"jeff_bohren@[EMAIL PROTECTED]
" <jeff_bohren@[EMAIL PROTECTED]
> wrote:
>
>Newton might have seen 30 year old ANALOG microwave systems. I really
>doubt that he has seen much less worked on a DIGITAL microwave system.
>He sure as hell doesn't understand a ring network or how long distance
>network switching works. These systems did just fine when jolted by a
>7+ earthquake.
Yeah, he mentioned 1978, right after it was installed,
as his time frame. Actually he's talking about VHF
links to the gate valves, not microwave, that were owned
and operated by Alyeska. Alascom of course owned and
operated the backbone microwave system.
Regardless, can you imagine controlling anything (a
pipeline or anything else) that would operate equipment
of any kind as a false response to a path fade???
Hhhhhhilarious!
For folks who don't know, these systems are fairly
common, and are called SCADA, for Supervisory Control
and Data Acquisition. They typically are the means by
which remote equipment is monitored and controlled at a
central control point. On a small scale, something like
the refinery next door to poor Gerald in North Pole
almost certainly monitors and controls the entire
refinery from one control room. They don't employ
dozens of people to watch meters at each pump, each
valve and each tank. It's all controlled via wireline
and fiber optics.
The only difference with the Trans-Alaska Pipeline is
that the equipment is a bit farther away from the
control room, and requires microwave in addition to the
copper and fiber cable. In either case a simple
interruption is absolutely NOT going to cause equipment
to do anything unplanned for.
Incidentally, to my knowledge, which covers the first 25
years of operations, the pipeline had *never* been
shutdown by a malfunction of the microwave system.
Problems with the VHF links had caused shutdowns, but
not for the type of problem Gerald suggested. If a gate
valve can not be accessed for a given length of time,
due to loss of control, that will cause the pipeline to
be (manually) stopped as a safety measure. And yes,
that has happened due to failure of Alyeska's VHF links.
>What kind of tune was Newt singing when the gubmint wanted to close
>Eielson?
He wants them to keep it, just not use it. Hmmm...
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@[EMAIL PROTECTED]
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