25 Jul
2005
25 Jul
'05
4:52 p.m.
Brent Hilpert wrote:
I don't know a lot about Foxboro, I believe they
were a spin-off or startup
company in the 60s that were early entrants into the (then small and
state-of-the-art) area of computer-based real-time process-control for large
industrial plants. They are one of those names you don't run across much unless
you run in those circles.
Additional comments about Foxboro and their systems from those who may know
more appreciated.
Foxboro was a british industrial instruments company with a very long
history. Among other achievements, they were the first to offer a pneumatic
process controller with proportional+integral action (pneumatic controllers
in those days were on/off or at most proportional). It was called
the "Stabilog", and it was introduced in 1930; it followed the introduction
of the negative-feedback pneumatic amplifier designed by Clesson E. Mason
(also at Foxboro) in 1929 to linearize the action of pneumatic-actuated
flow-control valves. This started the era of pneumatic-based analog
computation in process control equipment (on topic). I remember
seeing a brochure from those days, trying to lure control practitioners
to install "modern pneumatic process control equipment: imagine your
plant with pneumatic instrumentation so you can control it with signals
that move at the speed of sound" :-) . This may seem funny nowadays,
but it was really this kind of technology that allowed the feasibility
of _really big_ refineries, fertilizer plants and so on. Electronic
controls in industrial settings were still a few decades from commercial
success.
The first instance of closed-loop control using a digital computer
in an industrial setting supposedly happened at a Texaco refinery
in Port Arthur in March 15, 1959, using an RW-300 computer
(does anybode have a good reference on this?).
carlos.
--
Carlos E. Murillo-Sanchez
Universidad Autonoma de Manizales, Manizales, Colombia