Abstract: In a circuit arrangement having a linear variable differential transformer as a displacement sensor or force sensor, having a selection circuit which is connected to the primary coil of the transformer and which provides an output current for triggering the primary coil, and having an analysis circuit which is connected to the secondary coils of the transformer and which provides a message signal, a control circuit used for triggering the selection circuit and the analysis circuit and for processing the measurement signal provided by the analysis circuit is connected to the primary coil in order to calculate the temperature of the circuit arrangement, and is configured such that it determines the temperature-dependent ohmic resistance of the primary coil and calculates from it the temperature and corrects accordingly the measurement signal provided by the analysis circuit.

Abstract: An apparatus for inspecting a metallic post contoured in a single dimension for defects. The apparatus has a clamp having at least one jaw with a surface conforming to the contour to the metallic post. The conforming jaw or jaws also have a plurality of eddy current coils and the probe has at least one sensor configured to sense at least one of position or motion.

Abstract: A sensor and method that detects a mis-calibration and automatically recalibrates itself without operator intervention. If the sensor determines that it was calibrated over an object such as a stud, the sensor may automatically update the calibration value with a new lower value without operator intervention. This process may repeat until the calibration value is set to a value that represents the wall covering alone without hidden objects behind it.

Abstract: Inductive sensors measure the near surface properties of conducting and magnetic material. A sensor may have primary windings with parallel extended winding segments to impose a spatially periodic magnetic field in a test material. Those extended portions may be formed by adjacent portions of individual drive coils. Sensing elements provided every other half wavelength may be connected together in series while the sensing elements in adjacent half wavelengths are spatially offset. Certain sensors include circular segments which create a circularly symmetric magnetic field that is periodic in the radial direction. Such sensors are particularly adapted to surround fasteners to detect cracks and can be mounted beneath a fastener head. In another sensor, sensing windings are offset along the length of parallel winding segments to provide material measurements over different locations when the circuit is scanned over the test material.

Abstract: A speed meter unit has a magnetic pointer position detector, including an output coil, a detection coil and a magnetic piece. The output coil generates magnetic flux. The detection coil is for detecting the magnetic flux from the output coil. When a pointer has returned to an initial position, the magnetic flux generated in the output coil can reach the detection coil through the magnetic piece, so that a microcomputer can detect the initial position of the pointer. Such the magnetic pointer position detector is resistive to the soil or the oxidization, so that the speed meter unit can detect the initial position of the pointer accurately and securely.

Abstract: A method for balancing the flux density of a permanent magnet includes sensing flux density in a permanent magnet and if unbalanced relative to a physical center, adjusting the cross-sectional area and shape of the magnet by removing magnetic material from the magnetic pole with the stronger magnetic flux density. This method is repeated until the magnetic flux density is balanced between the opposite poles of the permanent magnet relative to the physical center.

Abstract: A device for automatically detecting a calibration termination of a geomagnetic sensor includes a detection unit for detecting signals X and Y outputted from X-axis and Y-axis coils of the geomagnetic sensor, respectively, a calculation unit for calculating slopes dX/dt and dY/dt of the signals X and Y, respectively, and the number of sign changes Nx and Ny of the slope dX/dt of the signal X and the slope dY/dt of the signal Y, respectively, a display unit for displaying the calibration termination and a calibration progress state for the geomagnetic sensor, and a control unit for outputting a driving signal to the display unit to display a state of the calibration termination based on the slope dX/dt of the signal X and the slope dY/dt of the signal Y and the number of slope sign changes Nx and Ny.

Abstract: The present invention provides an apparatus for processing a sheet. When a medium having various patterns detected by a plurality of detecting sections for individually detecting plural kinds of features from a sheet, each detecting section detects plural kinds of features from the medium. The features detected from the medium are compared with a predetermined reference value so that the condition of the apparatus can be judged.

