plc外文翻譯---plc在應(yīng)用中應(yīng)注意的問(wèn)題-plc設(shè)計(jì)(完整版)
【正文】 special intense, or installs uses improper, cannot guarantee PLC the normal operation, therefore should pay attention to the following question in the use. First, installment and wiring (1) The power line, the pilot wire as well as the PLC power line and the I/O line should distinguish the wiring, between the insulating transformer and PLC and I/O should use the double rubberized wire connection. (2) PLC should be far away from the strong jamming source like electric welding machine, the high efficiency silicon rectifier unit and the largescale power equipment, cannot install with the highpressured electric appliance in the identical switch cabi. (3) The input and output of PLC are best separate the line, the switch quantity and the simulation quantity must separate the placing. The simulation quantity signal39。s control system must establish the exterior electric appliance interlock protection。 If cannot meet this kind of requirements, must achieve with the other equipment public earth, forbids to establish contacts the earth with other equipment. The ground point should approach PLC as far as possible. Fifth, the redundant system and hot backup system in profession in and so on petroleum, chemical industry, metallurgy certain systems, the request control device has the extremely high reliability. If the control system breaks down, will create the production suspension, the raw material massive wastes or the equipment trouble, will create the enormous economic loss to the enterprise. But depends on the enhancement control system hardware39。 PLC 基本單元與擴(kuò)展單元以及功能模塊的連接線纜應(yīng)單獨(dú)敷設(shè)，以防止外界信號(hào)的干擾。但在同一組中的輸出只能用同一類型、同一電壓等級(jí)的電源。正反向運(yùn)轉(zhuǎn)等可逆操作的控制系統(tǒng)，要設(shè)置外部電器互鎖保護(hù)；往復(fù)運(yùn)行及升降移動(dòng)的控制系統(tǒng)，要設(shè)置外部限位保護(hù)電路。 四、 PLC 的接地 良好的接地是保證 PLC 可靠工作的重要條件，可以避免偶然發(fā)生的電壓沖擊危害。 1． 冗余控制系統(tǒng) 在冗余控制系統(tǒng)中，整個(gè) PLC 控制系統(tǒng)（或系統(tǒng)中最重要的部分，如 CPU 模塊）由兩套完全相同的系統(tǒng)組成如圖 2 所示。這一切換過(guò)程是由冗余處理單元 RPU控制的，切換時(shí)間在 13 個(gè)掃描周期， I/O 系統(tǒng)的切換也是由 RPU 完成的。為了抑制加在電源及輸入端、輸出端的干擾，應(yīng)給 PLC 接上專用地線，接地點(diǎn)應(yīng)與動(dòng)力設(shè)備（如電機(jī)）的接地點(diǎn)分開(kāi)；若達(dá)不到這種要求，也必須做到與其它設(shè)備公共接地，禁止與其它設(shè)備串連接地。但當(dāng)可編程控制器 CPU 故障時(shí)就不能控制輸出，因此，對(duì)于能使用戶造成傷害的危險(xiǎn)負(fù)載，為確保設(shè)備在安全狀態(tài)下運(yùn)行，需設(shè)計(jì)外電路加以防護(hù)。（ 3）采用繼電器輸出時(shí)，所承受的電感性負(fù)載的大
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