【導(dǎo)讀】格柵間三臺(tái)電機(jī)的自動(dòng)控制。文中首先介紹了城市污水處理工藝流程和PLC的。路的設(shè)計(jì)、PLC的選型與組態(tài)，還詳細(xì)介紹了西門子PLC的編程軟件STEP7。最后對(duì)控制系統(tǒng)的軟件系統(tǒng)進(jìn)行了開發(fā)與調(diào)試，實(shí)現(xiàn)了本次設(shè)計(jì)的主要功能。

　　

【正文】 應(yīng)用研究等。本文詳細(xì)闡述了 工業(yè)污水處理 工藝流程、 PLC 的基本結(jié)構(gòu)和工作原理以及細(xì)格柵 系統(tǒng) 的 軟硬件實(shí)現(xiàn)。 通過(guò)四個(gè)月的 課題 設(shè)計(jì)和調(diào)試，基本上 完成了細(xì)格柵間三臺(tái)電機(jī)的控制要求 ， 達(dá)到了預(yù)期的設(shè)計(jì)目標(biāo) 。在這個(gè) 過(guò)程 中 ， 我遇到了許多問(wèn)題： 手動(dòng)操作 需 不 需 要通過(guò) PLC 控制 原來(lái)設(shè)計(jì)的手動(dòng)方式不通過(guò) PLC 控制，操作員在操作面板上手動(dòng)控制，而底層是依靠單純的硬件接線回路來(lái)實(shí)現(xiàn)。下面是電機(jī) M2 的手動(dòng)控制電路： 圖 51 手動(dòng)操作不受 PLC 控制 圖 52 手動(dòng)操作受 PLC 控制 比較兩圖 可以看到手動(dòng)操作受 PLC 控制時(shí)的連鎖關(guān)系比較簡(jiǎn)單，所以控制回路比較簡(jiǎn)單，可以降低成本；由于 PLC 系統(tǒng)的可靠性高于硬件接線回路，所以 PLC 控制手動(dòng)操作時(shí)系統(tǒng)的可靠性也提高了； 如果設(shè)備出現(xiàn)故障 ，手動(dòng)將是蘭州理工大學(xué)畢業(yè)設(shè)計(jì)說(shuō)明書 36 檢查外部接線以及執(zhí)行元件有無(wú)異常的一種處理故障的捷徑，當(dāng)設(shè)備有故障時(shí)可以通過(guò)手動(dòng)方式停止故障設(shè)備，檢查外部接線，便于維護(hù)與檢修；況且既然系統(tǒng)中用到了 P LC，就有必要將手動(dòng)方式用 PLC 控制，否則就 是對(duì) 資源的一種浪費(fèi)，也是對(duì) PLC 的不合理使用。 當(dāng)然 PLC 也有可能出現(xiàn)故障，如果對(duì)于大系統(tǒng)而言，需要 PLC 系統(tǒng)冗余，小系統(tǒng)的話及時(shí)更換模塊即可。 PLC 控制手動(dòng)方式 能簡(jiǎn)化聯(lián)鎖關(guān)系的接線，并且能夠靈活變化聯(lián)鎖關(guān)系 ，所以本設(shè)計(jì)采用 PLC 控制手動(dòng)方式。 電機(jī)采用哪種啟動(dòng)方式 三相鼠籠型電動(dòng)機(jī)的啟動(dòng)方式有兩種： 直接啟動(dòng)和降壓?jiǎn)?dòng)，降壓?jiǎn)?dòng) 常用 星 三角降壓 啟動(dòng)。 直接起動(dòng)的起動(dòng)電流很大，可達(dá)到額定電流的 4～ 7 倍。巨大的起動(dòng)電流，特別是有大容量電動(dòng)機(jī)或者有多臺(tái)電動(dòng)機(jī)需要同時(shí)起動(dòng)時(shí)，對(duì)電網(wǎng)的影響極大 。 利用 星 三角降壓 起動(dòng)時(shí) 將定子三相繞組作星形連接，以限制起動(dòng)電流，待轉(zhuǎn)速接近額定轉(zhuǎn)速時(shí)再換接成三角形，使電動(dòng)機(jī)全壓運(yùn)行。采用這種起動(dòng)方法，起動(dòng)電流較小，起動(dòng)轉(zhuǎn)矩也較小，所以一般適用于正常運(yùn)行為三角形接法的、容量較小的電動(dòng)機(jī)作空載或輕載起動(dòng)。也可頻繁起動(dòng)。啟動(dòng)電流為角接時(shí)的三分之一。 圖 53 M2 主電路和控制電路 蘭州理工大學(xué)畢業(yè)設(shè)計(jì)說(shuō)明書 37 控制要求為： KA6 和 KA7 首先得電，電機(jī)星形啟動(dòng)，一分鐘后 KA7 失電，KA8 得電，電機(jī)全壓運(yùn)行。繼電器的控制在軟件中實(shí)現(xiàn)。 在程序設(shè)計(jì)中我還熟悉了定時(shí)器指令、 MOVE 指令和比較指令，總之 這次畢業(yè)設(shè)計(jì)使我學(xué)到了很多 知識(shí)， 積累了許多寶貴的經(jīng)驗(yàn)，鍛煉了自己的獨(dú)立思考能力和 實(shí)踐 動(dòng)手能力 ， 進(jìn)一步加深了解了 PLC 在實(shí)踐當(dāng)中的應(yīng)用。 蘭州理工大學(xué)畢業(yè)設(shè)計(jì)說(shuō)明書 38 六 、參考文獻(xiàn) [1]常曉玲 .電氣控制系統(tǒng)與可編程控制器 [M].北京：機(jī)械城市出版社， 2020. 1. [2]孫振強(qiáng)，王暉，孫玉峰 .可編程控制原理及應(yīng)用教程 [M].北京：清華大學(xué)出版社， . [3]唐宇毅 .電廠含油城市污水處理的 PLC 控制系統(tǒng)設(shè)計(jì) [D].廣州：廣東城市大學(xué)出版社， 2020. [4]廖常初 .PLC 編程及應(yīng)用 [M].北京： 機(jī)械城市出版社 ， . [5]張培山 ， 鐘昆 .基于 PLC 的城市污水處理廠自控系統(tǒng)的實(shí)現(xiàn) [J].控制系統(tǒng) ,2020,5（ 1） ： 8283. [6]李英輝 ， 趙豫龍 ， 戴青云 .基于 PLC 的中水處理系統(tǒng) [J].石家莊職業(yè)技術(shù)學(xué)院報(bào) ,2020,6（ 4） 7678. [7]何獻(xiàn)忠 .城市城市污水處理的 PLC 控制應(yīng)用 [J].