Magneto-resistive tachometer kit including two sensor modules providing different resolution quadrature outputs from the same rotor

• US 5,900,727 A
• Filed: 02/14/1997
• Issued: 05/04/1999
• Est. Priority Date: 01/17/1992
• Status: Expired due to Fees

• Current Assignee: Lake Shore Cryotronics, Inc.
• Original Assignee: Lake Shore Cryotronics, Inc.
• Inventors: Bioty, Joseph F., Griffen, Neil C., Stokes, Richard S.
• Primary Examiner(s): STRECKER, GERARD R
• Application Number:
  US08/799,367
• Time in Patent Office: 809 Days
• Field of Search: 324/160, 324/163, 324/165, 324/166, 324/173, 324/174, 324/175, 324/207.21, 324/207.25, 324/252, 361/239, 361/240, 340/671, 341/15, 318/461, 318/463, 318/464, 318/653, 310/68 B, 364/565, 73/510, 73/514.39
• US Class Current: 324/173
• CPC Class Codes: G01P 1/026 for speed measuring devices, e.g. pulse generator
• CPC Class Codes: G01P 21/02 of speedometers
• CPC Class Codes: G01P 3/481 of pulse signals
• CPC Class Codes: G01P 3/487 delivered by rotating magnets
• CPC Class Codes: G01P 3/489 Digital circuits therefor
• CPC Class Codes: H02K 7/20 Structural association with auxiliary dynamo-electric machines, e.g. with electric starter motors or exciters

Abstract

A rotary pulse generator kit for monitoring the rotation of a shaft includes an enclosure capable of accepting two different sensor modules. Each sensor module may include axially aligned magneto-resistive sensing elements that sense magnetic poles imprinted in a pattern on a rotor that rotates with the shaft. Two sensor modules having different incremental pulse output rates may be supplied with the tachometer kit. In this way, the shaft may be monitored by a pair of sensor modules pre-set at different incremental pulse output rates, mounted to the same enclosure.

Claims

1. A rotary pulse generator kit for use in measuring rotation of a rotatable shaft, the kit comprising:

a rotor for, in use, being coupled to and rotating with the shaft, the rotor carrying at least one magnetic pattern;

a first sensor module including at least a first magneto-resistive sensor element, the first sensor module, in use, sensing the magnetic pattern carried by the rotor and producing, in response, a first pair of output signals in quadrature at a first resolution;

a second sensor module including at least a second magneto-resistive sensor element, the second sensor module, in use, sensing the magnetic pattern carried by the rotor and producing, in response, a second pair of output signals in quadrature at a second resolution different from the first resolution; and

a housing having a first sensor module mounting structure for, in use, supporting and maintaining the first sensor module in proximity to the rotor so the first sensor module can magnetically sense the magnetic pattern carried by the rotor, the housing also having a second sensor module mounting structure for, in use, supporting and maintaining the second sensor module in proximity to the rotor so the second sensor module can magnetically sense the magnetic pattern carried by the rotor, the housing for, in use, at least partially enclosing and protecting the rotor.

2. A kit as in claim 1 wherein at least one of the first and second sensor modules comprises a programmable circuit arrangement providing a quadrature divider.

3. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a power supply regulator.

4. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a programmable logic device.

5. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a programmable logic circuit.

6. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a quadrature differential line driver.

7. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a programmable logic device programmed to provide a quadrature divide function.

8. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a differential bridge circuit producing a differential quadrature output.

9. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a waveform shaping circuit.

10. A kit as in claim 1 wherein at least one of the first and second sensor modules includes a voltage comparator.

11. A kit as in claim 10 wherein at least one of the first and second sensor modules further includes a circuit that provides an adjustable reference input to the voltage comparator.

12. A kit as in claim 1 wherein at least one of the first and second sensor modules produces a plurality of different resolution output signal pairs in quadrature and includes an arrangement for selecting between the plurality of different resolution quadrature output signal pairs.

13. A kit as in claim 1 wherein at least one of the first and second sensor modules also produces a marker pulse output signal.

14. A kit as in claim 1 wherein at least one of the first and second sensor modules produces a square wave output pulse train for use in position and velocity feedback and control applications.

15. A kit as in claim 1 wherein at least one of the first and second sensor modules produces a corresponding pair of output signals in quadrature at a frequency that is a multiple of the pulse frequency produced as the magnetic pattern carried by the rotor moves relative to the first and second sensor modules.

16. A kit as in claim 1 wherein at least one of the first and second sensor modules produces a corresponding pair of output signals in quadrature at a frequency that is a division of the pulse frequency produced as the magnetic pattern carried by the rotor moves relative to the first and second sensor modules.

17. A kit as in claim 1 wherein each of the first and second sensor modules is slidably inserted into their associated sensor mounting structures defined by the housing.

18. A kit as in claim 1 wherein said first sensor module produces, in response to an incremental pulse track carried by said rotor, said first pair of output signals in quadrature at a first incremental pulse output rate providing said first resolution;

and said second sensor module produces, in response to said same incremental pulse track carried by said rotor, said second pair of output signals in quadrature at a second incremental pulse output rate different from said first incremental pulse output rate, said second incremental pulse output rate providing said second resolution.

19. A kit as in claim 1 wherein said first sensor module is preset to provide said first pair of output signals in in quadrature at a first incremental pulse output rate, and said second sensor module is preset to produce said second pair of output signals quadrature at a second incremental pulse output rate different from said first incremental pulse output rate.

20. A kit as in claim 1 wherein said magnetic pattern carried by said rotor includes an incremental magnetic track comprising an alternating series of spaced, magnetically imprinted N and S poles, and said first and second magneto-resistive sensor elements each include interdigitated magneto-resistive sensing structures pitched in a predetermined relationship with said magnetically imprinted N and S pole spacing of said incremental magnetic track.

21. A kit as in claim 1 wherein:

said magnetic pattern carried by said rotor includes an incremental magnetic track comprising an alternating series of spaced, magnetically imprinted N and S poles,

said first sensor module provides said first pair of output signals in quadrature at a first incremental pulse output rate in response to movement of said incremental magnetic track in proximity to said first sensor module, and

said second sensor module provides said second pair of output signals in quadrature at a second incremental pulse output rate different from said first incremental pulse output rate, in response to movement of said incremental magnetic track in proximity to said second sensor module.