Enhancement of product quality and production system reliability by continuous performance assessment of automation systems

Novel strategies and systems have been developed and tailored for the performance assessment of control loops in steel processing plants. The methods have been implemented, adapted and applied to a complex structured temperature control and a zinc layer thickness control at hot-dip galvanising lines. The control performance tools created for both applications are integrated into the mill infrastructure and allow the responsible personnel to do performance analysis on demand. Retuning suggestions have been implemented for temperature control, and results show a remarkably improved control performance, also identified by the performance indices. A system for performance supervision of the different functions of automatic gauge control has been developed and installed in a hot strip mill. The system is now well proven as a powerful and useful tool to contribute to the maintainability of the hot strip mill AGC system. A powerful, friendly and configurable user graphical interface makes the results very easy to understand and permits the configuration of the supervisory system and the creation of specific user-defined analysis. A supervision system for continuous monitoring of the set-up system in a hot strip mill has been developed. The system is integrated in the process control architecture and analyses the trend/behaviour of the most relevant mill set-up model parameters, detecting inconsistencies and suggesting suitable countermeasures to technicians. The supervision system is entered via an intranet address allowing easy sharing of information elaborated. The application proved to be useful for 'model basic updates', thus improving rolling stability and performance.