Computer controlled energy monitoring system

• US 4,415,896 A
• Filed: 06/09/1981
• Issued: 11/15/1983
• Est. Priority Date: 06/09/1981
• Status: Expired due to Term

• Current Assignee: A-Dec Incorporated
• Original Assignee: A-Dec Incorporated
• Inventors: Allgood, Marvin D.
• Primary Examiner(s): Groody, James J.
• Application Number:
  US06/272,011
• Time in Patent Office: 889 Days
• Field of Search: 340/825.52, 340/870.02, 340/870.03, 340/870.04, 340/870.38, 340/870.11, 340/870.13, 340/606, 340/870.17, 340/825.07, 340/584, 338/22 R, 324/127, 364/480-483, 330/254, 330/278, 330/279, 330/284, 330/285
• US Class Current: 340/870.03
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01R 22/066 Arrangements for avoiding or indicating fraudulent use
• CPC Class Codes: G01R 22/10 using digital techniques
• CPC Class Codes: G01R 35/04 of instruments for measuring time integral of power or current
• CPC Class Codes: H04Q 9/16 by predetermined number of pulses

Abstract

Disclosed is a centralized data communications system incorporating a plurality of remote stations, each having a plurality of information channels associated therewith. A selected remote station and its associated information channels are tone addressed by a central station communicating with a group of remote stations over a respective communications channel. The remote stations may have a current sensor connected to one of the information channels for sending data corresponding to the amount of current sensed in an electrical path back to the central station upon being properly addressed. This data, together with data representative of the voltage on the monitored electrical path, is used by the central station to calculate energy consumption. The calculated energy consumption is retained at the central station and used for information and billing purposes. The central station may also send data to an addressed information channel at a remote station for controlling an operation thereat. The central station can also receive data from various parameter measuring sensors at a remote station, e.g. sensors measuring temperature, humidity, fluid flow, etc. which may be connected to other information channels and thus the system may be used as a general purpose data gathering or distributing communications system.

Claims

1. A data communications system comprising:

at least one communications channel;

at least one group of remote stations connected to a respective communications channel, each remote station comprising a plurality of information channels and tone addressable means for selectively connecting one of said plurality of information channels to a respectively communications channel, said tone addressable means comprising a tone detector for detecting clock tones on a respective communications channel, counting means for counting the number of clock tones detected, means for connecting one of said information channels to the respective communications channel in accordance with the number of clock tones which are counted, and means for enabling said connecting means only when the number of clock tones detected falls within a predetermined numerical range;

a central station connected to each said communications channel and comprising means for sequentially supplying clock tones in common to each said communications channel to cause sequential connection of the information channels at said remote stations to a respective communications channel associated therewith, and means for transmitting a signal to or receiving a signal from an information channel which is connected to a respective communications channel.

2. A data communications system as in claim 1, wherein said tone detector provides a clock signal upon the occurrence of each said clocking tone, said counting means comprises a first counter for counting the number of said clocking signals, said first counter providing a carry output signal when a predetermined number of clocking signals have been counted, said enabling means comprises means for presetting a predetermined remote station address, a second counter for counting the number of carry output signals and for providing an enable signal when said counted number of carry output signals is in a predetermined numerical relationship to said predetermined address, and said connecting means selectively connects one of said plurality of information channels to a respective communications channel in accordance with the number of clock signals counted by said first counter, said connecting means being rendered operative by said enable signal.

3. A data communications system as in claim 2, wherein said second counter provides said enable signal when said counter number of carry output signals numerically equals said predetermined address.

4. A data communications system as in claim 1, wherein at least one of said information channels has an electronic calibration component connected thereto which is selectively connected to a respective central communications channel by said connecting means when a predetermined number of clock signals have been counted by said counting means.

5. A data communications system as in claim 1, further comprising means at said remote stations coupled to a respective communications channel and responsive to a resetting tone thereon for providing reset signals to said counting means for resetting it to a predetermined operative counter state.

6. A data communication system as in claim 5, wherein said detecting means is responsive to a relatively short duration clocking tone on a said respective communications channel and said means for providing reset signals is responsive only to a relatively long duration resetting tone on said respective communications channel.

7. A data communications system as in claim 1, wherein said clocking tone is at a frequency of 100 Khz.

8. A data communications system as in claim 5, wherein said clocking tone and said resetting tone are at a frequency of 100 Khz.

