Abstract : A novel refiner control system based on the S7-200 was designed based on the working characteristics of the refiner. This system uses a PLC as its core, integrating a power transmitter and a frequency converter. It applies expert control principles to the control of the refiner's blade advance and retraction, and combines a self-learning algorithm to automatically correct inappropriate input/output quantization values. This results in advantages such as fast adjustment speed, short transition time, and small overshoot, enabling more accurate control of the refiner's blade advance and retraction displacement. The system exhibits high stability and rapid dynamic response, achieving smooth and precise control of the pulping process while significantly improving the reliability and safety of the control system, thus achieving the goals of high-quality, low-consumption, and automatic control. Keywords : Refiner; Expert control; Protection measures; Self-learning; S7-200 Improving the control performance and self-protection capabilities of refiners is a current hot topic for enterprises. This paper introduces a novel refiner control system based on the S7-200, based on the implementation of a refiner control project in a paper equipment plant. This system is specifically designed to support a dual-disc refiner manufactured by a certain company. It uses a PLC as its core, combined with a power transmitter and frequency converter, to implement process control of the dual-disc refiner. It features high stability and rapid dynamic response, enabling smooth and precise control of the pulping process while improving the refiner's control performance and self-protection capabilities, thus enhancing the reliability and safety of the control system. 1. New Control Process and Principle The overall structure of the system is shown in Figure 1. The main process actions are as follows: Before starting the main unit, the hydraulic pump motor is first started to ensure that the grinding chamber is flushed with water before pulp is introduced, providing pulp pressure for normal system operation. Next, the main unit starts, rapidly advancing the blade from the standby stop position to the designated position, and then slowly advancing to the normal operating position. Depending on specific work requirements, pulp can be cut off first, and then the blade can be manually or automatically retracted to the stop position. After normal blade retraction, the system will prompt whether flushing with water is required. Once flushing is confirmed, the entire machine can be stopped. In special circumstances, an emergency stop can be initiated first, and after safe blade retraction, the hydraulic pump can be stopped. [b][align=center]For details, please click: Design of a New Pulping Machine Control System Based on S7-200[/align][/b]