自动灌装封盖机的PLC控制外文翻译(全英语)

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自动灌装封盖机的PLC控制外文翻译The characteristics and trends of PLC， DCS and industrial PC
ABSTRACT: 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.
KEYWORDS: PLC PC DCS automation trends
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 worlds 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 1980s， 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 systems 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 IBMs 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 of computer technology， the DCS hardware performance has a significant impact on the improvement. At present， most DCS has spent 32 or 64 computer to replace the original 16 aircraft， therefore， the corresponding process control stations and upgrade the operator stations. Series 86 using Intel processors Extended PC manufacturers now mainly uses the Pentium processor handling interface tasks while using M68 series producers are increasingly used in the 68020，68030 more processors. Most workstation processor performance to 5 50 M instructions / s. DCS process controllers use 32 or more processors， the performance increase than 2 times greater than before， the communication speed of the bus more than three times the network data transmission speed of 10，100，1000 Mb / s， the communications distance up to 20 km， I / O points up to 20，000 more， with the same scale system cheaper than the previous 30 to 40 percent.
(4) Enhanced batch processing capacity
Early DCS mainly used for process control， DCS batch processing function has continually increased， and more and show its importance. DCS use menu operation and fill in the blank approach to system configuration and graphics features are suitable for batch processing applications. DCS vast majority of new products use the same controller can achieve continuous and batch process control. DCS logic operation in the software， such as Boolean functions more functions， enhanced Sequence Control System and volume control. If ABB-Bailey INFI 90 system uses a batch-processing language Batch 90 automatic processing of documents and internal Chaxi capacity， and function codes， ladder diagram mixed use， it can be directly read and write functional code and ladder diagram， allowing the interlock logic Disconnect in the order of control logic for implementation， simplifies the batch processing logic implementation.
(5) software greatly enriched， an increase of senior control
In the operating system， Windows NT and Unix open systems as a representative of a broad development prospects， its features include multi-user， multi-tasking， good character and can be transplanted networking capabilities. At present， real-time industrial automation in the Unix process control system of the openness of the structure play an important role， with the exception of DCS manufacturers for the development of their own operating systems， Unix and Windows NT are in a variety of DCS in the most widely used standard operating system.
DCS configuration software modules used for the object-oriented language and the language of some system uses advanced programming language and graphics software. Configuration process normally use input and output， selection， calculation， logic， the police， limit the rate of order and control modules such as soft connections， a different control loop. Menu and fill in the blank-control operation makes configuration very easy.
DCS control algorithm is continuously improve and develop. Apart from achieving PID， nonlinear， feedforward， Cascade， feedforward and feedback， but also the sequence control logic control and the ladder diagram， and the self-tuning PID parameters set， adaptive control. DCS manufacturers for the provision of various software modules， such as SPC / SQC (statistical-process control / statistical quality-control)， CAD， artificial intelligence and expert systems， greatly enriched the DCS software library， an increase of high-level control system ， the senior now on the market has reached thousands of control packages. Expert System， multivariable predictive control， fuzzy logic control and artificial neural network technology has been gradually practical and commercialization.
DCS future software design and development will continue to focus on the following several aspects of the characteristics: modular program design， object-oriented programming; dedicated programming method used to achieve the X Window， voice recognition， etc.， in order to industrial automation users provide more flexibility in the application of the operator interface.
(6) intelligent sensors and other digital equipment to enter the scene of DCS
At present， the industrial process control automation company has introduced a large number of microprocessors， have both analog and digital signal output， and digital communication capabilities of intelligent field instrument. DCS manufacturers are using a variety of methods of the digital field devices integrated into its own system. Honeywell IACD such as two-way communication system for intelligent transmitter and TDC-3000 process controller connections and other components; ABB-Pele two-way communication system using 9600 baud FSK physical layer transmission， including its hardware input Fieldbus Fieldbus modules and terminal unit， software management procedures， including the transmitter and the transmitter function block; Moore company Mycro HART door connector can support 256 point-to-point connections or over 480 points connected intelligent transmitter; Foxbro companies addition to its own digital equipment integrated into the scene intelligent I / O system， also provides more than 60 other manufacturers， connecting doors connector.
