Abstract: This paper introduces the anode carbon roasting system, common industrial Ethernet technology, and Ethernet redundancy technology. Based on the needs of the anode carbon roasting control system, a dual-redundancy industrial Ethernet network was constructed and successfully applied in an aluminum company. Keywords: Anode roasting; Industrial Ethernet; Modbus/TCP; Redundancy technology. With the development of the global economy and the increasing awareness of environmental protection, higher requirements have been placed on the aluminum industry, which is extremely power-consuming and polluting. To improve the technical indicators of aluminum electrolysis, reduce energy consumption, mitigate the environmental pollution caused by fluorine in aluminum electrolysis flue gas, and ultimately achieve economic growth, prebaked anode electrolysis technology has emerged, enabling the electrolytic cell to develop towards large-scale production. Prebaked anode production is the fundamental link in this technology; the prebaked anode production process, equipment, and product quality directly determine the quality, cost, and efficiency of electrolytic aluminum. As a key piece of equipment in the prebaked anode roasting process, it not only accounts for approximately 30% of the total anode investment but also significantly impacts product quality, energy consumption, and the environment. With the development of science and technology, the materials and technologies for roasting furnace construction have become increasingly mature, and China is now fully capable of constructing high-performance roasting furnaces. However, there is currently no mature calcining furnace control system in the world. The most advanced technology is the anode calcining control system of A.P. Company in France. The anode calcining furnaces of large aluminum plants in my country generally adopt open calcining furnaces, which are basically still at the technical level of Japanese light aluminum calcining furnaces. They have high energy consumption, low production capacity, low furnace temperature control accuracy, and large flue gas emissions. Under the national requirements of "taking the new industrialization path, using informatization to drive industrialization, using industrialization to promote informatization, and enhancing independent innovation capabilities", aluminum companies have actively carried out anode carbon calcining technology transformation. [b]1 Anode Carbon Calcining System[/b] 1.1 Composition and Function of Anode Carbon Calcining System The anode carbon calcining system mainly consists of a green block grouping system, a heavy oil system, a kiln calcining system, a cooked block disassembly system, and a flue gas purification system. The raw charcoal briquette grouping system transports pre-pressed anode charcoal briquettes manufactured in the molding workshop to the grouping station via chain conveyors and roller conveyors for grouping into alternating positive and negative (charcoal bowl) groups for loading into the furnace by overhead crane. The heavy oil system transports heavy oil from oil depots or oil trucks to heavy oil storage tanks, and maintains the temperature, pressure, and liquid level of these tanks. Heavy oil from any of the storage tanks is then pumped at a specific pressure and flow rate into the heavy oil transport pipeline in the roasting workshop, delivering it to the oil outlet at the roasting furnace surface for use by the combustion rack system. The kiln roasting system comprises two parts: the combustion rack system and the exhaust rack system. The combustion rack system receives heavy oil from the heavy oil system, increases its pressure via a booster pump, and maintains its temperature within a certain range using electric heaters and electric stirring devices. The pressurized heavy oil is then sent to the burners of the combustion rack. According to the temperature rise curve requirements, the controller controls the injection frequency of the electromagnetic pulse valves to inject the heavy oil into the furnace chamber. After combustion, the anode carbon blocks are heated according to the predetermined temperature rise curve, so that the binder asphalt and its components in the green blocks seep out, and the corresponding physical and chemical reactions occur in the carbon blocks, so that the performance of the carbon blocks meets the requirements of electrolytic anodes. The flue gas rack system uses the residual heat of the flue gas after combustion to preheat the green blocks according to the predetermined temperature rise curve, so that the green blocks reach the initial roasting temperature within a specified time, and controls the pressure of the flue gas and the opening of the electric valve to ensure that the heavy oil can be fully burned; the calcined block disassembly system transports the calcined anode carbon blocks that have been roasted for a specified time to the disassembly station for disassembly through a chain conveyor, and then transports them to the finished product warehouse through a roller conveyor; the flue gas purification system sends the flue gas generated by the roasting furnace after combustion through the underground ring flue to the flue gas purification device for treatment to meet environmental protection requirements. For a detailed introduction of the anode roasting production equipment and technical requirements, see reference [4]. 