Abstract: This paper introduces a method for innovatively controlling a cigarette-making line system using industrial Ethernet (PROFINET) and fieldbus. The paper analyzes the rigidity, fixed functions, and high maintenance costs of the original control system, and presents a design scheme for the new system and solutions to control difficulties. Through upgrades and improvements, the new cigarette-making line electrical control system is more flexible, meets the requirements of integrated information control, and ultimately improves the efficiency of cigarette production. Keywords: Real-time industrial Ethernet, cigarette-making line, PLC, industrial computer 1 Introduction The production process of cigarette enterprises mainly includes: cigarette making, cigarette spinning, and packaging. The cigarette-making line (Prime line) is the production line that ensures stable cigarette quality. It also has the longest process flow, the most complex procedures, and the most diverse equipment types. The automatic control method of the cigarette-making line is divided into process sections such as leaf line, stem line, blending, flavoring, and additives. First, each process section is independently controlled by connecting a PLC to a fieldbus. Then, the process sections are connected via Ethernet to finally complete the corresponding numerical control acquisition and monitoring. This control mode is currently the most widely used in the cigarette industry. 2. Introduction and Problem Analysis of Current Cigarette Processing Line Electrical Control System 2.1 Cigarette Factory Cigarette Processing Line Electrical Control System The cigarette processing line electrical control system is the core of the cigarette factory's cigarette processing production line control. The system diagram is shown in Figure 1. Figure 1. Schematic diagram of the cigarette factory cigarette processing line electrical control system The original electrical control system consists of PLC, touch screen, and field I/O stations for each process section. The field bus connects the components; the field layer and the monitoring and management layer are connected through an Ethernet switch. In the production field, the PLC of each process section is responsible for the control of its own process section. According to the production process requirements, it sends corresponding control commands; the field bus transmits commands to the field I/O station to complete the control of the field actuators, and at the same time collects the signals from the field sensors and sends them back to the PLC. The touch screen displays relevant production parameters so that field personnel can understand the production line status and receive production operation commands from field personnel. In the monitoring and management layer, the switch connects the field layer and the monitoring and management layer through Ethernet. The server collects the production information from the field and generates corresponding reports; the monitoring computer monitors the production status in real time and can publish production scheduling plans. Problems with the Existing System In the original electronic control system, each process segment was relatively independent, with fixed and simple procedures, suitable for mass production of fixed products. However, the current cigarette market is highly competitive, and the development and production of new products require continuous improvement in process technology. At this point, the rigidity of this type of electronic control system becomes glaringly apparent. When a process segment is adjusted, the entire electronic control system for that segment must be redesigned; adjusting the entire cigarette-making line is equivalent to building a new production line. Furthermore, the human-machine interface of the on-site touchscreens is limited in functionality, and when the on-site touchscreen malfunctions, the process segment it monitors cannot achieve human-machine interaction. More seriously, when the centralized monitoring computer of the control system shuts down (including normal shutdown and fault shutdown), the entire cigarette-making production line cannot operate normally. The entire electronic control system is complex, difficult to maintain, and cannot meet the requirements of current advanced flexible production concepts. Design of the New Electronic Control System Selection of Control System Automation in cigarette factories has extended from simple automatic control in the production workshop and computer use in the office to all aspects of management, control, and on-site operations. As Phoenix Contact first proposed the concept of integrated information control in 2004—connecting all devices within an enterprise using Real-Time Ethernet to achieve unimpeded information flow—the industrial Ethernet PROFINET selected here is based on this concept and was jointly launched by INTERBUS CLUB (led by Phoenix Contact) and PROFIBUS USER ORGANISATION (led by Siemens). PROFINET is a holistic solution that uses TCP/IP and IT standards, conforming to real-time automation systems based on industrial Ethernet. PROFINET enables seamless integration with fieldbus; it can meet the unified communication needs of all customers, organically combining the real-time performance, ease of use, strong diagnostic capabilities, and economy of fieldbus for transmitting field information with the multi-master, versatility, and ability to transmit large amounts of information at different rates characteristic of