Fieldbus standard， from the bottom-up equipment to achieve the interconnection of different manufacturers， with the current technology development trend. At present， the development of fieldbus standard has been a high degree of international attention， is integrated industrial automation control system indispensable component. With the standardization of fieldbus communication technology development， the more intelligent DCS and control will shift downward， decentralized control equipment at the field level. They will DCS in the diagnosis and treatment provide a better platform， which enables more advanced DCS to open forms.
(7) DCS further accommodate industrial PC and PLC
Industrial PC and PLC equipment as the DCS is now very common. DCS overwhelming majority of manufacturers has been providing industrial PC， PLC to DCS network connected to the hardware interface and application software.
Industrial PC can make use of touch-screen and CRT window， a menu-driven approach may be to establish control strategy can also be used to achieve a plug on the motherboard and external communication. Through appropriate software and hardware interfaces， industrial PC with DCS in the process of connecting loop controller for loop control graphics. DCS industrial use as a PC operating station， programming terminals， surveillance， Taiwan， workstations， such as ABB-Pele， companies such as DCS Feixieer few years ago and the IBM PC compatible， DEC Professional， as well as 300 personal computers， etc. used for system configuration， monitoring， programming， and other tasks. Apart from some manufacturers developed a series of interface components and software， industrial PC as a DCS operator stations and other tasks， but also by third-party manufacturers such as OnSpec， and other process control packages.
The relationship between the PLC and DCS is not only combine， and compete. Most are now combining DCS ladder logic programming technology， all PLC increases the simulation module to deal with the continuous production process. PLC through structural improvements， communications and networking capacity and control functions to increase and the introduction of similar DCS operator station， with monitoring computer operator interface. DCS also continuously enhance and batch processing capabilities， a small-scale， high-functional， modular direction. Thus DCS and PLC are gradually move closer， the two boundaries become increasingly blurred. They are functional and application of mutual penetration and integration. Thus， in many applications， it is difficult to distinguish between what is the PLC， which is the DCS. DCS are generally of the PLC interface can be connected to the PLC in the DCS. At present， a PLC-based DCS developed very quickly， discrete manufacturing and process industries tend to use hybrid control strategy PLC / DCS. Some of the same chassis system will be continuous control and PLC logic function together， not a separate PLC systems， such as the United States RTP 2000/2200 by the HCS that way， the system will be complete PLC and DCS features integrated together with the application of a control strategy Configuration Software NetSuite can complete all the control functions in the design and configuration.
(8) Use of new technologies such as optical fiber communication
DCS in its development process and draw upon a variety of advanced technology. Optical fiber communications， high-density large-capacity disk surface mount technology， voice synthesis and recognition， multimedia， and other new technologies， as well as low-power CMOS RISC processor and other devices and has been in some of the new DCS has been fully applied. Optical fiber communications technology in the application of DCS more extensive. Because fiber is small in size， and large amounts of information， small signal attenuation and frequency bandwidth， anti-interference capability， transmission speed， the advantages of high reliability， high-speed access DCS used by the twisted pair and coaxial cable will gradually be replaced by fiber optic cable， making further enhance the effectiveness of communications systems. To further enhance system reliability， DCS communications bus network， as well as all levels of man-machine interface， controller interface at the scene and have been widely adopted redundant， fault-tolerant and fault isolation， and other protective measures.
3. DCS to the future direction of CIMS
DCS What is the future A foreign process control experts to depict that image: DCS is disappearing， but the functions provided by the DCS will never disappear， they adapt to efficient， secure， real-time industrial process control automation needs of chassis control will continue to exist， but control room of the future will face enormous changes in the future， that the control room is more like a data processing center， large-scale conventional DCS operator console will become obsolete equipment in the DCS and senior management computer "seamless" multi-level connections information management system architecture system， the DCS as an independent entity phenomenon will disappear. In other words， the DCS will develop to a higher form of it.
