The logic of plc is programmed so that user can create a highly dedicated plc working system for their. A programmable logic controller plc is an industrial solidstate computer that monitors inputs and outputs, and makes logicbased decisions for automated processes or machines. The user can select which controllers will be used in the project microcontroller, programmable logic controller or both, and easily interconnect their pins to the peripheral modules, by using the implemented graphical. A programmable logic controller plc is a small, modular solid state computer with customized instructions for performing a particular task. Programmable logic controller a programmable logic controller plc is a specialized computer used to control machines and process. The following are some of the more common terms used to define the. The plc or programmable logic controller has revolutionized the automation industry. It covers programable logic controllers and their implementation. Plc definition programmable logic controller program. This is a powerpoint presentation used to complete a requirement for a technical communications project in college.
Programmable logic controller plc semantic scholar. This second edition, like the first, provides a comprehensive theoretical, yet practical, look at all aspects of plcs and their associated devices and systems. This second edition, like the first, provides a comprehensive theoretical, yet practical, look at all aspects of plcs and their associated devices and. They are one of the most advanced and simplest forms of control systems which are now replacing hard wired logic relays at a large scale. Programmable logic controllers free download as powerpoint presentation. Simple programming program changes without system intervention. The plc receives information from connected sensors or input devices, processes the data, and triggers outputs based on preprogrammed parameters. Programmable logic controllers university of pennsyl vania 1 definition a digitally operated electronic apparatus which uses a programmable memory for the internal storage of instructions for implementing specific functions such as logic, sequencing, timing, counting, and arithmetic to control, through digital or.
Find out inside pcmag s comprehensive tech and computerrelated encyclopedia. Introduction of programming logic controller plc working. Nemas definition nema or national electrical manufacturers association of a programmable logic controller is a. Plc can be found in almost all of the heavy industries which require process and sequences. The output ports of a plc are relay or opto isolator with transistor or triac, depending on the devices that are to be switched on or off. A programmable logic controller, also called a plc or programmable controller, is a computertype device used to control equipment in an industrial facility. Generally, the digital signal from an output channel of a plc is used to control an actuator, which in turn controls some process.
Plcs operate in realtime which means that an event taking place in the field will result in. Programmable logic controller plc is a microprocessor based. Jackson lecture 32 basic addressing for the allenbradley plcs and the simulator used, the input and output image areas in addition to other data are held in data files each data file holds information such as. Programmable logic controllers continuously monitors the input values from various input sensing devices e. A programmable logic controller plc is an industrial computer specialised for real time applications. A plc control system organization in which a central plc controls several machines or processes. A programmable logic controller plc is a special form of microprocessorbased controller that uses a programmable memory to store instructions and to implement functions such as logic, sequencing, timing, counting, and arithmetic to control machines and processes and is designed to be operated by engineers with. Programmable logic controllers nfi automation academy. Automationdirect is your source for programmable logic controllers plcs. Programmable logic controller synonyms, programmable logic controller pronunciation, programmable logic controller translation, english dictionary definition of programmable logic controller. Those making the buying decisions for programmable controller. Glossary of terms used in programmable controllerbased. A programmable logic controller plc or programmable controller is an industrial digital computer which has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability, ease of programming and process fault diagnosis plcs can range from small modular devices with tens of inputs and outputs.
Definition of programmable logic controller in the dictionary. A programmable logic controller plc is a special form of microprocessorbased controller that uses a programmable memory to store instructions and to implement functions such as logic, sequencing, timing, counting, and arithmetic to control machines and processes and is. Due to its robust construction, exceptional functional features like sequential control, counters and timers, ease of programming, reliable controlling capabilities and ease of hardware usage this plc is used as more than a specialpurpose digital computer in. Introduction to programmable logic controllers plcs. Programmable logic controller article about programmable. A programmable logic controller plc is an industrial computer control system that continuously monitors the state of input devices and makes decisions based upon a custom program to control the state of output devices almost any production line, machine function, or process can be greatly enhanced using this type of control system. Plcs are integrated systems containing a processor, main memory, input modules, output modules that are coupled together by a common bus.
Frequently, a combination of different technologies is used. The new control system had to meet the following requirements. Programmable logic controller definition of programmable. Utility plants, batch control application, chemical processing, conveyor systems, food. Can be used standalone or in conjunction with a scada or other system. The web application controls the programmers for the user accessible microcontroller and programmable logic controller. A programmable logic controller plc is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or lighting fixtures. Today plcs can be found in everything from factory equipment to vending machines, but prior to new years day 1968 the programmable controller didnt even exist. Furthermore, differentiation is made between hardwired programmable e. A programmable logic controller, or plc, is a ruggedized computer used for industrial automation. Unlike generalpurpose computers, the plc is designed for multiple inputs and output. General definitions of plc size are given in terms of program memory size.
In the course of this work, the student will be presented with real world programming problems that can be solved on any available programmable controller or plc. Programmable logic controller plc is a special computer device used in industrial control systems. The greatest benefit of automating with a programmable logic controller is the ability to repeat or change the operation or process while collecting and communicating vital information. However, plcs can be thought of in simple terms as. Bolton, in programmable logic controllers sixth edition, 2015. These controllers can automate a specific process, machine function, or even an entire production line. What does programmable logic controller actually mean. Plcs, which are used in industrial control systems for a wide variety of industries, have largely replaced mechanical relays. Programmable logic controller contains seven units of instruction. Information and translations of programmable logic controller in the most comprehensive dictionary definitions resource on the web. The kinds of equipment that plcs can control are as varied as industrial facilities themselves. It uses a programmable memory to store instructions and specific functions that include onoff control, timing, counting, sequencing, arithmetic, and data handling.
A programmable logic controller plc, or programmable controller is an industrial digital computer which has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis. A programmable logic controller plc is a digital system used to make electrical and mechanical processes become automated. To respond to these phenomenal changes, we introduce the second edition of programmable controllers. Pdf the concept of programmable logic controllers and its role. Early machines were controlled by mechanical means using cams, gears, levers and. Output devices in programmable logic controllers tutorial. Get unbeatable value on plc hardware, including fast shipping and free technical support. Programmable logic controller simple english wikipedia. They are basically used to control automated systems in industries. In essence, a plc is a special purpose industrial microprocessor based realtime computing system, which performs the following functions in the context of industrial. The first programmable logic controller plc was developed by a group of engineers at general motors in 1968, when the company were looking for an alternative to replace complex relay control systems. Instead what existed was a unique set of challenges that needed a solution. Define execution order for your tasks and programs. A typical block diagram of plc consists of five parts namely.
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