industrial Ethernet. Selection of Field Operator Terminals To better achieve field monitoring, the PPC 5315 industrial PC (Phoenix Contact) was selected. This model of industrial PC meets the original field display requirements and provides a universal Windows operating platform, allowing multiple host vendor-developed programs to run simultaneously. Its PCI and ISA universal expansion slots, dual Ethernet ports, and other interfaces make it exceptionally easy to enhance system functionality through external expansion cards. Furthermore, considering the high temperature, humidity, dust, and vibration frequency of equipment in industrial environments, this industrial PC adopts a fanless design, uses an industrial hard drive, and features a shockproof mounting device. It offers good maintainability and robust data protection. Selection of Other Control System Components Under normal circumstances, PLCs, field I/O devices, etc., can be selected from products conforming to IEC standards. However, due to the adoption of the latest industrial Ethernet PROFINET, new requirements have been placed on the interfaces of related devices. PLCs must have PROFINET interfaces, and the couplers of field I/O substations must also have PROFINET interfaces. In addition, switches must support PROFINET functionality to transmit real-time signals. Control System Implementation The new control system establishes a redundant fiber optic ring network using PROFINET switches. Electrical equipment in each process section is no longer physically separated; all are connected to the nearest PROFINET industrial Ethernet network. The logical structure of each process segment is completed during configuration and is independent of hardware location. Field operator terminals communicate with all control segment PLCs via PROFINET, enabling authorized monitoring of relevant control segment equipment. They also connect to the production management layer via PROFINET, directly obtaining production data such as production operation plans, batch tasks, and formula parameters, and transmitting production information from relevant production segments to the production management layer. The data server also connects to the industrial Ethernet PROFINET via Ethernet to collect relevant data. Wireless Ethernet switches allow engineers to easily connect their wireless devices to the network for work. New Tobacco Processing Line Control Flow The automatic leaf blending process automatically blends tobacco leaves and stems according to the cigarette leaf blend formula requirements; the tobacco leaf pretreatment process heats, rehydrates, loosens, and adds materials to tobacco leaves of various grades, completing batch blending tasks according to the leaf blend formula requirements; the tobacco leaf processing process outputs the blended tobacco leaves after storage for a specified time from the storage tank, and then proceeds through screening, cutting, and humidification before entering the drying stage; the tobacco stem pretreatment process rehydrates and softens the tobacco stems, making them suitable for tobacco stem processing; the tobacco stem processing process outputs the processed tobacco stems from the storage tank, and after steaming, pressing, air cooling, and metal detection, enters the stem cutting machine; the mixing and flavoring process achieves the proportional blending and uniform flavoring of tobacco leaves, stems, carbon dioxide expanded tobacco, thin sheet tobacco, and recycled tobacco; the tobacco storage and feeding process sends flavored tobacco stored for more than 8 hours to the corresponding cigarette making unit. Key Points for Control Network Construction Traditional fieldbus control systems require electrical devices in the same process section to be directly connected via bus cables. Industrial Ethernet PROFINET does not have this requirement; electrical devices can be connected to the switch nearby, and the logical structure can be built during configuration. Therefore, it requires breaking with old thinking and leveraging the advantages of information networks to complete network construction. The new industrial Ethernet PROFINET control system brings a problem: a large number of devices are directly connected to the network, resulting in a large number of data packets flooding the network and causing a decrease in communication efficiency. The solution is to use VLANs (Virtual Local Area Networks), that is, to enable the VLAN function in the switch (see the specific product manual), and group electrical devices logically belonging to the same process section into the same VLAN. Conclusion The new electrical control system's PROFINET network integrates powerful functions, from network installation to the implementation of the entire automation solution based on web-based diagnostics; PROFINET's modular structure can be easily expanded and includes other functions; PROFINET provides standardized, manufacturer-independent engineering interfaces, which can easily integrate equipment and components from various manufacturers into a single system. The PPC5135's user-friendly interface not only makes on-site monitoring more convenient, but its communication functions also allow the workshop control room to monitor on-site production in real time. The new control system simplifies the network communication protocol to a single protocol, greatly saving on construction costs and future maintenance costs. This also lays a solid foundation for the construction of future flexible filament production systems.