Abstract: Emerson tension inverters and programmable logic controllers (PLCs) are used for constant tension winding control on sizing machines to reduce equipment wear and ensure the stability and convenience of winding. I. System Overview The application of Emerson PLCs and inverters on sizing machines utilizes a PLC-based centralized management and distributed control electrical system. This system is centralized, simplified, and highly controllable, significantly reducing the failure rate. The configuration is as follows: The PLC system consists of an Emerson EC202416BAR main module, a 16-point digital input module, and a 4-channel analog output module. The operating interface uses an industrial-grade LCD touchscreen, allowing dynamic modification of control parameters and convenient display of current speed, current bobbin length, bobbin weight, and the system's dynamic operating status. The side shaft motor inverter uses the high-performance, general-purpose EV2000 series, and the warp beam winding inverter is a TD3300 22KW tension inverter. This inverter is a dedicated tension inverter with built-in tension control functionality. Employing an independent frequency conversion mode, this system features a simple structure, convenient maintenance, and high stability, ensuring stable and reliable tension and linear speed during winding, especially when transitioning from small to large rolls. Automatic compensation control during acceleration and deceleration further stabilizes tension, and a winding anti-breakage program facilitates easy operation during start-up. Advantages of this system include: tension setting via a human-machine interface for user-friendly operation; advanced control algorithms such as recursive roll diameter calculation; linear tension increase upon activation of hollow roll diameter; application of tension taper calculation formulas; dynamic torque compensation adjustment, etc.; and real-time, highly accurate roll diameter calculation, ensuring smooth output torque performance of the winding motor. Furthermore, the recursive roll diameter calculation automatically corrects the roll diameter to the correct value in case of operational errors. Because the rotational inertia of the winding device is significant, acceleration, deceleration, stopping, and reactivation by the operator during roll diameter changes can easily cause yarn breakage and loosening, directly impacting yarn quality. After the frequency conversion winding modification, winding is very stable and tension remains constant under all the above conditions. Furthermore, through PLC processing, dynamic adjustment measures are added during specific dynamic processes, resulting in better winding performance. Converting traditional mechanical transmission winding to frequency conversion winding is very simple and inexpensive, requiring virtually no modification to the original machinery. The modification cycle is short, generally two to three days for installation and commissioning. II. System Block Diagram III. Tension Control Principle Tension control, simply put, is the ability to control the force output by the motor, i.e., how many Newtons. This is reflected in the motor shaft, controlling the motor's output torque. True tension control differs from systems that rely on the speed difference between two power points to create tension. Adjusting tension based on speed difference is essentially PID control, requiring a tension sensor. Moreover, adjustments during the start-up, stop, acceleration, deceleration, and parking of rolls of different sizes cannot achieve the same effect as true tension control, resulting in unstable tension. This will definitely affect product quality. The essence of variable frequency drive (VFD) winding is to achieve tension control, that is, to control the motor's operating current, because the output torque of a three-phase asynchronous motor, T = CmφmIa, is proportional to the current. Furthermore, it ensures a relatively stiff mechanical characteristic curve for the motor when there are sudden load changes. Therefore, a vector inverter must be used, and an encoder-based closed-loop control is essential. Constant tension control using an inverter is essentially dead-loop vector control, i.e., with encoder feedback. The winding diameter changes from small to large; to ensure constant tension, the motor's output torque must also change from small to large. Simultaneously, corresponding torque compensation is required during different operating processes. That is, at the instant of starting a small roll, during acceleration, deceleration, and stopping, and when starting a large roll, different torque compensations are needed for different roll diameters. This ensures a stable winding process, avoiding excessive tension with small rolls and loose yarn during large roll starts. The principle of roll diameter calculation : The winding diameter is calculated based on V1 = V2. Because V1 = ω1 × R1, V2 = ω2 × Rx. Because the length of yarn traveled by the measuring roller is equal to the length