Please choose your delivery country and your customer group
Theoretical factors influencing the application of distributed control systems are highlighted by a post-project technical audit of a recent design/build contract to develop machine control, instrumentation, and information management systems for 20 highly automated stamping press lines. Originally conceived as a classical centralized design in a single programmable logic controller, changing requirements forced the decentralization of functions into additional PLC's, smart modules, and a real time computer system. The results of the technical audit reinforced some theoretical concepts and provided new insights into the practical limitations of others. The final design encompassed more than 6200 I/O points and 640 K memory divided between the two main PLC's; an array of coprocessing hardware modules for machine control and diagnostics, 3 dedicated PLC's for high speed decoding, timing, and synchronization functions; and a real-time microprocessor-based color graphics system for concentration, analysis, and tracking of setup, operations and performance data. Revised guidelines for the application of distributed control systems to industrial process machinery are presented.