PLC外文文献翻译--基于S7-300 PLC的污水处理自动化系统的设计与应用【中文2820字】 【中英文WORD】.zip
基于 S7-300 PLC 的污水处理自动化系统的设计与应用基于 S7-300 PLC 的污水处理自动化系统的设计与应用摘要.在县级城市生活污水处理的需求,集散控制系统在城市污水处理自动化系统的计划提出的。其中的主要功能是通过组态软件 WinCC,西门子 S7-300 的城市污水处理的每个子系统的 PLC 监控。该系统的功能主要有以下几点,PLC 的数据,协议转换器,通过光纤传输的数据的收集,项目,组态软件实现实时数据存储在数据库和各种报告的发布形式,曲线显示等报警事件。本文还提出了系统的系统名称和详细描述的想法。关键词关键词 污水处理系统 集散控制系统 西门子 S7-300 PLC WinCC 组态软件1 引言1 引言随着中国经济的快速发展,环保一个突出的问题。污水处理是环境保护最重要的任务之一。随着计算机技术和污水处理技术迅速发展,这是必要的监控污水处理过程与先进控制技术和设备。内蒙古呼和浩特市土默特左旗的污水处理项目是典型项目在呼和浩特市的县级市,采用循环式活性污泥系统系统(CASS)处理废水。于这个项目,我们设计的 DCS系统,其控制系统采用西门子 S7-300 PLC 的监控软件是西门子 WinCC6.2。2 CASS 工艺2 CASS 工艺 CASS生化处理系统是一个复杂的系统多参数(如液位、水质、流量、压力等)、多任务(如水进口,曝气,沉淀,排水等),多设备(如滗水器,风机,稳压器等)。它是整个生化处理系统的核心。CASS池主反应区的工程,按照“曝气,闲置,沉淀,和滗水器“的循环过程。其中,控制溶解氧在CASS池,厌氧段和好氧段是核心。3 控制系统的结构3 控制系统的结构自动污水处理控制系统的结构是集中管理和分散控制。控制系统采用的控制方法结合远程自动控制,远程手动控制和领域的自动控制。为了确保污水处理系统运行,主站和 PLC 从站是独立的。如果一个子系统发生故障,也不会影响其他系统设备的正常运行。即使整个控制系统出现故障,它也可以及时调整自己到现场手动控制模式,以确保污水处理系统的正常运行。在中央控制室的电脑采用双冗余模式,以实现实时监控。两台服务器的待机彼此共同执行监测任务。如果一个服务器发生故障了,其他人可以承担的任务,自动保证系统能继续提供服务无需人工干预的情况下。4 数据通信4 数据通信S7 系列 PLC 的通信网络主要包括以下内容:多点阳离子数据通信接口(MPI)协议的 PROFIBUS,工业以太网,点至点连接,通过 AS-I 的通信过程。这个项目有 PROFIBUS总线,工业以太网,点至点连接。A.S7-300 和 WinCC 之间的沟通A.S7-300 和 WinCC 之间的沟通PLC 和 PC 机通过工业以太网相互通信,PLC 的传输通过光纤到 PC 机的配置软件的实时数据库的实时生产数据。PC 可以监视现场设备从很远的地方。因为 PLC 在这个系统中选择的是 CPU315-2PN/DP,或已集成 PROFINET 接口。S7-300 和 WINCC 之间的通信使用 TCP/IP 网络协议。TCP/IP 网络协议,是事实上的 IT 标准有关通信协议服务。虽然响应时间是 100 毫秒左右的幅度,为应用工厂控制,响应时间是足够的。B.主站和从站 PLC 站之间的沟通B.主站和从站 PLC 站之间的沟通PLC 主站采用西门子 S7-300 PLC。PLC 的 ClO2车间使用西门子 S7-200 PLC通信主站和从站 PLC 站之间采用 PROFIBUS。PROFIBUS,国际化和开放的,不依赖于标准现场总线的设备制造商。这是一个用于控制工厂的现场总线自动化车间级和数据通信,并控制现场设备级。PROFIBUS 传输速度为 9600 波特1.2107 波特,当主系统启动时,一般线连接到的所有设备应设置在相同的速度。这可以实现分散的数字控制和现场通信网络现场设备级,车间级到从而为工厂提供一个可行的解决方案实现全面的自动化和智能化现场设备。处理器西门子 S7-300 PLC 模块,CPU 315-2 PN/DP的,它有其自己的 PROFIBUS 接口。在 S7-300 PLC Profibus 网络作为主站,S7-200 PLCProfibus网络作为从站。S7-200 PLC有没有PROFIBUS通讯接口本身,因此它具有与主站通过 EM277 的通信。C.PLC 之间的通信和电力设备C.PLC 之间的通信和电力设备根据设计要求,PLC 和权力之间的沟通需要建立的电流,电压和功率,在电源设备应监测系统。西门子 PLC 的点至点的通信链路通过通讯模块 CP341 的发电设备。电源设备提供了 RS485 半双工异步串行通信接口通信,并采用 MODBUS RTU 通讯协议。MODBUS 协议是在工业控制单元的网络协议之一。由不同厂家生产的控制设备可以连接作为工业 MODBUS 协议,该设备在不同网络中的网络链接可以进行数据通信。MODBUS 网络可以连接多个上一条线,每个设备的设备可以设置通讯地址本身。每个控制器可以区分设备的地址。此外,它发送什么消息由地址决定。如果需要回应,控制器将建立信息反馈和发送 MODBUS 协议。在另一个网络,有转换的 MODBUS 消息帧和封装结构协议。转换也扩展的方式来解决问题,如地址,路由路径及错误检测在特定的网络。5 西门子 S7-300 硬件5 西门子 S7-300 硬件S7-300 是一个模块化的 PLC。它由机架,CPU 模块,信号模块,功能模块,接口模块,电源模块和编程模块,通信处理器。该项目的 PLC 系统包含三个机架,主要机架与扩展机架 IM360/361 传达。第一阶段的污水治疗阶段有 23 个模拟输入点,3 个模拟量输出点,222 个数字输入分和 68 个数字输出点。在此 PLC 的硬件配置,15的所有储备的利润率是预留的,这是第二阶段的阔叶。S7-300 PLC 系统硬件框图如图 3 所示。6 PC Conitoring 系统组成系统组成以中国版本的 WinCC6.2 系统配置软件实现,监督外观配置功能。它提供了多种司机为 PLC,使 PLC 与 PC 的连接更容易和在 STEP7 中配置的变量列表可以是我们教育署直接与 WinCC 连接时。电脑监控系统的功能框图如图 4 所示。“电脑监控系统”的功能描述:1)控制功能:主要实现实时控制的上线的设备控制室设备,如启动/停止,模拟输出调节,PLC 运行在线等参数设置。2)显示功能:显示设备的运行状态,通过控制图形和动画,显示该领域的实时运行参数设备。3)档案管理:建立一个生产数据库,并保存原始数据计算和分析产品的生产,根据变化的速度,运行参数的重要性,在 R 的 EAL 时间和历史的运行状态。4)报警功能:实现不同的报警级别,根据不同的需求,当模拟值(如电流,压力,水位,浓度等)测量超过给定的范围内,或数字值(如电机启动/停止,阀门开/关)的订单。5)打印功能:可实现实时打印报告,图形,各种活动并报警。定时打印,事件触发打印和打印方式,可分为用户定义的打印。6)日志管理:记录的信息,以便为用户登录和注销搜索针对不同用户的使用间隔。7)权限管理:为不同的用户设置相应的访问保护,防止未经授权的用户访问的监控系统。7 7 PLC 的控制程序PLC 的控制程序该系统采用模块化设计,实现 PLC 控制系统的方案,通过在 STEP7 软件。程序流程图如图 5 所示。控制系统采用模块化的程序,分成 10 子程序根据技术性 CAL 在整个程序的研讨会。在主程序中,可以在正确的顺序调用每个子程序。首先,写一个模拟采集在组织块 35,子程序和模拟数据将被刷新每 100 毫秒。然后,控制计划被列为远程手动控制和远程自动控制,可以通过两种方式之间的切换标志位。远程手动控制,可以人为控制的设备的启动/停止,远程自动控制可自动调节设备的状态,通过对现场的变化参数。所以程序可以自动执行,并及时为每个周期,所有的设备可以自动停下来控制时有连锁故障。MODBUS 使用通信电源米多点轮询模式。