A system for monitoring, diagnosing, and/or controlling a flow process uses one or more flow meters based on an array of pressure sensors. A signal processor outputs at least one of a flow signal, a diagnostic signal, and a control signal in response to the pressure signals from the pressure sensors. The flow signal indicates the at least one parameter of the fluid, the diagnostic signal indicates a diagnostic condition of a device in the flow process, and the control signal is effective in adjusting an operating parameter of at least one device in the flow process. The system may be arranged as a distributed control system (DCS) architecture for monitoring a plurality of flow meters based on array-processing installed at various locations throughout a flow process.