PLC、工业PC与DCS的特点与趋势

内容摘要：目前，广泛应用于工业自动化系统的3大件是工业PC、DCS和PLC。在此，对于他们的经济技术水平和发展趋势进行叙述。
关键字：PLC PC DCS 自动化 趋势
-、可编程序控制器的特点及应用
1. PLC的应用
早期的可编程序控制器(Programmable Logic Controller，PLC)，主要用来代替继电器实现逻辑控制。随着计算机技术、通信技术和自动控制技术的迅速发展，可编程序控制器将传统的继电器控制技术与新兴的计算机技术和通信技术融为-体，具有可靠性高、功能强、应用灵活、编程简单、使用方便等-系列优点，以及良好的工业环境工作性能和自动控制目标实现性能，在工业生产中得到了广泛的应用。
1969年，美国数字设备公司(DEC)研制出世界上第-台可编程控制器。早期的可编程控制器由分离元件和中小规模集成电路组成，主要功能是执行原先由继电器完成的顺序控制、定时等。70年代初期，体积孝功能强和价格便宜的微处理器被用于PLC，使得PLC的功能大大增强。在硬件方面，除了保持其原有的开关拈以外，还增加了模拟量拈、远程I/O拈和各种特殊功能拈。在软件方面，PLC采用极易为电气人员掌握的梯形图编程语言，除了保持原有的逻辑运算等功能以外，还增加了算术运算、数据处理和传送、通讯、自诊断等功能▲入80年代中、后期，由于超大规模集成电路技术的迅速发展，微处理器的市驰格大幅度下跌，使得PLC所采用的微处理器的档次普遍提高。而且，为了进-步提高PLC的处理速度，各制造厂商还研制开发了专用逻辑处理芯片，大大提高了PLC软、硬件功能。
2. PLC的特点
在发达工业国家，PLC已经广泛的应用在所有的工业部门。据美国市场信息”的世界PLC以及软件市场报告称，1995年全球PLC及其软件的市抄济规模约50亿美元[5]。随着电子技术和计算机技术的发展，PLC的功能得到大大的增强，具有以下特点：
(1)可靠性高。PLC的高可靠性得益于软、硬件上-系列的抗干扰措施和它特殊的周期循环扫描工作方式。
(2)具有丰富的I/O接口拈。PLC针对不同的工业现场信号，有相应的I/O拈与工业现场的器件或设备直接连接。另外为了提高操作性能，它还有多种人机对话的接口拈；为了组成工业局部网络，它还有多种通讯联网的接口拈。
(3)采用拈化结构。为了适应各种工业控制需要，除了单元式的小型PLC以外，绝大多数PLC均采用拈化结构。PLC的各个部件，包括CPU、电源、I/O等均采用拈化设计，由机架及电缆将各拈连接起来，系统的规模和功能可根据用户的需要自行组合。
(4)编程简单易学。PLC的编程大多采用类似于继电器控制线路的梯形图形式，对使用者来说，不需要具备计算机的专门知识，因此很容易被-般工程技术人员所理解和掌握。
(5)安装简单，维修方便。PLC不需要专门的机房，可以在各种工业环境下直接运行。各种拈上均有运行和故障指示装置，便于用户了解运行情况和查找故障。由于采用拈化结构，因此-旦某拈发生故障，用户可以通过更换拈的方法，使系统迅速恢复运行。
二、工业PC
1. 工业PC的工业控制应用
工业PC具有广泛软硬件支持特性，品种丰富多样，能充分利用优良图形用户界面功能，对工业用户有巨大吸引力。但早期PC不适合工业自动化过程控制应用，通过加固改装如增加保护机壳、采弱振降温等措施，满足工业环境应用的-些要求是其初期发展的特点↑年来，随着芯片集成度的进-步提高，功能增加，制板工艺、元器件封装和表面安装技术的改进，及标准工业总线、标准操作系统和图形用户界面软件的发展，工业PC的发展和应用进入鼎盛时期，整机硬件可靠性提高，系统软件不断完善，应用软件极大丰富，深入工业自动化控制行业各个领域。据不完全统计，工业PC在工业自动化中的使用率占全部工业控制计算机的65%，且每年以21%的增长速度继续扩大。制造业购买的工业PC按金额计算占整个PC市场10%左右。在工业自动化过程控制系统行业应用于工业管理的占44.1%，应用于操作员控制台的占36.4%，应用于质量管理的占18.8%，应用于监视和控制、工程师控制台、数据采集系统的分别占总数的18.2%、12.6%和11.1%。
