Li Wei, Electromechanical Business Department, Shanghai Branch of Delta Electronics Co., Ltd. With the enrichment and improvement of Delta's electromechanical product categories, its automation engineering integration capabilities, providing overall solutions for production and manufacturing equipment, have shown diversified technological advantages. This article introduces the integrated application of Delta products in the rubber and plastic cable production line, showcasing the versatile customer service features of single-platform automation technology. 1 Introduction Over the past 20 years, the rubber and plastic cable machinery industry, like other industries, has developed rapidly. In the market competition after China's accession to the WTO, the rubber and plastic machinery industry faces severe challenges. Improving the automation technology level of rubber and plastic production equipment can effectively enhance the industry's overall strength. 2 Process Flow The wire enters the unwinding equipment. Under tension control, it passes through the pre-forming roller frame and is heated. The rubber material extruded by the extruder covers the outer sheath. The wire covered with the rubber sheath enters the main speed traction device of the production line. After high-temperature vulcanization, the production speed is controlled by a frequency converter, and then it enters the post-processing stage via crawler auxiliary traction. In the core wire breaking and forming process device, tension is detected by a tension frame as tension feedback. The speed is given by the main speed control, and the wire is fed at a uniform speed and constant tension. After being controlled by a meter counter, it is cut and formed. Throughout the production line, the main traction and auxiliary traction control systems operate in speed mode: including high-temperature treatment, microwave vulcanization, and post-heating speeds, they are synchronized in series; and each stage is required to be fine-tuned and the subsequent stages to be synchronously adjusted. The steel strip feeding and forming control system operates in constant torque mode. Torque fluctuations caused by speed changes are controlled by the torque control system, working together to ensure constant speed and tension. 3. Configuration Design Based on Delta Electromechanical Products The system architecture consists of Delta Electromechanical products forming the core automation technology platform, as shown in Figure 1. The configuration table is shown in Table 1. [IMG=Figure 1 Automation System Architecture]/uploadpic/news/2007/11/2007111314144959397F.jpg[/IMG] Figure 1 Automation System Architecture [IMG=Table 1 Automation System Configuration Table]/uploadpic/news/2007/11/2007111314150098212Z.jpg[/IMG] Table 1 Automation System Configuration Table Note: The interface program on the DOP-AE57CSTD HMI must also be present on the other two DOP-AE10THTDs, meaning that the DOP-AE10THTD can control the DVP12SA11R. However, the interface program on the DOP-AE10THTD does not need to be present on the DOP-A57CSTD, meaning that the DOP-AE10THTD does not control the EH PLC. 4. Overall Solution Based on Delta Electromechanical Products 4.1 One Machine, Multiple Screens Due to the long length of this production line, the customer needs to install HMIs at different locations along the line to operate and monitor the equipment without having to walk long distances. Based on this requirement, communication between HMIs is essential, which is what we commonly refer to as "master-slave" control. A key feature of Delta HMIs is their three communication ports, two of which can be freely configured with RS232, RS485, and RS422, and each port is independent. This allows communication to be achieved using one communication port of each HMI (in this example, COM3 of the HMI is set to RS485 communication format 7 E 1 9600). The master communication protocol uses MODBUS MASTER, while the slave uses MODBUS SLAVE. Data exchange between HMIs must be implemented using macro programs. 4.2 Communication Slave Station To meet the high-speed communication requirements of the system's frequency converter and temperature controller, two 10.4-inch HMIs communicate with two EH PLCs via two additional communication ports (COM1 and COM2). One might ask, as mentioned above, wouldn't a single machine with multiple screens achieve the same result? Why go through this extra step? The reason is that during actual debugging, I found that using macro programs for multi-screen communication, especially with large amounts of data exchanged between the HMIs via macro programs, was insufficient to meet the very high communication speed requirements due to the limited processing speed of the HMIs and baud rate limitations. Therefore, I installed a DVP-F485 card (which can only act as a slave station) on the PLC, enabling one PLC to communicate with two touchscreens. This allows me to communicate directly with the two PLCs without going through the HMIs for communication with the frequency converter and temperature controller, thus solving the slow communication problem. 4.3 EASYLINK Communication Due to the large number of inverters and temperature controllers requiring communication and high timeliness, the EASYLINK function of the Delta PLC was adopted. The advantage of this function is that the communication program is pre-written at the lower level, eliminating the need for you to write complex communication programs yourself. You only need to set the corresponding special registers, which is convenient, reliable, and fast. For details on the EASYLINK function, please refer to the Delta PLC programming manual. 4.4 Inverter Synchronization The entire production line controls eight inverters, with the frequency of each inverter controlling a single production line in seven segments. The convenience of Delta's communication technology is utilized. The inverter frequency is read anytime, anywhere via communication. If a change in the frequency of one inverter is detected, the subsequent inverters will adjust accordingly based on a certain ratio to handle the synchronization of the four speed segments and control the tension. When the frequency of one of the eight inverters is changed (through analog input or main frequency/proportional setting), the subsequent inverters will automatically adjust their frequencies according to the above relationship to ensure synchronization. Furthermore, when two or more frequency converters are simultaneously fine-tuned via analog signals or their proportional or main speed settings are changed via HMI, the first one must be used as the reference, and any subsequent frequency adjustments must be masked. For example, if two operators simultaneously adjust the analog signals of a second and third frequency converter for frequency fine-tuning, the frequency adjustment value should be based on the second converter. The frequency value is set by the main frequency and the analog auxiliary frequency. Since the timing of changes to the analog auxiliary frequency is unpredictable on-site, the program must read the frequency constantly to understand the frequency changes of the frequency converters. After reading the frequency, the program must calculate the proportional value based on the frequency changes and automatically write the calculated frequency value to the corresponding frequency converter via communication. Because the frequency is read constantly, and the frequency input has two sources, the challenge lies in determining when to send the written comparison value to the register and then compare this frequency value with the read frequency as a reference value. The following approach was used to write the program, and the customer was satisfied with the debugging results. Initially, we considered using 04AD+04DA, which would simplify programming. However, the customer's production line was too long (50-60 meters), and the analog signals for fine-tuning had to be close to each workstation. The customer's wiring was in poor condition, resulting in significant attenuation and interference on such a long line. Communication was a better option, so we opted for a completely communication-based approach to meet the customer's synchronization requirements. This made programming more complex, especially regarding when to provide the comparison value and how to shield the frequency variations of downstream units. 4.5 PID Function: This PID function is mainly used for controlling microwave heating. I improved the algorithm for variable-speed integral and integral saturation limiting, resulting in very small overshoot and high stability during control. 5 Conclusion Generally, the difficulty of overall solutions lies in how to form an efficient and stable network based on equipment process requirements, enabling effective communication between electrical products. This case study provides an in-depth analysis and design method for communication issues in automation system integration projects. Based on Delta's single automation platform, the solution offers engineering advantages for achieving seamless integration of system communication, compared to the often difficult integration challenges of heterogeneous automation platforms. (Proceedings of the 2nd and 3rd Servo and Motion Control Forums)