[b]1 Introduction[/b] In recent years, my country's economy has maintained a high-speed growth trend, especially with the rapid development of domestic demand and exports in the light industry markets such as food, beverages, electrical appliances and toys, which has also promoted the rapid development of the related packaging industry. Corrugated cardboard boxes account for a considerable proportion in the packaging field. The cross-cutting machine is an important link at the end of the corrugated cardboard production line. The performance of the cross-cutting machine is one of the important factors affecting product quality and production efficiency, and it is also the most complex link in the electrical control of the entire production line. With the increase in the variety and performance of Delta Electronics' electromechanical products, a complete cross-cutting control system composed of Delta Electronics' touch screen, PLC and frequency converter has now been applied to medium and low speed corrugated cardboard production lines, and the effect is very ideal. The main features of this system are: (1) Improved production efficiency and high yield; (2) Improved cross-cutting accuracy; (3) Convenient adjustment; (4) Stable operation; (5) Simple operation. 2. Industry Background Currently, there are two types of corrugated paper cross-cutting machines on the market, known in the industry as mechanical cross-cutting machines and computerized cross-cutting machines. Mechanical cross-cutting machines use mechanical linkages to drive different cams to complete the cross-cutting action. The advantage of mechanical cross-cutting machines is their low price. The disadvantage is that when cutting different lengths of cardboard, the length of the linkage must be readjusted each time, which is difficult and affects the cutting accuracy. In addition, due to the limitation of the linkage length, the adjustable range of paper cutting is very small. Computerized cross-cutting machines use microcontrollers, PLCs, or computers to control frequency converters or servo controllers to drive motors, thereby completing the paper cutting function. This type of cross-cutting machine has high production efficiency and a high yield rate, high cutting accuracy, is easy to debug, simple to operate, has a wide cutting range, and a simple mechanical structure, and is therefore widely used. In recent years, some manufacturers in Europe, America, and Taiwan have successively launched servo controllers specifically for corrugated paper cross-cutting, such as Lenze and Kobi from Germany, and Zhengpin from Taiwan. These systems can achieve a cutting accuracy of ±1mm, but they are very expensive, generally 4 to 5 times more expensive than frequency converter systems. Therefore, servo computer cross-cutting machine controllers are generally used on high-speed cross-cutting machines. Some domestic manufacturers also use industrial control computers, PLCs, and microcontrollers to develop their own algorithms to control frequency converters to complete the cross-cutting action. However, these systems are generally used on production lines with speeds below 60m/min, and the cross-cutting accuracy error is relatively large (about ±3mm). Their advantage is that the price is relatively low. At present, most production lines in the domestic market have a speed of around 100m/min, and there is an urgent need for computer cross-cutting machine control systems with performance between these two. This year, Delta Electronics launched the EH type PLC, making this idea a reality. The Delta Electronics EH PLC has a minimum basic instruction processing time of 0.24μs, and its high-speed counting input and output can reach 200kHz, greatly improving the controller's operating speed. The VFD-V type frequency converter, combined with a PG card, makes its performance approach that of a servo. Therefore, I used a cross-cutting control system composed of a Delta Electronics touch screen (DOP-A57GSTD), PLC (DVP-20EH), frequency converter (VFD075V43A), and encoder (ES3-11CG6941), along with a perfect algorithm. This system can be applied to a production line with a speed of 100m/min and an accuracy of ±1.5mm. [b]3 System Structure and Introduction[/b] l Touchscreen: Used for parameter input and control command issuance; l DVP-20EH: The core of the entire system, it processes signals and data and uses high-speed pulse control frequency converter to complete the cross-cutting action; l Cutting point proximity switch: Provides feedback signal when the cutter cuts the cardboard; l Encoder on the wheel blade shaft: Provides feedback signal on the wheel blade position; l Encoder on the measuring wheel: Provides feedback signal on the feeding speed and length; l Zhongda V-series frequency converter drive: Controls the frequency conversion motor, which directly controls the cutter wheel via the reducer; l Paper support roller: Supports the cardboard and measuring wheel. Some manufacturers use paper support rollers to save costs, but the effect is relatively poor; l Feed roller: Driven by a motor, it provides power for the cardboard to move forward and maintains a certain tension on the cardboard; l Output roller: Used for conveying and cutting the cardboard; l Feeding direction is from left to right, the upper cutter rotates counterclockwise, and the lower cutter rotates clockwise. [b]4 Implementation Method of Cross-Cutting Control[/b] First, the special functions of the PLC are utilized. To achieve the cross-cutting function, the PLC's floating-point arithmetic algorithm is essential. Delta Electronics' V5.8 PLC software has powerful floating-point arithmetic capabilities. To perform floating-point arithmetic, the data is first converted to decimal floating-point numbers, and then the decimal floating-point numbers are converted to binary floating-point numbers, thus completing the binary floating-point arithmetic function. The program also utilizes many PLC functions such as high-speed counting interrupt, external interrupt, timer interrupt, pointer register, and high-speed pulse output, all of which are essential functions for this control theory. Taking the upper cutting motion of the rotary cutter as an example, Figure 2 is a schematic diagram of the cutting action. The cutter's movement, as shown in Figure 2, is divided into three zones. The synchronization zone is where the cutter cuts the cardboard; it must maintain the same speed as the cardboard to ensure the cutter neither tears nor clogs the paper, resulting in a clean cut and producing qualified products. The speed of the high-speed return zone is calculated based on the cardboard speed, the cutting length, and the circumference of the rotary cutter. The speed of the deceleration zone must be fixed to ensure consistent cutter stop positions. The size of the three zones must be determined based on the specific machine conditions. The program design must also consider the impact of speed fluctuations and precisely control the cutter position to minimize errors and achieve optimal results. [b]5 Conclusion[/b] This system primarily targets medium- and low-speed corrugated paper production lines. Whether for retrofitting old equipment or integrating new equipment, the demand for cross-cutting machines is substantial. Furthermore, the system integration features of Delta Electronics products (using Delta DVP-EH PLC, Delta VFD-V frequency converter, encoder, and Delta DOP-A HMI) give this system excellent cost-effectiveness and a broad market prospect. [b]References[/b] [1] Delta Electronics. Delta PLC Manual [Z]. [2] Delta Electronics. Delta PLC Manual [Z]. [3] Delta Electronics. Delta Inverter Manual [Z]. About the Author: Zhu Maojian, male, graduated from Qingdao University of Science and Technology in 1993. He is currently the person in charge of Qingdao Shengdawei Automation Co., Ltd., and has rich experience in industry application fields.