9. A data communications system as in claim 2, wherein said means for detecting said clocking tone comprises a tuned filter having an output connected to the input of a one-shot multivibrator, the output of said multivibrator supplying said clocking signals.

10. A data communications system as in claim 5, wherein said means for providing reset signals comprises a tuned circuit and a timing circuit coupled to the output of the tuned circuit, said timing circuit producing an output signal only when a reset signal is applied to said tuned circuit for a predetermined period of time.

11. A data communication system as in claim 1 further comprising a power supply for supplying voltage to said tone detector, counting means, connecting means, and enabling means, said power supply deriving said voltage from tone signals present on said respective communications channel.

12. A data communications system as in claim 2, wherein said presetting means is programmable.

13. A data communications system as in claim 1, wherein said information channels and said respective communications channel are wire pairs.

14. A data communications system as in claim 13 further comprising a fuse in said communications channel at the entry thereof to each said remote station.

15. A data communications system as in claim 1 further comprising at least one parameter sensor connected to one of said information channels and wherein said central station further comprises means connected to said communications channel for measuring the output of said sensor during the time said one information channel is connected to said communications channel.

16. A data communications system as in claim 1 further comprising operative means at a remote station connected to one of said information channels which is responsive to a predetermined signal on said one information channel, and wherein said central station further comprises means connected to said communications channel for supplying said predetermined signal to said one information channel during the time said one information channel is connected to said communications channel.

17. A data communications system as in claim 16 wherein said predetermined signal is at least one instruction tone.

18. A data communicatins system as in claim 17 wherein said predetermined signal is one of a plurality of instruction tones and further comprising a programmable tone generator at said central station for generating one of said instruction tones, and a processor means for causing said programmable tone generator to generate a selected one of said instruction tones.

19. A data communications system as in claim 15, wherein said measuring means comprises an analog to digital converter means for converting said sensor output to a digital value and a processor means for storing said digital value.

20. A data communications system as in claim 19 further comprising means for combining a calibration signal obtained from said sensor under known conditions with said sensor output prior to the application of said sensor output to said analog to digital converter means.

21. A data communications system as in claim 19, wherein said sensor output is a changing resistance signal and further comprising means for converting said changing resistance to a changing voltage before the application of said sensor output to said analog to digital converter means.

22. A data communications system as in claim 21, wherein said converting means connects a voltage across the series connection of said sensor output and a resistor, said converter means being programmable by said processor means so that one of a plurality of possible voltage and resistor combinations is connected to the output of said sensor.

23. A data communications system as in claim 21, further comprising means for supplying a test voltage to the input of said analog to digital converter means, said processor means storing the digital value of said test voltage.

24. A data communications system as in claim 23, wherein said test voltage supplying means is programmable to supply one of a plurality of test voltages to said analog to digital converter means in accordance with instructions from said processor means.

25. A data communications system as in claim 1 further comprising:

at least one current sensor at at least one of said remote stations having an output connected to an associated information channel, said current sensor measuring the flow of current through an electrical path;

means at said central station for receiving the output of said current sensor during the period said associated information channel is coupled to a respective communications channel; and

,

means at said central station for computing the electrical power flowing through said electrical path, said computing means comprising;

means for deriving a voltage corresponding to the voltage on said electrical path;

means for multiplying a signal representative of said derived voltage by a signal representative of the output of said current sensor to provide a power value;

a first analog to digital converter means for digitizing the power value output of said multiplying means; and

,

processor means for storing the digitized output of said first analog to digital converter means.

26. A data communications system as in claim 25 wherein said processor means stores a plurality of digitized output signals of said first analog to digital converter means for each cycle of voltage on said electrical path and sums said digitized output signals for each said cycle.

27. A data communications system as in claim 26, wherein said voltage deriving means is connected to and derives said voltage from a power distribution system supplying voltage to said electrical path.

28. A data communications system as in claim 26, wherein said power distribution system is a multi-phase distribution system having at least one set of multiple phase input power lines and said voltage deriving means comprises means connected to each phase power line for deriving a voltage therefrom and means for selectively applying one of the derived voltages from said power lines to said multiplying means.

29. A data communications system as in claim 28, wherein said means for selectively applying selects one of said derived voltages in accordance with instructions received from said processor means.

30. A data communications system as in claim 25 further comprising at least one line voltage sensor at at least one of said remote stations having an output connected to an associated information channel, said line voltage sensor supplying an output signal representative of the voltage on said electrical path, said voltage deriving means comprising means at said central station for receiving the output of said voltage sensor during the period said information channel associated with said line voltage sensor is conneced to a respective communications channel.

