外文翻译---基于PLC和组态软件的原油储罐区监督与控制系统.docx

翻译部分2009 3rd International Conference on Power Electronics Systems and Applications PLC and Configuration Software Based Supervisory and Control System for Oil Tanks Area Xi CHEN1 Yanbo CHE1 K.W.E CHENG2 1School of Electrical Engineering & Automation, Tianjin University, Tianjin China. E-mail: 2Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, E-mail: .HK 中国矿业大学2012届本科生毕业设计 第11页 Abstract - A supervisory and control system for oil tanks area based on PLC S7-300 and configuration software Force Control is introduced in this paper. The hardware structure of the system and the software design are both described in detail. In this system, Superior computers communicate with PLC through Industrial Ethernet. The superior computers system adopts duplex redundancy and the PLC adopts software redundancy .This monitoring system integrates the merit of PLC and computer and improves the reliability. Keywords - PLC, configuration software, supervisory and control system, software redundancy I. I NTRODUCTIONWith the increasing competition of the oil marketoil depots are playing a more and more important role, and it has become a long-term important job to supervise and control the operation state of oil depots. This paper designs a supervisory and control system for a oil depot in Shandong Province. This oil depot collected tank information and controlled valves manually before. There were some shortcomings in it such as slow supervisory, great error and low reliability. So it is necessary to establish a better supervisory and control system that is timely, accurate and reliable. Programmable logic controllers PLC have been widely used in the industrial control fields because of its merits such as simple structure, flexible functions, high reliability and strong ability in communication. Computers have advantages in the data display and storage, as well as in human-computer communications. This paper designs a supervisory and control system for oil tanks area based on PLC and computer. PLC is the control centre and it completes all the details of the control task. It connects with digital and analog signals of field devices through general I/O interfaces, collects and process field data accurately and quickly, and completes the logic, timing, counting and mathe maticalo peration seasily. Computers provide human-machine interface, display the feild working staste dynamicly, and makes the operation easy. The system combines the advantages of PLC and computer, provides a remote real-time monitoring for the tanks area, ensure safety and reliability and improves the work efficiency. Considering oil depots high requirements on reliability and continuity, redundancy scheme is designed to improve the reliability further. II. H ARDWARE O F T HE S YSTEMA. the Overall structure and functionsFig. 1 Overall structure diagram of the system The structure of the supervisory system is shown in Fig. 1.There are three levels in the system : the first level is superior computers. They consist of dual redundant Industrial Computers installed with configuration software Force Control and placed in the monitoring center room, the second level is S7-300 PLC that adopts software redundancy and is placed in the local control rooms, and the field devices including electrically operated valves and liquid level switches form the third level. Industrial Computers are connected to the Industrial Ethernet through general network cards and PLC is connected to the same net by Ethernet communication module , so they could accomplish the communication by using TCP/IP protocol. PLC collects feedback dates of electrically operated valves, collects the status of liquid level switches and opens or closes valves according to the command from superior computers and the control program in the CPU module. In addition, PLC completes the interlock control of valve and liquid level switch. By exchanging data with PLC, superior computers installed with Force Control, monitor electrically operated valves and liquid level switches