Abstract: Systems, methods, and computer-readable media are disclosed for error-compensated counting of Hall states for motor position feedback and/or commutation. An indicated Hall state is detected by digital Hall state sensors and a duration of the Hall state is compared to a specified time period. When the duration exceeds the specified time period, the indicated Hall state is compared to one or more valid Hall states and a position counter is changed for valid states. When the indicated Hall state is invalid, the position counter is not changed. The Hall state sensors may be connected to logic means and may detect the position of a rotor of a permanent magnet motor relative to a stator. When noise induces a change in an indicated Hall state, corresponding noise-induced effects on the position counter may be may be removed through error-compensated counting.

Abstract: An inductive position sensor for rotary motion includes a transmitter coil and a receiver coil, the receiver coil generating a receiver signal when the transmitter coil is excited by an alternating current source. A moveable coupler element modifies the inductive coupling between the transmitter coil and the receiver coil so that the receiver signal is sensitive to the coupler element position. The ratio between the receiver signal and the reference signal is sensitive to the coupler element position, but substantially insensitive to common mode factors. The angular or positional range of the position sensor can be increased using a plurality of receiver coils.

Abstract: The invention relates to a magnetic flow sensor (1, 21, 51) comprising a) a loop-shaped magnetic field conductor comprising a point (2, 22, 32, 52) which expands to form a bar or a film (3, 23, 52), a loop-shaped part (3a, 23a, 53a) and at least one part (4, 24, 54?, 54?) which guides back the magnetic field lines of the probe, b) SQUID (7, 27, 57), c) and a diaphragm (5, 25, 35, 55) comprising a hole (6, 26, 36, 56), whereby the part (4, 24, 54?, 54?) which guides the magnetic field lines of the probe back to the loop-shaped magnetic field conductor is connected to the diaphragm (5, 25, 35, 55).

Abstract: A sonde includes an elongate flexible ferromagnetic core and a coil surrounds an intermediate segment of the core. A housing surrounds and supports the coil. An electronic drive circuit is mounted in the housing for supplying the coil with an electric signal that will induce the core to emit electromagnetic signals at a predetermined strength and frequency that can be remotely detected. Self-contained battery powered float-type and pill-type sondes are also disclosed.

Abstract: Tracking a boring tool is performed within an underground region using a locating signal. The boring tool is moved through the ground during a series of distance movements such that potential movement of the boring tool during any one of the distance movements is less than a maximum movement value. A current positional relationship is determined for a current one of the distance movements based on: a last-determined positional relationship established for an immediately preceding one of the distance movements, certain orientation parameters, the maximum movement value and the determined signal strength of the locating signal in the current positional relationship. Target coordinates are accepted and a target position, based on the target coordinates, is included as part of the current positional relationship. The position of the target is unconstrained with respect to system geometry. Steering command features are provided along with steering warnings.

Abstract: A rotation angle detecting device includes magnetic field forming members such as a permanent magnet and a yoke, a plurality of magnetic sensors disposed in the magnetic field to rotate relative to the magnetic field forming members to provide output signals that are 90 degrees in phase different from each other, a judgment level calculating circuit that provides a judgment level based on the output signals and judging circuit that judges the output signals normal if the judgment level is within a prescribed range and not normal if the judgment level is out of the prescribed range.

Abstract: A method and apparatus for detecting a defective disk for a hard disk drive. The method includes placing a disk into a tester so that a first side of the disk is adjacent to a first head of the tester and a second side of the disk is adjacent to a second head. First data is read from the first side of the disk, and second data is read from the second side of the disk. The disk is then flipped so that the second side is adjacent to the first head and the first side is adjacent to the second head. Third data is read from the first side. Fourth data is read from the second side. A first area between a curve generated from the first data and a curve generated from the third data is calculated. Likewise, a second area is calculated between a curve generated from the second data and a curve generated from the fourth data. An average of the first and second areas is then calculated and used to detect a defective disk.

Abstract: There is described a sensor comprising an excitation winding, a signal generator operable to generate an excitation signal and arranged to apply the generated excitation signal to the excitation winding, a sensor winding electromagnetically coupled to the excitation winding and a signal processor operable to process a periodic electric signal generated in the sensor winding when the excitation signal is applied to the excitation winding by the signal generator to determine a value of a sensed parameter. The excitation signal comprises a periodic carrier signal having a first frequency modulated by a periodic modulation signal having a second frequency, the first frequency being greater than the second frequency. In this way, the sensor is well suited to using digital processing techniques both to generate the excitation signal and to process the signal induced in the sensor windings. In an embodiment, the sensor is used to detect the relative position of two members.

Abstract: A pair of cores are arranged such that first end portions thereof face to each other with a gap via a conveying path through which a medium to be detected passes. Coils wound at the first end portions of the cores, respectively, are connected in series to each other, thereby constituting a first coil. Coils wound at second end portions on a side opposite to the first end portions are connected in series to each other, thereby constituting a second coil. There are provided an exciting coil which generates a detection magnetic field passing the cores and the gap, and a convergent magnetic field generating unit which generates, in the gap, a convergent magnetic field for converging the detection magnetic field in a direction perpendicular to a direction in which the first end portions of the cores are connected to each other.