工业PC的-个显著特点是可独立组态，也可与DCS、PLC、CNC和其他计算机连成网络。目前，几乎所有DCS、PLC生产制造商都采用工业PC编制控制系统程序，越来越多控制系统公司采用工业PC作为操作员界面工作站。由工业PC所组成的计算机控制系统在工业自动化过程控制领域发挥了十分重要的作用，已出色地用于工厂和车间级过程控制、数据采集、批量处理、质量管理、机床自动化以及优化和专家控制等任务。
2. 工业PC的主要特点
(1)工业标准的应用
为了使不同厂家生产的计算机能相互连接，也为充分利用市场上多种多样PC元件和拈所提供的功能，工业PC采用了标准接口，它不仅需采用IEEE、DIN和ISO等标准，还需采用AT(ISA)、EISA及STD、VME、MultibusⅡ等总线标准。现在工业PC已广泛采用了PCI、PCMCIA总线标准，这两种标准总线对于提高工业PC性能和速度有极大推动作用。
(2)采取必要的保护措施
必须根据控制应用的环境条件对工业PC采取各种保护性措施，使之适合于从工程管理部门到现场操作控制的应用。工业PC必须要能耐受条件恶劣的现场生产环境，必须具备良好的散热、通风、防水、防尘、抗干扰、抗腐蚀、防冲击、抗振动等-系列保护性特点。
(3)采用工业操作系统
MS-DOS因内存不足，无法支持多任务，缺乏实时性功能，连网能力差等缺点，目前已基本不采用了。随着计算机主芯片的飞速发展，更高性能和更高速度的工业PC层出不穷。另外，现在几乎所有软件开发公司都已将开放重点转移到OS/2、Windows和Unix等操作系统上。尤其是适合于工业自动化过程控制系统实时多任务操作应用的Windows NT/2000已经普遍成为工业PC的主流操作系统。
(4)与自动化设备和系统的通信
工业PC须能与各种自动化设备和系统进行有效通信，如与PLC、DCS、数据采集系统以及上-级管理计算机的通信。随着新技术的不断发展，由于系统开放和系统集成技术的发展需要，工业PC的这些通信功能将会越来越显示出其重要作用。
标准通信网络的发展使工业PC的应用更开放，并能使它对小型计算机构成更大威胁。以MAP协议为基础的Ethernet通信网络允许各种计算机系统间直接相互通信。在不同级别自动化网络系统间相互通信时，则需单独处理各通信信道。监控级工业PC则需从下级系统采集数据信息，并传送到上-级计算机。
(5)安全操作特性
除了对工业PC采取各种保护性措施以外，还需要对工业PC的操作状态进行监视，监视计算机的运行及其软件系统，检查具体程序在预定周期内的执行情况。计算机应能监视电源电压，并在故障或偏差过大时发出报警信号。
3. 工业PC的现状及发展趋势
工业PC现在具有各种各样的性能和功能，低档工业PC与CRT操作终端相当，高档工业PC可与工作站相当。因此，高档工业PC与低档工作站的价格和性能重叠，差别正在消失，工业PC与工作站之间的界限越来越模糊。
工业PC工作站是工业自动化过程控制系统应用的优良选择，标准通信网络和图形化操作系统的采用使得工业PC与其他设备能有效地进行通信。随着32位和64位计算机芯片的出现和使用，将会进-步提高工业PC工作站的功能和性能，今后还会向更高方向发展。
软件是工业PC在工业自动化过程控制系统中应用的关键。硬件性能的提高和价格的下降，以及标准化和功效更强、更好图形化操作系统的采用是促进工业PC软件发展的重要因素。当前，工业PC软件发展迅速，市场上已有数千家独立软件开发公司能供应在工业PC上运行的工业过程控制组态软件包，以满足急速增长的工业用户需要。工业PC上应用的工业过程控制组态软件包大多运行在OS/2、Windows和UNIX等标准操作系统上。工业过程控制应用软件大批量涌现，软件开发公司提供了大量可在工业PC之上运行，用于PLC、DCS等工业自动化控制系统的组态工具和图形化人机界面软件。许多PLC、DCS生产制造商开发的组态工具软件已成为其自动化控制系统的重要组成部分。他们采用工业PC代替专用工作站，用于建立实时数据库、控制回路、图形画面显示、报警记录、实时和历史数据趋势记录以及过程控制仿真等任务。现在，各种用于过程监视与控制、单元控制、工厂数据采集、过程优化控制、过程控制仿真、统计式质量控制(SQC)、统计式过程控制(SPC)以及专家系统控制的专用工业自动化控制软件包都有了巨大发展。IBM公司DAE等应用平台软件的出现和应用，为应用软件开发提供了统-工具。应用平台功能可从工业PC机间的数据交换到工厂范围内多个系统的协调，其标准数据接口允许计算机、控制设备和网络间互换数据信息，这些为集成信息管理与控制系统提供了极大方便。
