基于PLC控制的小車運料控制系統(tǒng)設(shè)計,基于PLC控制的小車運料控制系統(tǒng)設(shè)計,基于,plc,控制,節(jié)制,小車,控制系統(tǒng),設(shè)計 外文資料翻譯 The characteristics and trends of PLC, DCS and industrial PC At present, widely used in industrial automation systems of the three large industrial PC, DCS and PLC. Here, for their economic and technological standards and development trends described. First, the characteristics and Application of PLC 1. PLC Application Early PLC (Programmable Logic Controller, PLC), mainly to replace relay logic control to achieve. With computer technology, communications technology and the rapid development of automatic control technology, the PLC will be the traditional relay control technology and the emerging computer technology and communications technology integration, with high reliability, strong function and flexible, Programming simple, easy to use and a series of advantages, as well as good performance of the industrial environment and control targets of performance in industrial production in a wide range of applications. 1969, the United States Digital Equipment Corporation (DEC) developed the world's first programmable controller. Early separation from the programmable controller components and small and medium-sized integrated circuit component, the main function previously performed by the relay is completed sequence control, such as timing. The early 1970s, small size, strong function and cheaper microprocessors used PLC, makes the PLC function has been enhanced significantly. In terms of hardware, in addition to maintaining its original switch modules, has also increased the simulation module, remote I / O modules and special function modules all. In terms of software, easy to use PLC Electric staff in the ladder diagram programming language, in addition to maintaining the original logic functions, has also increased the arithmetic operations, data processing and transmission, communications and self-diagnostic capabilities. In the 1980's, the late, as ultra-large-scale integrated circuit technology is developing rapidly, microprocessor market a sharp price drop, the PLC makes the microprocessors used by the general improvement in grades. Furthermore, in order to further improve the processing speed of PLC, the manufacturer has developed a dedicated logic chip, greatly improving the PLC hardware and software functions. 2. Characteristics PLC In the developed industrial countries, PLC has been widely used in all industrial sectors. According to "The United States market information" World PLC and software market report, in 1995 the global software PLC and its economies of scale of about 5 billion US dollars [5]. As electronic technology and the development of computer technology, the PLC functions are greatly enhanced, with the following characteristics: (1) high reliability. PLC benefited from the high-reliability hardware and software on a series of anti-jamming measures and the cycle of its special scanning methods of work. (2) with rich I / O interface module. PLC for different industrial field signal and the corresponding I / O modules and industrial devices or equipment at the scene of a direct connection. In addition to improving performance, it also has a variety of man-machine dialogue interface modules to the industrial composition of local area networks, it also multiple communications network interface module. (3) modular structure. To meet the needs of various industrial control, in addition to a small PLC unit, the vast majority of PLC are modular structure. PLC various components, including the CPU, power supply, I / O, etc. is modular in design from the rack and cables will connect each module, the system's size and function in accordance with the needs of users of its own portfolio. (4) easy to learn programming. Most of the PLC programming relay control circuit similar to the ladder diagram form, the user, do not have computer expertise, it is easy to general engineering and technical personnel understand and master. (5) Installation is simple and easy maintenance. PLC does not require specialized equipment room in a variety of industrial environments can be directly run. Various modules are run and fault indication devices, user-friendly understanding of the operation and find fault. The modular structure, so any failure of a module, users can replace the module, allowing the system to rapidly resume operation. Second, the characteristics and Application of industrial PC 1. Industrial PC industrial control applications Industrial PC hardware and software support of a broad, diverse varieties can take full advantage of excellent graphical user interface capabilities, the industrial users an enormously attractive. Early PC but not suitable for industrial process control automation applications, such as increasing modified by strengthening the protection of the case, such as cooling damping taken measures to meet the industrial environment is the application of some of the requirements of the characteristics of its early development. In recent years, with the further integration of chips increase, the increase in functionality, system board technology, packaging components and surface mount technology improvements, and standard industrial bus, a standard operating system and graphical user interface software development, the Industrial PC development and application to enter its peak period, the complete machine reliability improved hardware, system software has continually improved, greatly enriched applications, in-depth industrial automation and control industries in various fields. According to incomplete statistics, in the industrial automation industrial PC usage in the total industrial control computer 65%, and an annual growth rate of 21 per cent continued to expand. PC manufacturing industry by buying rate of the PC market as a whole accounted for about 10 percent. In the industrial automation process control systems used in industrial management industry accounted for 44.1%, applied to the console operator of 36.4%, applied to the management of the quality of 18.8%, applied to monitor and control, engineers console, Data Acquisition System respectively of the total 18.2%, 12.6% and 11.1%. Industrial PC A notable feature is independent of configuration, but also with the DCS, PLC, CNC and other computer connected network. At present, almost all DCS, PLC manufacturers use industrial PC control system preparation procedures, more and more companies use industrial control system operator interface PC as a workstation. Formed by the industrial PC computer control system in the field of industrial automation process control play a very important role, has been outstanding for factory and workshop level process control, data acquisition, batch processing, quality control, automation and machine optimization and experts control, and other tasks. 