VMIVME-7750-746001燃機(jī)電氣,VMIVME-7750-746001模塊
數(shù)字濾波和工頻整形采樣，可有效消除周期性干擾；定時(shí)校正參考點(diǎn)電位，并采用動(dòng)態(tài)零點(diǎn)，可有效防止電位漂移；采用信息冗余技術(shù)，設(shè)計(jì)相應(yīng)的軟件標(biāo)志位；采用間接跳轉(zhuǎn)，設(shè)置軟件陷阱等提高軟件結(jié)構(gòu)可靠性。VMIVME-7750-746001
4正確選擇接地點(diǎn)，完善接地系統(tǒng)
接地的目的通常有兩個(gè)，其一為了安全，其二是為了抑制干擾。完善的接地系統(tǒng)是DCS控制系統(tǒng)抗電磁干擾的重要措施之一。
系統(tǒng)接地方式有：浮地方式、直接接地方式和電容接地三種方式。對(duì)DCS控制系統(tǒng)而言，它屬高速低電平控制裝置，應(yīng)采用直接接地方式。由于信號(hào)電纜分布電容和輸入裝置濾波等的影響，裝置之間的信號(hào)交換頻率一般都低于1MHz，所以DCS控制系統(tǒng)接地線(xiàn)采用一點(diǎn)接地和串聯(lián)一點(diǎn)接地方式。集中布置的DCS系統(tǒng)適于并聯(lián)一點(diǎn)接地方式，各裝置的柜體中心接地點(diǎn)以單獨(dú)的接地線(xiàn)引向接地極。如果裝置間距較大，應(yīng)采用串聯(lián)一點(diǎn)接地方式。用一根大截面銅母線(xiàn)（或絕緣電纜）連接各裝置的柜體中心接地點(diǎn)，然后將接地母線(xiàn)直接連接接地極。接地線(xiàn)采用截面大于22mm2的銅導(dǎo)線(xiàn)，總母線(xiàn)使用截面大于60mm2的銅排。接地極的接地電阻小于2Ω，接地極最好埋在距建筑物10～15m遠(yuǎn)處，而且DCS系統(tǒng)接地點(diǎn)必須與強(qiáng)電設(shè)備接地點(diǎn)相距10m以上。
信號(hào)源接地時(shí)，屏蔽層應(yīng)在信號(hào)側(cè)接地；不接地時(shí)，應(yīng)在DCS側(cè)接地；信號(hào)線(xiàn)中間有接頭時(shí)，屏蔽層應(yīng)牢固連接并進(jìn)行絕緣處理，一定要避免多點(diǎn)接地；多個(gè)測(cè)點(diǎn)信號(hào)的屏蔽雙絞線(xiàn)與多芯對(duì)絞總屏電纜連接時(shí)，各屏蔽層應(yīng)相互連接好，并經(jīng)絕緣處理。選擇適當(dāng)?shù)慕拥靥巻吸c(diǎn)接點(diǎn)。VMIVME-7750-746001燃機(jī)電氣DCS一般會(huì)使用很多個(gè)控制器對(duì)某個(gè)生產(chǎn)過(guò)程中的各個(gè)控制點(diǎn)實(shí)施控制，各個(gè)控制設(shè)備之間利用網(wǎng)絡(luò)連接之后，可對(duì)其中的數(shù)據(jù)進(jìn)行交換?，F(xiàn)在，我國(guó)的各項(xiàng)智能化越來(lái)越先進(jìn)，國(guó)產(chǎn)DCS系統(tǒng)在大型項(xiàng)目中網(wǎng)絡(luò)安全設(shè)計(jì)起到了重要的作用，提升了網(wǎng)絡(luò)安全性。本文以具體項(xiàng)目為例，針對(duì)國(guó)產(chǎn)DCS系統(tǒng)在大型項(xiàng)目中網(wǎng)絡(luò)安全設(shè)計(jì)做了詳細(xì)的分析。
real time, so as to effectively detect the fault state. Such as order tracking and vibration analysis to detect the operation of the machine.
4) Security. The data packet sent by PLC through Ethernet is unencrypted, so it is not suitable for preventing hacker intrusion. The packet sent by PAC can be encrypted. Although this is not the most important factor to consider at present, security is bound to become an important aspect in the future.
5) Deterministic application of multiple speeds. PLC can only run at a fixed speed, so it can not complete various tasks independently at different speeds. The operating system running on PAC has such characteristics that it can carry out parallel processing.
6) Flexible memory function. PAC has a module with upgradeable memory function, which allows users to execute the system to meet the current application requirements and can be expanded in the future. PLC has only fixed memory capacity.
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