Electricity meter

• US 6,617,978 B2
• Filed: 05/14/2001
• Issued: 09/09/2003
• Est. Priority Date: 10/15/1998
• Status: Expired due to Term

• Current Assignee: Landis+Gyr Innovations Incorporated (Landis+Gyr Group AG)
• Original Assignee: SchlumbergerSema Inc (Schlumberger NV)
• Inventors: Swanson, Scott, Ridenour, Ronald E.
• Primary Examiner(s): Edwards, Timothy
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US09/855,185
• Publication Number:
  US 20010052859A1
• Time in Patent Office: 848 Days
• Field of Search: 340/870.02, 340/870.03, 340/870.29, 340/870.01, 324/142, 250/231.15, 250/231.19, 250/231.16, 342/96
• US Class Current: 340/870.29
• CPC Class Codes: G01R 11/02 Constructional details
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G08C 19/36 using optical means to covert the input signal characterised by optical transfer means G01D5/26; optical analogue digital converters G02F7/00

Abstract

A meter for measuring electricity usage for a given load includes a housing and two light sources disposed in the housing and configured to output light at a predetermined frequency. Two light receivers are disposed in the housing so that a light path is defined between each light source and its respective light receiver. Each light receiver is configured to receive the light from its light source and to output a signal responsively thereto. A rotatable member is disposed in the housing in the light paths and is rotatable responsively to the electricity usage. The member has a first portion and a second portion. The first portion transmits incident light while the second portion blocks light. The first portion and the second portion are defined on the member so that the member modulates the light as it rotates. A filter circuit in communication with the light receiver is configured to receive the output signal from the light receiver and to detect therefrom modulation of the light by the rotatable member.

Claims

1. A meter for measuring electricity usage for a given load, said meter comprising:

a housing;

a first light source and a second light source, each of said light sources being disposed in said housing and configured to output light therefrom;

a first light receiver and a second light receiver, each of said light receivers being disposed in said housing, such that a first light path is defined between said first light source and said first light receiver and a second light path is defined between said second light source and said second light receiver, and wherein each of said light receivers is configured to receive light from its respective said light source and to output a signal responsively thereto; and

a rotatable member disposed in said housing and being rotatable responsively to said electricity usage, said rotatable member being disposed so as to intercept each of said first light path and said second light path as said rotatable member rotates.

2. The meter as in claim 1, wherein said rotatable member defines a first portion and a second portion so that said first portion and said second portion alternatingly intercept each of said first light path and said second light path as said rotatable member rotates.

3. The meter as in claim 2, wherein said first portion transmits incident light from a said light source to its respective said light receiver and wherein said second portion blocks said incident light, and wherein one of said first portion and said second portion is defined on said rotatable member so that said one of said first and second portions can intercept only one of said first light path and said second light path at a time.

4. The meter as in claim 3, further including filter processing means for filtering said output signals and processing same.

5. The meter as in claim 4, wherein said filter processing means further includes means for comparing said filtered and processed output signals with a predetermined value.

6. The meter as in claim 5, wherein said predetermined value comprises a threshold voltage.

7. The meter as in claim 3, further including a filter circuit having two band pass filters, each in communication with a respective one of said first light receiver and said second light receiver, wherein each said band pass filter receives said output signal from its said respective light receiver and passes a frequency range that includes the frequency of said light outputs of said first and second light sources so that said band pass filter outputs a signal at such frequency upon receipt of said light receiver output signal.

8. The meter as in claim 7, wherein said filter circuit further includes:

two acquisition circuits, each in communication with a respective one of said band pass filters, wherein each said acquisition circuit receives said output signal from its said respective band pass filter and is configured to output responsively thereto a signal having a magnitude based on the magnitude of said band pass filter output signal, and

two comparator circuits, each in communication with a respective one of said acquisition circuits, wherein each said comparator circuit receives said output signal from its said respective acquisition circuit and is configured to compare said acquisition circuit output signal with a threshold voltage and output a signal in one of two states depending on said comparison.

