Abstract : This paper analyzes the control process of a rewinder, proposes a strategy for controlling the rewinder using PLC and vector frequency converter, and describes the programming method for implementing this control. Keywords : Rewinder; PLC; Vector frequency converter; Functional module; Mathematical model The rewinder is an important piece of equipment in the paper production line. The production efficiency and quality of the rewinder directly affect the output and benefits of the entire paper mill. Our factory's original rewinder control used an early Siemens relay control and DC drive system. Due to the outdated system, several important analog control parameters experienced significant drift, resulting in low control accuracy, numerous faults, and extremely difficult maintenance. Furthermore, since the original maximum speed was only 400 m/min, when the paper machine speed increased to 350 m/min, the rewinder's speed could not keep up with production, seriously affecting normal production. Therefore, we improved the system by replacing the original early relay control with a new PLC control system and replacing the original DC control with a Siemens AC vector frequency converter. After improvements, our 4.26m rewinder can operate smoothly at a speed of 800m·min, and the main control parameters all meet production requirements. I. Analysis of the Rewinder System The rewinder mainly consists of two parts: the front winding mechanism and the rear unwinding frame. Its schematic diagram is shown in Figure 1. [b][align=center]For details, please click: S7-300 for Rewinder Control[/align][/b]