are solved by sticking complex modules toghter and who don't
(and many can't) really think about the probkem. I've see it all too
often.