June 16, 2002
June 16, 2002
June 19, 2002
7.920.1 - 7.920.6
PLC Laboratories – The Next Generation
James A. Rehg, Associate Professor, Pennsylvania State University
Programmable Logic Controllers (PLCs) were a novelty in the automotive industry after their introduction in the early 1970s. Thirty years after their debut, PLCs are the default industrial controller used in a broad range of control applications from simple machines to entire production facilities. In the last ten years, PLC development followed the computer industry trend toward networked devices and shared databases. In the last three years, however, vendor products that integrate the PLCs with other networks, smart sensors and smart actuators have increased significantly. Courses and laboratories covering PLC programming and interfacing started to appear in colleges and universities teaching engineering technology programs in the mid 1970s. Today PLC courses and a PLC laboratory are found in almost every engineering technology curriculum. In many institutions, however, the level of PLC technology taught has not progressed beyond simple discrete control using basic ladder logic programming on a stand-alone PLC. Engineering technology laboratories must include exercises using PLC and smart device networks to prepare graduates to work on the robust automation solutions adopted by manufacturing. This paper describes how PLC laboratories need to change to be aligned with current industrial usage.
PLC History – Three Distinct Periods
Programmable logic controllers (PLCs) were born in 1972 when the Oldsmobile division of General Motors asked a small company to develop a software-driven solid state replacement for racks of relays used to control production lines. Modicon, the first PLC company, designed a special purpose industrial computer that would translate discrete switch an sensor inputs into discrete outputs based on Boolean logical combinations of the inputs. The new device also had solid-state counters and timers for more complex control problems. From a beginning with one PLC company, the industry grew to a point today where over 50 companies offer PLC devices, and a robust industry of application development companies for PLC users exist.
Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright Ó 2002, American Society for Engineering Education
Rehg, J. (2002, June), Plcs In The New Automation Laboratory Paper presented at 2002 Annual Conference, Montreal, Canada. 10.18260/1-2--11275
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