Using Off-Line Analysis for Dynamic Feedback Composition control

A tunable feedback control algorithm is developed for a first-order plus dead time process which has a variable sample interval and a variable dead time. This variable sample interval, variable dead time (VSIVDT) controller is applied to controlling the product composition of a blender using off-line composition analysis. The blender and controllers are simulated using the IBM Advanced Control System. The VSIVDT controller performed better than an alternative controller based on the Dahlin algorithm which uses off-line analysis. When compared to controllers using on-line analysis, it performed as well as a PI controller but not as well as a controller using the Dahlin algorithm.