1.2 Anode Carbon Roasting DCS System Since the production and control equipment of the entire roasting system are dispersed in different locations, and the process is complex, with high control requirements and significant control difficulties, at the field control level, each subsystem is assigned to a different control station. PIC and HMI are used to achieve decentralized control and monitoring to meet process and control requirements and ensure reliability. At the monitoring level, monitoring computers and auxiliary equipment should be rationally configured according to the function and importance of each subsystem to achieve monitoring and coordination between control stations, ultimately realizing a PLC-based DCS control scheme. Based on the above principles, there are nine on-site control stations: raw block grouping control station (AC1), cooked block ungrouping control station (AC2), heavy oil system control station (AC3), flue gas purification control station (AC4), No. 1 exhaust frame control station (AC5), No. 2 exhaust frame control station (AC6), No. 1 combustion frame control station (ACT), No. 2 combustion frame control station (AC8), and No. 3 combustion frame control station (AC9). Among them, No. 1 exhaust frame control station (AC5) and No. 2 exhaust frame control station (AC6) are configured as "one in use and one on standby". There are four monitoring stations: anode raw block grouping monitoring station, anode cooked block ungrouping monitoring station, kiln common monitoring station, and kiln roasting monitoring station. To ensure the reliable implementation of the control scheme, a complete and reliable hardware and software system is adopted. The system uses TE series electrical components combined with power distribution integrated automation technology to achieve reliable power supply and distribution; Schneider Quantum series PIC, Magelis series HMI, Advantech industrial control computer and supporting monitoring software to realize field control station and monitoring station; and conventional instrument equipment from internationally renowned companies to realize accurate signal detection. In order to realize data communication between 4 monitoring stations and 9 field control stations, as well as production data interaction with the enterprise Intranet, a communication system still needs to be built. Since the anode carbon roasting system works continuously for 24 hours under normal conditions, data exchange between multiple control stations is required in the control. Therefore, it is necessary to ensure that there is a fast and reliable communication method between the control system. At the same time, it is necessary to consider the compatibility with the enterprise Intranet network and the ease of implementation and expansion. Therefore, it was decided to adopt 1OM/1OOM adaptive dual redundancy industrial field Ethernet network technology in the communication system. [b]2 Application of dual redundancy industrial Ethernet technology[/b]2.1 Industrial Ethernet technology Industrial Ethernet technology is the product of the extension of mature Ethernet technology to control network, and it is also the inevitable result of the increased requirements of control technology for the communication performance of field equipment[5]. In recent years, with the expansion of fieldbus applications and the need to establish enterprise information systems, coupled with the advantages of Ethernet technology such as open standards, simple structure, rapid technology updates, and smooth network upgrades, industrial Ethernet has rapidly emerged and continues to develop in the fieldbus fieldbus field. Numerous organizations and manufacturers, in addressing the application of ordinary Ethernet technology to control networks in industrial environments, have developed various industrial Ethernet technologies based on their technical characteristics and historical reasons. Currently, the mainstream industrial Ethernet technologies include: ① Modbus/TCP proposed by Modbus-IDA/Schneider Electric; ② EtherNet/IP proposed by ControlNet International (CI) and the Open Device Network Vendors Association (ODVA)/Rockwell Automation; ③ Profinet proposed by the Profibus Nutzer Organization (PNO)/Siemens; and ④ HSE proposed by the Fieldbus Foundation (FF). Modbus/TCP is an extension of Modbus, based on Ethernet and the standard TCP/IP protocol, and directly applies the Modbus protocol to the 4th layer. The real-time extension adopts Real-time Publisher Subscriber (RTPS) on UDP, forming a simple, open and widely used transmission protocol. It adopts a star topology and supports 10Mb/s, 100Mb/s and 1000Mb/s devices, which can form a network of almost unlimited scale. It is precisely because of these characteristics of Modbus/TCP that its application in industrial fields is becoming more and more widespread. For a detailed introduction of the other Ethernet technologies, see reference [6]. 2.2 Industrial Ethernet Redundancy Technology Due to the harsh industrial environment, industrial control networks have higher reliability requirements than commercial networks, which has led to the emergence of industrial Ethernet redundancy technology. Ethernet redundancy technology in industrial automation includes: power redundancy, media redundancy, network node redundancy, network redundancy and system redundancy. The basic redundancy requirement of a control system is that every part of the communication network can connect to a backup power source after a power failure. Once a power outage occurs, the backup power source takes over and sends a power failure alarm to management personnel via email or relay output. Media redundancy can provide a backup path when parts of the network are unavailable; a common method is to use a dual-star topology to build an immediately available automation system network. Network node redundancy requires that switches connected to devices be configured with dual network nodes, both connected to a dual-boot controller. In the event of a disaster, to ensure normal system operation, the controller ensures connection to the terminals; both Ethernet interfaces should be connected to two redundant switches, and the more stable one should be selected as the primary path. Network redundancy is essentially building