With the discontinuation of the VLT5000 and the commencement of full-scale sales of the FC300, the development of the FC300 product is nearing completion, and its functions are becoming increasingly comprehensive. This article mainly introduces the center winding function of the FC300 and some debugging experiences. I. Center Winding Functions: As shown in the diagram above, center winding control consists of three main parts: tension setpoint processing—tension control can change with the roll diameter; diameter calculation function; and tension PID control. Basic characteristics of center winding: Tension control refresh time is 10-30 ms. Tension setpoint ramp function. Tension control taper function and tension limit alarm. Multi-material tension PID parameter set. Speed ​​PID P-value adjustment. Acceleration compensation function. Roll diameter arrival indication. Multiple initial roll diameter selections and roll diameter measurement. Roll diameter calculation limit—the rate of change in roll diameter calculation is adjustable. Limitation when the roll diameter calculation direction is incorrect. 1. Tension Setting Processing: Tension setting processing, also known as taper control, aims to ensure consistent tension inside and outside the roll during winding, preventing roll deformation during storage, as the diameter changes. The relationship between tension setting and roll diameter is hyperbolic, not linear. 2. Tension Unit: As seen above, the actual PID setpoint is after considering the taper function. Par-194 is a crucial parameter with a significant impact on the tension system. 3. Diameter Calculation Function: Diameter calculation is based on D = line speed / winder speed × core1. Multiple initial roll diameters are selectable. After the roll diameter is reset, the effective roll diameter value is the first initial roll diameter. The calculated roll diameter value remains constant when the machine is powered on; after power failure and subsequent power-on, it is the same as the reset roll diameter. 4. Overall Block Diagram: The center winding also features manual forward and reverse adjustment. The inverter's overall setpoint is the speed setpoint corresponding to the roll diameter plus the PID adjustment. II. Several Important Parameters : 1. Three parameters related to roll diameter calculation: 1924—Line Speed ​​Scale: This parameter is a coefficient that measures the maximum linear speed relative to the given linear speed pulse. Its meaning is that when the linear speed encoder's lines per revolution are fixed, and the machine operates at its maximum linear speed, the linear speed value for roll diameter calculation is 100,000. It can be obtained using the following formula: 1926—Winder Speed ​​Scale: Similar to 1924, this parameter is adjusted to make the motor speed value in the roll diameter calculation unit 100,000 when the roll diameter is at its minimum, i.e., the motor speed is at its maximum, and the encoder's lines per revolution reflecting the motor speed are fixed. This parameter can also be obtained using the following formula: 1925—Speed ​​Match Scale: This parameter determines the speed at which the motor should operate when the roll diameter is at its minimum, when the given linear speed is at its maximum. This parameter is related to the mechanical transmission ratio, the PID adjustment amount, and the inverter's maximum speed setting. Several factors need to be considered: When the roll diameter is at its minimum, the motor should operate at its maximum linear speed based on the mechanical parameters. This speed is generally 90% of the maximum motor speed set by the inverter (parameter 3-03), meaning the maximum adjustment amount left for the PID is 10% of the maximum motor speed. It should also be noted that parameter 1940 (PID output limit) should be set to a maximum of 16384 x 10%. 2; Several parameters related to PID control require special attention: 1941—PID effect verses diameter: This parameter determines the PID P value corresponding to the roll diameter change. When the roll diameter is large, the PID adjustment amount will be smaller when the tension changes and speed needs to be adjusted compared to when the roll diameter is small, requiring a smaller P value. Conversely, when the roll diameter is small, a larger PID adjustment amount is needed. The following diagram illustrates this relationship visually: 1930 line speed acceleration feed forward: This parameter is used to compensate for tension fluctuations caused by changes in linear speed. When the linear speed changes rapidly, if the PID adjustment function is insufficient to maintain tension stability, this function can be considered. The principle is to superimpose a speed adjustment amount related to the linear speed change onto the PID output. Practice has proven that this function can effectively compensate for this. The P-values ​​of the speed loop PID corresponding to large and small rolls (1948 and 1949): These two parameters are the P-values ​​of the speed PID corresponding to empty and full rolls, respectively, when the motor control mode is speed closed-loop. These values ​​should be determined at the beginning of commissioning using the MCT10 oscilloscope function or the PID debugging interface of the synchronous control card, respectively, with empty and full rolls. The accuracy of these values ​​directly affects the tension stability during large and small rolls. These two parameters can be used in conjunction with 1941. The settings of other winding-related parameters are the same as the debugging settings of the frequency converter in non-winding control (such as motor parameter settings, AMA, closed-loop speed settings, etc.), and will not be elaborated further. Through the commissioning practice of some projects, it has been proven that the FC300's winding control function is relatively complete, has good performance, and high reliability, making it worthy of promotion and application.