PLC mainly refers to the operation of electronic digital computing system, programmable logic controller, used to control machinery of the production process. Is also a public limited company cars and so the name of the power cord short.
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abbreviation Introduction to Programming Programmable Logic Controller PLC 1, PLC basic concepts 2, PLC basic structure of the 3, PLC works 4, PLC internal operation of 5, plc is currently The major brands of PLC Power Line Communication PLC Caution Public Limited Company PLC access mode abbreviation. The recorder and the comparison of PLC plc new trend presents new PLC technology trends: PLC: Planar Lightwave Circuit technology (communications) abbreviation programmable logic controller PLC = Programmable logic Controller, programmable logic controller, a digital computing operation of electronic systems for applications in industrial environments designed. It uses a programmable memory for its internal storage procedures, logical, sequential control, timing, counting and arithmetic operations such as user-oriented instruction, and through digital or analog input / output control of all types machinery or production processes. Is the core of industrial control PLC = Programmable Logic Controller, PLC programmable logic controller also has the following several names: PLC = Power Line Communication, PLC, that are commonly called PLC = Public Limited Company, Public Limited Company, stock listed companies. PLC = Power-line Carrier, power line carrier, power line carrier, power cable cars. PLC = Power Loading Control, Dynamic load control. PLC = Preparative Layer Chromatography, preparation layer chromatography. PLC = Programming Language Committee, Programming Language Committee [the U.S.]. Introduction to Programming PLC 1, PLC programmable controller, the basic concept (Programmable Controller) is a member of the family computer is to PLC Atlas (7) industrial control applications, design and manufacture. Early called the programmable logic controller PLC (Programmable Logic Controller), referred to as the PLC, it is mainly used to replace the logic control relays. As technology advances, the device's functionality has been greatly exceeded the scope of logic control, therefore, such a device today called programmable logic controller, referred to as the PC. However, in order to avoid personal computer (Personal Computer) in the short confusion, it will be referred to as programmable logic controller PLC,
nike air force one, plc since 1966, the U.S., Japan, Germany, programmable controllers and excellent quality, and powerful. 2, PLC basic structure of the PLC is essentially a computer dedicated to industrial control, and its micro-computer hardware is basically the same basic components as: a, the power supply in the entire PLC system plays a very important role. If you do not have a good, reliable power system is not working, so the PLC manufacturers design and manufacture of power very seriously. General AC voltage fluctuations of +10% (+15%) range, you can not take other measures to PLC directly connected to the AC line to b. central processing unit (CPU) Central Processing Unit (CPU) is the PLC's control center. It is given by the function of PLC system program from the programmer receives and stores the user program and data type; check the power supply, memory, I / O and timer alert status, and to diagnose syntax errors in the user program. When the PLC into run-time, first it scans the scene to receive the status of various input devices and data, respectively, into I / O image area, and then one by one from the user program reads the user program memory, after a shell and press provisions of the Directive the result of logic or arithmetic operations into the I / O image area or data register. And all of the user program is finished, and finally I / O image area of the state or the output of the output register data to the appropriate output device, and so on to run until stopped. To further improve the reliability of PLC, PLC is also large in recent years constitutes a redundant dual-CPU system, or by three voting systems CPU. Thus, even if a CPU fails, the whole system can still work properly. c, the memory storage of system software called system memory program memory. Memory storage of application software known as the user program memory. d, input and output interface circuit 1, the field input interface circuit by the optical coupling circuit and computer input interface circuit, the role of PLC and field control of an interface for input channels. 2, field output interface circuit by the output data registers, interrupt request strobe circuit and integrated circuit, the role of PLC output interface circuit through the on-site implementation of parts of the output to the field corresponding control signal. e, function modules, such as counting, positioning modules f, communication modules such as Ethernet, RS485, Profibus-DP communication module 3, PLC works one. scanning technology into operation when the PLC, its work process is generally divided into three stages, namely the input sample, the user program execution and output refresh three stages. Completion of the three phases is called a scan cycle. During the entire operation, PLC's CPU scan speed of a certain repeat the above three stages. (A) of the input sampling phase of the input sampling stage, PLC to scan the input in order to read all the states and data, and deposit them with the I / O image area was in the corresponding unit. After the input sample, transferred to the user program execution and output refresh stage. In both phases, even if the input state and data changes, I / O image area in the state and the corresponding data elements will not change. Therefore, if the input is a pulse signal, the pulse width must be greater than a scan cycle, to ensure that in any case, the input can be read. (B) the user program execution stage of the implementation phase in the user program, PLC is always in the order by top-down scan the user program (ladder). When the scan each ladder, the ladder is always the first scan by the contact form on the left of the control line, according