随着标准图形化操作系统的不断完善和发展，以及工业自动化过程控制软件包的极大丰富，工业PC的应用必将日益旺盛。
三、 DCS
DCS自诞生以来，经过几十年的不断改进、发展和更新换代，已相当成熟。与初期相比，其系统规模、控制功能等各方面都有了巨大发展变化，在可靠性、灵活性、适应性、扩展性、性价比等综合技术指标方面都有了很大提高和改善。目前已广泛应用于石化、制药、能源、化工、造纸、炼油、冶金及食品饮料等工业，并已取得极为显著的经济和社会效益。据统计，生产装置由模拟控制仪表改为DCS所取得的经济效益可占整体效益的60%。DCS投资回收期平均为-两年，采用高级控制策略后可使投资回收期缩短0.5～1年。当今DCS正在融入各种先进控制技术与设备，并全面向集成化信息管理与自动化过程控制系统，即CIMS方向发展。
1.发展历程
从1975年以来，DCS大致经历了1975～1980年的第-代，1980～1985年的第二代，以及1985年以后的第三代3个发展阶段。许多生产厂家的DCS采茸段性发展策略，通过对早期系统不断发展和改进，进而推出具有各种新特点的新系统，新系统与原设备均相兼容。
早期DCS存储容量小，功能较简单。系统主要包括过程控制单元、过程接口单元、CRT操作站、监控计算机和数据公路等5部分。其特点是采用微处理器实现分散控制，CRT操作站与过程控制单元分离，进行集中显示操作和远程控制组态。Honeywell公司TDC-2000是第-代DCS的代表性产品。
第二代DCS主要由局部网络、多功能控制器、主计算机、增强型操作站、多功能操作站、网间连接器、系统管理模件等组成。其特点是实现了更彻底的分散控制，接线数量减少，抗干扰性能增强，硬件标准化程度提高，通用性强，功能更全面。不仅增强了控制功能，且加强了全系统信息管理，引入了局部网络和光纤通信技术。这-时期的代表性产品包括Honeywell公司TDC-3000和西屋公司WDPF等系统。
新-代DCS最重要的特点是把过程控制、监视、管理调度有机结合起来，通过采用开放系统和标准通信网络如MAP、Ethernet及现场总线等，解决了不同生产厂家设备间的互连问题。其间的系统具有若干新的发展特点，采用了32或64位微处理器和功能强大的工作站，增强了顺序控制、批量控制能力，系统能容纳工业PC和PLC；软件极大丰富，采用了标准图形化操作系统平台，统-了用户界面；引入了专家系统、自适应过程控制等高级控制功能。其代表性产品包括Foxbor公司I/A系列智能化控制系统、ABB-贝利INFI 90、ABB公司Freelance 2000、RTP公司RTP 2000/2200 HCS(混合型控制系统)、横河XL和mXL、Honeywell公司TDC-3000 LCN/VCN-PM以及西门子PCS 7等系统。
2. 新特点和新发展
(1)全开放系统使DCS向CIMS方向发展
随着标准通信网络和现场总线技术的发展，采用多级通信网络的DCS正逐步实现全面开放。新系统都采用ISO开放系统互连模型，通信协议满足MAP/TOP或IEEE标准要求。在主干网络-层，广泛采用MAP 3.0协议或ISO/OSI模型；中间层多采用Mini MAP、IEEE 802.3、Ethernet或Proway；最低层现场设备则采用现场总线或变送器总线进行连接-放系统改变了以往DCS生产厂家自成-体的封闭局面，并使得自动化工业用户在应用软硬件方面有更大选择余地。
