Rockwell Automation Company has launched an omni-directional e- manufacturing scheme and corresponding operating system, which allows manufacturers to combine the production department with the overall business system and supply chain of the enterprise through the existing e-commerce technology, and comprehensively improve the efficiency and competitiveness of the enterprise.
The concepts of computer integrated manufacturing system, enterprise resource planning and digital factory can be called early e-manufacturing products. With the perfect combination of network communication technology, information processing technology and electrical control, the concept of e- manufacturing has gone beyond the early thinking mode of focusing only on the complete system integration of a key product or manufacturing object in the product development and production process of an enterprise, without caring about the relationship between the whole enterprise and the supply chain. It has become a manufacturing system infrastructure based on operating system, Ethernet and Internet, which can realize the integration of management and control of enterprises. Electronic manufacturing characteristics
The communication between the traditional field layer equipment and the controller adopts one-to-one connection to transmit 4-20mA-4V DC signals. The information of this communication technology is limited, and it is difficult to exchange information between devices and between systems and the outside world, which makes the automatic control system an "information island" in the factory, which seriously restricts the realization of enterprise information integration and enterprise integrated automation. Fieldbus technology uses computer digital communication technology to connect intelligent field devices, so that the controller can obtain information from the field devices, realize the transmission of device status and parameter information, and complete remote control, parameterization and fault diagnosis of the devices.
Traditional control methods such as PLC and fieldbus have the following problems:
1. From the sensor to the main controller, data often passes through different CPUs and drivers, resulting in low transmission speed, lack of transparency and high software and maintenance costs;
2. The system linkage data communication between any controllers, whether it is single master-slave or token bus structure system, can't realize real-time high-speed data transmission, so it can't realize programming development and maintenance;
3. It is very difficult to combine the vertical and horizontal directions of data communication;
4. For the integration of several controllers, a wider logical entity system cannot be formed;
5. For the factory workshop with integrated wiring or broadband access to the enterprise intranet, the Ethernet controller can not only simply access the computer in the main control room to exchange control information, but also carry out "hard real-time" control similar to PLC on the enterprise intranet, but the traditional PLC or fieldbus technology is powerless.
Therefore, the traditional PLC or fieldbus technology can no longer meet the product control requirements under the concept of e-manufacturing. E- manufacturing integrates workshop layer and business decision-making layer, and replaces traditional PLC and customized controller with enterprise-enabled control and real-time information platform (such as e-controller or PC-based automation and control solution). Through the control elements such as sensors and limit switches in the workshop, the information is sent to the diagnosis system and monitoring system based on control, and then to the operating systems such as management, maintenance, modeling, scheduling and feedback, so that suppliers, OEMs and supply chain partners can access any system they need and send instructions to the system when necessary.
E- manufacturing provides structured methods and tools for developing manufacturing processes. It describes the manufacturing process as an electronic process list, and makes the manufacturing process more effective by connecting all devices to the Internet. It has the characteristics of network compatibility, I/O transparency, linkage operation compatibility, high production efficiency, strong flexibility, high reliability, low maintenance and manufacturing costs and great flexibility. Figure 2 e- Manufacturing system In the e- Manufacturing system shown in Figure 2, the e-commerce supply chain can realize seamless connection among suppliers, manufacturers and users, and fully integrate the functions of customer relationship management (CRM), supply chain management (SCM), business intelligence, e-commerce and workshop automation by using Internet technology to realize the sharing of resources and information. Manufacturers issue material purchasing and manufacturing instructions through enterprise resource planning (ERP) system. It can speed up the delivery and acquisition of orders, the acquisition of raw materials and the manufacture and distribution of products, realize zero inventory, and then realize the uninterrupted production of the factory on the basis of optimal capital operation cost.
The core of e- manufacturing is to comprehensively manage production activities and enterprises by using automation control technology, information technology and e-commerce, and to integrate with suppliers, customers and partners on the Internet to form a transparent information exchange, so that product development, production, delivery, customer service and supply management can be carried out in real time on the Internet. It is predicted that by 2003, 70% of business relationships between enterprises, whether long-term or short-term, will be non-traditional, and online B2B trade will increase from199 to $7.29 billion in 2004. Producer/consumer model
An efficient automation system requires all devices to be connected through the network, but the biggest difficulty is the coordination and maintenance of the whole system in the face of numerous devices and protocols. Three types of information are transmitted on the network:
1. Control information to complete high-speed and accurate information exchange;
2. Configuration information supports system configuration during startup and operation;
3. Data acquisition: data acquisition is carried out according to the requirements of cycle or HMI analysis.
However, the existing network can not meet these three requirements at the same time. Although it provides repeatable and predictable communication between devices, its data transmission rate and protocol efficiency can not meet its communication question and answer requirements, such as the need for multiple data packets to transmit the same information to multiple devices; Data arrive at different destinations at different times; Additional network traffic is generated, which affects the performance of the network; There are some problems such as requiring I/O data and using different networks in message sending and checking time.
