Abstract : This paper describes the addition of two cooling cylinders to the original BC coating machine, and details the use of AB PLC, AB frequency converter, electronic tracker, pressure sensor, transmitter, AC motor, speedometer, electronic sensor head, etc. to form a closed-loop control system. Keywords : BC coating machine; electrical control system; cooling cylinder mechanical diagram; AB PLC ladder diagram 1 Problem The BC coating machine was manufactured in the United States in the mid-1980s. It was introduced to two state-owned enterprises in Ningxia and Hebei in the 1990s, and acquired by Guangxi Tiansheng Paper Industry Co., Ltd. in 2005. The disadvantage of this machine is that the carbonless copy paper it produces is somewhat rough and wrinkled, requiring modification. 2 System The BC coating machine is mainly used to process base paper to produce carbonless copy paper. The paper feeder and receiver are designed with PLC automatic paper receiving, saving time and labor. DC drive systems are characterized by smooth control and powerful functions. ABB's PLCs and frequency converters are also powerful, reliable, easy to learn, and capable of controlling complex logic functions. 3. Modification (1) Before the modification, the coating machine's process flow was: paper feeder - pressing shaft - oven, calendering roller, heating cylinder - paper take-up machine. When the machine speed at each stage was 300m/5, roughness and wrinkles appeared. The reason was that there were problems in the heating cylinder and paper take-up machine stages. Because the paper was directly wound up after passing through the heating cylinder without being cooled, it was easy to cause roughness and wrinkles after cooling. Adding two cooling cylinders between the heating cylinder and the paper take-up machine to cool the paper can solve this problem. [b][align=center]For details, please click: Adding two cooling cylinders to the American BC coating machine and its electrical control[/align][/b]