With the widespread application of technologies such as variable frequency speed regulation, servo control, PLC control, and pneumatic control in industrial fields, their excellent control performance and reliability provide a reliable guarantee for the automation of packaging systems. Packaging is the final critical process in wire and cable production, and the structure of its winding system directly affects product quality. Traditional packaging of small wires such as BV, BVR, and RV typically uses a horizontal winding and laying system. The winding speed is adjusted using a slip differential speed regulator or a torque-controlled motor, and the laying mechanism uses a smooth rod or a lead screw driven by a winding motor. The wound wires are then manually cut, removed from a fixed coil, and tied with straps. This results in a loosely packaged product with messy wire arrangement and an unattractive appearance. Furthermore, this packaging method is not suitable for automated production lines. With the widespread application of technologies such as variable frequency speed regulation, servo control, PLC control, and pneumatic control in industrial fields, their excellent control performance and reliability provide a reliable guarantee for the automation of packaging systems. Design Concept Since automating the unwinding process using a horizontal winding and unwinding system is relatively difficult, a vertical winding and unwinding system is adopted based on the production process and control factors. A frequency converter is used to achieve automatic unwinding and packaging, while a PLC controls the coordinated operation of the above systems. A touch screen monitors the operation of the entire equipment, thus achieving automation of the entire process from winding to unwinding and packaging. Manual control functions are added to each stage to facilitate operation, adjustment, and emergency handling. Control System Composition 1. Hardware Composition of the Control System The control system consists of a PLC, touch screen, winding speed control system, winding system, unwinding mechanism, meter counting device, cable ties, fault alarm, etc. (1) PLC Hardware Configuration and I/O Allocation The core component of the control system, the PLC, adopts the Mitsubishi FX2N-48MT programmable controller. This model of PLC has 8KB of memory, a 32-bit CPU, and multiple built-in high-speed bidirectional counters. It can capture pulses of more than 20μs and can simultaneously and accurately capture the main motor speed pulse signal and the length pulse signal of the meter counting device. Its instruction system is rich. In addition to logic, arithmetic, timing, and stepping functions, its unique pulse output function can directly control the speed of the servo system without other auxiliary components. This model of PLC has 24 input and output points and is equipped with a 16-point expansion module, model Fx2N-16Ex. [align=center] Figure 1 Hardware Composition Diagram[/align] (2) Rewinding Speed ​​Control System The rewinding speed control system mainly consists of a frequency converter, a motor, and a wire storage position detection. The speed of rewinding depends on the speed setpoint and the feedback of the wire storage position. Therefore, the selected frequency converter must have at least one input terminal that can simultaneously input two frequency signals. By comparison, the Mitsubishi FR-A540 series inverter with advanced flux vector control was selected. It has three frequency setting input terminals, which can realize the superposition of the given signal and the feedback signal. At the same time, the Mitsubishi FR-A540 series inverter adopts the "soft-PWM" switching method, which can reduce operating noise and reduce external radio frequency interference, which is conducive to the reliable operation of PLC, servo controller and rotary encoder in the system. Its built-in braking unit can achieve fast stopping with an external braking resistor, ensuring the accuracy of meter length. The parameter copying function can copy the parameters from one inverter to another, which is extremely convenient when setting parameters of multiple inverters. The wiring diagram of the control system is shown in Figure 2. [align=center] Figure 2 Wiring diagram of the winding system[/align] (3) The main disadvantages of using bare rod wiring system are as follows: ① Due to the small width of the wiring, the reversal is very frequent, and the inertia of the bare rod wiring mechanism can easily cause the wiring to be uneven. ② The starting point and ending point of the wiring are difficult to control. ③ The fine adjustment of the wiring pitch is difficult to control. To overcome the shortcomings of bare rod wiring, a servo control system with a ball screw wiring mechanism is adopted. The servo motor has the advantages of fast response speed and high control accuracy. At the same time, the inertia of the ball screw is extremely small, which can ensure that the wires are neatly arranged when the wiring is reversed. Considering that the PLC is Mitsubishi FX2N-48MT, for convenient control, Mitsubishi servo controllers and servo motors of models MR-J2S-40A and HC-KFS43 are selected, and a ball screw with a feed rate of 5 mm is selected according to the size of the wiring pitch. At the same time, a rotary encoder is installed on the winding shaft to collect the winding speed signal to ensure that the wiring speed is synchronized with the winding speed. The wiring is shown in Figure 3. [align=center] Figure 3 Wiring diagram of wiring system[/align] (4) Unloading mechanism Unloading is a key step in realizing an automated production line. The process includes seven processes: clamping, holding, cutting, core extension and retraction, pushing rod, feeding, and transmission. A pneumatic control system composed of solenoid valves and cylinders is used to control the actuators of the above processes. Solenoid valves and cylinders are selected from cost-effective Airtac products. At the same time, magnetic switches are used to detect the movement of the cylinders and feed the piston position signal back to the PLC. (5) Cable tie device If the wound wire is not tied immediately after it is unwound, the wire is easy to come loose. To solve this problem, a cable tie device is installed at the unwound end. After the cable tie device detects the cable tie signal, it automatically ties a PP tape in the middle of the wire to ensure that the wire will not come loose during transmission. (6) Meter counting device The meter counting device is mainly composed of a meter counting