9. The meter as in claim 1, wherein said rotatable member is a disk.

10. The meter as in claim 1, wherein said first and second light sources are configured to output light therefrom at a predetermined frequency.

11. The meter as in claim 10, wherein said output signals of each of said light receivers is output at a frequency related to said predetermined frequency by a predetermined relationship.

12. The meter as in claim 11, wherein said rotatable member is disposed so as to alternatingly intercept each of said first light path and said second light path as said rotatable member rotates.

13. The meter as in claim 9, wherein said disk defines first and second slots therein.

14. The meter as in claim 13, wherein said first slot and said second slot are angularly offset from each other with respect to the axis of said disk, and wherein one of said first portion and said second portion has an angular width at a first arc defined by a radius extending from said axis to said first slot and at a second arc defined by a radius extending from said axis to said second slot less than the angular distance between said first slot and said second slot.

15. The meter as in claim 14, wherein said first arc and said second arc are the same.

16. The meter as in claim 2, wherein said first portion reflects said incident light.

17. The meter as in claim 2, wherein said first portion is transparent to said incident light.

18. The meter as in claim 2, wherein said second portion is transparent to said incident light.

19. The meter as in claim 2, wherein said second portion absorbs said incident light.

20. The meter as in claim 2, wherein said second portion reflects said incident light.

21. The meter as in claim 14, wherein said one of said first portion and said second portion defines an angular width at said first arc and at said second arc at least approximately 20°

.

22. The meter as in claim 21, wherein said one of said first portion and said second portion defines an angular width at said first arc and at said second arc of approximately 24°

.

23. The meter as in claim 2, wherein said rotatable member is a disk, wherein said first and second light sources and said first and second light receivers are disposed on the same side of a plane defined by said disk, and wherein said first portion reflects said incident light and said second portion is non-reflective to said incident light.

24. The meter as in claim 2, wherein said rotatable member is a disk, wherein each said light source and its respective said light receiver are disposed on opposite sides of a plane defined by said disk, wherein said first portion comprises at least one hole defined by said disk and transparent to said incident light, and wherein said second portion comprises a solid, nontransparent section of said disk.

25. The meter as in claim 1, wherein each of said first light source and said second light source includes an infrared light emitting diode and a circuit configured to drive said diode at a predetermined frequency.

26. The meter as in claim 1, wherein each said light source outputs said light having a frequency of approximately 8 kHz.

27. The meter as in claim 1, wherein each of said light receivers includes a photo-transistor.

28. A meter for measuring electricity usage for a given load, said meter comprising:

a housing;

a first light source and a second light source, each of said light sources being disposed in said housing and configured to output light at a predetermined frequency;

a first light receiver and a second light receiver, each of said light receivers being disposed in said housing, such that a first light path is defined between said first light source and said first light receiver and a second light path is defined between said second light source and said second light receiver, and wherein each of said light receivers is configured to receive light from its respective said light source and to output a signal responsively thereto at a frequency related to said predetermined frequency by a predetermined relationship; and

a rotatable member disposed in said housing and being rotatable responsively to said electricity usage, said rotatable member defining a first portion and a second portion so that said first portion and said second portion alternatingly intercept each of said first light path and said second light path as said rotatable member rotates.

29. A meter as in claim 28, wherein said first portion transmits incident light from a said light source to its respective said light receiver and wherein said second portion blocks said incident light, and wherein one of said first portion and said second portion is defined on said rotatable member so that said one of said first and second portions can intercept only one of said first light path and said second light path at a time.

30. A meter as in claim 29, further including a filter circuit, including:

two band pass filters, each in communication with a respective one of said first light receiver and said second light receiver, wherein each said band pass filter receives said output signal from its said respective light receiver and passes a frequency range that includes said related frequency so that said band pass filter outputs a signal at said related frequency upon receipt of said light receiver output signal,

two acquisition circuits, each in communication with a respective one of said band pass filters, wherein each said acquisition circuit receives said output signal from its said respective band pass filter and is configured to output responsively thereto a signal having a magnitude based on the magnitude of said band pass filter output signal, and

two comparator circuits, each in communication with a respective one of said acquisition circuits, wherein each said comparator circuit receives said output signal from its said respective acquisition circuit and is configured to compare said acquisition circuit output signal with a threshold voltage and output a signal in one of two states depending on said comparison.