2. Main features of the PC industry (1) an industry-standard application In order to enable different computer manufacturers can be linked to one another, as well as take full advantage of the market varied PC components and the functions provided by the module, industrial PC with standard interface, which not only required by the IEEE, DIN and ISO standards, to adopt AT (ISA), EISA and STD, VME, Multibus Ⅱ, and other bus standards. Industrial PC now has been widely adopted PCI, PCMCIA bus standard, the two industry-standard bus for improved performance and speed of a PC great role. (2) to take the necessary protection measures Applications must be based on the control of environmental conditions on the PC industry adopt various protective measures, adapted from a project management departments to the scene operational control applications. Industrial PC must be able tolerance of the harsh conditions at the production environment, we must have good heat dissipation, ventilation, waterproof, dustproof, anti-jamming and anti-corrosion and anti-shock, anti-vibration and a series of protective features. (3) industrial operating system MS-DOS because of lack of memory, unable to support multi-task, the lack of real-time features networking capacity and poor, has been basically not used. Along with the main computer chip, the rapid development of higher speed and better performance of industrial PC endless. In addition, almost all software development companies have shifted the focus will be open to the OS / 2, Windows and Unix, and other operating systems. Especially suitable for industrial process control automation real-time multi-tasking operating system application of Windows NT/2000 PC industry has generally become the mainstream operating system. (4) and automation equipment and communications systems Industrial PC should be able to with a variety of automated equipment and systems for effective communication, such as PLC, DCS, data acquisition systems, as well as on a management computer communication. With the continuous development of new technologies, due to open systems and system integration technology for the development needs of the PC industry these communications will be increasingly important role in the show. Standard communications network to the development of the industrial PC applications more open, and will enable its small computer pose a greater threat. MAP agreement to Ethernet-based communication networks to allow various computer systems communicate with each other directly. Different levels of automation in the mutual communication network systems, require separate handling of the communication channel. Industrial PC required monitoring level from the lower level data acquisition system and transmitted to a computer on. (5) the safe operation of In addition to the PC industry adopt various protective measures, the need for the operation of state industrial PC monitor, monitor the operation of computer systems and software, scheduled inspection procedures specified in the implementation of the cycle. Computer should be able to monitor the power supply, and failure or excessive deviation warning signal was issued. 2. Industrial PC the status quo and development trend Industrial PC now have a wide range of performance and functionality, low-grade industrial PC with a CRT terminal operators, high-grade industrial workstation with a PC. Thus, high-grade and low-grade industrial PC workstation performance and the price of overlap, the difference is disappearing, industrial PC and workstations increasingly blurred the boundaries between. Industrial PC workstation is the industrial automation process control system applications excellent choice, standard communication networks and the use of graphical operating system makes industrial PC and other equipment to effectively communicate. With 32-bit and 64-bit computer chips and the emergence of use, will be further enhanced industrial PC workstation functionality and performance, but also to a higher future direction. Industrial PC software is in the process of industrial automation control system of a key application. Hardware performance and the improvement of the drop in prices, as well as standardization and greater efficiency, better graphics and the use of the operating system to promote industrial PC software is an important factor in development. At present, the rapid development of industrial PC software on the market has thousands of independent software development company can supply in the industrial PC running on industrial process control configuration software package to meet the rapid growth of the industrial user needs. Industrial PC application of industrial process control software packages are running on the configuration of OS / 2, Windows, and UNIX operating system standard. Industrial process control applications have emerged in large quantities, software development companies can provide a large number of industrial PC on the run for the PLC, DCS, such as industrial automation and control system configuration tools and graphical user interface software. Many PLC, DCS manufacturers development of the software configuration tool for automatic control system has become an important component. They used to replace dedicated industrial PC workstations, for the creation of real-time database, the control loop, graphic footage showed police records, real-time and historical trend data recording and process control, simulation, and other tasks. Now, for the process of surveillance and control, unit control, factory data collection, process optimization control, process control, simulation, statistical quality-control (SQC), the Statistical Process Control (SPC) and expert system for the control of industrial automation and control package has been tremendous developments. DAE applications such as IBM's software platform and the emergence of applications, the application provides a unified software development tool. Application Platform features from the PC-industry data exchange within the factory to the coordination of multiple systems, the standard data interface allows computer control equipment and exchange of data and information networks, for integrated information management and control system provides great convenience. Along with the standard graphical operating system continuously improve and develop, process control and industrial