Adaptive Controller Simulated Process Results: Foxboro EXACT and ASEA Novatune

Mill test results are essential for demonstrating the control capability of adaptive controllers. However, the disadvantages of directly applying these devices to a mill process is that it is difficult, if not impossible, to test two different controllers under exactly identical mill process conditions. Simulations of a few generic processes added substantially to the understanding of how the Foxboro and the ASEA controllers work. Three models were used: 1) linear analog third-order; 2) nonlinear digital, as exhibited by a tank outflow orifice restriction; 3) linear digital fifth-order with long time delay. The digital simulations were synthesized on an IBM-compatible personal computer.