DCS系統(tǒng)是繼
PLC之外的一大自動(dòng)化控制系統(tǒng)，它在化工、火電等領(lǐng)域的應(yīng)用極為廣泛，但是生產(chǎn)方面的自動(dòng)化技術(shù)需求進(jìn)一步提高，傳統(tǒng)的DCS系統(tǒng)已不能滿足需要，需要進(jìn)行技術(shù)升級(jí)。
DCS系統(tǒng)由多臺(tái)計(jì)算機(jī)分別控制生產(chǎn)過程中多個(gè)控制回路，同時(shí)又可集中獲取數(shù)據(jù)、集中管理和集中控制的自動(dòng)控制系統(tǒng)。分布式控制系統(tǒng)采用微處理機(jī)分別控制各個(gè)回路，而用中小型工業(yè)控制計(jì)算機(jī)或高性能的微處理機(jī)實(shí)施上一級(jí)的控制。
經(jīng)過這些年來的不斷應(yīng)用，DCS系統(tǒng)在行業(yè)發(fā)展的一些局限性逐步體現(xiàn)出來，DCS存在的問題：
①1對(duì)1結(jié)構(gòu)。1臺(tái)儀表，1對(duì)傳輸線，單向傳輸1個(gè)信號(hào)。這種結(jié)構(gòu)造成接線龐雜、工程周期長、安裝費(fèi)用高、維護(hù)困難。
②可靠性差。模擬信號(hào)傳輸不僅***度低，且易受干擾。為此采用各種措施提高抗干擾性和傳輸***度，其結(jié)果是增加了成本。
③失控狀態(tài)。操作員在控制室既不了解現(xiàn)場模擬儀表的工作狀況，也不能對(duì)其進(jìn)行參數(shù)調(diào)整，更不能預(yù)測事故，導(dǎo)致操作員對(duì)其處于失控狀態(tài)。因操作員不能及時(shí)發(fā)現(xiàn)現(xiàn)場儀表故障，而發(fā)生事故已屢見不鮮。
④互操作性差。盡管模擬儀表已統(tǒng)一4～20mA信號(hào)標(biāo)準(zhǔn)，可大部分技術(shù)參數(shù)仍由制造商自定，致使不同品牌儀表無法互換。因此導(dǎo)致用戶依賴制造廠，無法使用性能價(jià)格比***的配套儀表，甚至出現(xiàn)個(gè)別制造商壟斷市場的局面
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