A system and a method are used for performing management and diagnostic functions in an advanced process control (APC) system (100). An APC management computer (112) retrieves (606) operating process data (444) from an APC control computer (150, 152) and performs an iterative step test (608) on the APC system. The iterative step test modifies at least one test parameter (448) of the operating process data and identifies changes to a set of remaining parameters of the operating process data resulting from modification of the test parameter. The APC management computer determines (610) at least one process variable (443) from the iterative step test and generates (614) at least one process model (352, 354, 356) based on the process variable. The APC management computer transmits (620) the process model to the APC control computer.