湖南冶金職業(yè)技術(shù)學(xué)院學(xué)報(bào) ， 2020， 43（ 4） ： 8687. 蘭州理工大學(xué)畢業(yè)設(shè)計(jì)說(shuō)明書 39 七 ．外文原文和譯文 原文 PLC technique discussion and future development Along with the development of the ages, the technique that is nowadays is also gradually perfect, the petition plays more and more strongly,the operation that list depends the artificial has already can39。t satisfied with the current manufacturing industry foreground, also can39。t guarantee the request of the higher quantity and high new the image of the technique business enterprise. The people see in produce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel39。s labor strength, reduce the establishment on the personnel. The target control of the hard realization in many plicated production lines, whole and excellent turn, the best decision etc., welltrained operation work, technical personnel or expert, governor but can judge and operate easily, can acquire the satisfied result. The research target of the artificial intelligence makes use of the calculator exactly to carry out, imitate these intelligences behavior, moderating the work through person39。s brain and calculators, with the mode that person39。s machine bine, for resolve the very plicated problem to look for the best path. We e in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after use in the mold a perhaps simple equipments of grassroots control that the electric appliances can do for the low level only。And the PLC emergence also became the epochmaking topic, adding the vivid software control through a very and stable hardware, making the automation head for the new high tide. The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculationses of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipments direct conjunction of the small power can. PLC internal containment have the CPU of the CPU, and take to have an I/ O 蘭州理工大學(xué)畢業(yè)設(shè)計(jì)說(shuō)明書 40 for expand of exterior to connect a people39。s address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation。 The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine。 The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to bee tired to add the machine and I/ Os to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and datas, the ROM can can do deposit o f the data permanence in the saving machine, but RAM only for the CPU putes the temporary calculation usage of hour of buffer space. The PLC anti interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer bee the topic that we fail, but stay to our is a concern to e to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle. PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy prehended the PLC language, and a lot of non electricity professiona