System and method for a mass flow controller
AssigneeCelerity, Inc.
InventorsJohn M Lull, Chiun Wang, William S Valentine, Joseph A Saggio, Jr.
Life of this patent
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Abstract
A system and method for controlling a mass flow controller to have a constant control loop gain under a variety of different types of fluids and operating conditions, and for configuring the mass flow controller for operation with a fluid and/or operating conditions different from that used during a production of the mass flow controller. Further, the system and method includes providing control by reducing the effects of hysteresis in solenoid actuated devices by providing a non-operational signal to the solenoid actuated device.
Claims43
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:
- accessing configuration data obtained during calibration of the mass flow controller with a plurality of test operating conditions using a test fluid;
- adjusting at least one control parameter based on the configuration data to tune the mass flow controller with the plurality of test operating conditions so that a dynamic response of the mass flow controller to each of a plurality of different changes in set point with the plurality of test operating conditions is substantially similar;
- and
- modifying the at least one control parameter based on the process operating conditions and the configuration data such that a dynamic response of the mass flow controller to different changes in set point with a plurality of process operating conditions that differ at least in part from the plurality of test operating conditions, does not substantially change from the dynamic response of the mass flow controller operating with the plurality of test operating conditions.
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 calibration and tuning of the mass flow controller with the test operating conditions wherein the calibration and tuning results in a substantially similar dynamic response of the mass flow controller to different changes in set point 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 maintain a dynamic response to different changes in set point with the process operating conditions that is substantially similar to the dynamic response of the mass flow controller to the different changes in set point with the test operating conditions.
Dependencies are inferred from the claim text.