3A99859G01好價格價格好

3A99859G01好價格價格好

3A99859G01好價格價格好

dcs系統(tǒng)接地的基本要求 
　　dcs系統(tǒng)接地是為了保證當進入dcs系統(tǒng)的信號、供電電源或dcs系統(tǒng)設備本身出現問題時，可靠的接地系統(tǒng)能承受過載電流并可以迅速將過載電流導入大地。接地系統(tǒng)能夠為dcs提供屏蔽層，消除電子噪聲干擾，并為整個控制系統(tǒng)提供公共信號參考點(即參考零電位)。當接地系統(tǒng)發(fā)生問題時(接地電阻過大，多點接地控制工程網版權所有，接地線斷線或接地線與高電壓、大電流設備相接觸等)，會造成人員的觸電傷害及設備的損壞，還會造成dcs系統(tǒng)經常“死機"(或不明原因的“死機")，大多是因為接地系統(tǒng)不良或存在問題所引起的。 
　　因此，完善、可靠、正確的接地，是dcs 系統(tǒng)能夠安全、可靠和良好運行的關鍵。
d cs系統(tǒng)的接地方法 
　　4.1 分散布置的dcs設備接地方法 
　　分散布置dcs系統(tǒng)設備之間的連接一般是網絡(通訊)線，例如：現場控制站分散到現場，而操作員站位于不同的控制室，分散直徑在500米的范圍內，各站點間使用多模光纖或5類雙絞線或dp屏蔽雙絞線等連接。 
　　(1) 使用光纖連接的站點：各站點內的接地方法同集中布置的dcs設備。 
　　(2) 使用5類雙絞線或dp屏蔽雙絞線連接的站點： 
　　(3) 控制室的各類地線先連接到公共連接板，公共連接板通過接地總干線與公共接地極相連。從公共接地極看過去，整個接地網絡是一個星型結構。

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LEICA 115-000-132    PCB ADAPTER CARD LEICA ERGOLUX

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KD Technology  10-1602-50  cover purge ring

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APPLIED MATERIALS (AMAT) 3190-51001    CHAIN SST

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DAI NIPPON SCREEN (DNS) 5-39-01819    FITTING, Teflon PILLAR

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