河南机电高等专科学校
Distributed Control System
课程名称： 自动化专业英语
课题名称： Distributed Control System
系部名称： 自动控制系
专业班级： 生产过程自动化091
组 员： 熊利明 王雪加 黄奎 徐挺 霍常金
愿上帝与你同在
2011年宁波雅思培训保过班 12月01日
Distributed Control System
DCS Distributed Control System is the abbreviation of (Distributed Control System), automation industry in the country is also known as distributed control system.
The so-called distributed control system, or in some of the information in the call distribution system, as oppod to centralized control systems, a new computer control system, which is a centralized control system bad on the development, evolution and come. It is a process by the process control level and the composition of monitoring level communications network as a link to the multi-level computer systems, integrated computer, communication, display and control technologies such as 4C, the basic idea is decentralized control, centralized operations, hierarchical management , flexible configuration, and configuration easy. Function in the system, DCS, and centralized control systems are not very different, but in the realization of system functions methods are completely different.
First, DCS's skeleton - the system network, which is the foundation and core DCS. As the network of the system for real-time DCS, reliability and scalability, play a decisive role, so the manufacturers have been careful in this area of design. For the DCS system
network, it must meet the requirements of real-time, that is completed within defined time limits transmission of information. Here the word "determine" the time limit is in any ca, the information transfer can be completed within this time limit, and this time limit is bad on real-time controlled process requirements identified. Therefore, indicators of network performance measurement system is not the network's rate, known as bits per cond (bps), but the real-time system network, which can ensure the long period of time to complete the required information transmission . System network also must be very reliable in any ca, network communications are not interrupted, so most manufacturers of DCS were double bus, ring or dual star network topology. Scalability to meet the requirements of the system, the system can access the network should be higher than the maximum number of nodes in the large number of nodes actually ud veral times. In this way, one can always add a new node, it can also make the system run in a lighter network traffic load conditions, to ensure that the system real-time and reliability. During the actual operation of the system, each node of the Internet and the net may occur at any time, in particular, operator stations, so that reconfiguration will always be, and this o
peration must not affect the normal operation, therefore, the system network should have a strong online network reconfiguration functions.
Secondly, this is a completely on-site I / O processing and realization of direct digital control (DDC) feature of network nodes. To t the general scene in a DCS I / O controllers, to share the entire system I / O and control functions. This site can be avoided due to a failure caud by the failure of the entire system, improve system reliability, the site also allows sharing of data acquisition and control functions, will help improve overall system performance. DCS operator station is run operation to deal with all the human-machine interface (HMI-Human Machine Interface, or operator interface) function of network nodes.scan
DCS engineer station is off-line configuration, the system configuration work, and online monitoring, control, maintenance of the network node, and its main function is to provide to the DCS configuration, software configuration tool (ie, the configuration software) and running online in real time DCS DCS network to monitor the operation of each node, the system engineer can engineer station to adjust the system configuration s
ettings and some system parameters, the DCS at any time under the best working condition. And centralized control systems, are required to have all of the DCS system configuration functions, it can be said, no system configuration functions of the system can not be called as a DCS.
DCS since its inception in 1975, has already experienced twenty years of development. In two decades, DCS system architecture although there is no significant change, but through constant development and improvement of its functionality and performance have been a huge increa. In general, DCS is toward more open, more standardized product in the direction of development.
As the field of process automation computer control system, the traditional DCS is only a narrow concept. If only the production process that DCS automation system, which will lead to wrong conclusions, becau the meaning of the computer control system has been greatly expanded, and it includes not only the DCS in the past included a variety of content, but also drill down to the each site measuring equipment, implementing agencies, upwards to the production management, all aspects of business. Traditional D
CS now only refers to this part of the production process control automation, and industrial automation system concept, should be targeted to enterpri-wide solution, total solution level. Only from this perspective to ask questions and solve problems, to really play the computer automation of its role.
DCS has the following characteristics:
(1) high reliability. DCS system to control the spread of the computer implementation, the system us fault-tolerant design of the structure, so a computer system malfunction will not cau the loss of other functions. In addition, each computer system, the tasks undertaken by relatively simple functions can be ud for the need to achieve a specific structure and special computer software, so that the reliability of each computer system has also been improved.
