PLC
- PLC is an abbreviation of public limited company, a British business term.
An example of PLC is a company in the UK with shares available to the general public.
PLC definition by Webster's New World
plc - Computer Definition
A technology that uses electric power transmission lines and inside wire for telecommunications transmission. The technology was invented in 1928 by AT&T Bell Telephone Laboratories, and has been used since that time by the electric power utilities in select internal low speed data communications applications. Some customer premises equipment (CPE), such as small key telephone systems and intercom systems, based on PLC technology has made use of embedded inside electrical wire to avoid the cost of special wiring. In Europe and most of the rest of the world, PLC standards allow for communications over the 240-volt power grid at frequencies from 30 kHz to 150 kHz. In the United States, the standards for the 120-volt grid allow the use of frequencies above 150 kHz, as well. Power utilities use the frequencies below 490 kHz for internal applications such as telemetry and monitoring and control of equipment at remote substations. In the 1990s, development began on broadband over power line (BPL), which since has been standardized. BPL includes Access BPL and In-House BPL. See also Access BPL, BPL, and In-house BPL.
(1) (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.
(2) (Power Line Communications) See broadband over power lines.
plc - Investment & Finance Definition
Stands for Public Limited Company Means, which is a commonly used term in the U.K., Ireland, and other English-speaking countries other than the U.S. It is equivalent to Inc. in the U.S.