of yarn received by the winding machine in the same amount of time. That is, L1/Δt=L2/Δt, Δn1×C1=Δn2×C2/i (Δn1——-number of revolutions of the traction motor per unit time, Δn2——-number of revolutions of the winding motor per unit time, C1——-circumference of the measuring roller, C2——-circumference of the winding head, i——-reduction ratio). Δn1×π×D1=Δn2×π×D2/i, D2=Δn1×D1×i/Δn2, because Δn2=ΔP2/P2 (ΔP2——-number of pulses generated by the winding encoder, P2——-number of revolutions of the winding encoder). Δn1=ΔP1/P1. Taking Δn1=1, that is, the measuring roller rotates once, and the encoder is connected to the PLC. Then D2=D1×i×P2/ΔP2, thus the diameter of the winding head is obtained. Dynamic Process Analysis of Winding To ensure the smoothness of the winding process, maintaining constant tension regardless of the size of the roll, acceleration, deceleration, activation, or stopping, torque compensation is necessary. For the entire system to activate, it must first overcome the torque generated by static friction, referred to as static friction torque, which only acts at the moment of activation. During normal operation, it must overcome the sliding friction torque generated by sliding friction, which exists continuously throughout operation and differs in magnitude at low and high speeds. Different amounts of compensation are required. During acceleration, deceleration, and stopping, corresponding torque compensation is also necessary to overcome the system's inertia, and the amount of compensation is proportional to the operating speed. The compensation coefficient differs at different speeds. These include acceleration torque, deceleration torque, stopping torque, and activation torque. After overcoming these factors, the load torque must also be overcome. This is calculated by dividing the real-time roll diameter by 2 and multiplying by the set tension, then converting the result to the motor shaft through the reduction ratio. This analysis reveals the torque compensation process throughout the entire winding process. Summary: The output torque of the motor = static friction torque (at the moment of activation) + sliding friction torque + load torque. Torque compensation standard 1) Compensation of static friction torque Because static friction torque only exists at the moment of activation and disappears after the system is activated. Therefore, the compensation of static friction torque is to compensate by multiplying the calculated output torque of the motor by a certain percentage. 2) Compensation of sliding friction torque The compensation of sliding friction torque is effective throughout the entire process of system operation. The compensation is based on the rated torque of the winding motor. The amount of compensation is related to the running speed. Therefore, when processing in the program, it is necessary to perform compensation in segments. 3) Compensation of acceleration, deceleration and stopping torque The compensation is based on the rated torque of the winding motor. The corresponding compensation coefficient should be relatively stable and not change much. Related calculation formulas [align=center] [/align] IV. Debugging process (1) First, perform self-tuning on the motor and read the stator inductance, stator resistance and other parameters of the motor into the frequency converter. (2) Connect the encoder signal to the frequency converter and set the number of encoder revolutions on the frequency converter. Then, use the panel to set the frequency and start/stop control, and observe whether the displayed operating frequency fluctuates around the set frequency. Because when using closed-loop vector control, the operating frequency is always close to the set frequency, so the operating frequency fluctuates around the set frequency. (3) Set the values ​​of the hollow core diameter and the maximum diameter in the program. Calculate the maximum pulse quantity (P2) and minimum pulse quantity (P2) generated by the encoder added to the motor tail using the formula for calculating the diameter above. Limit the speed of the winding motor by calculating the maximum pulse quantity, because if the maximum speed is not limited when the frequency converter is used for tension control, the winding motor will run away if there is a yarn breakage or other situation. The minimum pulse quantity is to avoid the winding frequency converter from running below 2Hz, because when the frequency converter runs below 2Hz, the torque characteristics of the motor are very poor and there will be a shaking phenomenon. (4) Through the dynamic process of the entire winding analyzed above, perform certain torque compensation at each stage of different diameters and different operating speeds. The compensation is set as a percentage of the rated torque of the motor. V. Parameter Summary Table Appendix 1: TD3300 Functional Parameter Summary Table [align=center] [/align] Conclusion: With increasingly rapid technological updates, we must improve product performance to ensure our products meet our process requirements.