automation package greatly enriched, the industrial PC applications will increasingly strong. Three, the characteristics and Application of DCS DCS since its birth, after decades of continuous improvement, development and modernization has been very mature. Compared with the early, the scale of their systems, control functions, and other areas have been tremendous developments in changes in the reliability, flexibility, adaptability, scalability, cost-effective integrated technical indicators have seen increased and improved. Has been widely used in petrochemical, pharmaceutical, energy, chemicals, paper, oil refining, metallurgy and food and beverage, and other industries, and has made very significant economic and social benefits. According to statistics, production facilities from analog instruments to DCS control the economic benefits can be achieved by the overall efficiency of 60%. DCS average payback period for 12, after the introduction of advanced control strategies can reduce the payback period of 0.5 to 1 year. DCS is today into various kinds of advanced control technology and equipment, and to the comprehensive integrated information management and automated process control systems, that is, CIMS direction. 1. Development process From 1975, the DCS roughly experienced the 1975 ~ 1980, the first generation, from 1980 to 1985 the second generation, and after 1985 the third generation of three stages of development. Many manufacturers take DCS phased development strategy, adopted in the early systems continue to develop and improve, then launched with a variety of new features of the new system, the new system compatible with the original equipment homogeneous. Early DCS storage capacity small, relatively simple function. System modules include process control, process interface modules, CRT operator station, control computer and data Highway, Part 5. Its characteristics are using microprocessors to achieve decentralized control, CRT operator station and the process control unit separation operation carried out on display and remote control configuration. Honeywell company TDC-2000 is the first generation of the representation of DCS products. DCS mainly by second-generation local area networks, multi-function controllers, the computers, enhanced operator station, multifunction operator station, the connector between the network, system management module, and other components. Its characteristics are achieved more thoroughly decentralized control, decrease in the number of wiring, and anti-performance enhancement, improved level of standardization of hardware, high universality, function more comprehensive. Not only strengthened control, and strengthening the system-wide information management, the introduction of local area networks and fiber optic communications technology. During this period the representation of the company products include Honeywell TDC-3000 and Westinghouse WDPF systems. DCS new generation is the most important feature of the process control, monitoring, management, scheduling organically integrate, through the use of open systems and standards such as MAP communication networks, such as Ethernet and Fieldbus solve different manufacturers equipment interconnection between issues. During the system is the development of a number of new features, using a 32 or 64-bit microprocessor, and a powerful workstations and enhanced the sequence control, volume control, the system can accommodate industrial PC and PLC; software greatly enriched by the standard graphical operating system platforms, and the user interface; introduction of the expert system, process control and other senior adaptive control function. Its products include Foxbor company representative I / A Series intelligent control system, ABB-Bailey INFI 90, ABB company Freelance 2000, RTP company RTP 2000/2200 HCS (Mixed Control System), and Yokogawa XL mXL, Honeywell Corporation TDC-3000 LCN / VCN-PM and Siemens PCS 7 systems. 2. New characteristics and new development (1) Open to the DCS system to develop in the direction of CIMS Along with the standard communication network and the development of fieldbus technology, a multi-level communications network DCS is the progressive realization of the full liberalization. The new system is the adoption of the ISO OSI model, the communication protocol to meet MAP / TOP or IEEE standards. In a backbone network, widely used MAP 3.0 agreement or ISO / OSI model; middle layer to use Mini MAP, IEEE 802.3, Ethernet or Proway; equipment is used at the lowest level fieldbus or bus to connect the transmitter. Open systems change the past DCS manufacturers self-contained closed situation, and make industrial users in the application of automation hardware and software have a greater choice. DCS is the new generation of multi-level multi-regional development. With multi-level communication networks as a tool for the entire factory or enterprise information management and production control integration, the lowest level in the factory using digital equipment integrated into the scene DCS, in the solution of local senior management of various types of computer networks and interconnection, thus achieving optimal scheduling, decision-making, as well as the overall production process optimization. This production with the use of computer programs, product development, production processes and the material flow and information flow, integrated management system requirements for the development of CIMS. DCS use of open systems gradually to the direction of CIMS is integrated automation control system integrated a basic method. (2) workstations and graphical user interface features strengthen the operating station Workstations (including industrial PC workstations) and the use of graphical user interface, making recognizable DCS operator station. Many DCS manufacturers will be more DEC, SUN and companies such as Apollo Unix workstation tasks for the operator interface and control certain tasks, and corresponding use of the Motif, Penlook, X Window, OS / 2, Windows and other graphical user interface. Workstations cost-effective prices, high efficiency, and provides a user-friendly operator interface equipment. High-function workstations and high-resolution graphics equipment used, making operation to handle the greater amount of information, higher quality information processing, and use the mouse, touch screen, the cursor to the ball-type, as well as a number of other human-machine engineering. (3) a 32 or 64-bit processor hardware performance improved 32 or 64-bit microcomputer development and use, is a milestone in the development o