Eddy current sensing arrays and system
AssigneeJENTEK Sensors, Inc.
InventorsDarrell E. Schlicker, Neil J. Goldfine, Eric L. Miller
Life of this patent
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Abstract
An apparatus that measures electrical impedance. The apparatus includes a signal generator controlled by a master microcontroller, a plurality of data acquisition channels, each channel containing a microcontroller, a host computer that processes and stores measured values, and a communication line between the host computer and the master microcontroller.
Claims50
An apparatus for measuring electrical impedance comprising:
- a microcontroller controlled signal generator;
- at least one microcontrolled data acquisition channel;
- a host computer for processing and storing measured values;
- and
- at least one data communication line.
A test circuit comprising:
- a primary winding having parallel extended portions simultaneously imposing a spatially periodic magnetic field of at least two spatial wavelengths in a test substrate when driven by an electric current;
- and
- a plurality of sensing elements sensing the response of the test substrate to the imposed magnetic field, each sensing element positioned between the extended portions of the primary winding, extended portions of the individual sensing elements being parallel to the extended portions of the primary winding, and the plurality of sensing elements being aligned with one another to sense the response at incremental areas along a path parallel to the extended portions of the primary winding, and have separate output connections.
An apparatus comprising:
- a primary winding of parallel winding segments that impose a spatially periodic magnetic field, with at least two periods in a single plane, in a test substrate when driven by electric current;
- one or more sensing windings that sense the response at incremental areas along the width between at least one adjacent pair of parallel winding segments;
- with the sensing elements located in a second plane, and with different distances between the sensing elements and the extended portions of the primary winding for at least one of the sensing elements.
A method for detecting material anomalies comprising:
- measuring the response of the material along several paths with a sensor;
- and
- for each path of measured responses, filtering the response by removing the mean response over a subset of data points, multiplying a match response that is characteristic of the sensor against a subset of the data, and adjusting the subset of data until the entire set of data in the path has been processed.
A method for detecting material anomalies comprising:
- calibrating the sensor;
- scanning over the test material to determine the background variation of properties;
- subtracting the response of distinct anomalies, if present;
- and
- setting the threshold for the inspection based on the background property variations.
An apparatus for measuring electrical impedance comprising:
- a signal generator controlled by a master microcontroller;
- a plurality of data acquisition channels, each containing a microcontroller;
- a host computer for processing and storing measured values;
- and
- a communication line between the host computer and master microcontroller.
A method for measuring electrical impedance comprising:
- passing an excitation signal having a frequency, amplitude, and phase set by a signal generator controlled by a master microcontroller into a test circuit;
- simultaneously measuring a plurality of electrical signals from the test circuit using at least one data acquisition channel containing a microcontroller;
- and
- transmitting the measurement data to a host computer for processing and storing measured values.
An apparatus for measuring electrical impedance comprising:
- a signal generator controlled by a master microcontroller;
- a data acquisition channel;
- a host computer for processing and storing measured values;
- and
- a wireless communication circuit between the host computer and master microcontroller.
A method of calibration of a sensor array comprising:
- providing a sensor array having a means for creating a magnetic field when driven by an electric current and a plurality channels connected to sensing elements for detecting changes in the magnetic field;
- measuring and storing the response of each channel placed in air at a distance from the material under test;
- and
- aligning the response from measurements on each channel with the response from a measurement database.
Dependencies are inferred from the claim text.