wheel and a rotary encoder. A rotary encoder with model OVW2-006-2MHL from NEMICON and a pulse count of 60 is used to collect the meter counting signal to achieve precise control of the winding length. (7) Monitoring system The monitoring system uses a Digital Proface GP series touch screen. Programming is performed using GP-PRO/PBⅢV5.05 software. This software, produced by Digital, is a human-machine interface application configuration software for GP series touch screens. It has the advantages of being easy to use and configure, and has powerful network communication functions. As long as the PLC type and communication parameters are set during configuration, and the correct PLC bit address or word address is set in the control properties of the monitoring screen, the touch screen can establish a connection and communication with the PLC's internal address according to the communication protocol of different PLCs when it is working. Software Design 1. PLC Programming Programming uses the MELSECMEDOC professional software package, which is based on a personal computer and is suitable for user program compilation and monitoring of Mitsubishi PLCs. It is connected to the PLC programming port through the SC-09RS232/RS422 interface and can be programmed using ladder diagrams or instructions. The PLC program of this system is divided into 6 modules according to function: winding module, cable laying module, meter counting module, offline transmission module, HMI communication module, and alarm processing module. 1) The winding module controls the start, stop, and speed conversion of the frequency converter according to the operation status of the previous process in the production line and the winding length. 2) The cable laying module calculates the number of pulses sent to the servo controller per unit time based on parameters such as winding speed, cable pitch, and cable width, achieving synchronization between the cable laying speed and winding speed. 3) The meter counting module calculates the length of a single pulse based on the number of pulses from the rotary encoder and the circumference of the meter counting wheel, and corrects the circumference of the meter counting wheel via the touch screen to ensure that the winding length error is controlled within 0.3%. Simultaneously, it sends a deceleration or stop signal when the winding length reaches the set length. 4) The unwinding and transmission module completes processes such as clamping, holding, cutting, reel extension/retraction, push rod, feeding, and transmission according to the unwinding command. Its flowchart is shown in Figure 4. [align=center] Figure 4 Unwinding Action Flowchart[/align] 5) The HMI communication module is mainly used in conjunction with the touch screen to set and manage parameters such as cable gauge, cable pitch, cable width, meter counting wheel circumference, and winding length. 6) The alarm handling module's main function is to output alarm signals when the frequency converter or servo controller malfunctions during the winding process, or when the unwinding mechanism or cable tie device triggers an alarm during execution, prompting operators to handle the situation promptly. 2. The human-machine interface software design includes seven screens: system main flowchart, operating status display, parameter settings, jog operation, cylinder status, fault information, alarm screen, and operation instructions. The operating status display screen shows various parameters and operating conditions of the equipment. The parameter settings screen allows users to access parameters such as the thread pitch and thread width of various packaging specifications set in the formula control, or to set parameters manually. In the stopped state, jog operation can be performed on each mechanism via the jog operation screen. The fault information screen displays the information from the previous 10 faults. For newly occurring faults, the alarm screen will automatically display the alarm content and issue an audible and visual alarm to alert the operator. To ensure system operation security, three user levels are set in the human-machine interface, with user login and password confirmation determining operating permissions. Level 0 is for operators, no password is required, and they can set and modify their own operating parameters and view the output of the current shift or the current month. Level 1 is for production management personnel, who can enter the process screen and modify the process flow. Level 2 is for electrical engineers to debug and diagnose, who can set and modify various parameters in the speed calculation formula in the PLC, directly display the working status of each sensor and relay, and provide a basis for fault diagnosis. System debugging (1) Calculation of electronic gear of servo controller Electronic gear refers to the input multiplier. For the input pulse, it can be multiplied by any multiplier to make the machine run. For the ball screw, the calculation formula is as follows: CMX/CDV=△LP/(nP[sub]b[/sub]) Where, △L represents the feed amount corresponding to each pulse; P represents the servo motor encoder resolution; z represents the reduction ratio; P[sub]b[/sub] represents the ball screw feed amount. (2) Parameter setting of frequency converter and servo controller 1) Parameter setting of frequency converter Set the input terminal according to the input signal, and adjust the parameters such as the highest frequency, the speed reduction frequency and the lower limit frequency according to the operation. 2) The parameters of the servo controller can be set through Mitsubishi SETUP SOFTWARE software. (3) Matching of winding speed feedback: According to the given signal, adjust the position feedback signal to ensure that the winding speed is zero when the wire storage reaches a certain level, so as to avoid the wire breaking during winding. (4) Tension adjustment of cable tie device: According to the outer dimensions of the wound wire, adjust the cable tie tension plate to avoid cable tie deformation or excessive looseness. Conclusion: This system, when matched with the original φ0 mm extruder, forms a production line, which greatly reduces the labor intensity of operators, improves production efficiency, and reduces the occurrence of wire breakage. At the same time, the packaged wires are neatly arranged, have a compact structure, and a smaller volume, which greatly improves the appearance of the finished product and avoids deformation, loose wires, and tangled wires during transportation, storage, and sales. It has been well received by users.