to the first left and right, the first following the order of the control circuit by the contact form logical operations , then the logical result of the operation, refresh the logic of the coil in the system RAM memory state of the corresponding bit; or refresh the output coil in the I / O image area in the state of the corresponding bit; or to determine whether the implementation of the ladder instructions provided for special functions. That is, the user program execution, only the entry point in the I / O image area of the state and the data will not change, while the other output point and the soft device I / O image area or system RAM storage area state and data are likely to change, and ranked in the top of the ladder, the program execution results came in below those who will use these coils work or data of the ladder; the contrary, the ladder came in below its be refreshed or data logic state of the coil to the next scan cycle can only be on the top row of the procedures in their work. In the course of program execution immediately if you use I / O commands, you can directly access the I / O points. That the use of I / O instruction,
nike air force 1, then the value of the input process image register is not updated, the program directly from the I / O module value, the output process image register will be updated immediately, which is an immediate input some differences. (C) Output refresh period when the scan after the end of user program, PLC to enter the output refresh stage. During this time, CPU in accordance with the I / O image area corresponding to the state and refresh all of the output data latch circuit, and then the output circuit driving the corresponding peripherals. At this time, is the PLC's real output. 4, PLC internal operation of the approach, while used by the PLC ladder program is often used to many relays, timers and counters and other names, but the PLC is not an entity that has the internal hardware, but to do the memory and programming logic control programmatically edit, and output devices connected through the external mechanical device to do physical control. Therefore, the controller can greatly reduce the required hardware space. PLC ladder program execution actually works is the first progressive ladder code to scan and read into the CPU in the control of the operation of the final implementation. Throughout the scanning process includes three steps, Sensor state (1 or 0 for open or closed), and its status is written in memory location corresponding to Xn. Step II The operation result is output coil into the memory location corresponding to withhold response to the output terminal Yn. Step Three These three steps known as the PLC of the scan cycle, the time required to complete the reaction time as PLC, PLC input signal is smaller than this time if the reaction time, the possibility of a misunderstanding. After each program execution before the next program execution, the output and input status will be updated once, so this mode of operation as an output, said input
PLC internal operation of the structure of 5, plc brands is currently the main U.S. AB, ABB, Panasonic,
air force 1 high, Siemens, Mitsubishi, Omron, Delta, Fuji, Schneider, PLC programmable logic controller such as the letter Jie Caution
PLC Caution (1)
PLC Caution (2)
PLC Caution (3)
PLC Program PLC manufacturers encrypt individual applications will protect their procedures are not copied by others, and equipment manufacturers in order to control the use and recovery of the purchase price. in the program to set some parameters within the control. The manufacturers have their own encryption methods: the most simple decryption Mitsubishi PLC, of which Siemens S7-200CN most complicated encryption, only disassemble from the chip to crack. Power Line Communication PLC Power Line Communication access mode, the English referred to as PLC, is the use of power line transmission of data and voice signals in a communication. The technique is to add high-frequency information contained in the current,
air force one high, and then wire transfer, then the modem to receive information separate from the current high frequency, and send to the computer or phone in order to achieve information transmission. The technology does not require re-routing based on the existing data on the wire, voice and video, multi-service bearer, that is, to achieve quadruple. End-users simply plug the power cord, you can achieve Internet access. 1.6M to 30M PLC frequency range used for signal transmission. Sending, the use of GMSK modulation or OFDM modulation technology to the user data, and then in the power transmission line; at the receiving end, the first modulated signal through the filter will filter out, and then through the modem, you can get the original communication signal. The current communication rate can be achieved by specific equipment between different in 4.5M ~ 45M. PLC equipment is divided into the central office and modem, PLC modem, central office responsible for internal and external communication and network connection. In the communication from the user's data into the modem modulation, through the user's distribution lines to the central office transmission equipment, central office out of the signal demodulation, and then go to the outside Internet. Public Limited Company's acronym. According to UK company law, company registration form of limited and unlimited company is divided into two, while the Limited is divided into Public Company Limited (Public Limited Company) the stock of listed companies and private limited company (Private Limited Company) (ie non-listed companies .) Establishment of the Open Company Limited, the company name must include the Public Limited Company PLC word or abbreviation for the comparison of PLC and PLC recorder functionally stronger than the recorder to many, but simple control and record the above may seem simple recorder and cost-type, and the PLC and the need for programming, need a computer or touch screen and so on. But the recorder as a finished product, stability seems a good comparison. PLC plc is a new trend in industrial environments specifically designed for digital computing applications operating in the electronic device. It can be programmed using the memory, used in its internal storage implementation of logical, sequential operation, timing, counting and arithmetic operations, such as operating instructions, and through the digital or analog input and output, control of all types machinery or production processes. PLC has been widely used in iron and steel, petroleum, chemical, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection and cultural entertainment and other industries, it has a high reliability, strong anti-interference ability, powerful, flexible, easy to use, small size,