8 结论8 结论在污水处理中使用的自动化系统是值得推广的,因为它能满足现代污水处理的要求,减少日常的一天维护管理,降低污水处理成本,并确保运行和出水的水质。随着工程的发展技术,在污水处理厂的自动化系统必将显示其明显的优势。该项目进行了测试于 2010.10。结果竟然系统是一个先进,可靠,操作简单的控制系统,从而能够更好地解决一些问题,如自动化低,可靠性低,大量的时间延迟和其他一些在过去的污水处理存在问题。外文出处:外文出处:Communications in Computer and Information Science,1,Volume 225,Applied Informatics and Communication,Part 2,Pages 479-486The Design and Application of Sewage TreatmentAutomation System Based on S7-300 PLCAbstract.For the demand of domestic sewage treatment in county-level 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 sub-system of municipal wastewater treatment via the configuration software WinCC,Siemens S7-300 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 real-time 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 S7-300 PLC,WinCC Configuration software.1IntroductionAlong 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 computer 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 county-level 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 S7-300 PLC and monitoring software is Siemens WinCC 6.2.2CASS ProcessCASS biochemical treatment system is a complex system of multi-parameter(such as liquid level,water quality,flow rate,pressure,etc.),multi-tasking(such as water-in,aeration,sedimentation,drainage,etc.),multi-equipment(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.3The Structure of Control SystemThe structure of automatic sewage treatment control system is centralized management and decentralized control.The control system employs the control method combined 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 sub-systems 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 dual-redundant to realize real-time 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.4Data CommunicationS7 series PLC communications network mainly includes the following:multi-point interface(MPI)protocol of data communi cations,PROFIBUS,industrial Ethernet,point-to-point connections,through AS-I process of communication.This project has PROFIBUS,used in industrial Ethernet,point-to-point connections.A.The communication between S7-300 and WinCCPLC and PC communicate with each other through industrial Ethernet,PLC transmit the data of real-time production to the real-time 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 315-2PN/DP,which has integrated PROFINET interface.Communication between S7-300 and WINCC uses TCP/IP network protocol.TCP/IP network protocol is a de facto standard about communication 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 PLCPLC master station uses Siemens S7-300 PLC.The PLC of ClO2 workshop uses Siemens S7-200 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 workshop-level and data communications,and control of field device-level.The transmission speed of Profibus is at 9600 bauds 1.2107 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 communications network from field device-level to workshop-level,so as to provide a viable solution for factory to realize the comprehensive automation and field device intellectualized.The processor module of Siemens S7-300 PLC is CPU 315-2 PN/DP,which has its own Profibus interface.The S7-300 PLC Profibus network is used as the master station,S7-200 PLC Profibus network is used as the slave station.S7-200 PLC has no Profibus communication interface itself,so it has to communicate with master station through EM277.C.The communication between PLC and power equipmentAccording to the design requirements,the communication 