(2) open. DCS an open, standardized, modular and rial design, the system means each computer using the LAN communication, to achieve information transmission, when the need to change or expand the system functionality can be added easily connected to a computer system communication network or Remove from the network, almost does not affect the work of other computer systems.
hsjHistory of development of DCS
DCS Distributed Control System is the abbreviation of (Distributed Control System), automation industry in the country is also known as distributed control system.
It is a process by the process control level and the composition of monitoring level communications network as a link to the multi-level computer systems, integrated computer (Computer), communication (Communication), display (CRT) and control (Control) and other 4C technology, The basic idea is decentralized control, centralized operations, hierarchical management, flexible configuration, easy configuration. )
Its development can be divided into three stages.
Stage :1975-1980, during this period the technical characteristics of distributed control system as follows:what is a youth
1) using microprocessor-bad control unit, to achieve decentralized control, a wide variety of algorithms, through the loop control configuration independently, with lf-diagnostic function
2) The operating station with a CRT display unit and the process of paration, centralize
d monitoring, centralized operation
3) a more advanced communication system redundancy
The cond pha :1980-1985., Distributed control system during this period the technical features as follows:
1) increa the number of bits microprocessors, CRT display resolution to improve
2) strengthening the modular system
3) strengthen the system of information management, strengthening communication
The third pha, after 1985, the third generation of distributed systems, and its technical characteristics were as follows:
1) The adoption of open systems management
2) 32-bit microprocessor operating station
3) using real-time multi-ur multi-tasking operating system
Into the next decade, computer technology advances, more new technology is being applied to the DCS. PLC is a quential logic control developed for electronic equipment, which is ud instead of inflexible and cumbersome relay logic. Fieldbus Technology in e
ntering developed very rapidly since the mid nineties that some people have to predict: FCS bad on field bus control system will replace the DCS as the protagonist.
邪蒿DCS is a Data Communication Subsystem (data communications subsystems) for short.
To rail transportation industry, for example, DCS is a pure non-transparent curity system, he is nt between the control center and train carrier packet.
DCS cond layer of meaning: Dorsal Column Stimulator [medical] spine stimulator
In the special control areas, such as nuclear power plant control system, DCS is the meaning of digital control system (Digital control system).
DCS main domestic manufacturers are: Shanghai Xinhua, the super control, State Power Zhishen, Zhejiang University in control, and Belgium, Shanghai Chine, Shanghai Leroy, from Zhejiang and so on. There Westinghou abroad (Emerson), FOXBORO, ABB, Siemens, Honeywell, Yokogawa, Yamatake - Honeywell, FISHER-ROSEMOUNT companies
Overview of characteristics and development of DCS
DCS is a distributed control system (Distributed Control System) for short, is commonly c
alled the domestic general distributed control system. It is a process by the process control level and the composition of monitoring level communications network as a link to the multi-level computer systems, integrated computer (Computer), communication (Communication), display (CRT) and control (Control) technologies such as 4C, the The basic idea is decentralized control, centralized operations, hierarchical management, flexible configuration, easy configuration.
DCS has the following characteristics:
(1) high reliability of the DCS system to control the spread of the computer implementation, the system us fault-tolerant design of the structure, so a computer system malfunction will not cau the loss of other functions. In addition, each computer system, the tasks undertaken by relatively simple functions can be ud for the need to achieve a specific structure and special computer software, so that the reliability of each computer system has also been improved.
(2) DCS open an open, standardized, modular and rial design, the system us the computer local area network communication means to achieve information transmission,
when the need to change or expand the system functionality can be added easily with a computer communication network into the system or removed from the network, almost does not affect the work of other computer systems.
(3) flexibility in the configuration software through the process of application objects according to different hardware and software configuration, which determine the measurement and control signals and inter-connection of the control algorithms from the library and lect the appropriate control law called from the basic graphic components graphic library required for various monitoring and alarm screen, thus easily constitute the required control system.