Abstract: A device for measuring magnetic field(s). The device includes at least one measurement acquisition pathway including a measurement current generator, a coil, a measurement resistor, at least one amplifier, and at least one antialiasing filter, delivering a measurement voltage. The device for measuring magnetic field(s) includes a device for determinating at least one electrical quantity representative of the acquisition pathway. The device for determining includes a mechanism for injecting a predetermined calibration current, including at least two frequency terms at at least two frequencies distinct from those of a measurement current, the calibration current being superimposed on the measurement current. The device for measuring magnetic field(s) also includes a calculation device delivering an estimate of the at least one electrical quantity at the frequency or frequencies of the measurement current.

Abstract: A method for measuring conductance of a sample using an eddy current probe with a sensing coil. The method includes N repetitions of measuring first and second voltage pairs including in-phase and quadrature components of an induced AC voltage in the sensing coil, calibrating the first signal based on the measured second signal at a different separation from the sample and reference material, determining a conductance function relating conductance with location along the selected curve, processing the calibrated first voltage pairs to generate a lift-off curve, determining an intersection voltage pair representing intersection of the lift-off curve with a selected curve, and determining the conductance of the sample from the intersection voltage pair and the conductance function.

Abstract: A process for measuring the thickness of a layer of oxide on a rod cladding in a fuel assembly comprising a bundle of rods parallel to each other and held in a framework comprising spacer grids for transversely holding rods distributed in an axial direction of the bundle.

Abstract: A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of: powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.

Abstract: A magnetometer for measuring a magnetic field, comprising a fluxgate sensor with at least one ferromagnetic core, a primary, electrically conducting coil arranged around the core for periodical magnetisation of the core into magnetic saturation by an alternating electric current through the primary coil, and a secondary, electrically conducting coil arranged around the at least one ferromagnetic core for producing a measurable electromotive force as a response signal, wherein the magnetometer has means for rotating the at least one core of the fluxgate sensor with a steady rotation inside the coils during the measurement of the magnetic field.

Abstract: In order to create a circuit configuration for a gradiometric current sensor with a bridge circuit in the form of a Wheatstone bridge for measuring gradients of the magnetic field strength of a current-carrying conductor, with four magnetoresistive resistors, two of which resistors form a sub-bridge in each case, while the sub-bridges are arranged symmetrically in relation to sub-conductors of the current-carrying conductor, and with a compensating circuit associated with the bridge circuit, which compensating circuit comprises compensating conductors associated with the magnetoresistive resistors, to which compensating conductors a compensating current can be applied, by means of which circuit configuration mounting tolerances can be compensated in a simple manner, it is provided that the sub-bridges (22, 24) can each have a separate compensating current (Icomp1, Icomp2) applied to them.

Abstract: An article handling system and method comprising a flow path along which articles travel and a metal detection system to detect the passage of metal items along the flow path. The system has a metal detector test system to support a metal test piece and positively move it along the flow path, and a metal detector to detect the metal test piece.

Abstract: A modified hybrid Hall effect device is provided which is the combination of a conventional Hall effect device and a second Hall effect device having a Hall plate coupled to a ferromagnetic layer. The hybrid Hall effect device can be used to determine the independent magnetic field vector components comprising a vector magnetic field, such as for determining the {circumflex over (x)} and the {circumflex over (z)} components of a magnetic field, or for measuring the total magnitude of a vector magnetic field of any orientation. The modified Hall Effect device can be adapted for use as a magnetic field sensor for the detection of macroscopic objects that have associated magnetic fields, or for microscopic objects that have been tagged by microscopic magnetic particles.

Abstract: A lifecycle analyzer includes a heating element for heating a plurality of magnetoresistive (MR) elements, which maybe, e.g., in bar form. At one location the MR elements are in contact with a stress probe card for applying a bias voltage or current stress. The MR elements are moved to a separate location, where there is a test probe card and magnetic field generator for testing the MR elements after being stressed. In one embodiment, a subset of the plurality of MR elements is tested at a time. The lifecycle analyzer includes an in-situ abrasive element that is used to abrade the probe pins of the stress probe card to remove oxidation that results from extended contact with the heated MR elements.

