【正文】 Abstract. For the demand of domestic sewage treatment in countylevel city, a plan of Distributed Control System in municipal wastewater treatment automation system is proposed. The main function of which is to supervisory control each subsystem of municipal wastewater treatment via the configuration software WinCC, Siemens S7300 PLC. The feature of the system is mainly as follows, collection of PLC data, protocol conversion, the transmission of data through fiber, the realization of projects in configuration software, the realtime data storage in database and the release of each kind of report forms, curves, alarm events in display and so on. The idea of the system designation and the detailed characterization of the system are also presented in this paper. Keywords: sewage treatment, Distributed Control System, Siemens S7300 PLC, WinCC Configuration software. 1 Introduction Along with the rapid development of economy in China, environmental protection has been a prominent issue. Sewage Treatment is one of the most important parts of environmental protection. As the puter technology and sewage treatment technology developed rapidly, it is necessary to monitor the wastewater treatment process with advanced control technology and equipment. The sewage treatment project of Inner Mongolian Huhhot Tumd Left Banner is the typical project among the countylevel city of Hohhot, using Cyclic Activated Sludge System (CASS) to treat wastewater. For this project, we designed a DCS system, whose control system is Siemens S7300 PLC and monitoring software is Siemens WinCC . 2 CASS Process CASS biochemical treatment system is a plex system of multiparameter (such as liquid level, water quality, flow rate, pressure, etc.), multitasking (such as waterin, aeration, sedimentation, drainage, etc.), multiequipment (such as water decanter, blower, regulator etc.). It is the core of the whole biochemical disposal system. The main reaction zone of CASS pool works according to “aeration, idle, sedimentation, and decanter” cycle procedures. Among them, the control of dissolved oxygen in CASS pool, anaerobic segment and aerobic segment is the core. 3 The Structure of Control System The structure of automatic sewage treatment control system is centralized management and decentralized control. The control system employs the control method bined with remote automatic control, remote manual control and field automatic control. In order to ensure sewage treatment systems well running, the master station and slave station of PLC are independent. If one of the subsystems breaks down, it will not affect the normal running of other system devices. Even if the whole control system malfunctions, it also can adjust itself to field manual control mode in time to ensure the normal operation of the sewage treatment system. The PC in the central control room uses the model of dualredundant to realize realtime monitoring. Two servers standby each other to jointly perform monitoring tasks. If one server conk out, the other one can undertake the tasks, automatically ensure the system can continue to provide services in the case without manual intervention. 