【正文】 oom 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。 Communication between master station and slave station of PLC uses Profibus. Profibus, is internationalized and open, do not depend on the standard fieldbus of equipment manufacturer. It is a fieldbus which is used for control of factory automation workshoplevel and data munications, and control of field devicelevel. The transmission speed of Profibus is at 9600 bauds ~107 bauds, and when the main system startup, all devices connected to the general line should be set at the same speed. This can achieve the dispersed digital control and scene munications work from field devicelevel to workshoplevel, so as to provide a viable solution for factory to realize the prehensive automation and field device intellectualized. The processor module of Siemens S7300 PLC is CPU 3152 PN/DP, which has its own Profibus interface. The S7300 PLC Profibus work is used as the master station, S7200 PLC Profibus work is used as the slave station. S7200 PLC has no Profibus munication interface itself, so it has to municate with master station through EM277. C. The munication between PLC and power equipment According to the design requirements, the munication between PLC and power equipment need to be established, for the current, voltage and power in the power supply system should be monitored. Siemens PLC make the pointtopoint munication link with the power equipment through the munication module CP341. The power equipment provides RS485 munication interface in halfduplex asynchronous serial munication, and uses MODBUS RTU munication protocol. MODBUS protocol is one of the work protocols in the industrial control unit. The control equipments produced by different manufacturers can be linked as industrial work by MODBUS protocol, and that equipments linked in the different works can make the data munication. The MODBUS work can connect multiple equipments on one line, and each of the equipments can set munication address itself. Each controller can distinguish the devices by the address. Also, it decides what to do with the message send by the address. If response is needed, the controller will create feedback information and send it by MODBUS protocol. On the other work, there are frame and package constructs converted by the message in the MODBUS protocol. The conversion also extends the way to solve the problems such as address, routing paths and mistake detection in the specific work. 5 Siemens S7300 Hardware The S7300 is a modular PLC. It consists of Rack, CPU Module。其中的主要功能是通過組態(tài)軟件 WinCC，西門子 S7300 的城市污水處理的每個(gè)子系統(tǒng)的 PLC 監(jiān)控。