Abstract: A magnetic-sensing apparatus and methods of making and using thereof are disclosed. The sensing apparatus may have one or more magneto-resistive-sensing elements, one ore more reorientation elements for adjusting the magneto-resistive-sensing elements, and semiconductor circuitry having driver circuitry for controlling the reorientation elements. The magneto-resistive-sensing elements, reorientation elements and semiconductor circuitry may be disposed in single package and/or monolithically formed on a single chip. Alternatively, some of the semiconductor circuitry may be monolithically formed on a first chip with the magneto-resistive-sensing elements, while a second portion of the semiconductor circuitry may be formed on a second chip. The first and second chips may be placed in close proximity and electrically connected together. Alternatively the chips may have no intentional electrical interaction.

Abstract: The invention relates to a device for setting an operating point of a magnetic field sensor having a periodic characteristic, in particular for a device for detecting a magnetic field and/or flux, having a SQUID as magnetic field sensor and a control unit which is connected downstream of the SQUID, has a control time constant (t) and has a feedback loop which acts on the SQUID and is designed such that it is active about a number of operating points of the SQUID, where flux quantum pump means are provided which are assigned to the SQUID, have a signal generation unit for generating a control and/or regulation signal for the SQUID and are designed such that, in order to pump at least one flux quantum into and out of the SQUID, a signal form of the control and/or regulation signal, generated by the signal generation unit, is different and, referred to a rising and a falling edge of a signal form, is unsymmetrical, where in each case only one of the edges of a signal form is short referred to the control time co

Abstract: The magnetometer includes a magnetic core (1) with at least one branch (2, 3), at least one exciting coil (4, 5) and one take-up coil (10) sensitive to ambient fields thanks to the excitation field (B). An additional magnetic field, to advantage perpendicular to the previous ones, is added to eliminate very low frequency noises, without it being measured.

Abstract: An accelerator pedal is positioned at a kickdown position. Then, an output value of a measurement device of an accelerator pedal position sensor is measured. Thereafter, the measured output value of the measurement device is stored in a correction output value storage of the accelerator pedal position sensor along with a corresponding correction value, which is used to correct the measured output value of the measurement device. A couple of fully opened position stop members is provided and is engaged with the accelerator pedal when the accelerator pedal is rotated to a fully opened position. Furthermore, a couple of fully closed position stop members is provided and is engaged with the accelerator pedal when the accelerator pedal is rotated to a fully closed position.

Abstract: A magnetic sensor package having a biasing mechanism involving a coil-generated, resistor-controlled magnetic field for providing a desired biasing effect. In a preferred illustrated embodiment, the package broadly comprises a substrate; a magnetic sensor element; a biasing mechanism, including a coil and a first resistance element; an amplification mechanism; a filter capacitor element; and an encapsulant. The sensor is positioned within the coil. A current applied to the coil produces a biasing magnetic field. The biasing magnetic field is controlled by selecting a resistance value for the first resistance element which achieves the desired biasing effect. The first resistance element preferably includes a plurality of selectable resistors, the selection of one or more of which sets the resistance value.

Abstract: A calibrated, low-profile magnetic sensor and method for forming such a sensor are described herein. Generally, a magnetic sensing device is formed within a housing, wherein the magnetic sensing device comprises at least one magnet. The magnetic sensor includes a compact integrated circuit package such as, for example, a small outline integrated circuit package (SOIC). A magnetic sensing element is generally mounted to the compact integrated circuit package. The magnetic sensing device can be configured to additionally incorporate a printed circuit board (PCB) having a hole formed therein such that the compact integrated circuit package can be surface mounted off-center on the printed circuit board, so that the hole can be located within the printed circuit board to match a shape of the magnet, allowing the magnet to pass through the circuit board adjacent to the SOIC to complete the magnetic circuit.

Abstract: A process control method is described which uses measurements from magnetic field sensors to monitor the condition of material, such as from a heat treatment process. The sensors can be single element sensors or sensor arrays, can be used to periodically inspect selected locations, mounted to the test material, or scanned over the test material to generate two-dimensional images of the material properties. The sensors can be exposed to the same process conditions as the material, such as elevated temperatures, or the shielding layers can be placed between the test material and the sensors to reduce sensor exposure to the processing conditions. Additional property measurements, such as sensor lift-off, can be used to ensure proper sensors operation.