in real time and give command to PLC to control the valves. Redundancy structure is adopted in the system. Force Control has taken the lead in providing complete support for redundancy among the China-made configuration software products, and it supports device redundancy, network redundancy and superior computer redundancy. There are two superior computers in the system, primary station and secondary station. In normal conditions, only the primary station communicates with PLC and the data in the secondary station synchronize with the primary station to make a backup. If the primary station fails, the secondary takes over the job. And the job 2009 3rdInternational Conference on Power Electronics Systems and Applications Digital Reference: K210509077 could come back to the primary station or manually after the primary station returns normal. Force Control supports PLC redundancy and normally communications with the master station of the PLC. If the master system of PLC is in the event of failure, the control job would be taken over by the reserve system, Force Control would disconnect the communication according to the switch flag and turn to the reserve station to exchange dates. B. Hardware Design of PLC System Before selecting PLC modules, analyze the controlled object to count out I/O points.The current requirement and 20% -30% margin should be considered, allowing the system to expand. According to this principle, I/O points are as follows:125 digital inputs,21 analog inputs,84 digital outputs. Based on the analysis of control task, the system chooses Siemens S7-300 series of products. This series PLC could Meet requirements of the medium-performance control system and adopt modular structure. Many different modules can be combined together and users should select appropriate modules according to the actual need. PLC modules selected are shown in Table 1. PLC in the system consists of two S7-300 stations each with a CPU 315-2DP and two ET200M slave stations. Its structure is shown in Figure 2. The Ethernet communication module CP343-1 provides a standard RJ45 interface, one of the functions is to connect the PLC to Industrial Ethernet to communicate with computers, and the other function is to provide redundant backup link for master CPU and reserve CPU to realize redundant communication between the two CPUs. Fig. 2 Hardware structure of PLC CPU315-2DP provides DP master interface and IM153-2 of ET200M provides two DP slave interfaces ,one is connected to the master station and the other to the reserve station through PROFIBUS-DP networks. PROFIBUS-DP could be Shielded Twisted Pair(RS485) network physically. Normal ET200M consist of a rail, a interface module and some general modules .The modules except power supply are connected through bus connectors. This structure doesnt support redundantcy functions. There is another configuration that is suitable for redundantcy. It uses a special rail that can take active bus modules and two interface modules. The modules except power supply are mounted on the active bus modules and it is possible to change modules during running. C. Connections of the Electrically Operated Valve Henchun CKD series electric operators are used and Fig. 3 shows its connection method. The feedback of electrically operated valve includes four digital signals and one analog signal. Digital signals are remote mode indicating contact, full open indicating contact, full off indicating contact and common alarm contact. The analog feedback, a 4-20mA current, shows the valves opening value .When the valve is in the remote control mode, digital outputs of PLC drive the relays and then control the valves. Four output control signals include open-valve signal, close-valve signal, stop signal and emergency protection signal esd. Fig. 3 Valve connection diagram III. SOFTWARE OS THE SYSTEMSoftware in the system includes two major parts, PLC programming software STEP7 V5.4 and superior computer configuration software Force Control V6.0. A. Communication between Superior Computer and PLC Force Control