Not long ago, the roles of industrial automation devices and systems were a little more straightforward. Most field devices and sensors were relatively “dumb” and were directly connected to controllers, which may have interacted with operator displays, and in rare cases some data may have flowed up to higher level enterprise systems. Today’s smart sensors, clever controllers, and more capable communications have improved upon this scenario, and end users are looking for the best ways to enable the enterprise host systems to access valuable field-level data.
A Programmable Logic Controller (PLC) is an electronic device used to monitor or control production processes. It is a device that a user can program to perform a series or sequence of events. These events are triggered by inputs received at the programmable logic controller through delayed actions such as time delays.
It’s been 51 years since the birth of the Programmable Logic Controller. We look back at the history of the PLC and how replacing hard wired relay systems changed the world of manufacturing.
Dick Morley, 1968
It was the year 1964 when a young cunning engineer, Dick Morley, was unemployed, had a new baby, a mortgage to pay and only $1,000 in the bank. Morley had previously worked a desk job designing atomic bombs, aeroplanes and communication systems performing the duties he was instructed to do. Morley did not enjoy his job, and, at that time, he had no plans in the pipeline to create such an influential piece of automated equipment. After finding his passion for skiing, Morely quit his job and focused on his hobby which eventually lead him to engineering ideas.
Morley eventually opened up his own professional consulting firm with friend Geogre Schwenk under the name ‘Bedford Associates’’ located in Bedford, Massachusetts, USA. Morley and Schwenk worked with local machine tool firms to help them evolve into the new, solid-state manufacturing sphere. Unfortunately, as his firm progressed, he began to notice that each project he worked on was practically the same; the manufacturing industry was using similar minicomputers and Morley found himself bored.
With his creativity and his engineering motive to ‘make things work’, Morley started to wonder if he could invent a controller which could automate industrial process with multiple input/output arrangements in real time. This would alternately replace the likes of hard wired relay control systems.
