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Plc Introduction Programmable controller is the first in the late 1960s in the
United States, then called Plc programmable logic controller
(ProgrammableLogicController) is used to replace relays. For the implementation of
the logical judgement, timing, sequence number, and other control functions. The
concept is presented Plc General Motors Corporation. Plc and the basic design is the
computer functional improvements, flexible, generic and other advantages and relay
control system simple and easy to operate, such as the advantages of cheap prices
combined controller hardware is standard and overall.
According to the practical application of target software in order to control the
content of the user procedures memory controller, the controller and connecting the
accused convenient target. In the mid-1970s, the Plc has been widely used as a central
processing unit microprocessor, import export module and the external circuits are
used, large-scale integrated circuits even when the Plc is no longer the only logical
(IC) judgement functions also have data processing, PID conditioning and data
communications functions. International Electrotechnical Commission (IEC)
standards promulgated programmable controller for programmable controller draft
made the following definition : programmable controller is a digital electronic
computers operating system, specifically for applications in the industrial design
environment. It used programmable memory, used to implement logic in their internal
storage operations, sequence control, timing, counting and arithmetic operations, such
as operating instructions, and through digital and analog input and output, the control
of various types of machinery or production processes.
Programmable controller and related peripherals, and industrial control systems
easily linked to form a whole, to expand its functional design. Programmable
controller for the user, is a non-contact equipment, the procedures can be changed to
change production processes. The programmable controller has become a powerful
tool for factory automation, widely popular replication.
