1. Overview of the control system for the 8000kg/h tobacco processing line at Wuhu Cigarette Factory
On the banks of the Yangtze River, in the beautiful river city of Wuhu, stands a large-scale cigarette manufacturing enterprise—the Wuhu Cigarette Factory—where a technological revolution is quietly taking place. From tobacco processing to packaging, from MES to ERP, brand-new integrated workshops, processing equipment, management philosophies, and methods are changing people's ways of thinking and improving work efficiency. Before long, a modern enterprise with an annual production capacity of 25 billion cigarettes will be completed and put into operation.
The core driving force behind this technological revolution is the world-leading 8000 kg/h silk-making line. This line selects key equipment from world-leading companies such as HAUNI in Germany and DICKINSON-LEGG in the UK, and its control system is integrated by the China Academy of Launch Vehicle Technology, which launched the Shenzhou 5 spacecraft into space.
This control system is an integrated management and control system for production line automation and management. It adopts a three-level network structure consisting of an information network, a control network, and a fieldbus. The main controller uses 15 S7 series programmable controllers from Siemens, Germany. The modern central control room houses three IBM servers and five IBM graphical workstations, forming a monitoring system and information management platform for unmanned field operations. The monitoring configuration software uses Siemens' WinCC 6.0, and the latest Oracle 9i database provides a robust information platform for the entire system. The fieldbus uses Profibus-DP and Profibus-PA. The key fieldbus components are products from Beckhoff, Germany.
2. Introduction to Beckhoff Fieldbus Components
BECKHOFF is a German company specializing in automation. Its main products include fieldbus terminals, high-performance industrial computers, control panels, and control software.
BECKHOFF's fieldbus terminals support almost all fieldbuses currently on the market. A variety of high-performance bus terminals meet the requirements of different field signals. In particular, their newly launched KL8001 motor starter terminal, paired with Siemens' 3RT10 series contactor, forms a completely new high-performance motor starter capable of fully controlling motors up to 5.5kW. It not only possesses the bus-controlled motor start, stop, and return-to-motor-status functions of other motor starters, but also offers strong diagnostic, detection, and protection capabilities for the motor.
The main features of BECKHOFF fieldbus terminals are high cost-effectiveness, reliable quality, compact structure, robust durability, and very convenient installation and wiring.
3. Application of Beckhoff Fieldbus Components in the Silk Fabrication Line Control System
Based on the superior quality of BECKHOFF fieldbus terminals and the high requirements of the tobacco processing line for field automation products, the field level of the newly built 8000kg/h tobacco processing line control system of Wuhu Cigarette Factory adopted BECKHOFF's fieldbus terminal system, including the bus coupler BK3120, bus controller BC3100, input/output terminals and motor starter terminals KL8001.
A key characteristic of tobacco production lines is the presence of numerous motors below 5.5 kW driving equipment such as vibrating troughs, pulleys, and trolleys. To ensure stable and long-term operation of this equipment and minimize downtime, timely control of these motors and monitoring of their operating status and fault information are crucial. All of this is accomplished using BECKHOFF's KL8001 motor starter terminal block.
KL8001 paired with a 3RTl0 series contactor forms a unidirectional circuit.
The motor starter, when paired with two 3RTl0 series contactors, can form a bidirectional motor starter. Therefore, the KL8001 motor starter terminals used for motors below 5.5KW are the same. This means that even with many motors on site, the required spare parts are few. Furthermore, its split structure, compared to the integrated structure of other manufacturers' motor starters, makes installation and disassembly convenient and quick, significantly reducing future equipment maintenance time and costs. The rated current of motors of different power ratings can be set via a rotary switch on the KL8001 panel or through software. The software allows setting the maximum values for overvoltage, undervoltage, overload, underload, and current difference for each phase of the motor. It can also be programmed to automatically and quickly disconnect the motor without controller operation in case of faults such as asymmetrical load, phase error, overvoltage, undervoltage, overload, or underload, thereby maximizing the protection of the motor and equipment. Simultaneously, detailed fault information can be provided via the bus for timely and accurate troubleshooting. The KL8001 not only controls the motor's forward and reverse rotation, stop, and return to its operating status via bus, but also displays detailed performance parameters of the motor during operation, including over 30 parameters such as real-time current, voltage, power, starting current, running time, and number of switching operations for each phase. Real-time current monitoring not only provides information on changes in motor load but also allows for more accurate setting of the motor's rated current. By using phase commutation, it strives to achieve a more balanced three-phase configuration for cam-type loads such as those with vibrating grooves. This allows for more rational motor control during commissioning, reducing the likelihood of future motor malfunctions.
Due to the powerful functionality of the KL8001, its process image occupies 12 bytes of input/12 bytes of output. To minimize the data volume on the fieldbus network and improve network reliability, the fieldbus slaves in this project extensively utilize the BC3100 fieldbus controller. The BC3100 and BK3120 are similarly priced; the BC3100 integrates a PLC based on the IEC61131-3 standard with 64KB of memory. In this system, since the input and output terminals do not require local control, they can all be configured in fieldbus mode. For input and output terminals, the BC3100 is equivalent to the BK3120, meaning the BC3100 only needs to handle the motor starter terminals (KL8001). The control bytes and status bytes of each KL8001, as well as key data such as the motor's real-time current, are directly uploaded to the master controller. Other motor performance parameters and status information detected by the KL8001 are stored in the BC3100 as a two-dimensional array through programming, and can be uploaded via master station query. This significantly reduces the amount of data on the network while ensuring all necessary data is available. Simultaneously, the programs of over 120 BC3100 slave stations in the field are unified into a single program, preventing errors caused by inconsistencies in the programs of different slave stations during future maintenance, reducing workload, and facilitating program preservation.
Whether considering the high requirements for automation control and computerized information management of the entire production line, or the timeliness, convenience, and economy of future equipment maintenance, BECKHOFF fieldbus products are undoubtedly the best choice for tobacco production automation equipment.
4. Conclusion
The BECKHOFF fieldbus components provided an excellent environment for the development of the control system for the 8000kg/h tobacco processing line at Wuhu Cigarette Factory. This advantage became increasingly apparent the deeper the development process went. Firstly, the BECKHOFF fieldbus components offer high reliability, providing a solid foundation for the commissioning of the control system. Secondly, they are powerful in function, as demonstrated earlier. Furthermore, their excellent performance-to-price ratio makes them widely applicable.
Proceedings of the 2nd Servo and Motion Control Forum and the 3rd Servo and Motion Control Forum