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 point-to-point communication link with the power equipment through the communication module CP341.The power equipment provides RS485 communication interface in half-duplex asynchronous serial communication,and uses MODBUS RTU communication protocol.MODBUS protocol is one of the network protocols in the industrial control unit.The control equipments produced by different manufacturers can be linked as industrial network by MODBUS protocol,and that equipments linked in the different networks can make the data communication.The MODBUS network can connect multiple equipments on one line,and each of the equipments can set communication 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 network,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 network.5Siemens S7-300 Hardware The S7-300 is a modular PLC.It consists of Rack,CPU Module;Signal Module,Function Module,Interface Module,Communications Processor,Power Module and Programming Module.The PLC system of the project contains three racks,the main rack communicated with Expansion rack by IM360/361.The Phase I of Sewage Treatment Phase has 23 analog input points,3 analog output points,222 digital input points and 68 digital output points.In this PLC hardware configuration,15%of all reserve margins is set aside,which is leaved for the phase II.The S7-300 PLC system hardware diagram is shown in Figure 3.6Composition of PC Conitoring SystemThis paper takes the Chinese version WinCC 6.2 as systematic configuration software to realize the configuration function of superv ision appearance.It provides a variety of drivers for PLC,which makes the connection of PLC and PC much easier and the variable list configured in STEP7 can be us ed directly when connected with WinCC.The functional block diagram for PC monitor system is shown in Figure 4.“PC monitoring system”functional description:1)Control function:to realize the real-time control of the on-line device in the main control room,such as equipments start/stop,analog output regulation,PLC operating parameters setting online,etc.2)Display function:to show the running state of the device being controlled via the graphics and animation,and display the real-time operating parameters of the field device.3)Archive management:to set up a production database and save the original data of the production for calculation and analys is,according to the change speed,the importance of operating parameters,the r eal-time and historical running state.4)Alarm function:to realize different alarm grades according to different needs,when an analog value(such as current,pressure,water level,concentration,etc.)measured exceed the given range,or a digital value(such as motor start/stop,valves on/off)is out of order.5)Print function:to realize the real-time print of reports,graphics,various events and alarm.The print way can be divided into timed print,event trigger print and user-defined print.6)Log management:to record the information for users to log in and out,in order to search the use interval for different users.7)Rights management:to set corresponding visit protection for different users,and prevent the users unauthorized to visit the monitor system.7PLC Control ProgramThe system uses modular design to realize the program of PLC system via the STEP7 software.The program flow chart is shown in Figure 5.The control system adopts modularization program,and