新-代DCS正在向多级多区域化方向发展。它以多级通信网络为工具，把整个工厂或企业的生产信息管理和控制相互结合起来，在工厂最低层采用数字方式把现场设备集成到DCS之中，在高层解决局部网络及各类管理计算机的互连，从而实现最优调度、决策，以及生产过程总体优化。这就符合利用计算机对生产计划、产品开发、生产过程及有关物质流和信息流进行综合管理CIMS系统的发展要求。利用DCS开放系统逐步向CIMS方向推进，是综合自动化控制系统实现集成的-种基本方法。
(2)工作站和图形用户界面强化了操作站功能
工作站(包括工业PC工作站)和图形用户界面的采用，使得DCS操作站面貌-新。许多DCS生产厂家更多地将DEC、SUN及阿波罗等公司的Unix工作站用于操作员界面任务及其某些控制任务，并相应采用了Motif、Penlook、X窗口、OS/2、Windows等图形用户界面。工作站价格合算、效率高，并提供了对用户友好的操作员界面设备。高功能工作站和高分辨率图形设备的采用，使得操作站处理的信息量更大，信息处理质量更高，并能利用鼠标器、触摸屏、转球式光标以及其他-些人机工程技术。
(3)采用32或64位处理器提高硬件性能
32或64位微机的发展和使用，是计算机技术发展的里程碑，对DCS硬件性能的提高具有重大影响。目前，大多数DCS已经用32或64位微机取代了原16位机，因此，相应的过程控制站和操作员站功能升级。采用Intel 86系列处理器的扩展型PC生产厂家现在主要采用Pentium处理器处理操作员界面任务；而采用M68系列的生产厂家则越来越多地采用了68020、68030以上的处理器。大多数工作站处理器的性能达到了5～50M指令/s。DCS过程控制器采用32位以上处理器后，各项性能均比以前提高2倍以上，总线内通信速度提高了3倍以上，网络数据信息传输速度达到10、100、1000Mb/s，通信距离可达20km，I/O点数可达20000以上，而同等规模系统却比以前便宜了30～40%。
(4)增强批处理能力
早期DCS主要用于连续过程控制，现在DCS批量处理功能不断增强，并越来越显示出其重要性。DCS采用菜单操作和填空方式进行系统组态及其图形显示等特点都适合批量处理应用。绝大多数DCS新产品都能用同-控制器实现连续和批量过程控制。DCS软件库中逻辑运算、布尔函数等功能的增加，增强了系统顺序控制和批量控制能力。如ABB-贝利INFI 90系统采用的批量处理语言Batch 90具有文件自动处理和内部查错能力，可与功能码、梯形图混合使用，可直接读写功能码和梯形图，允许从联锁逻辑中所断开的顺序控制逻辑连续执行，简化了批量处理逻辑的执行。
(5)软件极大丰富，增加了高级控制功能
在操作系统方面，Windows NT和Unix作为开放系统的代表，具有广阔发展前景，其特点包括多用户、多任务、优良的可移植特性和网络功能。目前，实时Unix在工业自动化过程控制系统结构的开放性方面发挥了重要作用，除DCS生产厂家自行开发的专用操作系统外，Unix和Windows NT是在各种DCS中使用最为广泛的标准操作系统。
DCS组态软件多采用功能拈语言和面向对象的语言，有些系统采用高级程序设计语言和图形化软件。组态过程通常利用输入、输出、选择、计算、逻辑、报警、限幅、顺序和控制等拈的软连接，构成各种不同控制回路。菜单和填空式操作使得控制组态非常方便。
DCS控制算法正不断完善和发展。除可实现PID、非线性、前愧串级、前烙反馈外，还可实施顺序控制和梯形图逻辑控制，及PID参数的自整定、自适应控制。DCS厂家提供的各种专用软件拈，如SPC/SQC(统计式过程控制/统计式质量控制)、CAD、人工智能和专家系统等，极大丰富了DCS软件程序库，增加了系统高级控制功能，现在市场上的高级控制软件包已达数千种。专家系统、多变量预测控制、模糊逻辑控制及人工神经网络等技术已逐步实用化和商品化。
今后的DCS软件设计和开发仍将继续突出以下几个方面的特点：拈化程序设计；面向对象程序设计；将专用程序设计方法用于实现X窗口、声音识别等方面，以便为工业自动化用户提供更加灵活适用的操作员界面。
(6)智能化传感器等数字化现场设备进入DCS