Abstract: Apparatus (10) for establishing the positions of metal objects in a mixed input stream of both metal and non-metal objects, the apparatus comprising a differential metal-detecting coil (14A) having a first coil portion wound in a first sense and a second coil portion of generally similar shape and size to the first, wound in a second sense opposite to the first sense, and conveying means (11) for moving objects with respect to, and past, the differential metal-detecting coil in a plane and in a direction with unit vector â, characterised in that the second coil portion is displaced from the first coil portion by a displacement B having a component in the plane in a direction with unit vector {circumflex over (b)}, wherein 0 < cos - 1 ? a ^ · b ^ < ? 2 , and in that the apparatus further comprises analysing means for analysing the form of the output voltage of the coil as a function of time to establish the position of said metal objects in a direction ? in the plane, where ? is d

Abstract: The Hall switch arrangement comprises a plurality of Hall switch elements connected in series with a first Hall switch element, wherein the first Hall switch element is formed to provide a first output signal, which has information about a switching state of the first Hall switch element and with a second Hall switch element, wherein the second Hall switch element is formed to receive the first output signal of the first Hall switch element and to provide a further output signal having information about the switching state of the first Hall switch element and further information about the switching state of the second Hall switch element.

Abstract: A target activated sensor including a magnet, a magnetic field sensing element located proximate the magnet and a single ferrous pole located proximate the sensing element. The sensing element senses a change in magnetic field caused by the presence of a target. The magnet, sensing element and single pole piece may be combined in a single package.

Abstract: A wheel speed sensor includes a rotation detector mounted in an opening formed in a holder which is in turn inserted in a casing having one end closed. A pair of lead pieces extend from the detector and have connecting portions connected to respective relay terminals. A lid having a projection is fitted in the opening of the holder so that the projection is inserted between the connecting portions. The projection thus separates and insulates the connecting portions from each other. A cover is formed by molding a resin to cover the open end of the casing and the portion of the holder protruding from the open end of the casing.

Abstract: A non-contacting position sensor having primary and secondary sensors detects relative displacement between two objects. The secondary sensor may function as a limit switch detection element in a limit switch circuit, and is positioned to be in the path of magnetic flux not detected by the primary sensor. The primary sensor is positioned in a flux path between sections of a flux gathering pole. A secondary sensor is positioned in a leakage flux path outside the first sensor or may be positioned in a secondary flux path.

Abstract: The present invention relates to an ultra sensitive in-situ magnetometer system, and more particularly to an ultra sensitive in-situ magnetometer system that can in-situ monitor a magnetic moment of a magnetic thin film with sub-monolayer precision while depositing and growing the magnetic thin film in an ultra high vacuum (UHV) chamber.

Abstract: A superconducting magnetic field generating apparatus includes a superconducting body for generating a magnetic field below a critical temperature of the superconducting body, a thermal insulation vessel having a space for accommodating the superconducting body, and a ferromagnetic body for adjusting a magnetic field distribution generated from the superconducting body wherein at least a part of the ferromagnetic body is disposed around the superconducting body and a magnetic circuit is formed so as to form the magnetic field distribution in a common side of the superconducting body and the part of the ferromagnetic body.

Abstract: A conductive wire held between a first magnetic core of a soft magnetic film and a second magnetic core, the area of the cross-section, perpendicular to a magnetic path, of which is made partially smaller constitutes a magnetic detection device, and a DC current for generating a DC bias magnetic field and a high-frequency carrier signal are let to flow through the conductive wire. The DC current is selected so that the portion at which the cross-sectional area of the above-mentioned second magnetic core is made smaller has an appropriate DC bias magnetic field intensity. When this magnetic detection device is placed in an external magnetic field, the intensity of the DC bias magnetic field changes depending on the intensity of the external magnetic field; hence, the level of the carrier signal in the conductive wire changes. The change of the level of the carrier signal is output as the change of an electrical signal, whereby the intensity and direction of the magnetic field are detected.

Abstract: A stationary position detection circuit and a motor drive circuit capable of more properly detecting the rotor position are disclosed. The stationary position detection circuit supplies an alternating current to each phase load of the motor. The time during which the current flows in a first direction and the time during which the current flows in a second direction opposite to the first direction are converted into electrical signals and amplified. In accordance with the value of the electrical signals, the position of the motor rotor in stationary mode is determined. The use of the alternating current, unlike the kickback voltage, makes it possible to improve the detection accuracy by amplifying the electrical signals with an increased number of alternations. An increased number of alternations can amplify the electrical signals without increasing the value of the alternating current, and therefore, unlike in the case of the kickback voltage, the alternating current of a large value is not required.

Abstract: A position detection system and method for linear and rotary sensing applications are disclosed herein, including a plurality of magnetoresistive sensing components for linear and rotary detection sensing, and an integrated circuit for amplifying and calibrating signals generated by the magnetoresistive sensing components in order to provide a full digital calibration and a ratio-metric output voltage or digital output signal indicative of linear and rotary position data.

Abstract: Magnetic field sensors, each generating an electrical output signal in proportion to the local magnetic field, are lithographically fabricated on a semiconductor substrate with a small spatial separation. The lateral dimension of the sensors and the separation length are the order of the minimum lithographic feature size. Comparing the electrical signals of the sensors results in a measurement of the local magnetic field gradient. Large field gradients, that vary on a small spatial scale, may be associated small magnetic structures such as microscopic magnetic particles. Detection of a field gradient can be used to infer the presence of a magnetic particle.