The History of Programmable Logic Controller (PLC)

Programmable Logic Controller (PLC) has introduced first time in 1960’s. PLC made to decrease the cost of maintenance and replacement of the machine control system that use relay. Bedford Associates propose MODICON (Modular Digital Controller) for the company in America. MODICON 084 is the first PLC that used on commercially production. The production process requirement that is getting much cause the system has to be changed. If used system is mechanic relay, that thing will become a big problem indeed. Besides its useful period is limited, system also requires careful treatment. If damage occurred, hence will very difficult to find it. Therefore, controlling that is facilitating either in maintenance and or using is required.
In 1970’s, the dominant PLC technology is sequencer machine and CPU which is based on bit slice. Processor AMD 2901 and 2903 popular enough used in MODICON and PLC A-B. The ability of communication on PLC emerges in the early of 1973. The first system is Modbus dari MODICON.
In 1980’s the effort to standardize communications with protocol property of General Motor (MAP) has done. In 1990’s the reduction of new protocol and the modernization of physical layer of protocols that popular in the year of 1980 had done. The last standard was IEC 1131-3, it tried to combine the programming language PLC into one standard.