air force one low nike, light weight, low cost features. PLC technology presents new trends: 1: product size to large and small development of large two directions: I / O points up to 14336 points, 32-bit microprocessor, multi-CPU parallel work, large-capacity memory, high-speed scanning speed . Small: the overall structure of the modular structure to the development of small-scale, increased configuration flexibility, reducing costs. 2: PLC in a closed loop process control is used widely 3: continue to strengthen communication 4:. Continue to introduce new components and modules in addition to the main use of high-end PLC CPU to increase processing speed, there EPROM or RAM with a processor, the smart I / O modules, high-speed counting module, remote I / O modules, and other special of the module. 5: tools for diverse programming, function continuously improved, standardized programming languages tend to have a variety of simple or complex programmer and programming software, the use of ladder, function chart, and other programming languages Statement List, there are 6 high-end PLC instruction: the development of fault-tolerant technology using hot standby or parallel work,
air force one shoes, a majority vote of the work. 7: the pursuit of standardization of hardware and software. PLC History Origin: 1968 General Motors made the request to replace the relay control device. In 1969, Digital Equipment Corporation developed the first programmable controller PDP-14, General Motors Corporation in the United States successful trial production line for the first time by means of procedures used in electrical control, this is the first generation of programmable program controller, called Programmable, is recognized as the world's first PLC. In 1969, the United States developed the world's first PDP-14 1971, the Japanese developed the first DCS-8 1973, Germany developed the first PLC 1974, China developed the first PLC development: the 20th century, 70 the early emergence of the microprocessor. It soon will be introduced into the programmable controller, the PLC increased the computing, data transmission and processing functions, complete with computer features a real industrial control devices. At this time of the PLC, computer technology and the concept of conventional control relay product of the combination. Developed a personal computer, in order to facilitate and reflect the functional characteristics of programmable controllers, programmable logic controller known as the Programmable Logic Controller (PLC). The mid to late 70s of the 20th century, the programmable controller into the practical stage of development, the introduction of computer technology has been fully programmable controller, it features a leap occurs. Higher operation speed, ultra-small size, more reliable design of industrial interference, analog computing, PID function and a high price to lay its position in modern industry. 20th century, early 80s, the programmable controller in the advanced industrial countries has been widely used. Production of the world's countries, increasing the programmable controller, the output rise. This marks the programmable controller has entered the mature stage. The 20th century, mid 80's to 90, is the PLC of the fastest growing period, annual growth rate has been maintained at 30 to 40%. During this period, PLC capability in dealing with analog and digital computing power, man-machine interface capabilities and network capabilities have been greatly improved, PLC gradually entering the field of process control, in some applications in the field of process control replaced the dominant DCS system. The late 20th century, is characterized by the development of programmable logic controller more responsive to the needs of modern industry. This period of development of the mainframe and super-minicomputer, the birth of a variety of special function units, the production of various man-machine interface unit, communications unit, make the application of industrial control equipment, programmable controllers supporting much easier. PLC: Planar Lightwave Circuit Technology (Communications) PLC is the abbreviation of Planar Lightwave Circuit in English, translated into Chinese as: planar waveguide (technology). The so-called planar optical waveguide, that is located in a plane waveguide. As you are familiar with single-layer circuit boards, all circuits are located in a plane as the substrate. Thus, PLC is a technology, it is not generally refers to certain types of products, but not the splitter! We are the most common PLC splitter is silicon dioxide (SiO2) do, in fact, the materials involved in PLC technology is very broad, such as glass / silica (Quartz/Silica/SiO2), lithium niobate (LiNbO3), III-V semiconductor compounds (such as InP, GaAs, etc.), silicon on insulator (Silicon-on-Insulator, SOI / SIMOX), silicon oxynitride (SiON), polymers (Polymer) and so on. Planar waveguide technology solutions based on the device include: splitter (Splitter), star coupler (Star coupler), variable optical attenuator (Variable Optical Attenuator, VOA), optical switch (Optical switch), optical frequency comb ( Interleaver) and AWG (Array Waveguide Grating, AWG) and so on. According to the needs of different applications (such as response time, ambient temperature, etc.), these devices can choose different material systems and processing technology produced. It is worth mentioning that these devices are passive devices, and is independent. Between them can be combined with each other, or another combination with other active devices, can pose a