develops a special driver for the S7-300 PLC, 2009 3rd International Conference on Power Electronics Systems and Applications Digital Reference: K210509077 therefore it is not necessary for the users to be familiar with the communication protocol between them, and neither necessary to program or configure network in the PLC, the communication between PC and PLC can be achieved easily. The main problem in this system is that due to PLCs soft redundant structure, when the control task switches to resereve CPU from the master one, Force Control should switch to the correct communication object to exchange datas. For this purpose, when device PLC is created in Force Control ,it should be configured properly and a data point should be defined in the real-time database as a redundancy switching flag. First configure I /O device for Force Control, create PLC whose equipment address is set to 2, if set to 1, Force Control will not be able to connect to the PLC. The standby channel is enabled and the device IP address and standby IP address should correspond with PLCs two Ethernet communication modules CP343-1. After I/O device PLC is created , define a data point in real-time database whose data type is selected as redundancy switching flag . The flags value is 0 in normal state, when its value is 1, Force Control will switch to PLCs another IP address, then the value 1 will be cleared automatically. Here the data point is linked with MW16 of PLC. Corresponding program is loaded into PLC ,when the CPU is working as master station, MW16 is set to 0, when the CPU is working as reserve station, MW16 is set to 1, program in PLC is as follows: L DB5.DBB9L W#16#2AWSRW 1T MW16B. Software of Superior Computer Force Control configuration software solves problems (1 )Creating a I/O device PLC (2 )Creating a real-time database and linking the data points with datas in PLC; (3) Drawing graphical interfaces to display the work state of tank area and the state of alarm signals and to display the operation buttons; (4) Interconnecting the graphics with the variables so that graphics will change with the datas to make sound and light alarms; (5) Programming action script to control valves. When the button is pressed ,a mouse event will be triggered and then the corresponding script program will be close-valve flag or stop flag to 1 or 0. C. Software of PLC Functions that STEP7 completes in the system are : (1)Hardware configuration. Create a project with two stations(e.g. station A and station and then open station A . Select a module rack for station A ,insert the power supply unit, the CPU 315-2DP and CP343-1, establish a PROFIBUS DP network and an Ethernet network, insert and configure ET200M. Open station B, create a new PROFIBUS DP network, connect CP343-1 to the same Ethernet network with A, copy ET200M of station A because the configuration of ET200M must be identical on both stations. (2)Network configuration. Open the network configuration window Netpro, create a connection between station A and station B, select connection type ISO. (3)Writing software redundancy program. Software Redundany Package provides the library SWR_LIB that contains special FB and FC. Invoke these FB and FC in corresponding OB according to the requirements of the Siemens software redundancy manual; (4) Writing the program for valve control Fig. 4 Variable relation Fig. 4 shows the relationship among variables in Force Control, in PLC and in electric valves. Because there are a large number of valves to control in the system and the control methods are the same, a special function FC1 for valve control is written in order to simplify the structure of the program. Fig.5 is the flowchart of FC1. The valve has two control modes, local control mode and remote control mode. It is necessary to judge whether the valve is in the remote mode because only in this mode can the valve be controlled by the PLC. Valve opening process is as follows: click the mouse on open-valve button in Force Controls graphical interface, the open-valve flag in PLC is set to 1 