A programmable logic controller, or PLC, is a ruggedized industrial computer built to control manufacturing processes such as assembly lines, machines and robotic devices with high reliability, and to be reconfigured by loading new code rather than by rewiring hardware as the relay logic systems it replaced required. Bedford Associates, a Massachusetts firm, built the first PLC in 1969 in response to General Motors' request for an electronic replacement for hardwired relay control panels; the device was called the 084 because it was the company's eighty-fourth project, and Bedford Associates went on to found Modicon, short for modular digital controller, to develop and sell the technology. Dick Morley, the Bedford Associates engineer behind the 084, is generally credited as the father of the PLC, alongside Odo Josef Struger, who did parallel development work on programmable controllers.
Facts
SignificanceMore reliable, compact and lower maintenance than the relay systems it replaced 1 FAQs
Why do programmable logic controllers use ladder logic?
Because the original General Motors criteria asked for programming in line with already accepted relay ladder logic.
General Motors set design criteria for the first programmable controller that included being easily maintained and programmed in line with already accepted relay ladder logic. The Modicon 084 that won the contract in 1969 therefore used a form of ladder logic to solve its algorithms. The tradition continues: when the International Electrotechnical Commission began defining PLC languages in 1994, IEC 61131-3 named five, and Ladder is the first of them.
Connections
Associated With
PLCs are a standard mechatronic control element
In Field
Source Programmable logic controller (Wikipedia)
Invented By
Source Programmable logic controller (Wikipedia)
Sources
1. Programmable logic controller (Wikipedia)
History
Dick Morley is credited with having invented the first PLC, the Modicon 084, for General Motors in 1968.
Advantages
It was designed to tolerate the industrial environment better than systems intended for office use, and was more reliable, compact, and required less maintenance than relay systems.
In Field: Industrial Engineering, Lead section
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis.
Invented By: Dick Morley, Introduction
Dick Morley is credited with having invented the first PLC, the Modicon 084, for General Motors in 1968.
In Group: Factory Automation and Measurement, Introduction
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis.
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