Control system of largescale screw polishing machine based on PLC

MA Cai-yun, LI Zhen-hua, HU Jia-wen

(School of Ship and Ocean Engineering, Zhejiang Ocean University, Zhoushan 316000, China)

Abstract: Aiming at the problems of low automation degree, high labor costs, low polishing efficiency, difficult polishing and no-failure warning for large-scale screw polishing machine, programmable logic controller (PLC) technology and human-machine interface were used on the control system of the machine. After the analysis of the rotational speed of large-scale screw and movement speed of polishing belt, the relationship of the rotational speed of two motors was established. It was proposed that adjusting the initial position of the large screw in dynamic regulation, detecting the position of the abrasive belt with a limit switch, and detecting the operating temperature of the motor by the temperature sensor. The overall block diagram, flow chart and an electrical schematic diagram of the control system were given. Moreover, control software for the system was developed. The results indicate that, the control system can solve the problems of difficult polishing and low efficiency for traditional large-scale screw. The interface of the control system gets the advantages of simple and easy to operation. The introduction of sound and light alarms is convenient for discovering and maintaining troubles of motor, and improves safety performance of the system.

Key words: polishing machine; PLC; control system; largescale screw; auto-alarm