a network where all devices have redundancy capabilities. A fully redundant system includes: redundant switches, redundant communication ports, and a pair of redundant devices. All Ethernet devices and workstations must be connected to two independent network loops. Full system redundancy can create a reliable network with minimal data loss and rapid redundancy time. 2.3 Implementation of Dual Redundancy Industrial Ethernet in Anode Baking DCS To construct a 10M/100M adaptive dual redundancy industrial field Ethernet communication network, a matching network type must be selected and reasonable redundancy configuration implemented. First, the selection of the industrial Ethernet type must consider compatibility with the existing control platform and the characteristics of various networks. Since the control platform uses Schneider Quantum series PLCs, and the Quantum series PLCs have the NOE77110 industrial Ethernet communication module based on the Modbus/TCP protocol, and Modbus/TCP industrial Ethernet is simple, efficient, and has significant advantages in terms of initial investment and full utilization of existing resources, the NOE77110 Ethernet module is used in the system to implement a 10M/100M adaptive industrial Ethernet based on the Modbus/TCP protocol. Second, to ensure the reliability of the communication network, reasonable redundancy must be implemented for the control network equipment according to the actual situation on site. ① Power Supply Reliability: To ensure the normal power supply of the network equipment, all PLC controllers, monitoring computers, and switches are powered by UPS. ② Equipment Redundancy: Each control station PLC is equipped with two 10M/100M adaptive NOE77110 Ethernet modules, two Cisco 6-port switches are configured in the switching equipment, and each monitoring computer is equipped with two 3Corn Ethernet cards. Due to the redundancy of the network equipment, redundant communication paths exist between each device, thus eliminating the need for redundant communication media for each device. Through the above redundancy technology, a dual-redundant star-topology 10M/100M adaptive industrial Ethernet based on the Modbus/TCP protocol is finally realized. The system structure diagram is shown in Figure 1. As can be seen from Figure 1, the reliability of the communication system is guaranteed by redundancy technology. If any device in one communication channel fails, the system can switch to another communication channel via software; if devices in both communication channels fail, communication can be restored simply by manually adjusting the connection positions of the communication media. The speed of the communication system is guaranteed by the network hardware equipment and communication protocol. Through actual field operation, the star-topic 10M/100M adaptive industrial Ethernet communication network based on the Modbus/TCP protocol with dual redundancy provides a reliable communication platform for the anode carbon roasting control system. In addition, this network also has other scalable functions: ① Through the built-in HttpServer service function in the NOE77110 Ethernet module, remote fault diagnosis and repair functions can be realized, achieving a truly "transparent factory." ② It provides a universal communication platform, facilitating future system expansion. For example, during subsequent technical upgrades to the molding workshop, simply adding an Ethernet communication module can achieve data sharing across the entire roasting section. ③ By introducing Ethernet technology, it provides all equipment-level data for enterprises to implement CIMS or ERP technologies, avoiding "automation" silos and enabling seamless connection with the enterprise's MIS system. 3 Conclusion In recent years, industrial Ethernet technology has made great progress. The adoption of star topology instead of bus topology, the use of Ethernet switching technology, full-duplex communication technology and virtual LAN technology have ensured the real-time and deterministic nature of Ethernet communication. The Ethernet network has been improved from the physical layer and protocol aspects, achieving the high reliability required by industry. The information security of the Ethernet network is ensured by introducing gateway and firewall technology, and the production safety of the Ethernet network is ensured by introducing common explosion-proof and explosion-proof technologies. Through the joint cooperation of international organizations and companies, the interoperability of various Ethernet networks has been strengthened, and the standardization of network system has been promoted. In short, with the maturity and unification of industrial Ethernet technology, the application of industrial Ethernet technology will become more and more widespread, providing a more powerful and reliable guarantee for the realization of automation technology, and will play an increasingly important role in the process of "driving industrialization with informatization" in the country. References: [1] Cui Dongsheng. The development direction of carbon for aluminum in China and measures to improve its quality [J]. Mining Research and Development, 2003, 23 (S1): 56-59. [2] Sun Yi, Cui Dongsheng, Xu Yingdi. [3] Wang Xiaobin. Automatic control system for calcining furnace temperature [J]. Carbon Technology, 1997, 16(6): 34-37. [4] Liu Jie. New process and equipment for anode calcining technology [J]. Light Metals, 2003, 23(1): 47-51. [5] Yang Xianhui. Industrial data communication and control network [M]. Beijing: Tsinghua University Press, 2003. [6] Tong Weiming, Liu Yong, Zhao Zhiheng. Several mainstream industrial Ethernet [J]. Low Voltage Electrical Appliances, 2005, 260(6): 41-43. Click to download: Application of dual redundancy industrial Ethernet in anode calcining system Editor: Chen Dong