A minor Adventure in Vintage Computing

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?).