Abstract: A position sensor including: a reduction gear train having an input gear and an output gear. The input gear is configured for coupling to an output shaft of a drive motor for driving a vehicle seat on an associated seat track, and a magnet disposed on the output gear for rotation therewith. A Hall Effect sensor is disposed adjacent the magnet for providing a sensor output signal in response to rotation of the magnet. A lock out mechanism for a position sensor, a method of sensing the position of a vehicle seat, and a method of calibrating a vehicle seat position sensor are also provided.

Abstract: A magnetic sensor system and a method for installing magnetic sensors for detecting metal objects that allows ease of manipulation, control and access. A carrier conduit is used to position a magnetic sensor in an outer conduit. The outer conduit may be disposed beneath a surface where objects to be detected may be positioned. Alternatively, a conduit having multiple channels may be placed in a pathway. Magnetic sensors may be placed in the channels and a top placed over the conduit. Multiple embodiments for orienting the magnetic sensor systems are provided.

Abstract: A method and apparatus is disclosed for improving the accuracy of directional surveys using magnetometers and accelerometers. The method corrects errors in bias, scale-factor, misalignment of cross-axial magnetometers, and bias or scale-factor of axial magnetometer by requiring the magnitude of measured cross-axial magnetic field to be as constant as possible over several tool face angles at a survey point in a wellbore and the magnitude of the measured total magnetic field and dip angle equal to the reference values, respectively. The axial component of the measured magnetic field is also determined. The method also corrects accelerometers similarly. The calibration parameters obtained at one survey point are applied to measurements at other survey points to improve the accuracy of surveys and the efficiency of drilling operations.

Abstract: Techniques for calibrating an electromagnetic logging tool equipped with a plurality of antennas, with at least one antenna having its axis at an angle with respect to a tool axis, include disposing a test loop about the tool such that an axis of the tool and a plane on which the test loop lies form a tilt angle that is between about 0 and 90 degrees. An induced signal is measured at one of the antennas by energizing another of the antennas. Embodiments analyze the induced signal corresponding to a max or min extrema associated with a coupling effect due to the test loop. In other embodiments a corrected signal is compared with a calculated signal.

Abstract: A method and apparatus are provided for measuring a thickness of a nonconductive coating disposed over portions of first and second conductive surfaces that intersect at an intersection angle. The apparatus is a thickness measurement gauge having an eddy current sensor. The thickness measurement gauge includes an eddy current sensor and electronic analyzer. The thickness gauge may be provided with a pressure enclosure. A method of calibrating a thickness measurement gauge and a calibration stand are also provided. The calibration stand has third and fourth conductive surfaces intersecting at the intersection angle. The conductivities of the third and fourth surfaces correspond to the conductivities of the first and second surfaces.

Abstract: The present invention relates to a compliant laminar eddy current sensitivity standard which comprises a sheet of nonconductive, nonmagnetic material having at least one strand of highly conductive metallic material embedded in the sheet and an adhesive layer attached to a surface of the nonconductive, nonmagnetic material to allow the standard to be adhered to a surface of a part to be inspected. A method using the compliant laminar eddy current sensitivity standard is also described.

Abstract: A device and a method for determining a magnetic field with respect to its intensity and direction at at least one detection location, and uses a first arrangement for superimposing an auxiliary magnetic field, known at least in intensity, on the magnetic field, and a second arrangement for measuring at least the direction of the magnetic field resulting from the superimposition of the magnetic field to be determined and of the auxiliary magnetic field at the detection location. The magnetic field is determined at the detection location in that the resultant magnetic field produced by the magnetic field to be determined and the auxiliary magnetic field is determined with respect to its direction for at least two different auxiliary magnetic fields; and the magnetic field to be determined is calculated therefrom. The method is especially suited for determining the intensity and direction of a magnetic field in the immediate vicinity of the surface of a magnet.

Abstract: A tunable magnetic device which includes a permanent magnet in the shape of a ring, an inner aperture, a tuning member, and a field sensor secured to the permanent magnet. The tuning member may be a ferrous or magnetic material and may be secured to a non-magnetic tuning device. The inner aperture is preferably small compared to the permanent magnet. The magnetic device provides a magnetic field that is sensitive to the proximity of a ferrous object and provides a tunable mechanism to locally balance the magnetic field where the field sensor is located.