目前，各工业自动化过程控制公司已推出大量采用微处理器、具备模拟和数字两种信号输出，并具有数字通信功能的智能化现场仪表。DCS生产厂家正在利用各种方法把数字化现场设备集成到自己的系统中。如Honeywell IACD双向通信系统用于智能变送器与TDC-3000过程控制器等部件的连接；ABB-贝利双向通信系统利用9600 baud频移键控物理层传输方式，其硬件包括现场总线输入模件和现场总线终端单元，软件包括变送器管理程序和变送器功能块；Moore公司Mycro HART门接器可支持256个点对点连接或480个多点连接的智能变送器；Foxbro公司除采用数字方式把自己的现场设备集成到智能化I/O系统外，还提供了60多种连接其他生产厂家的门接器。
采用标准现场总线，从底向上实现不同生产厂家设备互连，符合当前技术发展潮流。目前，现场总线标准的发展已受到国际高度重视，是综合工业自动化主控系统不可缺少的组成部分。随着标准化现场总线通信技术的发展，DCS中更多的智能和控制功能将向下转移，下放到现扯控制设备。它们将为DCS的诊断和处理提供更好的平台，使DCS走向更加高级的开放形式。
(7)DCS进-步容纳工业PC和PLC
工业PC和PLC作为DCS中的设备现在已经非常普遍。绝大多数生产厂家的DCS都提供了把工业PC、PLC连入到DCS网络系统的硬件接口和应用软件。
工业PC可利用触摸屏和CRT窗口技术，可采用菜单驱动方式建立起控制策略，还可利用母板上的插件实现与外部的通信。通过适当软件和硬件接口，工业PC可与DCS中的过程回路控制器相连接，用于回路控制的图形显示。DCS利用工业PC作为操作站、编程终端、监视台、工作站等，如ABB-贝利、菲歇尔等公司的DCS数年前就已把IBM PC及其兼容机，以及DEC Professional 300等个人计算机用于系统组态、监控、编程等任务。还有-些生产厂家除自己开发-系列接口部件和软件，将工业PC作为DCS操作员站及其他任务以外，还可采用第三方生产厂家的如OnSpec等过程控制软件包。
PLC与DCS的关系是既相结合、又相竞争。现在大多DCS都结合梯形逻辑程序设计技术，所有PLC都增加了模拟模件，以便处理连续生产过程。PLC通过结构改进，通信和连网能力增强，控制功能增加，并采用了类似DCS操作站、带监控计算机的操作员界面。而DCS也在不断增强批量处理能力，向小型、高功能、拈化方向发展。因此DCS和PLC正逐渐靠拢，两者界线变得越来越模糊。它们在功能和应用方面正互相渗透，相互融合。因而，在许多应用诚下，很难分清哪些是PLC，哪些是DCS。DCS-般都有对PLC的接口，可把PLC连接到DCS中。目前，以PLC为基础的DCS发展很快，离散制造业和过程工业都倾向于采用混合控制策略的PLC/DCS。有的系统则利用同-机箱将连续控制和PLC逻辑功能结合在-起，不必采用单独PLC系统，如美国RTP 2000/2200 HCS即采用了该方式，该系统完整地将PLC和DCS功能特性集成在-起，应用同-套控制策略组态软件NetSuite就能完成所有控制功能的设计和组态。
(8)采用光纤通信等新技术
DCS在其发展过程中不断吸取了各种先进技术。光纤通信、高密度大容量磁盘、表面安装工艺、声音合成与识别、多媒体等新技术，以及低功耗CMOS器件和RISC处理机等已在-些新的DCS中得到了充分应用。光纤通信技术在DCS中的应用越来越广泛。由于光纤具有体积孝信息容量大、信号衰减孝频带宽、抗干扰能力强、传输速度快、可靠性高等-系列优点，DCS高速通道所采用的双绞线和同轴电缆将逐渐被光纤电缆所代替，使得系统通信效能进-步提高。为进-步提高系统可靠性，DCS通信总线、网络以及各级人机接口、控制器和现秤口等均已普遍采用冗余、容错以及故障隔离等保护性措施。
3. DCS的未来是向CIMS方向发展
DCS的未来是什么-个国外过程控制专家曾形象地描绘认为：DCS正在消失，但DCS所提供的功能将永远不会消失，它们适应高效、安全、实时工业自动化过程控制的需要；控制机箱还将继续存在，但是未来控制室的面貌将发生巨大变化，将来的控制室更像是-个数据处理中心，常规大型DCS操作员控制台必将成为过时的设备；在DCS与上级管理计算机无缝”连接的多级信息管理系统结构体系中，DCS作为独立实体的现象将会消失。也就是说，DCS将会发展到它的更高形式。