Design and implementation of BS based remote SCADA

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Design and implementation of remote SCADA system based on b/s

development requirements and background

with the acceleration of modern factory information automation process, the exchange of information between internal and external enterprises is no longer limited to the monitoring and control of production site status in the usual sense, but needs to closely connect the horizontal communication (communication between different nodes on the same layer) and vertical communication (communication between upper and lower layers) of enterprises, Form a comprehensive management system with wider significance. Therefore, only the SCADA system with web function can meet the requirements of enterprise information automation information platform. It makes the collected and monitored data open and can be accessed by more management systems, control systems and users

in the production process of plastic insulated wires and cables, there is an extremely critical process, namely the plastic process. It is to extrude the insulating PVC plastic on the conductive core. The process requires that the insulation thickness must be within the tolerance range, otherwise it is a waste product. Wire and cable manufacturers pay special attention to this process, but the scrap rate is still high. In order to save energy and reduce consumption, a set of Web-based SCADA system has been developed for a wire and cable manufacturer using Advantech's network controller uno-2053 and PC based PLC controller adam5510. The effect is good, which has laid a solid foundation for enterprises to realize "factory information automation"

system design

the web-based SCADA system is mainly composed of the following parts: database and web server, field measurement and control equipment, monitoring equipment, switched Ethernet, browser, etc., of which the switched Ethernet is the main data channel. To truly realize the small flow SCADA based on Web, we should not only consider the characteristics of network technology and control technology, but also consider the new characteristics of modern control system. For example, the reliability and accuracy of data transmission and the accuracy of data communication are the primary requirements of remote measurement and control system. Without reliable data, it is impossible to control. There are also the real-time requirements of some devices, which must ensure their priority. In addition, the simplification of the protocol can realize less delay and fast delivery. The connection and update of the network database are not only dynamic and real-time, but also have high programming efficiency and good compatibility. The compatibility of tcp/ip protocol and Fieldbus protocol can truly achieve data unimpeded

in the design, the workshop level intranet is mainly composed of workshop web server (for external Ethernet connection and connection with team network), workshop production server (for production planning, scheduling, report statistics, etc.) and workshop control server (workshop production control process, production process control, equipment real-time monitoring, etc.). Optical fiber communication medium is used for external connection, Ma Kai, vice premier of the State Council of the people's Republic of China, is responsible for the 100M Ethernet connection of all servers within the team leaders, including uno-2053 servers of all teams. Considering the real-time control requirements of the equipment, PC based soft PLC adam5510 controller is used as the main controller, and ADAM4000 is used as the auxiliary SCADA component to control the operation of each production equipment in real time

the remote SCADA system adopts a fully distributed architecture, and the main station system and sub station system are connected through the data network based on the internal IP of the enterprise. Remote monitoring station, remote operation station and equipment maintenance station together constitute the main station system, which is the part that directly contacts with users, and has a friendly man-machine interface; The robust and upward Chinese economic no at the workshop level constitutes a sub station system, which is closely related to the monitored object. All monitoring functions act on the maintained object through the sub station system. The web-based SCADA system structure of the plastic workshop is shown in Figure 1

in order to integrate the system into a measurement and control system with measurement, control and management functions, the whole computer management network structure adopts b/s (browser/server) structure, real-time data exchange technology DDE, and embedded real-time database technology to realize effective management and control integration management. The process control server is composed of real-time database, console browser, etc., which mainly completes the real-time monitoring function of the production process. In addition to the conventional Windows Server 2000, Microsoft SQL Server 6.5 and Power Builder 7.0, the real-time service database of production process control is also installed, so that the on-site intelligent control equipment can access and download process control parameters in real time. The production server is composed of database server, office user browser, etc., which mainly completes the real-time monitoring function and production data management function of the production process. It is installed with Windows Server 2000, Microsoft SQL Server 6.5 and production scheduling control database. The workshop web server is composed of enterprise Internet station and user browser, which mainly completes the function of remote data interaction

the whole workshop adopts 100m fast state as the backbone, connecting each intelligent control unit PLC, process control server, production server and workshop web server. The system adopts star network topology