31. A data communications system as in claim 25, wherein said multiplying means includes a second analog to digital converter means for digitizing said signal representing derived voltage and a multiplier for multiplying said signal representative of the output of said current sensor by said digitized derived voltage signal.

32. A data communications system as in claim 25, wherein said multiplying means includes an automatic gain control circuit for amplifying said signal representing the output of said current sensor by an amount required to place the output of said multiplying means within a predetermined signal level range.

33. A data communications system as in claim 32, wherein said automatic gain control circuit comprises means for detecting whether the output of said multiplying means is within said predetermined signal level range, programmable amplifying means for amplifying said signal representing the output of said current sensor by a factor determined by a value programmed therein, and means for repeatedly altering said programmed value until said detector indicates the output of said multiplying means is within said predetermined signal level range.

34. A data communications system as in claim 33, wherein said altering means comprises a counter for counting a counting signal, means for repeatedly supplying a counting signal to said counter until said detector indicates the output of said multiplying means is within said predetermined signal level range, and, means for decoding the contents of said counter to form said programmed value and for supplying said programmed value to said programmable amplifying means.

35. A data communications system as in claim 34, further comprising means for supplying the output of said counter to said processor means when the output of said multiplying means is within said predetermined signal level range, said processor means storing said counter output.

36. A data communications system as in claim 25, wherein said processor means calculates from stored power value outputs of said multiplying means energy consumed through said electrical path and provides an output display of said energy consumption.

37. A data communications system as in claim 25, wherein said multiplying means produces an inherent D.C. offset voltage during operation and said multiplying means including a capacitor means which is periodically charged to said D.C. offset voltage prior to the performance of a multiplying operation by said multiplying means by a periodically operated charging means, the charge on said capacitor means offsetting said offset voltage during operation of said multiplying means.

38. A data communications system as in claim 35, wherein said charging means is periodically operated by said processor means to charge said capacitor means.

39. A data communications system as in claim 1, further comprising:

a plurality of communications channels each having a respective group of remote stations associated therewith, each remote station of a group being able to connect an information channel thereof to a respective central communications channel in accordance with the number of detected clock tones which are counted by a counting means,

said central station being coupled to said plurality of communications channels such that clock tones from said central station are sequentially applied to each of said communications channels in common,

said central station further comprising means for transmitting a signal to or receiving a signal from an information channel connected to any one of said communications channels.

40. A data communications system as in claim 39, further comprising

at least one signal path in said central station;

and

a signal path selector means for selectively connecting said signal path to one of said communications channels, said signal path selector means comprising;

a plurality of input lines respectively connected to said plurality of communications channels, and a programmable line selector for connecting one of said input lines to said signal path.

41. A data communications system as in claim 40, further comprising a processor means for instructing said programmable line selector to connect one of said input lines to said signal path.

42. A data communications system as in claim 41, wherein said programmable line selector has at least two switching sections, each associated with a respective group of input lines, each section selectively connecting one of the input lines associated therewith to a respective output line of the section, means for coupling the output lines of said sections to respective signal paths in said central station, said signal path selector further comprising means operable by said processor means for selectively coupling the output lines of said sections together.

43. A data communications system as in claim 25, wherein said current sensor output is a voltage signal.

44. A data communications system as in claim 25, further comprising means for supplying a test voltage to the current sensor input of said multiplying means, said processor means storing the digital value of said test voltage.

45. A data communications system as in claim 44, wherein said test voltage supplying means is programmable to supply one of a plurality of test voltages to said analog to digital converter means in accordance with instructions from said processor means.

46. A data communications system as in claim 26, wherein said processor means controls said first analog to digital converter means to digitize the power value output of said multiplying means and to store the digitized values by means of an interrupt program which is executed by said processor means in response to receipt of a first periodically generated interrupt signal.

47. A data communications system as in claim 46, wherein said periodically generated interrupt signal is generated by a frequency multiplier which is phase locked to the frequency of said derived voltage.

48. A data communications system as in claim 47, wherein said voltage deriving means is connected to and derives said voltage from a power distribution system supplying voltage to said electrical path, said power distribution system being a multi-phase distribution system having at least one set of multiple phase input power lines, said data communicating system further comprising means for selectively connecting one of said input power lines to said frequency multiplier.