31. A meter for measuring electricity usage for a given load, said meter comprising:

a housing;

a first light source and a second light source, each said light source disposed in said housing and configured to output light at a predetermined frequency;

a first light receiver and a second light receiver, wherein each said light receiver is disposed in said housing so that a first light path is defined between said first light source and said first light receiver and so that a second light path is defined between said second light source and said second light receiver, and wherein each said light receiver is configured to receive said light from its respective said light source and to output a signal responsively thereto at a frequency related to said predetermined frequency by a predetermined relationship;

a rotatable member disposed in said housing and being rotatable responsively to said electricity usage, said rotatable member defining a first portion and a second portion so that said first portion and said second portion alternatingly intercept each of said first light path and said second light path as said rotatable member rotates,

wherein said first portion transmits incident light from said light source to its respective said light receiver and wherein said second portion blocks said incident light, and wherein one of said first portion and said second portion is defined on said rotatable member so that said one of said first and second portions can intercept only one of said first light path and said second light path at a time; and

a filter circuit in communication with a respective one of said first light receiver and said second light receiver, wherein said filter circuit receives said output signal from said respective light receiver and passes a frequency range that includes said related frequency so that said filter circuit outputs a signal at said related frequency upon receipt of said light receiver output signal,

an acquisition circuit in communication with said filter circuit, wherein said acquisition circuit receives said output signal from said filter circuit and is configured to output responsively thereto a signal having a magnitude based on the magnitude of said filter circuit output signal, and

a comparator circuit in communication with said acquisition circuit, wherein said comparator circuit receives said output signal from said acquisition circuit and is configured to compare said acquisition circuit output signal with a threshold voltage and output a signal in one of two states depending on said comparison.

32. Meter for measuring electricity usage for a given load, said meter comprising:

a housing;

a plurality of light sources, each of said plurality of light sources disposed in said housing and configured to output light at a predetermined frequency;

a plurality of light receivers, wherein each of said plurality of light receivers is disposed in said housing so that a plurality of light paths are defined between respective ones of said plurality of light sources and said plurality of light receivers, and wherein each of said plurality of light receivers is configured to receive said light from a respective one of said plurality of light sources and to output a signal responsively thereto at a frequency related to said predetermined frequency by a predetermined relationship;

a rotatable member disposed in said housing and being rotatable responsively to said electricity usage, said rotatable member defining a plurality of first portions and a plurality of second portions so that said plurality of first portions and said plurality of second portions alternatingly intercept each of said plurality of light paths as said rotatable member rotates,

wherein said plurality of first portions transmits incident light from said plurality of light sources to their respective said plurality of light receivers and wherein said plurality of second portions blocks said incident light and wherein one of said plurality of first portions and said plurality of second portions is defined on said rotatable member so that said one of said first and second portions can intercept only one of said plurality of light paths at a time; and

a plurality of filter circuits in communication with respective ones of said plurality light receivers, wherein said plurality of filter circuits receive said output signals from said plurality of light receivers and pass a frequency range that includes said related frequency so that said plurality of filter circuits output a signal at said related frequency upon receipt of said plurality of light receiver output signal.

33. A meter for measuring electricity usage for a given load as in claim 32, further comprising a plurality of acquisition circuits, in communication with said plurality of filter circuits, wherein said plurality of acquisition circuits receives said output signal from said plurality of filter circuits and are configured to output responsively thereto a signal having a magnitude based on the magnitude of said plurality of filter circuits output signal, and

a plurality of comparator circuits, in communication with said plurality of acquisition circuits, wherein said plurality of comparator circuits receives said output signal from said plurality of acquisition circuits and are configured to compare said plurality of acquisition circuits output signal with a threshold voltage and output a signal in one of two states depending upon said comparison.