falls into 10 subprogram according to the workshop in the whole techni cal procedures.In the main program,it can call each subprogram in proper order.First,writting an analog acquisition subprogram in the orgnization block 35,and the analog data will be refreshed every 100 millisecond.Then,the control program which is classified as remote manual control and remote auto control can switch through the bit flags between the two ways.Remote manual control can artificially control the devices start/stop,and remote auto control can automatically adjust the state of the device by the change of on-the-spot parameters.So the program can execute automatically and timely for every cycle,and all the devices can auto-stop to control when there are cascading failures.Modbus uses multi-site polling mode to communicate with power meters.8ConclusionsThe automation system used in the sewage treatment is worthy of popularization,for it can meet the requirements of modern sewage treatment,reduce the day-to-day maintenance management,decrease the cost of sewage treatment,and ensure the operation and water quality of effluent.With the development of engineering technology,the automation system in the sewage treatment plant will surely show its obvious advantages.The project was tested in 2010.10.The result turned out that the system is an advanced,reliable and simply operated control system,which can better resolve some problems such as low automation,low reliability and large time delay and some other exist problems in the past sewage treatment.2 Communications in Computer and Information Science,1,Volume 216,Advances in Computer Science,Environment,Ecoinformatics,and Education,Pages 552-556
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基于 S7-300 PLC 的污水处理自动化系统的设计与应用基于 S7-300 PLC 的污水处理自动化系统的设计与应用摘要.在县级城市生活污水处理的需求,集散控制系统在城市污水处理自动化系统的计划提出的。其中的主要功能是通过组态软件 WinCC,西门子 S7-300 的城市污水处理的每个子系统的 PLC 监控。该系统的功能主要有以下几点,PLC 的数据,协议转换器,通过光纤传输的数据的收集,项目,组态软件实现实时数据存储在数据库和各种报告的发布形式,曲线显示等报警事件。本文还提出了系统的系统名称和详细描述的想法。关键词关键词 污水处理系统 集散控制系统 西门子 S7-300 PLC WinCC 组态软件1 引言1 引言随着中国经济的快速发展,环保一个突出的问题。污水处理是环境保护最重要的任务之一。随着计算机技术和污水处理技术迅速发展,这是必要的监控污水处理过程与先进控制技术和设备。内蒙古呼和浩特市土默特左旗的污水处理项目是典型项目在呼和浩特市的县级市,采用循环式活性污泥系统系统(CASS)处理废水。于这个项目,我们设计的 DCS系统,其控制系统采用西门子 S7-300 PLC 的监控软件是西门子 WinCC6.2。2 CASS 工艺2 CASS 工艺 CASS生化处理系统是一个复杂的系统多参数(如液位、水质、流量、压力等)、多任务(如水进口,曝气,沉淀,排水等),多设备(如滗水器,风机,稳压器等)。它是整个生化处理系统的核心。CASS池主反应区的工程,按照“曝气,闲置,沉淀,和滗水器“的循环过程。其中,控制溶解氧在CASS池,厌氧段和好氧段是核心。3 控制系统的结构3 控制系统的结构自动污水处理控制系统的结构是集中管理和分散控制。控制系统采用的控制方法结合远程自动控制,远程手动控制和领域的自动控制。为了确保污水处理系统运行,主站和 PLC 从站是独立的。如果一个子系统发生故障,也不会影响其他系统设备的正常运行。即使整个控制系统出现故障,它也可以及时调整自己到现场手动控制模式,以确保污水处理系统的正常运行。在中央控制室的电脑采用双冗余模式,以实现实时监控。两台服务器的待机彼此共同执行监测任务。如果一个服务器发生故障了,其他人可以承担的任务,自动保证系统能继续提供服务无需人工干预的情况下。4 数据通信4 数据通信S7 系列 PLC 的通信网络主要包括以下内容:多点阳离子数据通信接口(MPI)协议的 PROFIBUS,工业以太网,点至点连接,通过 AS-I 的通信过程。这个项目有 PROFIBUS总线,工业以太网,点至点连接。A.S7-300 和 WinCC 之间的沟通A.S7-300 和 WinCC 之间的沟通PLC 和 PC 机通过工业以太网相互通信,PLC 的传输通过光纤到 PC 机的配置软件的实时数据库的实时生产数据。PC 可以监视现场设备从很远的地方。因为 PLC 在这个系统中选择的是 CPU315-2PN/DP,或已集成 PROFINET 接口。S7-300 和 WINCC 之间的通信使用 TCP/IP 网络协议。TCP/IP 网络协议,是事实上的 IT 标准有关通信协议服务。虽然响应时间是 100 毫秒左右的幅度,为应用工厂控制,响应时间是足够的。B.主站和从站 PLC 站之间的沟通B.主站和从站 PLC 站之间的沟通PLC 主站采用西门子 S7-300 PLC。PLC 的 ClO2车间使用西门子 S7-200 PLC通信主站和从站 PLC 站之间采用 PROFIBUS。PROFIBUS,国际化和开放的,不依赖于标准现场总线的设备制造商。这是一个用于控制工厂的现场总线自动化车间级和数据通信,并控制现场设备级。PROFIBUS 传输速度为 9600 波特1.2107 波特,当主系统启动时,一般线连接到的所有设备应设置在相同的速度。这可以实现分散的数字控制和现场通信网络现场设备级,车间级到从而为工厂提供一个可行的解决方案实现全面的自动化和智能化现场设备。处理器西门子 S7-300 PLC 模块,CPU 315-2 PN/DP的,它有其自己的 PROFIBUS 接口。