6ES7518-4AP00-0AB0

我們已經知道有的FCS是由PLC發(fā)展而來，而有的FCS是由DCS發(fā)展而來，那么，今天FCS已走向實用化，PLC與DCS前景又將如何？

　　PLC于60年代末期在美國首先出現，目的是用來取代繼電器，執(zhí)行邏輯、計時、計數等順序控制功能，建立柔性程序控制系統(tǒng)。1976年正式命名，并給予定義：PLC是一種數字控制電子計算機，它使用了可編程序存儲器儲存指令，執(zhí)行諸如邏輯、順序、計時、計數與演算等功能，并通過模擬和數字輸入、輸出等組件，控制各種機械或工作程序。經過30多年的發(fā)展，PLC已十分成熟與完善，并開發(fā)了模擬量閉環(huán)控制功能。

　　PLC在FCS系統(tǒng)中的地位似乎已被確定并無多少爭論。PLC作為一個站掛在高速總線上。充分發(fā)揮PLC在處理開關量方面的優(yōu)勢。另外，火力發(fā)電廠輔助車間，例如補給水處理車間、循環(huán)水車間、除灰除渣車間、輸煤車間等，在這些車間的工藝過程多以順序控制為主。PLC對于順序控制有其的優(yōu)勢。編者以為，輔助車間的控制系統(tǒng)應以遵循現場總線通訊協(xié)議的PLC或能與FCS進行通訊交換信息的PLC為優(yōu)選對象。

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