A model based multivariable coordinated control algorithm is presented in this paper to meet the complex requirements of industrial process. The control algorithm takes both the control performance of controlled variables and the Ideal Resting Values(IRV) of manipulated variables into consideration. In a system with more inputs than outputs the controller first makes every effort to drive the controlled variables to their setpoints

then if it is possible

makes some of the manipulated variables approach their IRV in economic consideration. For a system with less inputs than outputs

the controller enforcesdiffer-ent control efforts to the controlled variables according to their economic importance. The condition for a unique solution

steady state property and stability of the controller are given in this paper

providing a theoretical guideline for the controller parameter tuning. A FCCU fractionator is introduced here as a case study

for which an multivariable control strategy is developed by using the coordinated algorithm. Simulated results demonstrated that the control algorithm presented in this paper possesses good control performances and practical significance.