With the development of processing paper production technology and the updating of coating processing paper equipment, the detection and control of the paper tension running between the production equipment during the coating production process is an important technical measure to improve product quality and output. The coating machine is a device that coats the raw materials (paper, cloth, plastic, etc.) with a layer of selected paint (adhesive, ink, etc.), and then dries it, and then winds it up. In the whole process, it is divided into several processes: unwinding, intermediate multi-level synchronous control and winding. The paper tension is required to be constant during the working process, that is, the linear speed is constant.