在 S7-300 PLC Profibus 网络作为主站,S7-200 PLCProfibus网络作为从站。S7-200 PLC有没有PROFIBUS通讯接口本身,因此它具有与主站通过 EM277 的通信。C.PLC 之间的通信和电力设备C.PLC 之间的通信和电力设备根据设计要求,PLC 和权力之间的沟通需要建立的电流,电压和功率,在电源设备应监测系统。西门子 PLC 的点至点的通信链路通过通讯模块 CP341 的发电设备。电源设备提供了 RS485 半双工异步串行通信接口通信,并采用 MODBUS RTU 通讯协议。MODBUS 协议是在工业控制单元的网络协议之一。由不同厂家生产的控制设备可以连接作为工业 MODBUS 协议,该设备在不同网络中的网络链接可以进行数据通信。MODBUS 网络可以连接多个上一条线,每个设备的设备可以设置通讯地址本身。每个控制器可以区分设备的地址。此外,它发送什么消息由地址决定。如果需要回应,控制器将建立信息反馈和发送 MODBUS 协议。在另一个网络,有转换的 MODBUS 消息帧和封装结构协议。转换也扩展的方式来解决问题,如地址,路由路径及错误检测在特定的网络。5 西门子 S7-300 硬件5 西门子 S7-300 硬件S7-300 是一个模块化的 PLC。它由机架,CPU 模块,信号模块,功能模块,接口模块,电源模块和编程模块,通信处理器。该项目的 PLC 系统包含三个机架,主要机架与扩展机架 IM360/361 传达。第一阶段的污水治疗阶段有 23 个模拟输入点,3 个模拟量输出点,222 个数字输入分和 68 个数字输出点。在此 PLC 的硬件配置,15的所有储备的利润率是预留的,这是第二阶段的阔叶。S7-300 PLC 系统硬件框图如图 3 所示。6 PC Conitoring 系统组成系统组成以中国版本的 WinCC6.2 系统配置软件实现,监督外观配置功能。它提供了多种司机为 PLC,使 PLC 与 PC 的连接更容易和在 STEP7 中配置的变量列表可以是我们教育署直接与 WinCC 连接时。电脑监控系统的功能框图如图 4 所示。“电脑监控系统”的功能描述:1)控制功能:主要实现实时控制的上线的设备控制室设备,如启动/停止,模拟输出调节,PLC 运行在线等参数设置。2)显示功能:显示设备的运行状态,通过控制图形和动画,显示该领域的实时运行参数设备。3)档案管理:建立一个生产数据库,并保存原始数据计算和分析产品的生产,根据变化的速度,运行参数的重要性,在 R 的 EAL 时间和历史的运行状态。4)报警功能:实现不同的报警级别,根据不同的需求,当模拟值(如电流,压力,水位,浓度等)测量超过给定的范围内,或数字值(如电机启动/停止,阀门开/关)的订单。5)打印功能:可实现实时打印报告,图形,各种活动并报警。定时打印,事件触发打印和打印方式,可分为用户定义的打印。6)日志管理:记录的信息,以便为用户登录和注销搜索针对不同用户的使用间隔。7)权限管理:为不同的用户设置相应的访问保护,防止未经授权的用户访问的监控系统。7 7 PLC 的控制程序PLC 的控制程序该系统采用模块化设计,实现 PLC 控制系统的方案,通过在 STEP7 软件。程序流程图如图 5 所示。控制系统采用模块化的程序,分成 10 子程序根据技术性 CAL 在整个程序的研讨会。在主程序中,可以在正确的顺序调用每个子程序。首先,写一个模拟采集在组织块 35,子程序和模拟数据将被刷新每 100 毫秒。然后,控制计划被列为远程手动控制和远程自动控制,可以通过两种方式之间的切换标志位。远程手动控制,可以人为控制的设备的启动/停止,远程自动控制可自动调节设备的状态,通过对现场的变化参数。所以程序可以自动执行,并及时为每个周期,所有的设备可以自动停下来控制时有连锁故障。MODBUS 使用通信电源米多点轮询模式。8 结论8 结论在污水处理中使用的自动化系统是值得推广的,因为它能满足现代污水处理的要求,减少日常的一天维护管理,降低污水处理成本,并确保运行和出水的水质。随着工程的发展技术,在污水处理厂的自动化系统必将显示其明显的优势。该项目进行了测试于 2010.10。结果竟然系统是一个先进,可靠,操作简单的控制系统,从而能够更好地解决一些问题,如自动化低,可靠性低,大量的时间延迟和其他一些在过去的污水处理存在问题。外文出处:外文出处:Communications in Computer and Information Science,1,Volume 225,Applied Informatics and Communication,Part 2,Pages 479-486The Design and Application of Sewage TreatmentAutomation System Based on S7-300 PLCAbstract.For the demand of domestic sewage treatment in county-level 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 sub-system of municipal wastewater treatment via the configuration software WinCC,Siemens S7-300 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 real-time 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 S7-300 PLC,WinCC Configuration software.1IntroductionAlong 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 computer 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 county-level 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 S7-300 PLC and monitoring software is Siemens WinCC 6.2.2CASS ProcessCASS biochemical treatment system is a complex system of multi-parameter(such as liquid level,water quality,flow rate,pressure,etc.),multi-tasking(such as water-in,aeration,sedimentation,drainage,etc.),multi-equipment(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.3The Structure of Control SystemThe structure of automatic sewage treatment control system is centralized management and decentralized control.The control system employs the control method combined 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 sub-systems 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 dual-redundant to realize real-time 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.4Data CommunicationS7 series PLC communications