These electronic control units were designed to control the level of water in air/water hydraulic accumulator systems. They were introduced in the 1970s and replaced all former mercury and search-coil type systems.
They were extremely reliable and robust in their construction, mostly employing solid-state components of the highest military-grade quality.
The inbuilt fail-safe characteristics of these control units offered significant improvements in the overall safety of accumulator control systems at a time when the new Health and Safety at Work Act (1974) was beginning to gain strength.
The units were designed by Peter Salter, formerly a Colonel in the army, who worked as a design engineer in the Electrical Department. He also developed the early closed-loop speed-control systems used on numerous copper and aluminium extrusion presses.
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