if mouse is down, then return to 0 if mouse returns up, PLC energizes the open-valve relay for 1 second according to the rising edge of open-valve flag,compares the actual valve opening with the preset value, once the former is equal to or greater than the latter, energizes the stop relay for 1 second immediately. Valve off process is similar with the above process. When the high-level switch alarms, PLC drives the esd relay, then valve will open. 2009 3rd International Conference on Power Electronics Systems and Applications Digital Reference: K210509077 IV. CONCLUSION Superior computers in which Force Control configuration software are installed provide good human-machine interface, communicate with PLC through Industrial. Ethernet, then supervise and control the system. PLC perform reliable and effective control. Dual redundancy and software redundancy is adopted, improving the reliability of the system greatly. This system combines the advantages of computer and PLC, provides simple interface and high reliability, makes operation easy , and improves the automatic level of the oil depot. R EFERENCES 1 Liu Meijun. Siemens S7-PLC Application and Maintenance, China Machine Press, 2008 2 Beijing Sunway Force Control Technology Co.Ltd.Graphical interface and development system, Beijing,2007 3 Siemens Ltd., China. Software Redundancy for SIMATIIC S7-300 and S7-400,Siemens Ltd., China, Industry Sector, Industry Automation & Drive Technologies, 2008 4 Siemens Ltd., China. ET 200M Distributed I/O operation manual, Siemens Ltd., China, Industry Sector, Industry Automation & Drive Technologies, 2004 Fig. 5 Valve control flowchart 中文译文基于PLC和组态软件的原油储罐区监督与控制系统摘要这篇论文介绍了基于plc300控制系统及其组态软件的监控系统。系统硬件结构和软件设计都进行了较为详细的论述。在这个系统中,优越的电脑通过工业以太网与PLC连接。优越的计算机系统采用双冗余和PLC采用软件冗余。该监测系统集成PLC与计算机的优点提高了可靠性。关键词 PLC 组态软件 高性能控制系统 软件冗余一、简介随着竞争竞争日益激烈的原油市场，仓库正在发挥着越来越重要的作用,监督和控制油库运行状态已成为一个长期的重要的工作。本文在山东设计了一个油库监督和控制系统。该系统在控制阀门手动之前收集油库信息。以前它有一些缺点,比如缓慢的监督,重大错误,很低的可靠性。因此有必要建立一个更好的能够及时、准确、可靠的监督和控制系统。可编程序逻辑控制器plc广泛用于工业控制领域因为它的优点结构简单,灵活的功能,可靠性高和较强的沟通。电脑在数据显示和存储方面具有优势,以及在人机通信方面。本文设计了一个基于PLC和电脑的油库监控系统。可编程序控制器(PLC)作为控制中心完成所有细节控制任务。它通过通用I / O接口连接到数字和模拟信号的现场设备、准确、快捷的收集和传输数据,并容易的完成逻辑、时间、计数和数学运算。计算机提供人机界面,显示工作动态,使操作很容易。该系统结合了PLC和电脑的优点,提供了一个远程实时监控的油库,确保了安全和可靠性和提高工作效率。鉴于油库对可靠性和连续性的高要求、冗余方案进一步了提高了仪表的可靠性。二、系统硬件组成A 总结构和作用图1系统总体结构框图介绍了监控系统的结构被显示在图。1、该系统具有三层:第一级为优越的电脑。它们是由双冗余工业计算机安装配置软件控制放置在监控中心的房间里。第二个层次是S7 - 300 PLC采用软件冗余，被放置在当地控制室,第三层次包括电动阀和液位开关。工业电脑通过一般网卡连接到工业以太网，PLC通信模块连接到相同的以太网,所以它们能够采用TCP / IP协议完成通信。可编程序控制器(PLC)收集电动阀的反馈数据,检测液位开关的状态，根据电脑和控制模块的命令打开或关闭开关。另外,PLC完成控制阀门和液位开关的联锁。通过和可编程序控制器(PLC)交换数据,安装ForceControl的优越的电脑、准确的监控电动阀和液位开关和给命令给可编程序控制器(PLC)控制阀门。采用冗余结构系统。在中国制造的组态软件产品，ForceControl已率先提供完整的支持冗余的系统,它支持设备冗余、网络冗余和超级电脑冗余。在系统中有两台高级计算机、一次站和二次站。在正常条件下,只有一次站与PLC相连，二次站作为一次站的备份。如果一次站连接失败,二次接管这项工作。当一次站恢复正常后能够自动或手动的接着工作。ForceControl支持PLC冗余和plc的正常通讯。如果掌握系统的可编程逻辑控制器(PLC)发生故障,储备体系将接管控制工作,ForceControl会断开连接，根据开信号而转向储备站交换数据。B PLC控制系统的硬件设计在选择PLC模块之前,分析了控制项目数出I / O点数。应考虑当前的要求和20%-30%的预留,以适应的系统扩展。根据这一原理,I / O点数如下:125数字输入、21模拟输入,84数字输出。再此分析的基础上,该系统选择了西门子S7 - 300系列的产品。本系列可编程序控制器(PLC)可以满足要求的采用模块化结构控制系统。许多不同的模块可以结合一起,用户应该根据实际需要选择适当的模块。可编程序控制器(PLC)模块选择显示在表1。表1:硬件的可编程序控制器(PLC)该系统由)两个S7 - 300可编程序控制器(PLC）组成每处理器315 - 2 - DP和两个副站ET200M，采用的结构是如图2所示。以太网通讯模块CP343-1提供了一个标准 RJ45界面,其中一个作用使PLC连接到工业以太网,然后再连接到电脑。另一个功能是提供冗余备份链接主CPU和储备处理器实现两个CPU之间的沟通。图二 硬件结构CPU315-2DP提供主接口和IM153-2 DP提供了两个ET200M DP的副接口,通过profibus - dp网络站一个连接到主站，一个连接到储备站。RS485网络可以屏蔽profibus - dp。ET200M通常是由一些线、界面模块和一些通用的模块。该模块除电源都连接在总线上.这种结构并不支持冗余功能。 有另一个适合redundantcy配置。 它使用一种特殊的轨道,可以采取积极的总线模块和两个接口模块。除了电源模块外，其它都安装在活跃的总线模块上，是有可能的在运行时改变模块的。C 连接之电动阀门使用Hengchun CKD系列电动开关图3显示它的连接方法。反馈的电动阀门包括四个数字信号和一个模拟信号。数字信号远程模式联系标注,断开联系标注,连接联系标注和普通报警指示标注。模拟反馈,一个4-20mA电流,显示阀门的开启时刻。当阀门处于远程控制模式,数字输出的PLC驱动继电器,然后控制阀门。四个输出控制信号包括开通信号,关断信号和紧急停止、保护信号。三 软件操作系统软件系统包括两个主要部分,可编程序控制器(PLC)的STEP7V5.4和ForceControl V6.0。A:电脑和可编程序控制器(PLC)之间的通讯ForceControl开发了针对S7 - 300 PLC的一个特殊的驱动器,因此对于用户来说没有必要熟悉他们之间的通信协议,和程序或配置网络，可以很容易实现PC与PLC之间的通信。这个系统的一个主要问题是由于PLC的软件冗余结构,当控制任务开关从主存储器断开CPU,ForceControl应该和正确的对象交换数据。为了这个目的,当装置可编程序控制器(PLC)在ForceControl建立,它该配置适当，实时的数据库应该被建立，作为一个冗余切换标志。ForceControl