Development of human-machine interface for automatic control of electro-slag remelting process

This paper describes the developmental study of HMI (human-machine interface) for a user-friendly automatic control system for the ESR process running in Changwon Specialty Steel in South Korea. ESR is a second-phase refining process, commonly applied to production of high purity specialty steel like high-speed tool steels. Because the current ESR system is fully manually operated for five hours, (1) the working condition is very hard, (2) the product quality varies according to time, product and worker, and (3) there is no standard control scheme especially in the transient stage of the start up and the ending hot top phases. Therefore, the main objective of this research is to develop a user-friendly automatic control system with human machine interface for unmanned operation. For this purpose, a melt rate measurement system is developed; real process variables are measured and analyzed; a standard control scheme is developed utilizing the expertise of experienced workers; a human machine interface system is developed utilizing graphical user interface; H/W and S/W is developed for integrated process control; and finally based upon a series of experiments the results are discussed. With this enhanced system, the workers can standardize their individual work knowledge and reach the optimum control pattern of their own as their work experiences accumulate.