Systems and methods for using calibration profiles in valve actuators
AssigneeTri-Tec Manufacturing, LLC
InventorsRoy Gilbert, Richard Lynn Cordray
Life of this patent
Estimating the term…
Abstract
Disclosed is a valve actuator configured to determine, during operation of a valve by an alternating current (AC) motor of the valve actuator, an amount of torque produced by the AC motor. A process for measuring the amount of torque produced by the AC motor includes actuating a valve using the AC motor of the valve actuator, measuring, by a microcontroller of the valve actuator and during the actuating of the valve, a time interval between: (i) a first zero crossing of a waveform of AC voltage applied to the AC motor, and (ii) a second zero crossing of a waveform of AC current drawn by the AC motor, and determining, based on the time interval, an amount of torque produced by the AC motor during the actuating.
Claims20
A method, comprising:
- actuating a valve by a valve actuator including an alternating current (AC) motor;
- detecting a first zero crossing of a waveform of AC voltage applied to the AC motor;
- detecting a second zero crossing of a waveform of AC current drawn by the AC motor;
- determining a time interval between the first zero crossing and the second zero crossing;
- identifying a reference torque value from a calibration profile including reference time intervals with corresponding reference torque values;
- and
- outputting a torque value corresponding to the time interval based on the reference torque value of the calibration profile.
A system, comprising:
- a valve;
- an alternating current (AC) motor that, in operation, operates the valve;
- a microcontroller that, in operation:
- receives a first signal indicative of a first zero crossing of a waveform of AC voltage applied to the AC motor;
- receives a second signal indicative of a second zero crossing of a waveform of AC current drawn by the AC motor;
- identifies a time interval between the first zero crossing and the second zero crossing based on the first and second signals;
- identifies a reference torque value from a calibration profile;
- and
- outputs a torque value corresponding to the time interval based on the reference torque value of the calibration profile and the time interval.
A valve actuator comprising:
- an alternating current (AC) motor that, in operation, operates a valve;
- and
- a microcontroller that, in operation:
- measures a time interval between:
- (i) a first zero crossing of a waveform of AC voltage applied to the AC motor, and (ii) a second zero crossing of the waveform of AC voltage applied to the AC motor, the measuring including:
- interrupting, by a first programmable interrupt, the microcontroller in response to the first zero crossing;
- and
- interrupting, by a second programmable interrupt, the microcontroller in response to the second zero crossing;
- compares the time interval to calibration values in a calibration curve, the calibration values including one or more reference time intervals with corresponding reference torque values;
- and
- outputs a first amount of torque produced by the AC motor during the operation of the valve based on the calibration values and the time interval.
Dependencies are inferred from the claim text.