基于多點網(wǎng)絡的水廠自動監(jiān)控系統(tǒng)設計Design of MPI Based Automatic Monitoring and Control System in Water Works劉 美 俊(湖南工程學院,湘潭411101)摘要針對水廠工作水泵多、現(xiàn)場離控制站距離遠的特點,提出了一種基于MPI多點網(wǎng)絡的自動監(jiān)控系統(tǒng)的設計方法,分析了系統(tǒng)的工作原理,介紹了系統(tǒng)中數(shù)據(jù)的采集與處理、主站與從站的通信原理以及系統(tǒng)軟件的設計。由于這種系統(tǒng)的主、從站PLC之間采用MPI網(wǎng)絡通信,具有運行可靠、性能價格比高的特點,所以適用于中小規(guī)模水廠的分布式監(jiān)控場合。關(guān)鍵詞多點網(wǎng)絡主站從站監(jiān)控系統(tǒng)Abstract Ina ccordancew ithth efe atuersof w aterw orks,i. e. ,manyp umpsin o perationa ndth ep umps, farfor mt hec ontrolst ation,th em ethodo fdesigninga na utomati(〕monitoringa ndc ontorlsy stemb asedo nM PIis p resented.Th eo perationalpr incipleo fth esy stemi san alyzed,th ed atac olection,data processing; communication between master station and slave station as wel as design and system software are discussed. Because MPI network communicationis used among master station, slave stations and PLC, the system is reliable and high cost-efective. It is, suitable for smal and mediumsized water works for distrbuted monitoring and control.Keywords MPI Masterst ation Slaves tation Monitoringa ndc ontorlsy stem
自來 水 廠 的自動控制系統(tǒng)一般分為兩大部分,一對組態(tài)硬件要求較高,投資較大。相對而言,MPI網(wǎng)是水源地深水泵的工作控制,一是水廠區(qū)變頻恒壓供絡速度可達187.5 M bps,通過一級中繼器傳輸距離可水控制,兩部分的實際距離通常都比較遠。某廠水源達Ikm 。根據(jù)水廠的具體情況,確定以MPI方式組地有3臺深井泵給水廠區(qū)的蓄水池供水。水廠區(qū)的成網(wǎng)絡,主站PLC為S7-300系列的CPU3121FM,從任務是對水池的水進行消毒處理后,通過加壓泵向管站為S7-200系列的CPU222。這樣既滿足了系統(tǒng)要路恒壓供水。選用Siemens公司的S7系列可編程控求,又相對于Profibus網(wǎng)絡節(jié)省了三分之一的成本,制器(PLC)和上位機組成實時數(shù)據(jù)采集和監(jiān)控系統(tǒng), 這種分布式監(jiān)控系統(tǒng)具有較高的性能價格比。系統(tǒng)對深水泵進行遠程控制,對供水泵采用變頻器進行恒中PLC的物理層采用RS - 485接口,網(wǎng)絡延伸選用壓控制以保證整個水廠的電機設備安全、可靠地運帶防雷保護的中繼器,使系統(tǒng)的安全運行得到了保行。證。MPI網(wǎng)絡的拓撲結(jié)構(gòu)如圖1所示。1 多點網(wǎng)絡(NWI)監(jiān)控系統(tǒng)的組成Sie me ns 公司S7系列PLC通常有MP」多點網(wǎng)絡與Profibus現(xiàn)場總線網(wǎng)絡兩種組網(wǎng)方式。Profibus現(xiàn)場總線的應用目前較為普遍,通用性較好,它由Profibus一DP, Profibus一FMS, Profibus一PA組成。Profibus - DP型用于分散外設間的數(shù)據(jù)傳輸,傳輸速率為9.6kbps一12Mbps,主要用于現(xiàn)場控制器與分散1/0之間的通信,可滿足交直流調(diào)速系統(tǒng)快速響應的時間要求,特別適合于加工自動化領(lǐng)域的應用;Profibus - FMS主要解決車間級通信問題,完成中等傳輸速度的循環(huán)或非循環(huán)數(shù)據(jù)交換任務,適用于紡織、樓宇自動化、可編程控制器、低壓開關(guān)等;Profibus - PA型采用了OSI模型的物理層和數(shù)據(jù)鏈路層,適用于過程自動化的總線類型。
針對飛行模擬器座艙數(shù)據(jù)采集的復雜性,設計了一種基于以太網(wǎng)分布式的數(shù)據(jù)采集控制系統(tǒng),該系統(tǒng)是RCM5700微處理器模塊上的以太網(wǎng)應用。在系統(tǒng)的基礎(chǔ)上具體討論了PoE技術(shù)的應用,在傳輸數(shù)據(jù)的網(wǎng)線上同時提供電流,提出并實現(xiàn)了一種包括輔助電源在內(nèi)的完整可靠的PoE供電方案。設計采用美國國家半導體的LM5073和LM5576并根據(jù)不同的負載情況,進行穩(wěn)定可靠的電壓轉(zhuǎn)換,以滿足數(shù)據(jù)采集電路的要求。實驗結(jié)果表明:該設計穩(wěn)定可靠,滿足低于13 W的采集節(jié)點供電要求,提高了模擬器信號采集系統(tǒng)的通用性和標準化程度,避免了以往數(shù)據(jù)采集節(jié)點單獨繁瑣的電源設計。
Abstract:
Aiming at the complexity of large avion simulation and controlling,the simulator cabin distribute data collecting and control system was designed. This system is the application of RCM5700 on Ethernet. Based on this system,PoE technique that makes Ethernet can also provide power were expounded with emphasis and included FAUX design the PoE resolution was realized. To achieve the requirement of this system,LM5073 and LM5576 were used to DC-DC switch. From the data of experiment,the design filled the requirement of power-need of node whose power was lower than 13W. The application of the technique can advance the degree of simulation data collections currency and standardization and avoid designing additional power system.