A new approach to designing plantwide control systems that is based on a linear dynamic process model and output optimal control is extended in this paper. The design of a plantwide architecture is split into four stages, and the results from one stage are used as the input to the next. During the design process, transient responses are easily calculated, and they can be used to compare candidate architectures to one another to eliminate architectures with poor dynamic performance. The design methodology is facilitated through a user-friendly software package that makes use of the best currently available algorithms for solving output optimal control problems. In this paper, the design methodology is extended to cover cases where a set of step disturbances and/ or step set-point changes is important, as well as to cases where a common control system is required for multiple-steady-state operation. The approach is illustrated on the Tennessee Eastman process.