variety of different functions of the high-end devices. English name PLC Programmable Logic Controller, Programmable logic controller full name in Chinese, is defined as: a digital electronic computers operating system designed for applications in industrial environments designed. It uses a programmable memory for its internal storage procedures, logical, sequential control, timing, counting and arithmetic operations such as user-oriented instruction, and through digital or analog input / output control of all types machinery or production processes. Main product type PLC 1) and medium-sized PLC ◆ 2006, China's large and medium-sized PLC market, total sales reached 168 million and 154 million U.S. dollars, compared to 2005 increased by approximately 13.3% and 1.6%. By 2009, the market size will reach about 2.5 million and 175 million U.S. dollars. ◆ PLC mainly medium and large applications in metallurgy, automobile, electric power, infrastructure and other areas. Which in the most widely used in metallurgical industry, accounting to over 30% market share. ◆ In the Eleventh Five-Year period, the overall rate of growth than small and medium-sized PLC PLC.'s Procurement for the client or supplier side of the sales data, and medium-sized PLC have shown stronger growth. ◆ PLC drivers and medium-sized market countries in recent years, infrastructure construction, and municipal construction increased investment. And thus increase the demand for a large PLC. ◆ China's automobile industry developed rapidly in recent years, the automotive industry for medium-sized PLC equipment demand is relatively large. Therefore the development of the industry is to promote medium-sized PLC market. and medium-sized PLC market barriers to large-scale PLC ◆ metallurgical industry is the major application areas, but it is the focus of national macro-control in restraint of trade, the bank is limited to the scheme Government loans to small and medium sized projects in the development of smelting plant to take restrictive measures, leading to lower investment returns, which are large-scale PLC market development will be the limiter. 2) Small PLC ◆ 2006, the small PLC market in China grew by about 11.3% over the previous year, the market scale reached 219 million U.S. dollars. By 2009, the market size will more than 280 million U.S. dollars. ◆ Small PLC is mainly used in textile, food processing, automotive and other industries, the textile industry is one of the most important application of a small PLC industry, its 2006 market share of about 29.7%. ◆ With the major textile manufacturers have completed automation of the future of the industry demand is expected for small PLC will be relatively lower. ,2007-2009 affected the overall market growth rate of small PLC is expected to remain at 9.0% - 10%. ◆ small PLC market drivers with increased automation, small plc applications will be gradually expanded to other industries from industrial control, such as fast-food restaurant, hospital operating rooms, revolving doors and vehicles, and even the introduction of family homes, places of entertainment and the business sector, which is expected to be in the future for small PLC to provide a new market space. ◆ China is gradually becoming a global manufacturing base for machinery and equipment, making the rapid development of the domestic OEM manufacturers. Some OEM manufacturers in order to avoid fierce competition, the pursuit of higher profits, will replace the relay with a small PLC or microcontroller control program. ◆ small PLC market barriers to the textile industry is the most important application of a small PLC industry, with some of the major textile manufacturers have already completed the automation of the future of the industry demand is expected for small PLC will be relatively lower. ◆ ensure the PLC in a complex industrial environments with high reliability is still a lot of new entrants to the field of small PLC manufacturers face technical problems. Industry application of PLC 1) Textile Machinery �� PLC applications in the textile equipment has been popular, Qing Hua, carding, drawing, combing, roving, winding, doubling, twisting, warping, sizing, non woven machines have been used. �� textile industry is the most important application of small-scale industries PLC, PLC, for use on equipment I / O points range 8-1024 points, of which about 85% of 8 to 112 points. �� with some of the major textile manufacturers have already completed the automation of the industry demand for the next few years the growth rate PLC is expected to slow down. 2) Printing Machinery �� PLC in the industry is mainly used to complete each unit of water roller clutch accurate control of motor coordination. �� printing machinery to the low-end Chinese products, the overall level of automation in the printing machinery greater than the gap between Europe and America. �� foreign printing machinery has PLC as standard, while the domestic and more than one third of the printing machinery in the use of relay control, the industry have a greater demand for equipment renewal. 3) Packaging Machinery �� domestic packaging machinery industry, PLC based control system still dominates, with a high degree of automation and large-scale sets of packaging machinery design, production capacity of small firms. �� PLC equipment is usually in the bottom of the device to provide reliable, real-time control. �� packaging equipment manufacturers more and more to consider in the device is equipped with advanced automation products, to improve the technological content of products to enhance market competitiveness. 4) The existence of the metallurgical industry �� China has more than 6,000 metallurgical enterprises, PLC's application of the scale of over 500 million yuan, mainly in large-scale PLC based. �� PLC metallurgical industry is currently the mainstream products, the main controller, and is expected in the short term this position will not be shaken. �� the impact of macroeconomic regulation and control by the state, the next few years the growth of the metallurgical industry will slow, the industry demand for PLC will be affected accordingly. 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