(4) easy maintenance features a single small or micro-dedicated computer, with easy maintenance, convenient features, and when a local or a computer failure, you can run the system without affecting the ca of line replacement, rapid troubleshooting .
(5) coordination between the various stations of various data transmission through the communication network, the whole system of information sharing, coordination of work to complete the control system's overall functionality and optimization.
(6) control functional control algorithm rich t of continuous control, quence control and batch control in one, can be realized cascade, feedforward, decoupling, adaptive and predictive control, advanced control, and easily add the necessary Special control algorithms. The composition of DCS approach is flexible, managed by a dedicated computer stations, operator stations, engineering stations, recording station, site controller and data acquisition stations and other components, but also by a common rver, industrial computer and programmable controller was. At the bottom of the process control level are generally distributed on-site controllers, data acquisition stations, data acquisition and control in place, and through the data communications network to monitor and control level computer. Production control level on the data from the process control level centralized operations management, such as various optimization, statistical reports, fault diagnosis, alarm and so on. With the development of computer technology, DCS can follow a more high-performance needs and computer equipment connected through the network to achieve more advanced centralized management features, such as planning and scheduling, warehou management, energy management.
DCS in the development and application of state at home and abroad
In 1975, the largest U.S. companies Honeyw ell instrument control to the world launched its first integrated distributed control system TDC-2000 (Toal D ist ribu ted Con t ro l -2000), published in the system, immediately aroud the U.S. industrial control community highly, calling it "the most inspiring event." Major companies around the world quickly followed, introduced one by one distribution system, from process control to enter a new era of distributed systems.
During this period the Japane Yokogawa introduced CEN TUM, the United States Taylor Instrument Company MO SË, Fischer's DCÉ -400, Bailey's N -90, Foxboro Cpect rum and the German company Siemens Company Telepermm.
With micro-computer and computer networks in particular, the rapid development of technology, coupled with fierce competition of the manufacturers, so that DCS quickly from the first generation of the 70s to the early 90s the development of the third generation of DCS. Although distribution systems before that the technical level is already high, but there is a major drawback is: the major companies introduced dozens of models
of the system, almost all of the company's patented product, each company in order to protect their own interests, patents are ud in the network, which is the whole plant, the management of enterpri-wide cau problems.
As computers and web development companies to make more u of the control computer technology business, late 80's many companies introduced a new generation of distributed control system, who main feature is a new system of local network using MA P Agreement; Intelligent variable reference transmitter with fieldbus structure; in the control software on the order of the introduction of PLC control and batch control, the DCS also has the function of PLC.
Countries in the early 90s to the DCS are well known: 3000, Bailey's IN FI-90, Ro moun t of the RS-3, W est Hoo of WDPF, L eeds & Non th rup the MAX-1000, Foxbo ro's IöAS , Japan, Yokogawa's CEN TUM. Mentioned here are large-scale DCS, in order to meet the market needs a lot of the development of small and medium manufacturers of DCS systems such as S-9000, MAX-2, LXL, A 2 PACS and more.
Currently DCS are: Xinhua XDPS, Luneng LN2000, State Power Zhishen DCS, the contr
ol DCS, and when Lee DCS, Nanjing Branch far DCS, from Zhejiang and so on. There Westinghou abroad (Emerson) ovation, FOXBORO, ABB, Siemens PCS7, Honeywell, Yokogawa DCS and so on.
