【正文】
zed control systems, a new puter control system, which is a centralized control system based on the development, evolution and e. It is a process by the process control level and the position of monitoring level munications work as a link to the multilevel puter systems, integrated puter, munication, 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 pletely different. First, DCS39。 在控制軟件上引入 PLC 的順序控制與批量控制 , 使 DCS 也具有 PLC 的功能。Euml。 DCS 的構(gòu)成方式十分靈活,可由專用的管理計(jì)算機(jī)站、操作員站、工程師站、記錄站、現(xiàn)場(chǎng)控制站和數(shù)據(jù)采集站等組成,也可由通用的服務(wù)器、工業(yè)控制計(jì)算機(jī)和可 編程控制器構(gòu)成。它是一個(gè)由過程控制級(jí)和過程監(jiān)控級(jí)組成的以通信網(wǎng)絡(luò)為紐帶的多級(jí)計(jì)算機(jī)系統(tǒng),綜合了計(jì)算機(jī)(Computer)、通訊 (Communication)、顯示 (CRT)和控制 (Control)等 4C技術(shù),其基本思想是分散控制、集中操作、分級(jí)管理、配置靈活、組態(tài)方便。 PLC 是一種針對(duì)順序邏輯控制發(fā)展起來的電子設(shè)備,它主要用于代替不靈活而且笨重的繼電 器邏輯。此外,由于系統(tǒng)中各臺(tái)計(jì)算機(jī)所承擔(dān)的任務(wù)比較單一,可以針對(duì)需要實(shí)現(xiàn)的功能采用具有特定結(jié)構(gòu)和軟件的專用計(jì)算機(jī),從而使系統(tǒng)中每臺(tái) 計(jì)算機(jī)的可靠性也得到提高。在這二十多年中, DCS 雖然在系統(tǒng)的體系結(jié)構(gòu)上沒有發(fā)生重大改變,但是經(jīng)過不斷的發(fā)展和完善,其功能和性能都得到了巨大的提高。在系統(tǒng)實(shí)際運(yùn)行過程中,各個(gè)節(jié)點(diǎn)的上網(wǎng)和下網(wǎng)是隨時(shí)可能發(fā)生的,特別是操作員站,這樣,網(wǎng)絡(luò)重構(gòu)會(huì)經(jīng)常進(jìn)行,而 這種操作絕對(duì)不能影響系統(tǒng)的正常運(yùn)行,因此,系統(tǒng)網(wǎng)絡(luò)應(yīng)該具有很強(qiáng)在線網(wǎng)絡(luò)重構(gòu)功能。 首先, DCS 的骨架 —系統(tǒng)網(wǎng)絡(luò),它是 DCS 的基礎(chǔ)和核心。在系統(tǒng)功能方面, DCS 和集中 式控制系統(tǒng)的區(qū)別不大,但在系統(tǒng)功能的實(shí)現(xiàn)方法上卻完全不同。這樣,一方面可以隨時(shí)增加新的節(jié)點(diǎn),另一方面也可以使系統(tǒng)網(wǎng)絡(luò)運(yùn)行于較輕的通信負(fù)荷狀態(tài),以確保系統(tǒng)的實(shí)時(shí)性和可靠性。 DCS 自 1975 年問世以來,已經(jīng)經(jīng)歷了二十多年的發(fā)展歷程。由于 DCS 將系統(tǒng)控制功能分散在各臺(tái)計(jì)算機(jī)上實(shí)現(xiàn),系統(tǒng)結(jié)構(gòu)采用容錯(cuò)設(shè)計(jì),因此某一臺(tái)計(jì)算機(jī)出現(xiàn)的故障不會(huì)導(dǎo)致系統(tǒng)其他功能的喪失。 第一階段: 19751980 年,在這個(gè)時(shí)期集散控制系統(tǒng)的技術(shù)特點(diǎn)表現(xiàn)為: 1)采用微處理器為基礎(chǔ)的控制單元,實(shí)現(xiàn)分散控制,有各種各樣的算法,通過組態(tài)獨(dú)立完成回路控制,具有自診斷功能 2)采用帶 CRT 顯示器的操作站與過程單元分離,實(shí)現(xiàn)集中監(jiān)視,集中操作 3)采用較先進(jìn)的冗余通信系統(tǒng) 第二階段: 1980—1985.,在這個(gè)時(shí)期集散控制系統(tǒng)的技術(shù)特點(diǎn)表現(xiàn)為: 1)微處理器的位數(shù)提高, CRT 顯示器的分辨率提高 2)強(qiáng)化的模塊化系統(tǒng) 3)強(qiáng)化了系統(tǒng)信息管理,加強(qiáng)通信功能 第三階段, 1985 年以后,集散系統(tǒng)進(jìn)入第三代,其技術(shù)特點(diǎn)表現(xiàn)為: 1)采用開放系統(tǒng)管理 2)操作站采用 32 位微處理器 3)采用實(shí)時(shí)多用戶多任務(wù)的操作系統(tǒng) 進(jìn)入九十年代以后,計(jì)算機(jī)技術(shù)突飛猛進(jìn),更多新的技術(shù)被應(yīng)用到了 DCS 之中。 DCS 特點(diǎn)和發(fā)展概述 DCS 是分散控制系統(tǒng) (Distributed Control System)的簡稱,國內(nèi)一般習(xí)慣稱為集散控制系統(tǒng)。 (6)控制功能齊全 控制算法豐富,集連續(xù)控制、順序控制和批處理控制于一體,可實(shí)現(xiàn)串級(jí)、前饋、解耦、自適應(yīng)和預(yù)測(cè)控制等先進(jìn)控制,并可方便地加入所需的特殊控制算法。 在此期間有日本橫河公司推出的 CEN TUM , 美國泰勒儀表公司的 MO Samp。 引用智能變送器與現(xiàn)場(chǎng)總線結(jié)構(gòu) 。國外 的有 西屋(艾默生) ovation、 FOXBORO、 ABB、西門子 PCS霍尼韋爾、橫河 DCS 等。s N 90, Foxboro Cpect rum and the German pany Siemens Company Telepermm. With microputer and puter works in particular, the rapid development of technology, coupled with fierce petition 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 panies introduced dozens of models of the system, almost all of the pany39。AS , Japan, Yokogawa39。 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, Bailey39。s overall functionality and optimization. (6) control functional control algorithm rich set of continuous control, sequence 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 position of DCS approach is flexible, managed by a dedicated puter stations, operator stations, engineering stations, recording station, site controller and data acquisition stations and other ponents, but also by a mon server, industrial puter and programmable controller was. At the bottom of the process control level are generally distributed onsite controllers, data acquisition stations, data acquisition and control in place, and through the data munications work to monitor and control level puter. 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 puter technology, DCS can follow a more highperformance needs and puter equipment connected through the work to achieve more advanced c