■ team level network controller uno-2053

in the design of workshop team level SCADA, it is necessary to focus on the harsh industrial site environment, stability, electromagnetic compatibility and other issues, and at the same time to avoid unnecessary troubles caused by the use of computers by operators during non working hours. Therefore, the industrial embedded micro pc-uno2053 of Advantech company is selected as the data gateway, which integrates computer, communication and control, and has good compatibility with SCADA controller adam5510. Chip mounted low-power CPU avoids the problems of heat dissipation, electromagnetic compatibility, impact resistance and vibration resistance caused by fan failure and socket structure in industry. At the same time, it has the characteristics of dust prevention, earthquake resistance and impact resistance, and can meet the requirements of harsh industrial sites. It is a real industrial embedded network controller with the concept of "network is controller"

■ "the network is the controller"

the so-called "the network is the controller" is to remove the internal bus and the external bus, adopt a single bus, the transmission protocol adopts the standard tcp/ip protocol, and the same data flow is used in the whole system. The data transmission is selected by switch and route, and does not pass through the CPU of the controller, so as to realize the real-time access of data. There is no interface problem at all, and the management layer, control layer Various interfaces between the field layers, and can be seamlessly connected with the Internet. Under this technology, the whole system is considered as the bus interconnection of the same controller rather than multiple intelligent controllers, which is called "the network is controller"

uno-2053 network controller is a part of the control network connecting the field intelligent control module. The network hub is integrated in each controller to separate the internal communication from the external communication by allocating space. The integration of this hub technology and the underlying protocol ensures the certainty and compatibility of Ethernet, which can almost eliminate the collision problem of data communication. The Ethernet system bus can be regarded as a field bus, It can be connected to each independent intelligent control module. The whole process and system are regarded as a logic unit, or even an independent field control unit, without considering the concept of each layer of the network, which eliminates the bottleneck effect of CPU. All data is expressed only once in the network layer, and the network plays the role of a real server. This is a major reason why industrial Ethernet can be successfully applied to the real-time industrial control environment, It enables the network to realize the direct communication from the field control unit to the Internet, intranet and management layer

■ multi agent environment of networked workshop scheduling

multi agent environment of networked workshop scheduling with the development of computer technology and network communication technology, the relevant manufacturing equipment in the workshop can be connected with each other through local areas, which provides the most basic hardware platform for the networking of workshop manufacturing system. On this basis, the workshop application software system is constructed by using object-oriented technology, and the original application system is encapsulated. After agent processing, a multi-agent system is formed. In this system, the agents related to workshop scheduling mainly include: main production planning Ag company has the domestic leading lithium smelting and low temperature vacuum distillation purification technology ent, process control agent, process expert agent, dispatcher agent, workshop scheduling agent, equipment information base agent, auxiliary resource information agent, etc. in the multi-agent scheduling environment, each agent has autonomy and intelligence, Through cooperation and coordination, they jointly complete the dynamic allocation of tasks in the networking workshop, and deal with various disturbances in time to ensure the stable and reliable operation of the system. In the whole system, every link is based on the realization of reasonable cooperation strategy and communication. Therefore, solving the problem of cooperation and communication between agents is one of the key problems in the design of multi-agent system

Figure 2 is a schematic diagram of a remote real-time control module using agent technology. It can be seen from Figure 2 that the monitoring module is composed of three types of agents: real-time monitoring agent, control agent and decision agent

conclusion: enterprise informatization is the primary task of national economic informatization in China, and enterprise integrated automation is the development direction of enterprises. SCADA based on Web has laid a solid foundation for enterprise informatization. To realize enterprise informatization and integrated automation, we should not only develop control network and build information network, but also pay attention to the integration of control network and information network, and realize computer collaborative work and information sharing, which is the development direction of digital enterprises in the future. Advantech, the initiator of eautomation in the field of control, provides a powerful information hardware platform and effective solutions for the information platform. We believe that with the accelerated pace of enterprise information automation in China, more Advantech eautomation products will be successfully applied to the construction of enterprise informatization. (end)

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