分布式控制系统
DCS是分布式控制系统的英文缩写（Distributed Control System），在国内自控行业又称之为集散控制系统。
即所谓的分布式控制系统，或在有些资料中称之为集散系统，是相对于集中式控制系统而言的一种新型计算机控制系统，它是在集中式控制系统的基础上发展、演变而来的。它是一个由过程控制级和过程监控级组成的以通信网络为纽带的多级计算机系统，综合了计算机，通信、显示和控制等4C技术，其基本思想是分散控制、集中操作、分级管理、配置灵活以及组态方便。在系统功能方面，DCS和集中式控制系统的区别不大，但在系统功能的实现方法上却完全不同。
首先，DCS的骨架—系统网络，它是DCS的基础和核心。由于网络对于DCS整个系统的
实时性、可靠性和扩充性，起着决定性的作用，因此各厂家都在这方面进行了精心的设计。对于温泉英语DCS的系统网络来说，它必须满足实时性的要求，即在确定的时间限度内完成信息的传送。这里所说的“确定”的时间限度，是指在无论何种情况下，信息传送都能在这个时间限度内完成，而这个时间限度则是根据被控制过程的实时性要求确定的。因此，衡量系统网络性能的指标并不是网络的速率，即通常所说的每秒比特数（bps），而是系统网络的实时性，即能在多长的时间内确保所需信息的传输完成。系统网络还必须非常可靠，无论在任何情况下，网络通信都不能中断，因此多数厂家的DCS均采用双总线、环形或双重星形的网络拓扑结构。为了满足系统扩充性的要求，系统网络上可接入的最大节点数量应比实际使用的节点数量大若干倍。这样，一方面可以随时增加新的节点，另一方面也可以使系统网络运行于较轻的通信负荷状态，以确保系统的实时性和可靠性。在系统实际运行过程中，各个节点的上网和下网是随时可能发生的，特别是操作员站，这样，网络重构会经常进行，而这种操作绝对不能影响系统的正常运行，因此，系统网络应该具有很强在线网络重构功能。
其次，这是一种完全对现场I/O处理并实现直接数字控制（DDC）功能的网络节点。一般一套DCS四级听力mp3下载中要设置现场I/O控制站，用以分担整个系统的I/O和控制功能。这样既可以避免
由于一个站点失效造成整个系统的失效，提高系统可靠性，也可以使各站点分担数据采集和控制功能，有利于提高整个系统的性能。DCS的操作员站是处理一切与运行操作有关的人机界面（HMI-Human Machine Interface或operator interface）功能的网络节点。
工程师站是对DCS进行离线的配置、组态工作和在线的系统监督、控制、维护的网络节点，其主要功能是提供对DCS进行组态，配置工作的工具软件（即组态软件），并在DCS在线运行时实时地监视DCS网络上各个节点的运行情况，使系统工程师可以通过工程师站及时调整系统配置及一些系统参数的设定，使DCS随时处在最佳的工作状态之下。与集中式控制系统不同，所有的DCS都要求有系统组态功能，可以说，没有系统组态功能的系统就不能称其为DCS。
DCS自1975年问世以来，已经经历了二十多年的发展历程。在这二十多年中，气球英语DCS虽然在系统的体系结构上没有发生重大改变，但是经过不断的发展和完善，其功能和性能都得到了巨大的提高。总的来说，DCS正在向着更加开放，更加标准化，更加产品化的方向发展。
作为生产过程自动化领域的计算机控制系统，传统的DCS仅仅是一个狭义的概念。如果以为DCS只是生产过程的自动化系统，那就会引出错误的结论，因为现在的计算机控制系
统的含义已被大大扩展了，它不仅包括过去DCS中所包含的各种内容，还向下深入到了现场的每台测量设备、执行机构，向上发展到了生产管理，企业经营的方方面面。传统意义上的DCS现在仅仅是指生产过程控制这一部分的自动化，而工业自动化系统的概念，则应定位到企业全面解决方案，即茉莉酮酸total solution 的层次。只有从这个角度上提出问题并解决问题，才能使计算机自动化真正起到其应有的作用。
DCS具有以下特点：
（1） 高可靠性。由于DCS将系统控制功能分散在各台计算机上实现，系统结构采用容错设计，因此某一台计算机出现的故障不会导致系统其他功能的丧失。此外，由于系统中各台计算机所承担的任务比较单一，可以针对需要实现的功能采用具有特定结构和软件的专用计算机，从而使系统中每台计算机的可靠性也得到提高。
（2） 开放性。DCS采用开放式，标准化、模块化和系列化设计，系统中各台计算机采用局域网方式通信，实现信息传输，当需要改变或扩充系统功能时，可将新增计算机方便地连入系统通信网络或从网络中卸下，几乎不影响系统其他计算机的工作。