本文還提出了系統(tǒng)的系統(tǒng)名稱和詳細(xì)描述的想法。 污水處理是環(huán)境保護(hù)最重要的任務(wù) 之一。 內(nèi)蒙古呼和浩特市土默特左旗的污水處理項(xiàng)目是典型項(xiàng)目在呼和浩特市的縣級市，采用循環(huán)式活性污泥系統(tǒng)系統(tǒng)（ CASS）處理廢水。 2 CASS 工藝 CASS生化處理系統(tǒng)是一個(gè)復(fù)雜的系統(tǒng)多參數(shù) (如液位、水質(zhì)、流量、壓力等 )、多任務(wù) (如 水進(jìn)口 ,曝氣，沉淀，排水等），多設(shè)備（如潷 水器，風(fēng)機(jī)，穩(wěn)壓器等）。 CASS池主反應(yīng)區(qū)的工程，按照 “ 曝氣，閑置，沉淀，和潷水器 “ 的循環(huán)過程。 3 控制系統(tǒng)的結(jié)構(gòu) 自動(dòng)污水處理控制系統(tǒng)的結(jié)構(gòu)是集中管理和分散控制。 為了確保污水處理系統(tǒng)運(yùn)行，主站和 PLC 從站是獨(dú)立的。即使整個(gè)控制系統(tǒng)出現(xiàn)故障，它也可以及時(shí)調(diào)整自己到現(xiàn)場手動(dòng)控制模式，以確保污水處 理系統(tǒng)的正常運(yùn)行。兩臺(tái)服務(wù)器的待機(jī)彼此共同執(zhí)行監(jiān)測任務(wù)。 4 數(shù)據(jù)通信 S7 系列 PLC 的通信網(wǎng)絡(luò)主要包括以下內(nèi)容：多點(diǎn)陽離子數(shù)據(jù)通信接口（ MPI）協(xié)議的 PROFIBUS，工業(yè)以太網(wǎng)，點(diǎn)至點(diǎn)連接，通過 ASI 的通信過程。 A. S7300和 WinCC之間的溝通 PLC 和 PC 機(jī)通過工業(yè)以太網(wǎng)相互通信， PLC 的傳輸通過光纖到 PC 機(jī)的配置軟件的實(shí)時(shí)數(shù)據(jù)庫的實(shí)時(shí)生產(chǎn)數(shù)據(jù)。因?yàn)?PLC 在這個(gè)系統(tǒng)中選擇的是 CPU3152PN/DP，或已集成 PROFINET 接口。 TCP/ IP 網(wǎng)絡(luò)協(xié)議，是事實(shí)上的 IT 標(biāo)準(zhǔn)有關(guān)通信協(xié)議服務(wù)。 B. 主站和從站 PLC 站之間的溝通 PLC 主站采用西門子 S7300 PLC。 PROFIBUS，國際化和開放的，不依賴于標(biāo)準(zhǔn)現(xiàn)場總線的設(shè)備制造商。 PROFIBUS 傳輸速度為 9600 波特 ? 107 波特，當(dāng)主系統(tǒng)啟動(dòng)時(shí)，一般線連接到的所有設(shè)備應(yīng)設(shè)置在相同的速度。處理器西門子 S7300 PLC 模塊， CPU 3152 PN / DP的，它有其自己的 PROFIBUS 接口。 S7200 PLC有沒有 PROFIBUS通訊接口本身，因此它具有與主站通過 EM277 的通信。西門子 PLC 的點(diǎn)至點(diǎn)的通信鏈路通過通訊模塊 CP341 的發(fā)電設(shè)備。 MODBUS 協(xié)議是在工業(yè)控制單元的網(wǎng)絡(luò)協(xié)議之一。MODBUS 網(wǎng)絡(luò)可以連接多個(gè)上一條線，每個(gè)設(shè)備的設(shè)備可以設(shè)置通訊地址本身。此外，它發(fā)送什么消息 由 地址決定。 在另一個(gè) 網(wǎng)絡(luò)，有轉(zhuǎn)換的 MODBUS 消息幀和封裝結(jié)構(gòu)協(xié)議。 5 西門子 S7300 硬件 S7300 是一個(gè)模塊化的 PLC。 該項(xiàng)目的 PLC 系統(tǒng)包含三個(gè) 機(jī)架 ，主要機(jī)架與擴(kuò)展機(jī)架 IM360/361 傳達(dá)。在此 PLC 的硬件配置， 15％的所有儲(chǔ)備的利潤率是預(yù)留的，這是第二階段的闊葉。 6 PC Conitoring 系統(tǒng)組成 以中國版本的 系統(tǒng)配置軟件實(shí)現(xiàn)， 監(jiān)督 外觀配置功能。電腦監(jiān)控系統(tǒng)的功能框圖如圖 4 所示。 2）顯示功能：顯示設(shè)備的運(yùn)行狀態(tài)，通過控制圖形和動(dòng)畫，顯示該領(lǐng)域的實(shí)時(shí)運(yùn)行參數(shù)設(shè)備。 4）報(bào)警功能：實(shí)現(xiàn)不同的報(bào)警級別，根據(jù)不同的需求，當(dāng)模擬值（如電流，壓力，水位，濃度等）測量超過給定的范圍內(nèi)，或數(shù)字值（如電機(jī)啟動(dòng) /停止，閥門開 /關(guān)）的訂單。定時(shí)打印，事件觸發(fā)打印和打印方式，可分為用戶定義的打印。 7）權(quán)限管理：為不同的用戶設(shè)置相應(yīng)的訪問保護(hù)，防止未經(jīng)授權(quán)的用戶訪問的監(jiān)控系統(tǒng)。程序流程圖如圖 5 所示。在主程序中，可以在正確的順序調(diào)用每個(gè)子程序。然后，控制計(jì)劃被列為遠(yuǎn)程手動(dòng)控制和遠(yuǎn)程自動(dòng)控制，可以通過兩種方式之間的切換標(biāo)志位。所以程序可以自動(dòng)執(zhí)行，并及時(shí)為每個(gè)周期，所 有的設(shè)備可以自動(dòng)停下來控制時(shí)有連鎖故障。 8 結(jié)論 在污水處理中使用的自動(dòng)化系統(tǒng)是值得推廣的，因?yàn)樗軡M足現(xiàn)代污水處理的要求，減少日常的一天維護(hù)管理，降低污水處理成本，并確保運(yùn)行和出水的水質(zhì)。該項(xiàng)目進(jìn)行了測試于 。