Abstract: A method for inspecting a metallic component comprises providing an inspection standard having an eddy current signature substantially similar to an eddy current signature of the metallic component, wherein the inspection standard body is fabricated from a non-metallic material. The method also comprises inspecting the metallic component with an eddy current probe with reference to the inspection standard.

Abstract: Methods and apparatus are described for the inspection of materials and the detection and characterization of hidden objects, features, or flaws. Sensors and sensor arrays are used to image form two-dimensional images suitable for characterizing the hidden features. Magnetic field or eddy current based inductive and giant magnetoresistive sensors may be used on magnetizable and conducting materials, while capacitive sensors can be used for dielectric materials. Enhanced drive windings and electrode structures permit nulling or cancellation of local fields in the vicinity of the sense elements to increase sensor sensitivity. The addition of calibration windings, which are not energized during measurements, allows absolute impedance and material property measurements with nulled sensors. Sensors, sensor arrays, and support fixtures are described which permit relative motion between the drive and sense elements. This facilitates the volumetric reconstruction of hidden features and objects.

Abstract: There is provided a measurement system in which the calibration data is easily incorporated into or obtained by the position sensing and/or displacement sensing system's processing unit. A scale-based encoder has a signal processor that corrects for scale inaccuracy based on a limited set of correction coefficients. The correction coefficients are the slopes and offsets that define a piecewise linear correction curve corresponding to the errors inherent in the scale. Several ways for communicating the coefficients to the processor are envisioned. Correction is applicable to linear or rotary encoders.

Abstract: A method for offset compensation of a magnetoresistive position or angular position measuring system includes at least one Wheatstone bridge with four locally offset magnetoresistive resistors to which a DC voltage is applied and past which a permanent magnet is moved, wherein the respective bridge voltage is measured, by which method a subsequent offset compensation of magnetoresistive position or angular position measuring systems is also possible on site. Provision is made for a calibration cycle to be run through upon start-up of the measuring system, by moving the permanent magnet past the bridge(s) for a measuring cycle, evaluating the extreme values of the bridge voltages measured during this procedure by deriving the mean values thereof, and deriving from these mean values corresponding compensation values in the form of offset values to be taken into consideration by the measuring system, the compensation values being stored in a register.

Abstract: A self referencing eddy current probe for determining conductive coating thickness includes a housing having a reference sample area, for accommodating a reference sample, and a testing edge, for positioning on a component during a coating thickness measurement. The eddy current probe further includes a reference eddy current coil situated in the housing adjacent to the reference sample area and a test eddy current coil, which is located at the testing edge. A self referencing eddy current measurement system, for measuring a thickness of a conductive coating on a component, includes the self referencing eddy current probe. The system further includes a signal generator for energizing the test and reference coils and a comparison module for comparing a test signal received from the test coil and a reference signal received from the reference coil and outputting a compared signal.

Abstract: A method is disclosed for determining the presence of response abnormalities in magnetic sensors. The method includes placing the sensor in an applied magnetic field and collecting sensor resistance information as the magnitude and direction of the applied field is altered. The resistance values are then examined to determine the presence of response abnormalities.

Abstract: Improved calibrations associated with superconducting quantum interference devices (SQUIDs) are accomplished using a single calibration ring that is placed on an outer dewar wall. During initial calibration, a standard current is passed through the calibration ring and channel responses are measured and recorded. During re-calibration, any channel responses that have changed from the original value U to a new value U′, are identified and the corresponding empirical coefficients for these channels are changed from an old value of C to a new value C′ given by: C′=(U′/U)C Channel responses in subsequent measurements are divided by these coefficients C′ in order to make them equal for equal magnetic field inputs, or to provide equal channel sensitivities.

Abstract: An inductive proximity sensor or switch and a method of using same. The sensor or switch includes an Application Specific Integrated Circuit (“ASIC”) and a plurality of external components. The ASIC is implemented in CMOS technology and has an oscillator. A switch point of the sensor or switch is predetermined by selection of a bias voltage to a potential node of the oscillator.

