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Article: Retrofitting PLCs to electromechanical relay control systems. (programmable logic controller)
- Article from:
- Plant Engineering
- Article date:
- September 23, 1993
- Author:
CopyrightCOPYRIGHT 1993 Reed Business Information, Inc. (US). This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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When an electromechanical relay control panel deteriorates to the point where it is a perennial headache, a PLC is often the remedy that provides the most immediate and long-lasting relief
The programmable logic controller, or PLC, dates to the year 1969, when three manufacturers individually introduced their respective versions. The concept gained immediate and rapid acceptance, and within four years, there were more than a dozen manufacturers in the field. Acceptance, however, was thwarted to some extent by inertia. Many plant engineers and electricians experienced in electromechanical relay control were uncomfortable with the new technology, and were hesitant to ...