The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 2022
Filed:
Mar. 30, 2021
Hitachi Metals, Ltd., Tokyo, JP;
Alexei V. Smirnov, Fort Collins, CO (US);
Hitachi Metals, Ltd., Tokyo, JP;
Abstract
Mass flow controllers and methods for controlling mass flow controllers are disclosed. A method includes providing a gas through a thermal mass flow sensor of the mass flow controller and processing a sensor signal from the thermal mass flow sensor to produce a flow signal. A total nonlinearity characteristic function is determined based on nonlinearity effects on the flow signal and includes a first and second nonlinearity component function based on a first and second source of nonlinearity respectively. The total nonlinearity characteristic function is calibrated, and the first nonlinearity component function is adjusted responsive to changes in the first source of nonlinearity, after which the total nonlinearity characteristic function is updated. The flow signal is corrected to produce a corrected flow signal using the total nonlinearity characteristic function. A valve of the mass flow controller is controlled using the corrected flow signal and a setpoint signal.