Abstract: The invention relates to a device for measuring magnetic field(s). This device comprises at least one measurement acquisition pathway (221, 222, 223; 231, 232, 233) comprising a measurement current generator (24), a coil (25), a measurement resistor (26), at least one amplifier (27) and at least one antialiasing filter, delivering a measurement voltage.

Abstract: A linear variable differential transformer (LVDT) assembly comprises a housing. A tube extends into the housing. An armature mounts inside of the tube and can move longitudinally within the tube. A coil assembly, which includes a primary coil and two secondary coils mounts on the outside of the tube. The coil assembly has adjustable connection with the housing. Consequently, the coil assembly can be adjusted longitudinally with respect to the armature until the LVDT is in the null position. That occurs when the differential voltage from alternating current through the secondary coils is zero.

Abstract: A method for inspecting a metallic component comprises providing an inspection standard having an eddy current signature substantially similar to an eddy current signature of the metallic component, wherein the inspection standard body is fabricated from a non-metallic material. The method also comprises inspecting the metallic component with an eddy current probe with reference to the inspection standard.

Abstract: Improved calibrations associated with superconducting quantum interference devices (SQUIDs) are accomplished using a single calibration ring that is placed on an outer dewar wall. During initial calibration, a standard current is passed through the calibration ring and channel responses are measured and recorded.

Abstract: A method is disclosed for determining the presence of response abnormalities in magnetic sensors. The method includes placing the sensor in an applied magnetic field and collecting sensor resistance information as the magnitude and direction of the applied field is altered. The resistance values are then examined to determine the presence of response abnormalities.

Abstract: An apparatus and method that tests an NMR system, including MRI scanners, by taking H-B measurements for the apparatus at any stage during the manufacture thereof, to thereby detect any defects of the NMR system at any point during the manufacture thereof.

Abstract: The sensor for measuring a magnetic field comprises a substrate (1), a first magnetic element (2), a second magnetic element (3), a third magnetic element (4) and a fourth magnetic element (5) in a bridge configuration on the substrate (1), a first bridge portion (8), wherein the first element (2) and the second element (3) are connected in series, and a second bridge portion (9), wherein the third element (4) and the fourth element (5) are connected in series, being situated between a first contact (6) and a second contact (7).

Abstract: A method and system for calibrating a magnetic sensor having at least one magnet and at least one sensing element incorporated therein is disclosed. A magnetization direction of a magnet is altered in at least one axis until a sensing element is balanced. The magnet can be calibrated separately from the electronic components associated with the magnetic sensor to thereby achieve an improved calibration over temperature variations associated with the magnetic sensor. The magnetic sensor can be configured to include one or more magnets and one or more sensing elements. Such magnets may be calibrated according to the methods and systems disclosed herein, in association with such sensing elements. Each magnet may be calibrated separately from the electronics associated with the magnetic sensor. The magnetization direction of the magnet may be altered in one or more axis until the sensing element is balanced. The magnetic sensor may, for example, comprise a gear tooth sensor or a wheelspeed sensor.

Abstract: A method and a device for detecting mispolarization in a signal transducer is described, with which the output signal of the signal transducer—that has at least one singularity—is converted into a square-wave signal. Intervals between specifiable signal-level changes are monitored in the region of the singularity, or plausibility windows are set, within which specifiable events must occur. If the intervals do not correspond to the expected intervals, or if specifiable events do not occur within the specifiable time windows or plausibility windows, mispolarization is detected. The method for detecting mispolarization is used, for example, in the case of a signal transducer having a plurality of uniform angular points and one reference point, but it is not limited to such transducers.

Abstract: A method and apparatus for non-destructively measuring the depth of a crack with precision and accuracy in a workpiece using an eddy current process. The method involves empirically creating a response curve of the eddy current response produced from crack(s) in a sample workpiece(s), wherein the depth of the crack(s) in the sample workpiece(s) may be modified a plurality of times and an eddy current response reading is taken at each different crack depth. The response curve is then used to interpolate the depth of a crack in a workpiece composed of the same material non-destructively by measuring the eddy current response in the workpiece crack and then obtaining the predetermined crack depth value form the response curve.