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How process-control automaton has transformed the industrial world over the last 30 years – although widely recognized – remains a great untold story. While almost everyone is familiar with the handful of individuals who envisioned the PC, dozens of near equally important advances have been accomplished by highly talented, near-anonymous individuals.
(For example, this editor once interviewed a retired IBMer who in his golden years was documenting how some early, key client-server concepts, still relevant today, were first promulgated in British IT labs in the 1970s and 1980s.)
In 1981 when this editor for the first time walked into an engineering department, all the project engineers, lead designers and detailers worked on drafting boards. The project engineers made great use of their Texas Instruments portable calculators, although each still had a slide rule in a drawer. Every engineering job had two folders, one for bills of material and drawings, and one for contracts and correspondence. Together the two files could get to be nine inches thick.
The company had just taken delivery of a computer-aided design (CAD) system. The three workstations involved — and the young guys hired to work on them — were carefully cordoned off in a glass enclosure. In a couple of years, the first material resources planning (MRP) systems came on the scene.
A library’s worth of microfilm cards held the company’s history in mechanical and electrical drawings. The drawing nomenclature told you the type and size of the furnace depicted as well as other details. But when the MRP consultants came in they insisted part numbers and drawing numbers should not carry context but rather be just random numbers in series.
The first departmental PC, with the processor and keyboard mounted in a single squat console, was used to generate spreadsheets, assembled using function keys, for job scheduling and tracking. Need it be added that the results indicated that way too many projects ran over the number of hours originally estimated for their completion?
Just as important, though, and more relevant to actual process operations, was that the electrical engineers — instead of using relays, timers and other devices to accomplish control, sequencing and safety in the heat-treat furnaces we were building – had started to do so by entering ladder logic into programmable logic controllers (PLCs).
PLCs today are configured much like other devices; and programming can be accomplished by multiple means. But ladder logic was used first because it represents a software program using graphical diagrams much like those used to represent electrical circuitry. As such, plant people were already familiar with it.
As the PC has changed daily lives, the PLC transformed automation. Today simple PLCs are affordable for the most basic automation projects. Addition of advanced features and PC-based supervisory control software — originally developed by industrial software vendors Intellution, Wonderware and USDATA — means they also are specified for sophisticated, distributed-control projects. But where did the PLC come from?
Many accounts say that in 1968 GM Hydramatic issued a request for proposal for an electronic replacement for hard-wired relay systems. The winning proposal came from Bedford Associates, which founded the automation vendor Modicon to supply the product. One key person on the project was Dick Morley, who has often been described as the “father” of the PLC, while he himself points to the accomplishments of others.
Morley was for a number of years a columnist for a magazine edited by this journalist. He is a delightful man who has enjoyed to the fullest any material benefits that came with his invention. His columns, besides pointing to topics that joined the larger world of science to that of automation, were very funny. For many years he has lived in his New Hampshire “Barn” where he and his wife have raised 40 foster children.