PLC


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PLC

PLC

(1) (Power Line Communications) See broadband over power lines.

(2) (Programmable Logic Controller) A programmable microprocessor-based device that is used in discrete manufacturing to control assembly lines and machinery on the shop floor as well as many other types of mechanical, electrical and electronic equipment in a plant. Typically RISC based and programmed in an IEC 61131 programming language, a PLC is designed for real-time use in rugged, industrial environments. Connected to sensors and actuators, PLCs are categorized by the number and type of I/O ports they provide and by their I/O scan rate.

In the late 1960s, PLCs were first used to replace the hardwired networks of relays and timers in automobile assembly lines, which were partially automated at that time. The programmability of the PLC enabled changes to be effected considerably faster. Contrast with PAC and DCS. See IEC 61131.
References in periodicals archive ?
Options: Heating, floating upper platen, PLC controls for different accuracy levels, vacuum cabinet for entire press, high-heat platens (up to 600 F), closed cooling system, data recording, multiple daylights.
Features: Electrically heated platens, digital temperature control, PLC controls.
367(a) rules, PLC or its subsidiary must have an active business outside the U.
companies (including nonresident shareholders) own less than 60% of PLC after the transfer, or if PLC is engaged in a substantial business activity in the U.
For communications, the PLC offers direct connections to programming devices or operator interfaces, as well as options for DH-485 networking, DeviceNet, and EtherNet/IP.
If PLC size is the overriding factor, the next step in terms of compactness is the nano controller.
Called Tech II, these controls still require a central PLC on the vacuum pump--but only to handle the "master on/off" tasks, says v.
To date, more than 150 man-years have been invested in the company's PLC technology.