Granted Patent B2

US 6,962,164 · App. 10/131,603 · Granted Nov 8, 2005

Abstract

Claims (80)

1. 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 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;

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.

2. The method of claim 1 , wherein the process operating conditions include a process fluid different than the test fluid and wherein the act of modifying the at least one control parameter includes an act of modifying at least one control parameter based at least in part on process fluid species information.

3. The method of claim 1 , wherein the act of modifying the at least one control parameter includes an act of determining a plurality of process gain terms associated with the plurality of individual components of the mass flow controller based on the process operating conditions, the plurality of individual components forming a control loop of the mass flow controller.

4. The method of claim 3 , wherein the act of modifying the at least one control parameter further includes an act of determining a process reciprocal gain term formed by taking a reciprocal of a product of the plurality of process gain terms, the process reciprocal gain term being a function of at least one variable operating condition.

5. The method of claim 4 , wherein the act of modifying the at least one control parameter includes an act of modifying at least one control parameter to equal the process reciprocal gain term such that the control loop has a constant loop gain with respect to at least the at least one variable operating condition.

6. The method of claim 1 , wherein the act of setting at least one control parameter further 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.

7. 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.

8. The method of claim 7 , wherein the act of determining at least one gain term includes determining a valve actuator gain term associated with a valve actuator from the valve gain term, the valve actuator gain term related to drive level as a function of valve displacement.

9. 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.

10. The method of claim 9 , wherein the act of modifying at least one control parameter includes an act of modifying the first control parameter to equal a reciprocal of the second composite gain term.

11. The method of claim 9 , wherein the act of determining the process valve gain term includes determining valve displacement as a function of flow rate from a physical model of the valve.

12. The method of claim 11 , wherein the act of determining the second composite gain term includes acts of:

determining a process full scale range associated with a process fluid of the process operating conditions, the process fluid differing from the test fluid; and

determining a process flow meter gain term based on the process full scale range; and

modifying the second control parameter based on the process flow meter gain term.

13. The method of claim 12 , wherein the act of determining valve displacement as a function of flow rate from a physical model includes applying process operating conditions including a process fluid to the physical model of the valve as parameters.

14. The method of claim 12 , wherein the act of determining the second composite gain term includes determining a process valve actuator gain term associated with the valve actuator by determining drive level as a function of valve displacement based on the physical model of the valve.

15. The method of claim 12 , wherein the second composite gain term is formed from the process flow meter gain term, the process valve actuator gain term and the process valve gain term such that it is a function of flow rate as indicated by a set point of the mass flow controller operating with the process operating conditions; and

wherein the act of modifying the first control parameter includes an act of applying a reciprocal of the second composite gain term to a control loop including the plurality of individual components of the mass flow controller such that the control loop gain is constant with respect to set point.

16. 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.

17. The computer readable medium of claim 16 , wherein the act of modifying at least one control parameter includes an act of determining at least one process gain term associated with at least one of the plurality of components of the mass flow controller, the at least one process gain term including a process valve gain term determined from a physical model of the valve and based on the process operating conditions.

18. The computer readable medium of claim 17 , wherein the act of determining at least one process gain term includes an act of determining a process flow meter gain term, a process valve actuator gain term, and the process valve gain term, and determining a process reciprocal gain term formed by taking a reciprocal of a product of the at least one process gain term.

19. The computer readable medium of claims 18 , wherein the act of modifying at least one control parameter includes an act of modifying the at least one control parameter to equal the process reciprocal gain term.

20. The computer readable medium of claim 16 , in combination with the mass flow controller, wherein the processor is included in the mass flow controller, wherein the program is stored in a memory of the mass flow controller that is coupled to the processor, wherein the input is an input of the mass flow controller that is coupled to the processor, wherein when the program is executed on the processor, the mass flow controller is configured for operation with process operating conditions received at the input, and wherein the configuration data is stored in the memory of the mass flow controller.

21. The computer readable medium of claim 16 , in combination with a computer that includes the processor upon which the program is executed, the computer including a memory in which the configuration data obtained from the mass flow controller is stored.

22. 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.

23. The computer readable medium of claim 22 , wherein the act of determining configuration data includes an act of determining a process full scale range associated with a process fluid of the process operating conditions, the process fluid differing from a test fluid of the test operating conditions.

24. The computer readable medium of claim 23 , wherein the act of determining the plurality of process gain terms includes determining at least a process valve gain term associated with the valve from a physical model of the valve, the physical model of the valve being adapted to take the process operating conditions as parameters.

25. The computer readable medium of claim 24 , wherein the act of determining at least a process valve gain term includes determining a process valve actuator gain term associated with the valve actuator from the physical model of the valve.

26. The computer readable medium of claim 23 , wherein the act of determining a plurality of process gain terms includes an act of determining a process flow meter gain term based on the process full scale range.

27. The computer readable medium of claim 22 , in combination with the mass flow controller, wherein the processor is included in the mass flow controller, wherein the program is stored in a memory of the mass flow controller that is coupled to the processor, wherein the input is an input of the mass flow controller that is coupled to the processor, and wherein when the program is executed on the processor, the mass flow controller is configured for operation with process operating conditions received at the input.

28. 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.

Assignments (17)