Abstract: This paper introduces the mechanical structure of the ASFA306 drawing machine, analyzes the process requirements of the drawing machine control system, and designs a control system based on a programmable logic controller (PLC), frequency converter, and human-machine interface (HMI), which improves the reliability of the control system. The variable frequency speed regulation ensures smooth start-up and convenient speed adjustment. A touch screen is used to realize human-machine interaction and has a fault display function, which facilitates rapid troubleshooting and improves machine uptime. Keywords: drawing machine; programmable logic controller; frequency converter; human-machine interface [b][align=center]The application of PLC in the control system of ASFA306 type drawing machine ZHU Long·biao' , WANG Chang·guo, ZHANG Xing·guo' (1. Mechanical Engineering College of Nantong University, Nantong 226007, China; 2. Haian Textile Machinery Co, LTD, Nantong, 226007, China)[/align][/b] The control system is composed of PLC, transducer, and man-machine interface. In this way, the reliability of the control system is greatly improved. The transducer has the peculiarities of starting stabilization and timing convenience. Using the interface realizes man-machine communication. The function of malfunction display is favorable to eliminate the error rapidly. More, it can increase the application of the machine. Key words : drawing machine; PLC; transducer; man-machine interface 0 Overview Drawing is one of the key processes in cotton spinning production. The quality of drawing directly affects the quality of yarn. The main tasks of drawing are threefold: (1) to improve the uniformity of long segments and fully mix the fibers; (2) to lengthen and thin the sliver and improve the internal structure of the sliver; (3) to package and form the yarn, which is convenient for subsequent processing... The drawing frame is the production equipment that completes this process. The developed ASFA306 drawing frame inherits the features of the FA306 model, designed for 2-eye output, with an output speed of 148-600 m/min and a total draft ratio of 4.18-13.5. The drawing frame control system utilizes a programmable logic controller (PLC), a widely adopted and advanced technology in the current control field. Frequency converter technology is used to adjust the output speed, and a touchscreen technology is used for human-machine interaction. This model of drawing frame is suitable for pure and blended spinning of cotton, cotton-type synthetic fibers, and medium-length fibers with a diameter of 20-76 mm. High-quality slivers can be obtained for all yarn types at the end of the drawing process. [b][align=center]For more details, please click: Application of PLC in the ASFA306 Drawing Frame System[/align][/b]