4 Data Communication S7 series PLC munications work mainly includes the following: multipoint interface (MPI) protocol of data muni cations, PROFIBUS, industrial Ether, pointtopoint connections, through ASI process of munication. This project has PROFIBUS, used in industrial Ether, pointtopoint connections. A. The munication between S7300 and WinCC PLC and PC municate with each other through industrial Ether, PLC transmit the data of realtime production to the realtime database of configuration software of PC via optical fiber. PC can monitor the field device from far away. Because the PLC selected in this system is CPU 3152PN/DP, which has integrated PROFINET interface. Communication between S7300 and WINCC uses TCP/IP work protocol. TCP/IP work protocol is a de facto standard about munication protocol in IT services. Although the response time is about 100 ms magnitude, for application of factory control, the response time is enough. B. The Communication between master station and slave station of PLC PLC master station uses Siemens S7300 PLC. The PLC of ClO2 workshop uses Siemens S7200 PLC。隨著計(jì)算機(jī)技術(shù)和污水處理技術(shù)迅速發(fā)展，這是必要的監(jiān)控污水處理過程與先進(jìn)控制技術(shù)和設(shè)備?？刂葡到y(tǒng)采用的控制方法結(jié)合遠(yuǎn)程自動(dòng)控制，遠(yuǎn)程手動(dòng)控制和領(lǐng)域的自動(dòng)控制。這個(gè)項(xiàng)目有 PROFIBUS總線，工業(yè)以太網(wǎng)，點(diǎn)至點(diǎn)連接。 PLC 的 ClO2車間使用西門子 S7200 PLC通信主站和從站 PLC 站之間采用 PROFIBUS。 C. PLC之間的通信和電力設(shè)備 根據(jù)設(shè)計(jì)要求， PLC 和權(quán)力之間的溝通需要建立的電流，電壓和功率，在電源設(shè)備應(yīng)監(jiān)測系統(tǒng)。如果需要回應(yīng)，控制器將建立信息反饋和發(fā)送 MODBUS 協(xié)議。 S7300 PLC 系統(tǒng)硬件框圖如圖 3 所示。 5）打印功能：可實(shí)現(xiàn)實(shí)時(shí)打印報(bào)告，圖形，各種活動(dòng)并報(bào)警。 首先，寫一個(gè)模擬采集在組織塊 35，子程序和模擬數(shù)據(jù)將被刷新每 100 毫秒。結(jié)果竟然系統(tǒng)是一個(gè)先進(jìn)，可靠，操作簡單的控制系統(tǒng)，從而能夠更好地解決一些問題，如自動(dòng)化低，可靠性低，大量的時(shí)間延遲和其他一些在過去的污水處理存在問題。但有許多挑戰(zhàn) PLC 編程教學(xué)學(xué)生。虛擬的 PLC，使用相應(yīng)的控制器，允許用戶運(yùn)行和調(diào)試應(yīng)用程序代碼，而在影視小卡車，排版。一些虛擬環(huán)境中進(jìn)行仿真控制程序，植物模型的可視化顯示相應(yīng)的植物模型反映的變化在 PLC 模擬的虛擬系統(tǒng)的狀態(tài)。 SCADA 軟件提供最大的連接選項(xiàng)，選擇數(shù)以百計(jì)的 PLC和其他硬件設(shè)備。設(shè)備在實(shí)驗(yàn)裝置如圖 . 1。虛擬模型虛擬實(shí)驗(yàn)系統(tǒng)的核心。我們建立這些復(fù)雜的三維模型，并通過 OpenGL 和 VB6。所有的植物模型離散時(shí)間模型，并給出了采樣頻率。熱交換模型離散時(shí)間模型 是 干擾模型離散時(shí)間模型 是 水箱溫度之間的關(guān)系，電壓和蒸汽閥門液體流量閥的電壓 我們創(chuàng)建 y,yp,xp,yd,xd 標(biāo)簽 組態(tài)王 中。他們是特別適合模擬系統(tǒng)，這是不可能提供在在實(shí)驗(yàn)室環(huán)境中減少物理模型的形式。另一方面，也有講師有意義的處 。組態(tài)王 3? 5，計(jì)算他們每 5 秒和升級(jí)的圖形狀態(tài)。 4 插圖 根據(jù) [5]，我們建立了一個(gè)稱為 “攪拌槽 ”的化學(xué)反應(yīng)模型描述以下。用戶還可以控制寫入或讀取標(biāo)簽的三維模型。圖形模型層顯示相應(yīng)的植物反映虛擬系統(tǒng)不斷變化的狀態(tài)模型（二維或三維圖形模型）在模擬過程中。 PLC 必須連接到電腦，通過特殊的串行電纜。本文的目的是提出了一個(gè)虛擬實(shí)驗(yàn)系統(tǒng)，能夠連接不同類型的 PLC。但驗(yàn)證程序移植到實(shí)際的 PLC 系統(tǒng)，是不容易的，因?yàn)椴煌?PLC具有不同的程序語言。 CX 模擬器是一種工具，它作為一個(gè)虛擬功能歐姆龍 PLC。傳統(tǒng)實(shí)驗(yàn)室的缺點(diǎn)包括需要一個(gè)合格的教師，制度空間的需求，對(duì)學(xué)生的安全概率的問題，經(jīng)常性的維護(hù)等實(shí)驗(yàn)實(shí)驗(yàn)室的時(shí)間限制，但是，代表重大投資的資金和空間，學(xué)校可能無法滿足 [2, 3]。 they appreciate the low maintenance demands and trouble free performing of the virtual models. In the future, the possible remote access through Inter for employment of programmable logic controller