Distributed Microprocessors Applied in Steel Bar Rolling Mills

The electrical control system of a 10-stand steel bar rolling mill has been modernized effectively using a new concept in the application of microprocessors. A three-level control hierarchy was installed which uses a high degree of commonality of hardware and software for levels I, II, and III of the system. The microcomputer system resulted in fast dynamic response of motor drive regulators, storage of mill setup tables, automatic calculation and presetting of mill stand and auxiliary motor speeds, and a variety of control functions. Programmed logic sequences and fault reporting were included in the same microprocessors used for dc motor speed regulation. Since these functions were combined in individual microcomputers distributed throughout the system (one per motor drive) each could be commissioned separately, simplifying and speeding the startup.