基于plc恒壓供水變頻控制系統(tǒng)設計含開題及4張CAD圖-版本2
基于plc恒壓供水變頻控制系統(tǒng)設計含開題及4張CAD圖-版本2,基于,plc,供水,變頻,控制系統(tǒng),設計,開題,CAD,版本
外文資料
In the high-end market, PLC and industrial PC something together, because the industrial PC in the data integration and communication capabilities to the user a lot of temptation.
PC also introduced Ethernet TCP / IP network and interconnection with the concept of the Internet. But now, PLC manufacturers can claim, "If you want this, we can do."
European leader in the PLC, Siemens A & D and Schneider Electric, provides a powerful high-end controller family, regardless of PLC or industrial PC, and at the same time promoting the field of PLC and industrial PC development.
The recent announcement by Siemens S7-400 PLC series of significant performance increase, the CPU performance of the previous 3 times the communications capacity is 2 times the previous.
Siemens is still the most high-end of the S7-400 series, an increase of another innovation： communications processor with integrated 4-port Ethernet switch. The need for external switch, the Ethernet can be used for small-scale model of the economy. However, the communications processor real difference is that from now on it is a higher stage of development to middle-class, at a higher stage, Siemens will use high-end PLC and integrated Profinet V3 switch external devices, can provide real-time control.
Schneider Electric has developed a substantial high-end CPU's performance, the introduction of the new Unity software programming, XML data format. In the embedded web server and multi-port communication, the new functions of the CPU more and more like PC.
Integrated design of the platform
Mitsubishi Electric PLC will be the further development of 2-3 years, and now the horizon： multi-processor and system platform. "From the users point of view means that function blocks can be placed on a plate", PLC and network of experts believe that Hugh Tasker, "These can include standard PLC technology, but a mix of motion control and process control, or full-featured PC performance, the use of SCADA or local program Soft HMI technology. "
The development of what is it? In his view, the users, the biggest benefit is the simplified control system. "Do not have to integrate a lot of PLC, they are connected, and then operation and maintenance, and now many of the system will reduce the number of PLC, and even the introduction of a. This can greatly save time for installation and maintenance, the durability of the whole system is also more .
He also speculated the future, "in a very long period of time, Bluetooth technology and wireless Ethernet technology will be more extensive. It will first start in a small area, but in terms of reliability, durability and easy acceptance will be improved, manufacturers will be likely to seek the application of wireless technology may one day even the most basic cable they have not been saved.
B & R Automation is a supplier of control products, the provision of industrial PC, but compared to other PLC manufacturers, which in the field of PLC is also quite a long time. But they never dwell on the PC and the PLC Which Which weak strong together in the common development. B & R and now see the development of some opportunity, perhaps both to the continuous integration of technology.
"In the past few years, the classic development of programmable logic controller has always been to the embedded PC technology development," B & R Business Manager Anton Meindl think, "PC technology has its advantages - the enormous computing power, and the Internet The combination of technology, fast Ethernet and USB interface, can combine the traditional advantages of the PLC system, such as practical, durable and strong, and modularity. "
Omron's PLC + Inverter
Omron introduced its first AC inverter 3G3MV, can be used for motion control product lines. Applicable to small-scale motor control (0.1 to 7.5 kW). It allows users to choose non-sensor vector control can provide high torque at low speed in the output frequency of 1 Hz was also able to guarantee 150 percent of torque. Also has the I / O and communication functions.
However, in November last year, it increased by another function, it can be some unusual, an increase of Omron PLC Plug & Play modules used, and not just an annex, is a complete PLC, equivalent to the standard Omron CPM2C -S PLC. The use of dual-port RAM, PLC and inverter direct the I / O, data and associated parameters. PLC has its own I / O, can provide data directly to the inverter： input encoding, interrupt output, as well as digital, and PWM output pulse.
Omron believes that this combination of products for the network or provide an ideal control program, to meet the location and sequence context in the precise control requirements, but also for manufacturing of multi-step production lines and intelligent packaging conveyor lines.
Omron PLC + The combination of inverter, if the order for the pump controller, in the composition of the three pump hydraulic control system. PLC + converter combination of the first pump of the closed-loop continuous control, the other two pipes connected in parallel to the pump on / off control. Man-machine interface (MMI) can monitor SMS wireless signal can be sent to maintenance personnel.
PAC in the United States
In the United States, market strategy and sometimes even more than the technology itself attention in 2003, the industry there is a new popular vocabulary： Programmable Automation Controllers (Programmable Automation Controller, PAC).
Terms of the new ARC Advisory Group from the market research company Craig Resnick, he thought, "PLC is very active and well-developed, with a strong vitality. However, PLC an effective tool for this industry is changing many aspects, and continuously increase its charm. automation suppliers are committed to the development of PLC in order to meet market and special user needs. functional enhancements to a new series of the surface of the system. PAC based on open industry standards, features a multi-field, General open platforms and high performance. ARC coin the term, in order to help user-defined applications to help manufacturers when talking about their products more clearly.
