Mass flow controller and method for improved performance across multiple fluid types

摘要

Systems and methods have been described that improve the control of the flow of various types of fluids. The method includes selecting a process gas type for the process gas to be controlled and obtaining molecular weight information for the selected type of process gas. General characterization data is obtained that includes corresponding control signal values for each of the plurality of pairs of flow values and pressure values. Also, motion characterization data is generated by modifying the flow value in the general characterization data according to the formula Fadj = Fcal * (Mcal / Mpr) k. Where Fadj is the adjusted flow value, Fcal is the calibrated flow value, Mpr is the molecular weight of the selected type of process gas, and Mcal is the molecular weight of the calibration gas. The operational characterization data is then used to operate the mass flow controller valve in an open loop control mode.