network mainly includes the following:multi-point interface(MPI)protocol of data communi cations,PROFIBUS,industrial Ethernet,point-to-point connections,through AS-I process of communication.This project has PROFIBUS,used in industrial Ethernet,point-to-point connections.A.The communication between S7-300 and WinCCPLC and PC communicate with each other through industrial Ethernet,PLC transmit the data of real-time production to the real-time 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 315-2PN/DP,which has integrated PROFINET interface.Communication between S7-300 and WINCC uses TCP/IP network protocol.TCP/IP network protocol is a de facto standard about communication 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 PLCPLC master station uses Siemens S7-300 PLC.The PLC of ClO2 workshop uses Siemens S7-200 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 workshop-level and data communications,and control of field device-level.The transmission speed of Profibus is at 9600 bauds 1.2107 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 communications network from field device-level to workshop-level,so as to provide a viable solution for factory to realize the comprehensive automation and field device intellectualized.The processor module of Siemens S7-300 PLC is CPU 315-2 PN/DP,which has its own Profibus interface.The S7-300 PLC Profibus network is used as the master station,S7-200 PLC Profibus network is used as the slave station.S7-200 PLC has no Profibus communication interface itself,so it has to communicate with master station through EM277.C.The communication between PLC and power equipmentAccording to the design requirements,the communication 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 point-to-point communication link with the power equipment through the communication module CP341.The power equipment provides RS485 communication interface in half-duplex asynchronous serial communication,and uses MODBUS RTU communication protocol.MODBUS protocol is one of the network protocols in the industrial control unit.The control equipments produced by different manufacturers can be linked as industrial network by MODBUS protocol,and that equipments linked in the different networks can make the data communication.The MODBUS network can connect multiple equipments on one line,and each of the equipments can set communication 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 network,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 network.5Siemens S7-300 Hardware The S7-300 is a modular PLC.It consists of Rack,CPU Module;Signal Module,Function Module,Interface Module,Communications Processor,Power Module and Programming Module.The PLC system of the project contains three racks,the main rack communicated with Expansion rack by IM360/361.The Phase I of Sewage Treatment Phase has 23 analog input points,3 analog output points,222 digital input points and 68 digital output points.In this PLC hardware configuration,15%of all reserve margins is set aside,which is leaved for the phase II.The S7-300 PLC system hardware diagram is shown in Figure 3.6Composition of PC Conitoring SystemThis paper takes the Chinese version WinCC 6.2 as systematic configuration software to realize the configuration function of superv ision appearance.It provides a variety of drivers for PLC,which makes the connection of PLC and PC much easier and the variable list configured in STEP7 can be us ed directly when connected with WinCC.The functional block diagram for PC monitor system is shown in Figure 4.