Whether manufacturers will be the product name changed from the PLC to PAC, remains to be seen. However, GE Fanuc has not the slightest hesitation, they immediately accepted the concept of PAC, but also show in Hanover publicly announced that its new flagship product known as the PACSystems. GE Fanuc name used to express a combination of its traditional PLC products and the advantages of PC hardware with a common programming environment, Cimplicity Machine Edition software. There is a separate software-controlled engine, a development tool, multi-goal programming hardware. Hardware includes not only the two new PACSystems processor, including GE Fanuc Automation to other products, such as Tablet PC, Embedded PC, MHI and its new motion control system of the S2K.
"PACSystems control on behalf of industry innovation, which enables centralized control, rather than have nothing to do all the parts together," GE Fanuc Automation (Europe) John Pritchard. Believe that the "one engine, with a development tool, the user can make use of powerful engineering environment for multiple applications. "
PAC you have I have
November 2003 Rockwell announced that its technology for the PAC leader, and its products ControlLogix and CompactLogix PLC fact that PAC.
"We have seen the user data control system of unlimited enthusiasm, the user can collect security, finance, quality assurance procedures, and other information," that Ken Deken, Rockwell Automation, "to meet the requirements of users, users need to control the between business systems and the direct contact information at all times. "
He believes that, with the constant development, PAC will be a lot of ways to deal with data and with scalability in multi-project control, integrated business systems analysis and life cycle cost management can march forward
Programmable logic controller (PLC) technology has made remarkable achievements and become a subject of rapid development and innovation in the field of automation. With the increasing maturity of technology, PLC has gradually developed into an industrial control device with microprocessor technology as the core, integrating computer technology, automation control technology and communication technology. With the cooperation of network technology and configuration software, the application of PLC is like a tiger with wings.Programmable logic controller (PLC) is widely used in the industrial field, which is not only a substitute for relay logic circuit, but also a component of field control and the core part of control equipment. With the improvement of automation, it can be used not only as a part of field control, but also as a control part of field higher-level management. With the development of network technology, as a mature technology, PLC has been widely used in machinery, metallurgy, chemical, petrochemical, cement, food and beverage, pharmaceutical and other fields, greatly improve labor productivity and automation.Mitsubishi, Siemens is China's leading industrial solution provider in a number of business areas, providing innovative, reliable, efficient, and quality products in manufacturing automation, process industrial automation, motion control, drive, low voltage control, and electrical installation technologies. And to provide a comprehensive system of solutions and services. Products cover a wide range of information and communications, automation control, power, transportation, medical, lighting and other industries in the leading edge.Mitsubishi, Siemens control technology, can continue to integrate new technologies, new methods, innovation. Among them, Siemens control technology further makes new breakthroughs in e-manufacturing and e-control technology, and new products keep emerging, providing very reliable control and application for a variety of automation control equipment.History of PLCIn the 1960s, the automatic control system of automobile production line was basically composed of relays. Each modification of the car at that time led directly to the redesign and installation of relay controls. With the development of production, the cycle of vehicle model update is getting shorter and shorter, so the relay control device needs to be redesigned and installed frequently, which is very time-consuming, laborious and costly, and even hinders the shortening of the update cycle. In order to change this situation, general motors in the United States in 1969 public bidding, the requirements of the new control device to replace the relay control device, and put forward ten bidding indicators, the requirements of easy programming, field modification procedures, easy maintenance, the use of modular structure. In 1969, American digital company developed the first PLC, which was successfully used on the automatic assembly line of American general motors.This new type of industrial control device with its simple and easy to understand, easy to operate, high reliability, general flexibility, small size, long service life and a series of advantages, soon in the United States other industrial applications, and soon successfully applied to food, beverage and other industrial fields. The emergence of this new industrial control device is also highly valued by other countries. In 1971, Japan introduced this new technology from the United States and soon developed Japan's first PLC. 1973 western European countries also developed the first PLC. China began to develop from 1974, in 1977 began to enter the industrial application.Since 1980 s, with large scale and very large scale integrated circuit, such as the rapid development of microelectronics technology, and a handful of 32-bit microprocessor with a 16 bit of PLC has been amazing development, makes the PLC in design, performance, price and application has the new breakthrough, not only enhanced control function, power consumption and reduced volume, cost reduction, increased reliability, programming is more flexible and convenient, and the fault detection and remote I/O and communication network, data processing and the development of image display, also include a convenient debugging and testing tools, simulation tools, etc., PLC has been widely used to control complex continuous production processes. At present, PLC has become one of the three pillars of factory automation.In February 1987, the international electrotechnical commission (IEC) defined a programmable controller as follows: a programmable controller is an electronic system for digital operations, designed for use in industrial environments. It USES a class of programmable repositories to internally store programs that perform customer-facing instructions such as logical operations, sequence control, timing, counting, and arithmetic operations, and control various types of machinery or production processes through digital or analog input/output. The programmable controller and its related