Development of CAD for Plant-Wide Control Loop Configuration

For plant-wide control, many single loop controllers are utilized. Although tuning of a control loop is focused in control theory, control loop configuration problem is more essential problem. If control loop configuration is not adequate, controller cannot be stabilized with any tuning of controller parameters. Moreover, controller can be unstable by mode change of some other controllers. These are called “inconsistency” problems and “partial inconsistency” ones. This paper introduces a CAD (Computer Aided Design) tool to analyze them. It is based on DAE (Differential and Algebraic Equations), which are commonly registered in modules of plant CAD. Because quantitative information of model parameters is not necessary for it, model building is easy even for large-scale plants. In this paper, an algorism for analysis of loop configuration is proposed and the developed CAD is illustrated.