Abstract: This paper mainly studies the application of Mitsubishi CC-LINK bus in the vacuum potting control system of flyback transformers (FBT). Considering the production characteristics, process requirements, and existing PLC control systems for flyback transformer (FBT) potting, the composition and implementation method of the control system are introduced. The network advantages, configuration, and topology of the CC-LINK bus control system are also discussed. Keywords: flyback transformer, CC-LINK control system 1 Introduction Flyback transformers (FBT) are core components of CRT display products. The design and manufacturing technology of flyback transformers was a patented technology introduced from Japan in the 1990s. Most domestic enterprises have digested and absorbed this technology and combined it with China's national conditions for manufacturing. Large-scale mass production is now common. In the FBT manufacturing process, epoxy resin potting is crucial. The quality of its manufacturing process directly affects the product's lifespan and reliability. This dedicated fully automatic control equipment is called an Automatic Vacuum Potting System (AVCS) in the industry. The main process of the Automatic Vacuum Potting System is shown in Figure 1. Figure 1. Automatic Vacuum Encapsulation System Task Diagram 2. CC-LINK Bus CC-Link is short for Control & Communication Link, an open fieldbus introduced by Mitsubishi Electric in 1996. It features large data capacity, multi-level selectable communication speeds, and is a composite, open, and highly adaptable network system capable of accommodating networks ranging from higher management layers to lower sensor layers. CC-Link is a device-layer-based network. Typically, a single CC-Link layer consists of one master station and sixty-four slave stations. The master station is a PLC, while slave stations can be remote I/O modules, special function modules, local stations with CPUs and PLCs, HMIs, frequency converters, and various measuring instruments, valves, and other field instruments. It also enables connections from CC-Link to the AS-I bus. CC-Link boasts high-speed data transmission, reaching up to 10Mbps. CC-Link's underlying communication protocol follows RS-485. Generally, CC-Link primarily uses a broadcast-polling method for communication. CC-Link also supports instantaneous communication between the master station and local stations, as well as between smart device stations. CC-Link communication can be divided into two modes: cyclic communication and instantaneous transmission. Cyclic communication means continuous data exchange. Various types of data exchange include remote input (RX), remote output (RY), and remote registers (RWr, RWw). The data capacity that a slave station can transmit depends on the number of virtual stations it occupies. Occupying one slave station means accommodating 32-bit RX and/or RY, redirected in four-word increments. If a device occupies two virtual stations, its data capacity doubles. In addition to cyclic communication, CC-Link also provides instantaneous transmission capabilities between the master station, local station, and smart device stations. Information is transmitted from the master station to the slave station in 150-byte increments. If information is transmitted from the slave station to the master station or other slave stations, each batch of information is a maximum of 34 bytes. Instantaneous transmission requires dedicated instructions. Instantaneous transmission does not affect the time of cyclic communication. CC-Link features: (1) High-speed and high-capacity data transmission; (2) Topology with multi-point access, T-branch, and star structures; (3) CC-Link makes distributed control a reality; (4) Automatic refresh function and reservation station function; (5) Complete RAS (Reliability, Effectiveness, Maintainability) functions. Backup master station function, online replacement function, automatic communication recovery function, network monitoring function, and network diagnostic function provide a reliable network system, helping users restore the network system in the shortest possible time; (6) Noise resistance and compatibility; (7) Interoperability and plug-and-play; (8) Instantaneous transmission function. In summary, CC-Link has outstanding advantages such as excellent performance, wide application, simple use, and cost savings. CC-Link's design provides users with the simplest usage and maintenance methods and measures. 3. Control System Process Flow and Component Configuration 3.1 The basic structure of the vacuum resin potting system is shown in Figure 2. It mainly consists of six parts: a degassing section, a metering and mixing section, a potting section, an electrical control section, a preheating furnace section, and a curing furnace section. Before the potting operation begins, preparatory work must be carried out, including feeding, degassing, and adjusting the ratio of resin (i.e., component A) and curing agent (i.e., component B). After the preparatory work is completed, potting can begin. During potting, the metering cylinder is pressed down, and components A and B are pumped into the mixer from cylinders A and B according to the adjusted ratio. The mixer thoroughly mixes components A and B and then sends them to the potting chamber section. In the potting chamber section, the mixture is injected into the workpiece through the nozzle. The workpiece is placed on a tray, preheated in the preheating furnace, and then enters the potting chamber. Each tray has several stations. After potting one workpiece, the tray moves forward one fixed position and changes to a new station. One tray can be used to pot 45 workpieces continuously. After potting, a new tray must be placed before potting can continue. After filling, it enters the curing oven for curing. Figure 2 Simplified diagram of vacuum resin filling system 3.2 System composition The entire control system is divided into four parts: (1) Preheating tunnel-type furnace unit; mainly completes the preheating treatment of the product to be filled, process requirements: 105+/-3℃, time: not less than 1 hour; (2) Computation and casting unit; mainly completes the weighing, full mixing and vacuum pouring of material A and material B into the product; (3) Material deaeration control unit; mainly completes the vacuum deaeration of material A and material B under different conditions, that is, the preparation treatment before use; (4) Solidify tunnel-type furnace unit. Mainly completes the curing treatment of the filled product, which requires strict adherence to the chemical characteristics of epoxy resin material and is carried out in a specific atmosphere. 3.3 System Configuration In the design of the engineering automation, after analysis and comparison, it was considered that the original factory had partially implemented workshop PLC control and the PLC brands currently in use included Mitsubishi Fx2n-80MR, etc. After price and performance analysis and comparison, it was determined that Mitsubishi's CC-LINK fieldbus product was selected as the main control device. CC-Link is a network based on the device layer. In order to improve the safety and reliability of the entire control system, the system adopts a dual-machine redundancy structure. As shown in Figure 3. Figure 3 Bus system topology (1) The master station and the backup station are managed by Mitsubishi A series PLCs, which are responsible for the management of the CC-Link network, sending data to the host PC for analysis, and sending instructions issued by the central control room to the field slave stations. The host is equipped with a PCI bus CC-Link bus network adapter card A80BD(E)-JB1BT13. Mitsubishi A series PLCs have fast response speed and large information processing capacity. (2) The configuration of the four slave stations is the same, using FX2NPLC+32CCL to control the four production lines respectively. The Mitsubishi A985GOT touchscreen serves as the lower-level human-machine interface (HMI). The Modbus protocol used in this system is encapsulated in RTU format, enabling high baud rates for information transmission. The Modbus communication protocol (RS-485 mode) is selected, with twisted-pair cable as the communication medium. It was developed and adopted by Modicon in its early days and is widely used in industrial control. 4. Conclusion This vacuum resin infusion system is now in use. It is expected to significantly improve work efficiency, infusion quality, and the worker's operating environment. It achieves integrated management and control, realizes data and information sharing, and optimizes process control performance and efficiency. It allows for the exploration of the organic integration of modern control technology—fieldbus—with traditional industries, enhancing the automation level of enterprises.