基于PLC的水厂滤池控制系统毕业论文外文翻译.doc

附录A：外文文献Based on PLC control system of waterworks ponds The control system of the cryogenic facility in the waterworks ponds system has been replaced by employing the PLC (Programmable Logic Controller) and SCADA (Supervisory Control And Data Acquisition)system. The original control system was constructed about 20 years ago by specifying the DCS (Distributed Control System) computer to deal with 400 feedback loops. Recently, troubles on this control system have increased due to itsage-induced deterioration. To maintain the high reliability of the cryogenic facility, a new control system has been planned with the PLC and SCADA systems. Their attractive features include high market availability and cost-effectiveness, however, the use of PLC for such a large facility with 400 feedback loops has not been established because of insufficient processing capability of the early PLC.Meanwhile, the recent progress in the PLC enables to use the FBD (function block diagram) programming language for 500 function blocks. By optimizing the function blocks and connecting them in the FBD language, the feedback loops have been successfully replaced from DCS to PLC without a software developer. Moreover, an oscillation of the liquid He level, which often occurs during the cooldown mode of the cryopumps, can be automatically stabilized by easily adding a new processprogram in the PLC. At present, the new control system has worked well.Fiber winding tension is an important factor in the molding techniques of composite material which influences the quality of winding product directly, and the tension control is a key technique in fiber winding techniques. This paper introduces a closed-loop tension control system with the programmable logic controller (PLC) with function modules as its control kernel ,thealternating current (AC) servo motor as execute element and the radius-following device to accomplish the real-time radius compensation. The mechanism of the tension control system is analyzed and the numerical model is set up. The compensation technique of the radius of the scroll is analyzed. Experimental results show that the system is well qualified with high control precision and high reaction speed.Water is the source of life, water supply natural relations to the peoples livelihood important point, water supply that not only meets industrial water, and also to meet the water for living, agricultural water and so on, of which the most important is the water for living, each city medium small waterworks is the direct source of the life in the water, water quality term of not only affects the quality of the water, the more relationship to peoples life safety, so the water in the water in term plays very important role, most of the water before viewing using artificial control, not only arduous, and the intensity of labor, labor efficiency is low, the water quality also is very difficult to guarantee, therefore, viewing of water automation reconstruction has put forward is very be necessary things.At the beginning of design, network from the current term of waterworks is generally used to filter method, and the deficiency, but each kind of method is not perfect, and only through continuous improvement, to gradually achieve the optimization design.This design from viewing a water control system minimum control requirements and control technology of the design based on PLC control system of waterworks ponds, and in the process of viewing a normal filter, in order to realize constant water level filtering, designed for the flow of water out of the liquid level control parameters for viewing the PID control system. And in the system to receive to reverse wash signal, this system in the design is how to better and PLC control the PLC coordinated control term of reverse wash scheme comparison and optimization, strengthening the control of the idea of clarity, achieve the expected effect of control.According to the systems control requirements, the hardware equipment selection, design the hardware of control system configuration chart, I/O modules the wiring diagram, and write to realize the control algorithm procedures.外文文献翻译：基于PLC的水厂滤池控制系统在水厂滤池控制系统中已被运用PLC(Programmable Logic Controller)和SCADA (Supervisory Control And Data Acquisition) 系统.原控制系统前20年构建了根据指定的DCS(集散控制系统)做了电脑处理，大约有400条反馈路线，最近,由于其age-induced的恶化，该控制系统应用的困难已经增加了。为了保持高低温设施的可靠性,如今提出了一种新的控制系统已计划于PLC和SCADA系统。他们吸引力的特征包括高市场供应和成本效益,然而,使用可编程控制器(PLC)为这样一个大型设备,大约需要400个反馈回路，早起加工能力的不足,导致早期的可编程序控制器(PLC)不被广泛应用。与此同时,近年来利用可编程序控制器(PLC)使功能框图增为500功能块的编程语言。通过优化和连接它们的功能块在增语言,已经成功地取代了反馈回路中集散可编程序控制器(PLC)里没有软体工程师的设计。此外,一个振荡的液体水平,经常发生在cryopumps冷却模式,可以自动稳定的增加一个新的工艺方案，即可编程序控制器(PLC)。 目前,新控制系统具有运行良好的特点。纤维缠绕张力是一种重要的因素，复合材料成型工艺对产品质量的线圈有很大的影响,并且直接张力控制的关键技术是纤维缠绕技术。一种闭环张力控制系统与可编程逻辑控制器(PLC)作为控制核心功能模块,这个设计作为执行元件和radius-following装置完成实时半径补偿。张力控制的机制系统进行分析,建立了数值模型。还对补偿技术的滚动半径进行了分析。实验结果表明,系统很有资格与高控制精度相媲美，并且有很高的反应速度。水是生命之源，供水自然关系到国计民生的重要地步，供水不仅要满足工业用水，还要满足生活用水，农业用水等等，其中最为重要的是生活用水，各城市的大中小水厂是生活用水的直接来源，水厂滤池的好坏不仅影响出水的质量，更关系到人民的生命安全，所以水厂滤池在供水中起到很重要的作用，以前的水厂滤池大都使用人工控制，不仅费力，而且劳动强度大，劳动效率低，出水的质量也很难保证，因此，对水厂滤池提出自动化改造已经是很有必要的事情了。在设计之初，从网络上查阅了当前水厂滤池普遍采用的过滤方法，以及存在的不足，但是每一种方法