Magneto-resistive tachometer sensor module with different resolution outputs for the same magnetic drum
First Claim
1. A tachometer including an enclosure for monitoring the speed and direction of rotation of a rotatable shaft, the tachometer comprising:
- a drum member attachable to the shaft for rotation therewith, the drum member being at least in part enclosed by the enclosure, the drum member having at least one magnetic pattern thereon; and
a sensor module, removably mountable to the enclosure, the sensor module comprising;
at least one magnetoresistive sensor disposed to cooperate with said drum member, and adapted to sense rotation of said shaft via said at least one magnetic pattern and further adapted to provide at least a responsive pair of electrical signals in quadrature; and
a programmable circuit connected to receive said pair of quadrature electrical signals, said programmable circuit scaling timings of said quadrature signal pair to provide at least a pair of scaled quadrature output signals, said programmable circuit including an output resolution selection circuit for setting the output resolution of said sensor module;
wherein said drum member in combination with a sensor module can be used to produce at least any selected one of plural different quadrature output resolutions each responsive to the same drum member magnetic pattern, the resolution of the sensor module quadrature output signals being determined by the output resolution set by the output resolution selection circuit.
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Accused Products
Abstract
A tachometer for monitoring the rotation of an output shaft (e.g. of a motor, where the motor is enclosed within a standard NEMA housing), includes an enclosure (e.g. adapted to be secured to an end plate of the motor housing), the enclosure having a radial center and a longitudinal axis which, when the enclosure is secured to the housing, are aligned with a longitudinal axis of the output shaft. The enclosure has at least one mounting surface in a peripheral wall portion thereof, the mounting surface having an aperture formed therein which opens in a radial direction. A sensor module including a pair of axially aligned magneto-resistive sensors is mountable on the mounting surface of the enclosure such that the module protrudes through the aperture with the sensors facing radially inwardly. An annular drum having a pair of magnetic patterns arranged on a peripheral end surface thereof is operatively fixed on the motor output shaft via a hub member such that the magnetic patterns on the drum are automatically aligned with the sensors and radially spaced therefrom by a predetermined radial gap when the drum is fixed to the output shaft and the enclosure is mounted on the end plate in an operatively assembled relationship.
59 Citations
42 Claims
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1. A tachometer including an enclosure for monitoring the speed and direction of rotation of a rotatable shaft, the tachometer comprising:
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a drum member attachable to the shaft for rotation therewith, the drum member being at least in part enclosed by the enclosure, the drum member having at least one magnetic pattern thereon; and a sensor module, removably mountable to the enclosure, the sensor module comprising; at least one magnetoresistive sensor disposed to cooperate with said drum member, and adapted to sense rotation of said shaft via said at least one magnetic pattern and further adapted to provide at least a responsive pair of electrical signals in quadrature; and a programmable circuit connected to receive said pair of quadrature electrical signals, said programmable circuit scaling timings of said quadrature signal pair to provide at least a pair of scaled quadrature output signals, said programmable circuit including an output resolution selection circuit for setting the output resolution of said sensor module; wherein said drum member in combination with a sensor module can be used to produce at least any selected one of plural different quadrature output resolutions each responsive to the same drum member magnetic pattern, the resolution of the sensor module quadrature output signals being determined by the output resolution set by the output resolution selection circuit. - View Dependent Claims (2, 3, 11, 12, 13, 14)
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4. A tachometer for providing at least one electrical quadrature output indicating rotation of a shaft member, said tachometer including a housing for at least partially enclosing either of at least first and second interchangeable drum members, said first and second drum members having different diameters and each having magnetic indicia thereon, and each drum member being adapted for selective mounting on the shaft member for rotation therewith, the housing having at least one sensor module mounting structure,
the tachometer comprising at least one quadrature sensor module for, in use, being mounted to the sensor module mounting structure and being magnetically coupled to a selected one of the first and second drum members, said sensor module cooperating with either of said first and second interchangeable drum members to sense the magnetic indicia disposed on either of said first and second drum members, said sensor module being programmable to provide any of: - (a) a first resolution quadrature output responsive to drum member magnetic indicia and indicative of drum member rotation, and (b) a second resolution quadrature output responsive to the same drum member magnetic indicia and indicative of drum member rotation, the second resolution being different from the first resolution, said quadrature sensing module including;
a magneto-resistive sensing array for magnetically coupling to the drum member mounted on the shaft member, the sensing array producing a quadrature signal responsive to drum member rotation, and a programmable quadrature scaling circuit coupled to the magneto-resistive sensing array, the programmable quadrature scaling circuit scaling the frequency of the quadrature signal produced by the sensing array to produce a scaled quadrature output, the sensor module including at least one component that can be configured to select at least one of said first resolution quadrature output and said second resolution quadrature output for the same magnetic drum member magnetic indicia. - View Dependent Claims (5, 6, 7, 8)
- (a) a first resolution quadrature output responsive to drum member magnetic indicia and indicative of drum member rotation, and (b) a second resolution quadrature output responsive to the same drum member magnetic indicia and indicative of drum member rotation, the second resolution being different from the first resolution, said quadrature sensing module including;
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9. A method for monitoring the speed and direction of rotation of a rotatable shaft having, attached thereto, a drum member that rotates with said shaft, the drum member being at least partially enclosed by a drum enclosure, the drum member carrying a magnetic pattern having a number of magnetic poles, said method comprising:
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(a) providing a sensor module including at least one magneto-resistive sensor array and at least one digital circuit capable of providing any of a plurality of different resolution outputs for the same drum member magnetic pattern; (b) configuring and/or connecting the sensor module to output at least a selected one of the plurality of different resolution outputs for the same drum member magnetic pattern; (c) removably mounting the sensor module to the enclosure and magnetically coupling the sensor module to the drum member; (d) sensing said magnetic pattern poles with the magneto-resistive sensor array; (e) generating, with the magneto-resistive sensor array, at least a pair of electrical signals in quadrature responsive to the magnetic pattern poles sensed by sensing step (d); and (f) processing, with the digital circuit, said quadrature signal pair to provide a pair of quadrature output signals at the output resolution selected by step (b), the quadrature output signals indicating the direction of rotation of said shaft and also indicating, at the selected output resolution, the speed of rotation of said shaft. - View Dependent Claims (10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method for providing an electrical output signal indicating rotation of a shaft member, said method comprising:
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(a) at least partially enclosing, within a housing, either of at least first and second interchangeable drum members, said first and second drum members each having magnetic patterns thereon, said magnetic patterns each including a number of magnetic poles, the first drum member magnetic pattern having a different number of magnetic poles than the second drum member magnetic pattern; (b) mounting either of said first and second drum members on the shaft member for rotation therewith; (c) providing at least one sensor module including a magneto-resistive sensing array and a programmable logic device, the sensor module being configured to select at least one of a plurality of different output resolutions, the sensor module being capable of providing multiple different output resolutions for the magnetic pattern of the mounted drum member; (d) slidably inserting the sensor module into the housing and magnetically coupling the sensor module to the drum member mounted by step (b); (e) sensing, with the inserted sensor module, the magnetic pattern disposed on the one of said first and second drum members mounted by said mounting step; and (f) generating, with the sensor module in response to said sensing step, quadrature output signals indicative of drum member rotation, said quadrature output signals having an output resolution that depends at least in part upon (1) the number of magnetic pattern poles on the drum member mounted by said mounting step, and (2) the output resolution selected by the sensor module configuration. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification