Real-time data acquisition system

• US 6,608,566 B1
• Filed: 02/07/2000
• Issued: 08/19/2003
• Est. Priority Date: 02/07/2000
• Status: Expired due to Fees

• Current Assignee: Larson Davis Incorporated
• Original Assignee: Larson Davis Incorporated
• Inventors: Davis, Larry J.
• Primary Examiner(s): EDWARDS JR, TIMOTHY
• Application Number:
  US09/499,847
• Time in Patent Office: 1,289 Days
• Field of Search: 340/870.11, 702/54, 702/56, 702/35, 735/83, 738/02, 735/88, 737/73
• US Class Current: 340/870.11
• CPC Class Codes: G01H 1/00 Measuring characteristics of vibrations in solids by using direct conduction to the detector G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G01H 3/00 Measuring characteristics of vibrations by using a detector in a fluid G01H7/00, G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G01V 1/22 Transmitting seismic signals to recording or processing apparatus
• CPC Class Codes: G08C 19/02 in which the signal transmitted is magnitude of current or voltage G08C19/36, G08C19/38 take precedence
• CPC Class Codes: G08C 19/24 using time shift of pulses
• CPC Class Codes: G10K 11/004 Mounting transducers, e.g. provided with mechanical moving or orienting device mountings specially adapted to a particular sound-producing device, see the preceding groups G10K1/00 - G10K9/00, e.g. G10K1/26, G10K1/28, G10K9/22; arrangements of sonic watch equipment on submarines B63G8/39; buoys B63B22/00

Abstract

A real-time, or synchronous, sensor data acquisition system acquires physical characteristics or properties associated with a structure or physical system using a plurality of sensors coupled in series to a single cable. The sensors may sense vibration, noise, temperature, acceleration, pressure, strain, force, etc. The sensors transmit data along the cable at greater than 100 dB dynamic range, with a bandwidth between about 5 to 20 KHz, and in a digital, single bit wide data stream. The sensors include modulators to code the data signals with distinct codes. A receiver has a demodulator to decode and separate the data signals.

Claims

1. A real-time, sensor data acquisition system configured to acquire data from a physical system, comprising:

a plurality of sensors, configured to be located on the structure and electrically coupled in series to a single cable, and configured to sense properties associated with the physical system and transmit data signals representing the properties along the cable; and

a controller, electrically coupled to the cable, configured to receive the data signals; and

the controller including a delay control counter and clock phase selector which match arrival times of the data signals transmitted from different location distances to one-half a period of a chip clock frequency.

2. The system of claim 1, wherein the sensors are selected from the group consisting of:

vibration sensors, acoustic sensors, temperature sensors, pressure sensors, strain sensors, force sensors, and accelerometers.

3. The system of claim 1, wherein the cable is over 100 feet long.

4. The system of claim 1, wherein the sensors are configured to transmit the data signals at greater than 100 dB dynamic range.

5. The system of claim 1, wherein the sensors are configured to transmit the data signals at a bandwidth between approximately 5 to 20 KHz.

6. The system of claim 1, wherein the cable includes at least two wire pairs, including:

a first signal pair configured to carry data signals from the sensor circuitry; and

a second clock pair configured to carry clock signals; and

wherein either pair is configured to provided power.

7. The system of claim 1, wherein the cable includes at least three wire pairs, including:

a first signal pair configured to carry data signals from the sensor circuitry;

a second clock pair configured to carry clock signals; and

a third power pair configured to provide power to the sensor circuitry.

8. The system of claim 1, further comprising display means, electrically coupled to the controller, configured for displaying the physical characteristics associated with the structure.

9. The system of claim 1, wherein the plurality of sensors includes nearer sensors located nearer the controller along the cable and a furthest sensor located furthest from the controller along the cable;

and wherein the nearer sensors have delays in transmission of signals to match a delay in transmission of a signal from the furthest sensor, such that all the signals are received synchronously at the controller.

10. The system of claim 1, wherein the control includes circuitry configured to correct for delay of the data signals to within 25 nanoseconds.

11. The system of claim 1, wherein the sensors are configured to code the data signals, and the controller is configured to decode the data signals.

12. The system of claim 1, wherein the sensors and controller utilize code division multiple access techniques to respectively send and receive the data signals.

13. The system of claim 1, wherein each sensor is configured to produce a sensor signal, and includes a modulator configured to modulate the sensor signal with a distinct code to produce the data signal;

and wherein the controller includes a demodulator to demodulate the data signals.

14. The system of claim 1, wherein the controller includes circuitry to correct intersymbol interference by summing the data signals to produce a sum, multiplying the sum by a corrective ratio to produce a correction signal, summing the correction signal to the data signals.

15. The system of claim 1, wherein the sensor is configured to produce a sensor signal, and the sensor includes:

an analog-to-digital converter configured to convert the sensor signal to a digital bit stream; and

a modulator configured to encode the digital bit stream with an m-sequence modulation.

16. The system of claim 1, wherein the sensor is configured to produce a single bit wide data stream.

17. The system of claim 1, wherein each sensor includes a chip generator configured to generate one of a plurality of distinct chip codes;

and wherein the plurality of sensors connected to the cable is less than or equal to a number of distinct chip codes.

18. The system of claim 1, wherein each sensor includes a chip generator configured to generate one of 63 distinct chip codes;

and wherein the plurality of sensors connected to the cable is 48 or less.

19. The system of claim 1, wherein the single cable is one of a plurality of cables, each of the plurality of cables being connected to a plurality of sensors, such that each sensor is connected to a cable in series with another sensor.

20. The system of claim 1, wherein the sensors are located at separate locations.

21. The system of claim 1, wherein the sensors are located at a common location.

22. The system of claim 1, wherein some of the sensors are configured to sense a different properties of the physical system.

23. A real-time, sensor data acquisition system configured to sense data from a structure, comprising:

a cable;

a plurality of sensors, configured to be located on the structure and electrically connected in series to the cable, and configured to sense physical characteristics associated with the structure and having sensor circuitry configured to transmit data signals representing the physical characteristics along the cable;

a controller, electrically coupled to the cable, and having controller circuitry configured to receive the data signals;

the controller including circuitry to correct intersymbol interference by summing the data signals to produce a sum, multiplying the sum by a corrective ratio to produce a correction signal, summing the correction signal to the data signals.

24. The system of claim 23, wherein the sensors are selected from the group consisting of:

vibration sensors, acoustic sensors, temperature sensors, pressure sensors, strain sensors, force sensors, and accelerometers.

25. The system of claim 23, further comprising display means, coupled to the controller, configured for displaying the physical characteristics associated with the structure.

26. The system of claim 23, wherein the cable is over 100 feet long.

27. The system of claim 23, wherein the sensor circuitry is configured to transmit the data signals at greater than 100 dB dynamic range.

28. The system of claim 23, wherein the sensors are configured to transmit the data signals at a bandwidth between approximately 5 to 20 KHz.

29. The system of claim 23, wherein the cable includes at least two wire pairs, including:

a first signal and control pair configured to carry data signals from the sensor circuitry and to carry control signals from the controller; and

a second clock pair configured to carry clock signals from the controller; and

wherein either pair is configured to provided power.

30. The system of claim 23, wherein the cable includes at least three wire pairs, including:

a first signal and control pair configured to carry data signals from the sensor circuitry and to carry control signals from the controller;

a second clock pair configured to carry control signals from the controller; and

a third power pair configured to provide power to the sensor circuitry.

31. The system of claim 23, wherein the plurality of sensors includes nearer sensors located nearer the controller along the cable and a furthest sensor located furthest from the controller along the cable;

and wherein the nearer sensors have delays in transmission of signals to match a delay in transmission of a signal from the furthest sensor, such that all the signals are received synchronously at the controller.

32. The system of claim 23, wherein the control circuitry includes circuitry configured to correct for delay of the data signals to within 25 nanoseconds.

33. The system of claim 23, wherein the control circuitry includes a delay control counter and clock phase selector which match arrival times of the data signals transmitted from different locations distances to one-half a period of a chip clock frequency.

34. The system of claim 23, wherein the sensor circuitry is configured to produce a single bit wide data stream.

35. The system of claim 23, wherein the sensor circuitry is configured to code the data signals, and the control circuitry is configured to decode the data signals.

36. The system of claim 23, wherein the sensor circuitry and controller circuitry utilize code division multiple access techniques to respectively send and receive the data signals.

37. The system of claim 23, wherein each sensor is configured to produce a sensor signal, and the sensor circuitry of each sensor includes a modulator configured to modulate the sensor signal with a distinct code to produce the data signal;

and wherein the control circuitry includes a demodulator to demodulate the data signals.

38. The system of claim 23, wherein the sensor is configured to produce a sensor signal, and the sensor circuitry includes:

an analog-to-digital converter configured to convert the sensor signal to a digital bit stream; and

a modulator configured to encode the digital bit stream with an m-sequence modulation.

39. The system of claim 23, wherein the sensor circuitry of each sensor includes a chip generator configured to generate one of a plurality of distinct chip codes;

and wherein the plurality of sensors connected to the cable is less than or equal to a number of distinct chip codes.

40. The system of claim 23, wherein the sensor circuitry of each sensor includes a chip generator configured to generate one of 63 distinct chip codes;

and wherein the plurality of sensors connected to the cable is 48 or less.

41. The system of claim 23, wherein the single cable is one of a plurality of cables, each of the plurality of cables being connected to a plurality of sensors, such that each sensor is connected to a cable in series with another sensor.

42. The system of claim 23, wherein the sensors are located at separate locations.

43. The system of claim 23, wherein the sensors are locates at a common location.

44. The system of claim 23, wherein some of the sensors are configured to sense a different physical property.

45. A real-time, sensor data acquisition system configured to sense vibration of a structure, comprising:

a cable;

a plurality of vibration sensors, configured to be located on the structure and electrically connected in series to the cable, and configured to sense vibration of the structure and having sensor circuitry configured to transmit data signals representing the vibration along the cable;

a controller, electrically coupled to the cable, and having controller circuitry configured to receive the data signals;

the control circuitry including a delay control counter and clock phase selector which match arrival times of the data signals transmitted from different location distances to one-half a period of a chip clock frequency.

46. The system of claim 45, further comprising display means, coupled to the controller, configured for displaying the vibration associated with the structure.

47. The system of claim 45, wherein the cable is over 100 feet long.

48. The system of claim 45, wherein the sensor circuitry is configured to transmit the data signals at greater than 100 dB dynamic range.

49. The system of claim 45, wherein the sensors are configured to transmit the data signals at a bandwidth between approximately 5 to 20 KHz.

50. The system of claim 45, wherein the cable includes at least two wire pairs, including:

a first signal and control pair configured to carry data signals from the sensor circuitry and to carry control signals from the controller; and

a second clock pair configured to carry clock signals from the controller; and

wherein either pair is configured to provided power.

51. The system of claim 45, wherein the cable includes at least three wire pairs, including:

a first signal and control pair configured to carry data signals from the sensor circuitry and to carry control signals from the controller;

a second clock pair configured to carry control signals from the controller; and

a third power pair configured to provide power to the sensor circuitry.

52. The system of claim 45, wherein the plurality of sensors includes nearer sensors located nearer the controller along the cable and a furthest sensor located furthest from the controller along the cable;

and wherein the nearer sensors have delays in transmission of signals to match a delay in transmission of a signal from the furthest sensor, such that all the signals are received synchronously at the controller.

53. The system of claim 45, wherein the control circuitry includes circuitry configured to correct for delay of the data signals to within 25 nanoseconds.

54. The system of claim 45, wherein the sensor circuitry is configured to produce a single bit wide data stream.

55. The system of claim 45, wherein the sensor circuitry is configured to code the data signals, and the control circuitry is configured to decode the data signals.

56. The system of claim 45, wherein the sensor circuitry and controller circuitry utilize code division multiple access techniques to respectively send and receive the data signals.

57. The system of claim 45, wherein each sensor is configured to produce a sensor signal, and the sensor circuitry of each sensor includes a modulator configured to modulate the sensor signal with a distinct code to produce the data signal;

and wherein the control circuitry includes a demodulator to demodulate the data signals.

58. The system of claim 45, wherein the sensor is configured to produce a sensor signal, and the sensor circuitry includes:

an analog-to-digital converter configured to convert the sensor signal to a digital bit stream; and

a modulator configured to encode the digital bit stream with an m-sequence modulation.

59. The system of claim 45, wherein the sensor circuitry of each sensor includes a chip generator configured to generate one of a plurality of distinct chip codes;

and wherein the plurality of sensors connected to the cable is less than or equal to a number of distinct chip codes.

60. The system of claim 45, wherein the sensor circuitry of each sensor includes a chip generator configured to generate one of 63 distinct chip codes;

and wherein the plurality of sensors connected to the cable is 48 or less.

61. The system of claim 45, wherein the controller includes circuitry to correct intersymbol interference by summing the data signals to produce a sum, multiplying the sum by a corrective ratio to produce a correction signal, summing the correction signal to the data signals.

62. The system of claim 45, wherein the single cable is one of a plurality of cables, each of the plurality of cables being connected to a plurality of sensors, such that each sensor is connected to a cable in series with another sensor.

63. The system of claim 45, wherein the sensors are located in different locations.

64. The system of claim 45, wherein the sensors are located in a common location.

65. The system of claim 45, further comprising other sensors configured to sense a different physical characteristic other than vibration.

66. A method for real-time, sensor data acquisition, the method comprising the steps of:

a) locating a plurality of sensors at desired sensor locations;

b) locating a single cable along the desired sensor locations;

c) electrically connecting the plurality of sensors in series to the single cable;

d) sensing properties of a physical system with the sensors;

e) producing data signals representing the properties;

f) transmitting the data signals with distinct delays along the single cable;

g) receiving the data signals synchronously at a controller; and

h) matching arrival times of the data signals to one-half a period of a chip clock frequency using a delay control counter and clock phase selector.

67. The method of claim 66, wherein locating the plurality of sensors at the desired sensor locations includes locating the sensors on a structure.

68. The method of claim 66, wherein the sensors are selected from the group consisting of:

vibration sensors, acoustic sensors, temperature sensors, pressure sensors, strain sensors, force sensors, and accelerometers.

69. The method of claim 66, further comprising displaying the properties associated with the physical system.

70. The method of claim 66, wherein the cable is over 100 feet long.

71. The method of claim 66, wherein transmitting the data signals includes transmitting the data signals at greater than 100 dB dynamic range.

72. The method of claim 66, wherein transmitting the data signals includes transmitting the data signals at a bandwidth between approximately 5 to 20 KHz.

73. The method of claim 66, wherein the cable includes at least two wire pairs, including:

a first signal and control pair configured to carry data signals from the sensor circuitry and to carry control signals from the controller; and

a second clock pair configured to carry clock signals from the controller; and

wherein either pair is configured to provided power.

74. The method of claim 66, wherein the cable includes at least three wire pairs, including:

a first signal and control pair configured to carry data signals from the sensor circuitry and to carry control signals from the controller;

a second clock pair configured to carry control signals from the controller; and

a third power pair configured to provide power to the sensor circuitry.

75. The method of claim 66, wherein the plurality of sensors includes nearer sensors located nearer the controller along the cable and a furthest sensor located furthest from the controller along the cable;

and further comprising delaying capture of the data signals to match a delay of the furthest sensor.

76. The method of claim 66, further comprising delay correcting the data signals to within 25 nanoseconds.

77. The method of claim 66, wherein producing data signals includes producing data signals with in a single bit wide data stream.

78. The method of claim 66, wherein producing the data signals includes coding the data signals;

and further comprising decoding the data signals.

79. The method of claim 66, wherein producing data signals includes producing sensor signals, and modulating the sensor signals with distinct codes to produce the data signals;

and further comprising demodulating the data signals.

80. The method of claim 66, wherein the sensor includes:

an analog-to-digital converter configured to convert the sensor signal to a digital bit stream; and

a modulator configured to encode the digital bit stream with an m-sequence modulation.

81. The method of claim 66, wherein the sensor circuitry of each sensor includes a chip generator configured to generate one of a plurality of distinct chip codes;

and wherein the plurality of sensors connected to the cable is less than or equal to a number of distinct chip codes.

82. The method of claim 66, wherein the sensor circuitry of each sensor includes a chip generator configured to generate one of 63 distinct chip codes;

and wherein the plurality of sensors connected to the cable is 48 or less.

83. The method of claim 66, further comprising correcting intersymbol interference by summing the data signals to produce a sum, multiplying the sum by a corrective ratio to produce a correction signal, summing the correction signal to the data signals.

84. The method of claim 66, wherein locating the single cable includes locating a plurality of cables;

and wherein connecting the plurality of sensors includes connecting each sensor to one of the plurality of cables, such that each sensor is connected to a cable in series with another sensor.

85. The method of claim 66, wherein locating the sensors includes locating the sensors in different locations.

86. The method of claim 66, wherein locating the sensors includes locating the sensors in a common location.

87. The method of claim wherein some of the sensors are configured to sense a different properties of the physical system.