Introductory Remarks

Probably the major shortcoming of Multivariable Control Applications are the poor costs put into the economic optimizers in the controllers. The current practice in most applications of the technology is to put cost into the optimizer to make the controller go where Operations feels comfortable. This approach makes people content, but usually leaves significant money on the table. The control engineer goes along with this scenario either because he does not want to fight the politics of the status quo or because he does not know how to put the correct economics into the optimizer. Putting the correct economics in is not as simple as it may appear from the surface. The complexity comes from the need to integrate the Dynamic Controller Model with a Steady State Yield Model. Some of the independent variables in the Yield Model do not match those in the Controller Model. This paper will give the details of the math required to put these models in the right context.