System and method for a mass flow controller

A method of configuring a mass flow controller for operation with process operating conditions that differ at least in part from test operating conditions used during production of the mass flow controller, the method comprising acts of:

• obtaining configuration data during operation of the mass flow controller with the test operating conditions having a test fluid;
• setting at least one control parameter based on the configuration data to facilitate establishing a dynamic response of the mass flow controller with the test operating conditions;
• and
• modifying the at least one control parameter based on the process operating conditions and the configuration data such that the dynamic response of the mass flow controller operating with the process operating conditions does not substantially change;
• wherein the act of modifying the at least one control parameter includes an act of determining at least one gain term associated with at least one of a plurality of individual components of the mass flow controller based on the process operating conditions and an act of determining a reciprocal gain term formed by taking a reciprocal of a product of the at least one gain term;
• wherein the plurality of individual components includes a valve, and wherein the act of determining the at least one gain term includes determining at least one gain term from a physical model of the valve;
• and
• wherein the act of determining at least one gain term from a physical model of the valve includes determining a valve gain term as a change in fluid flow divided by a corresponding change in valve displacement at a plurality of predetermined flow rates.

A method of configuring a mass flow controller for operation with process operating conditions that differ at least in part from test operating conditions used during production of the mass flow controller, the method comprising acts of:

• obtaining configuration data during operation of the mass flow controller with the test operating conditions having a test fluid;
• setting at least one control parameter based on the configuration data to facilitate establishing a dynamic response of the mass flow controller with the test operating conditions;
• and
• modifying the at least one control parameter based on the process operating conditions and the configuration data such that the dynamic response of the mass flow controller operating with the process operating conditions does not substantially change;
• wherein the act of setting at least one control parameter includes an act of setting at least one control parameter to facilitate establishing a steady-state response of the mass flow controller with the test fluid under the test operating conditions;
• wherein the mass flow controller has a plurality of individual components including a flow meter, a valve, and a valve actuator;
• wherein the act of obtaining the configuration data includes an act of obtaining at least one of sensor tuning data relating to a dynamic response of the flow meter, valve characterization data relating to a response of the valve and the valve actuator, and calibration data relating to a steady-state response of the mass flow controller with the test fluid under the test operating conditions;
• wherein the act of obtaining the configuration data further includes an act of determining a first composite gain term including a gain term associated with the flow meter of the mass flow controller operating with the test fluid under the test operating conditions;
• wherein the act of setting at least one control parameter includes setting a first control parameter to adjust the gain term associated with the flow meter to essentially a constant to facilitate establishing the steady-state response and setting a second control parameter based on a reciprocal of the first composite gain term to facilitate establishing the dynamic response;
• wherein the act of modifying the at least one control parameter includes an act of determining a second composite gain term associated with the plurality of individual components of the mass flow controller based on the process operating conditions and the first composite gain term;
• and
• wherein the act of determining the second composite gain term includes acts of:
• decomposing the first composite gain term into component gain terms including a test valve gain term;
• determining a process valve gain term from the test valve gain term and the process operating conditions;
• and
• determining the second composite gain term based on the process valve gain term.

A computer readable medium encoded with a program for execution on a processor, the program, when executed on the processor performing a method of configuring a mass flow controller for operation with process operating conditions that differ at least in part from test operating conditions used to establish a dynamic response of the mass flow controller during production, the method comprising acts of:

• receiving as an input at least one of process fluid species information and at least one process operating condition;
• obtaining a first composite gain term determined during operation of the mass flow controller with the test operating conditions;
• determining a second composite gain term based on the first composite gain term and the input;
• modifying at least one control parameter of the mass flow controller based on the second composite gain term to facilitate maintaining essentially the same dynamic response;
• and
• accessing configuration data stored on the computer readable medium, the configuration data being obtained when the response of the mass flow controller was established with the test operating conditions;
• wherein the act of accessing configuration data includes an act of determining at least one test gain term associated with at least one of a plurality of components of the mass flow controller operating with a test fluid under the test operating conditions;
• wherein the act of accessing configuration data includes the act of obtaining the first composite gain term, and wherein the act of determining the second composite gain term includes an act of decomposing the first composite gain term into a plurality of test gain terms associated with the plurality of components of the mass flow controller, the plurality of test gain terms including a test valve gain term associated with a valve of the mass flow controller.

A computer readable medium encoded with a program for execution on a processor, the program, when executed on the processor performing a method of configuring a mass flow controller for operation with process operating conditions that differ at least in part from test operating conditions used to establish a dynamic response of the mass flow controller during production, the method comprising acts of:

• receiving as an input at least one of process fluid species information and at least one process operating condition;
• obtaining a first composite gain term determined during operation of the mass flow controller with the test operating conditions;
• determining a second composite gain term based on the first composite gain term and the input;
• and
• modifying at least one control parameter of the mass flow controller based on the second composite gain term to facilitate maintaining essentially the same dynamic response;
• wherein the act of determining the at least one process gain term includes an act of determining a plurality of process gain terms associated, respectively, with a flow meter, a valve, and a valve actuator of the mass flow controller based on the process operating conditions.

A method of configuring a mass flow controller for operation with process operating conditions that differ at least in part from test operating conditions used during production of the mass flow controller, the method comprising acts of:

• obtaining configuration data during operation of the mass flow controller with the test operating conditions having a test fluid;
• setting at least one control parameter based on the configuration data to facilitate establishing a dynamic response of the mass flow controller with the test operating conditions;
• and
• modifying the at least one control parameter based on the process operating conditions and the configuration data such that the dynamic response of the mass flow controller operating with the process operating conditions does not substantially change;
• wherein the mass flow controller has a control loop that includes:
• a flow meter that monitors an actual flow of fluid provided by the mass flow controller and provides a conditioned output signal, the flow meter having a first gain term;
• a control section that receives a second input signal indicative of a desired flow of the fluid to be provided by the mass flow controller and provides a control signal, the control section having a second gain term that is a function of at least one variable operating condition;
• a valve that permits fluid flow based on the displacement of one or more elements of the valve, the valve having a third gain term;
• and
• a valve actuator that receives the control signal and adjusts the displacement of one or more elements in the valve, the valve actuator having a fourth gain term;
• the method further comprising an act of configuring the mass flow controller to have a substantially constant control loop gain, wherein:
• the act of obtaining configuration data includes an act of determining the first, third, and fourth gain terms with the test fluid using the test operating conditions;
• the act of modifying at least one control parameter includes an act of predicting how the first, third, and fourth gain terms will change with at least one of a process fluid and the process operating conditions;
• and
• the act of modifying the at least one control parameter further includes an act of changing the second gain term to a constant times the reciprocal of the product of the first, third and fourth gain terms to provide the substantially constant control loop gain with respect to at least the at least one variable operating condition.