Abstract: A control apparatus is disclosed that comprises a primary proportional, integral, differential (“PID”) controller capable of receiving a first setpoint and a first process variable and generating therefrom a second setpoint; and a secondary controller capable of receiving the second setpoint and a second process variable and generating therefrom an output control signal, wherein the primary PID controller is capable of receiving from the secondary controller a feedback signal 1) that indicates that a previous value of the second setpoint exceeds a limit associated with an output control signal of the secondary controller, and 2) that transfers a value of a signal from the secondary controller. The primary PID controller is then capable of limiting the contribution of the integral calculation component in a PID calculation that generates a new current value of the second setpoint.

Abstract: Controllers and methods of operating the same are introduced for use with a process facility that includes a plurality of associated processes. An exemplary controller includes circuitry that maintains a range of possible values of at least one measurable characteristic associated with at least one process of the plurality of associated processes, and a processor. The processor is capable of selecting at least one value of the range of possible values from the circuitry in response to one of an input or an output of the at least one process, and generating control data as a function of the selected at least one value of the range of possible values and the input or the output of the at least one process. The controller is capable of using the control data to manage the at least one process.