“PC monitoring system”functional description:1)Control function:to realize the real-time control of the on-line device in the main control room,such as equipments start/stop,analog output regulation,PLC operating parameters setting online,etc.2)Display function:to show the running state of the device being controlled via the graphics and animation,and display the real-time operating parameters of the field device.3)Archive management:to set up a production database and save the original data of the production for calculation and analys is,according to the change speed,the importance of operating parameters,the r eal-time and historical running state.4)Alarm function:to realize different alarm grades according to different needs,when an analog value(such as current,pressure,water level,concentration,etc.)measured exceed the given range,or a digital value(such as motor start/stop,valves on/off)is out of order.5)Print function:to realize the real-time print of reports,graphics,various events and alarm.The print way can be divided into timed print,event trigger print and user-defined print.6)Log management:to record the information for users to log in and out,in order to search the use interval for different users.7)Rights management:to set corresponding visit protection for different users,and prevent the users unauthorized to visit the monitor system.7PLC Control ProgramThe system uses modular design to realize the program of PLC system via the STEP7 software.The program flow chart is shown in Figure 5.The control system adopts modularization program,and falls into 10 subprogram according to the workshop in the whole techni cal procedures.In the main program,it can call each subprogram in proper order.First,writting an analog acquisition subprogram in the orgnization block 35,and the analog data will be refreshed every 100 millisecond.Then,the control program which is classified as remote manual control and remote auto control can switch through the bit flags between the two ways.Remote manual control can artificially control the devices start/stop,and remote auto control can automatically adjust the state of the device by the change of on-the-spot parameters.So the program can execute automatically and timely for every cycle,and all the devices can auto-stop to control when there are cascading failures.Modbus uses multi-site polling mode to communicate with power meters.8ConclusionsThe automation system used in the sewage treatment is worthy of popularization,for it can meet the requirements of modern sewage treatment,reduce the day-to-day maintenance management,decrease the cost of sewage treatment,and ensure the operation and water quality of effluent.With the development of engineering technology,the automation system in the sewage treatment plant will surely show its obvious advantages.The project was tested in 2010.10.The result turned out that the system is an advanced,reliable and simply operated control system,which can better resolve some problems such as low automation,low reliability and large time delay and some other exist problems in the past sewage treatment.2 Communications in Computer and Information Science,1,Volume 216,Advances in Computer Science,Environment,Ecoinformatics,and Education,Pages 552-556
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