The control network and device network used for network management and connecting device communication is a new solution based on open network technology-producer/consumer mode. On the control network link, information is transmitted by establishing connections between nodes. Each message sent by the producer contains 1 connection identifier (cid), and the configured node recognizes the cid to accept the message, thus becoming 1 customer.
The network model based on producer/consumer has the following characteristics:
1. Multiple nodes on the network can access the same data from a single producer (data source), and messages are identified by directories;
2. Nodes can be synchronized, and more devices can join the network, but there is no need to increase network traffic, and the data of all nodes arrive at the same time;
3. Optimizing the low bandwidth potential can be used to enhance the function of the system;
4. Use the same network for programming and I/O information transmission.
In A54NO+66 automation network with global information connection in manufacturing industry, Ethernet, control network and device network have network performance that allows information exchange among devices, computer platforms and operating systems. Fig. 3 Three-layer structure of Rockwell automation network: Fig. 3 The information layer of the three-layer structure of Rockwell automation network adopts Ethernet which implements TCP/IP protocol, and is used for data acquisition and program maintenance of the whole plant;
The control layer uses high-speed deterministic control network to transmit time-critical control information such as I/O status and control interlock, as well as non-time-critical information such as program loading and downloading. I/O, real-time interlocking, point-to-point communication message transmission and programming operations on the same link all have the same bandwidth. For discrete and continuous process control applications, it is deterministic and repeatable;
The equipment layer directly connects the bottom equipment and the workshop-level controller by using the equipment network to realize low-cost and high-efficiency information integration. The equipment network can effectively use the network bandwidth, so that the control data can reach all operating units at the same time, greatly reducing the network traffic. Because it allows the message of state switching to be sent, it makes a faster response. At the same time, messages are sent regularly to provide better certainty, and point-to-point communication allows devices to exchange data and status information. Key Electronic Technologies Implemented in Manufacturing Industry
The key of e- manufacturing is to produce according to the order and keep uninterrupted operation. One of its main contents is the connection and reliable operation of various parts in the manufacturing system, so that the whole system can establish the control information of various switches, relays, contactors, pumps, valves, motors and so on. It has become an enterprise dictionary library with 1 copy, and its I/O can be effectively adjusted at any time at high speed to meet the fluctuating needs of production, market and supply chain. In the implementation of e- manufacturing strategy, combined with the specific situation of China's manufacturing industry, I think we should start from the following aspects:
1. Establish a highly integrated automation control and information network platform based on standard network connection in the production workshop, collect and transmit all kinds of data timely and accurately, and ensure the precise control of the production process. At the same time, we need to pay attention to the visualization of information and the openness of the network.
2. Synchronize production and business process. Network the production control system, production execution system and enterprise resource planning system, so that the workshop system and business system are closely linked, and the enterprise decision-makers can obtain 1 first-hand production data in time, so as to effectively implement and adjust production activities and realize the integration of enterprise management and control.
3. Integrated design and production process establish an effective management system and maintenance mechanism for production equipment, personnel and processes, and fully tap the potential of improving efficiency and reducing costs.
4. Collaborative supply chain management uses e-commerce to manage suppliers and directly transmit customer orders to the production system. Monitor the daily purchase, sales and inventory of downstream customers through the network, replenish goods in time, let upstream suppliers know the inventory of raw materials in time, and keep the inventory at a minimum level. Realize cross-period supply chain management, online control and management of finished goods inventory in distribution system, and dynamic procurement management of suppliers.
5. 24 hours a day, 7 days a week, 365 days a year electronic customer service mode, keep in touch with customers, enhance customer satisfaction and loyalty, and predict demand through customer relationship management to provide new business value-added. label
Facing the development trend of economic globalization and informatization, all countries in the world are facing the challenge of using information technology to transform traditional industries and improve the competitiveness of manufacturing industry in the international market. At present, the major e-commerce companies in the world are rapidly developing electronic manufacturing solutions to realize e-commerce and make manufacturing capacity and inventory transparent to the supply chain. Use existing equipment to share information with other systems, quickly respond to users' needs, and configure agile and reconfigurable manufacturing systems, so that product production tends to be customized, variant and batch, and delivery is timely.
Electronic manufacturing is the decisive factor of future manufacturing industry, which integrates manufacturing industry into the process of e-commerce. Customers can know the performance and price of products through the Internet and place orders with manufacturers. Manufacturers issue material purchasing and manufacturing instructions through ERP system, and complete material purchasing and payment through electronic means. After the manufacturing is completed, the goods are finally delivered to the users on time, and the transaction settlement is completed online. The close combination of supply and demand chain can realize the uninterrupted flow of materials and zero inventory, which is the inevitable trend of future manufacturing development.