peripheral equipment are designed according to the principle that the system is easy to form a whole and easy to expand the function.PLC is so widely used, and its superior performance is inseparable. Main features of PLC:1. High reliability, strong anti-interference abilityIn the traditional relay control system, a large number of intermediate relays are used, and the reliability of the system is greatly reduced due to the aging and falling off of the components, the vibration of electric shock and bad contact. In the PLC control system, a large number of switch action is completed by non-contact semiconductor circuit, due to poor contact and other reasons caused by the fault greatly reduced.In addition, PLC in the hardware and software also took the following strong measures to improve its reliability.In terms of hardware, photoelectric isolation is adopted for all I/O interface circuits, so that the external circuit in the industrial site is electrically isolated from the internal circuit of PLC. Each module adopts photoelectric shielding measures to prevent radiation interference. The switching power supply with excellent performance and various forms of filtering are used for the power supply system and the input circuits to eliminate or suppress the high-frequency interference. Select the selected device strictly; Adopt the module structure more, once a module has a fault, can quickly replace the module, so as to shorten the system downtime as possible.In terms of software, PLC has a good self-diagnosis ability, once the power supply or other software, hardware abnormal situation, CPU immediately take effective measures to prevent the expansion of the fault; PLC set a monitoring timer, if the program cycle execution time exceeded the specified value, it indicates that the program has entered a dead cycle, can immediately alarm.For large PLC systems, it is also possible to adopt a redundant system composed of two cpus or a voting system composed of three cpus to improve the reliability of the system.2. Rich I/0 interface modulesPLC for different industrial field signals, such as: ac or dc, switching or analog, voltage or current, pulse or potential, strong or weak electrical signals, can choose the corresponding I/O module to match. For industrial field devices or equipment, such as buttons, trip switches, proximity switches, sensors and transmitters, solenoid coils, control valves and other equipment can choose the corresponding I/O module to connect with it.In addition, in order to improve the PLC operation performance, it has a variety of man-machine dialogue interface module; In order to form industrial control network, also equipped with a variety of communication network interface modules.3. Adopt modular structureIn order to adapt to a variety of industrial control needs, in addition to the unit type of small PLC, the vast majority of PLC are modular structure. All parts of PLC, including CPU, power supply, I/0, etc., adopt modular design. Each module is connected by rack and cable.4. Programming is simple and easy to learn, system design, short debugging cyclePLC programming is mostly similar to relay control lines in the form of ladder diagram, for users, do not need to have computer expertise, so it is easy to be the general engineering and technical personnel to understand and master. In addition, because PLC is through the program to achieve the control of the system, so the designer can design and modify the program in the laboratory, but also in the laboratory to facilitate the system simulation and operation debugging, so that the workload of the site is greatly reduced.5. Simple installation and easy maintenancePLC does not need special machine room, can run directly in a variety of industrial environments. When in use, only connect all kinds of equipment in the field with the corresponding I/O terminal of PLC, and it can be put into operation.PLC failure rate is very low, and has a perfect self - diagnosis and display function. When the PLC or external input device and actuator failure, according to the PLC module on the operation and failure indication device or programming software to provide information, easily find out the cause of the failure. Due to the modular structure, once a failure occurs, the user can replace the module, so that the system can quickly resume operation.In short, a programmable controller is a computer designed and manufactured for industrial applications. Has the rich input/output interface, and has the strong driving ability. But programmable controller products are not for a specific industrial application, in the actual application, its hardware needs to be selected according to the actual needs of configuration, its software needs to be designed according to the control requirements of programming.How PLC works1. Scanning modePLC has two basic working modes, namely RUN mode and STOP mode. In operation mode, the PLC realizes the control function by repeatedly executing the user program. In order to make the PLC output in time to sound, should be at any time possible to change the input signal, the user program is not only executed once, but continue to repeat the execution, until the PLC STOP or switch to STOP mode.2. Scan cycleWhen the PLC is in Run mode, the time required to perform a scan operation is called the scan cycle, and its typical value is about 1~100ms. The length of the scan cycle depends on the length of the user program, the type of instructions, and the speed at which the CPU executes the instructions. When the user program is long, the instruction execution time takes up a large proportion in the scanning cycle. Some programs or programmers can provide the current value of the scan cycle, while others can provide the maximum and minimum values of the scan cycle.3. Time after input/outputThe time after input/output is also called system response time, which refers to the time interval between the time when the external input signal of PLC changes and the time when the external output signal changes under its control.The RC filter circuit of the input module is used to filter the interference noise introduced by the input end and eliminate the bad influence caused by the jitter caused by the external input contact. The time constant of the filter circuit determines the length of the input filter time, and its typical value is about 10ms. The lag time of the output module depends on the type of module. The lag time due to the way the scan works may be up to two or three scanning cycles.The total response delay time of PLC is usually only a few tens of milliseconds, which is irrelevant to the general system. The system that the lag time between the requirement input and output signal is as short as possible, can choose the PLC that the scan speed is fast or take other measure
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