49. A data communication system as in claim 15 further comprising a first temperature sensor connected to a first of said information channels and located so as to be affected by the flow of fluid in a flow path, a second temperature sensor connected to a second of said information channels and located so as to be effected by said flow of fluid and downstream of said first temperature sensor, and said central station further comprising a processor means for receiving output signals from said first and second temperature sensors, said processor means forming a difference value from the outputs of said first and second temperature sensors, said processor means storing a table of fluid flow rates verses temperature difference values for said temperature sensors and determining a fluid flow rate by looking up a determined temperature difference value in said table.

50. A data communication system as in claim 49 wherein said processor means further stores calibration data relating to said temperature sensors which is combined with the output signals of said sensors in forming said difference value.

51. A data communications system as in claim 15, wherein said parameter sensor is a temperature sensor.

52. A data communication system as in claim 15, wherein said parameter sensor is an electrical current sensor.

53. A data communications system as in claim 15, wherein said parameter sensor is a humidity sensor.

54. A data communications system as in claim 49, wherein said second temperature sensor comprises a temperature sensing device having an output signal which varies in accordance with a sensed temperature, a resistor thermally bonded to said temperature sensing device, and a voltage source connected across said resistor.

55. A data communications system as in claim 54, wherein said resistor and temperature sensing device are bonded together by a highly conductive material which forms a housing surrounding at least a portion of said resistor and said temperature sensing device.

56. A data communications system as in claim 55, wherein said housing has an oval shape.

57. A data communications system as in claim 55, wherein said second temperature sensor further comprises a metal layer surrounding said resistor, temperature sensing device and material housing.

58. A data communications system as in claim 49, wherein said fluid flow path is on the input side of a heat exchanging device and wherein a third temperature sensor is connected to a third information channel and is located so as to be affected by said flow of fluid as it exits from said heat exchanging device, said processor means further determining a BTU rate for said heat exchanging device from said determined flow rate and the outputs of said first and third temperature sensors.

59. A data communications system as in claim 51, wherein said central station further comprises means for comparing the output signal of said temperature sensor at different points in time and for issuing an alarm signal if the difference between the compared output signals exceeds a predetermined value.

60. A data communications system comprising:

at least one central communications channel;

at least one group of remote stations connected to a respective communications channel, each remote station comprising a plurality of information channels, addressable means for selectively connecting an addressed one of said plurality of information channels to said central communications channel, and at least one current sensor having an output connected to an associated information channel, said current sensor measuring the flow of current through an electrical path;

a central station connected to each said central communications channel and comprising means for selectively addressing the information channels at said remote stations, means for receiving the output of said current sensor during the period said associated information channel is connected to a respective communications channel; and

means for computing the electrical power flowing through said electrical path, said computing means comprising;

means for deriving a voltage corresponding to the voltage on said electrical path;

means for multiplying a signal representative of said derived voltage by a signal representative of the output of said current sensor to provide a power value;

a first analog to digital converter means for digitizing the power value output of said multiplying means; and

processor means for storing the digitized output of said first converter means.

61. A data communications system as in claim 60 further comprising means for combining a calibration signal obtained from said multiplying means under known conditions with the output of said multiplying means prior to application of the output of said multiplying means to said analog to digital converter means.

62. A data communications system as in claim 60, wherein said processor means stores a plurality of digitized output signals of said first analog to digital converter means for each cycle of voltage on said electrical path and sums said digitized output signals for each said cycle.

63. A data communications system as in claim 60, wherein said voltage deriving means is connected to and derives said voltage from a power distribution system supplying voltage to said electrical path.

64. A data communications system as in claim 63, wherein said power distribution system is a multi-phase distribution system having at least one set of multiple phase input power lines and said voltage deriving means comprising means connected to each phase power line for deriving a voltage therefrom and means for selectively applying one of the derived voltages from said power lines to said multiplying means.

65. A data communications system as in claim 64, wherein said means for selectively applying selects one of said derived voltages in accordance with instructions received from said processor means.

66. A data communications system as in claim 62, further comprising at least one line voltage sensor at at least one of said remote stations and having an output connected to an associated addressable information channel, said line voltage sensor supplying to a central communications channel when addressed by said central station an output signal representative of the voltage on said electrical path, said voltage deriving means comprising means at said central station for receiving the output of said voltage sensor during the period said information channel associated with said line voltage sensor is connected to a respective communications channel.

67. A data communications system as in claim 66, wherein said voltage deriving means further comprising means connected to and deriving voltage from a power distribution system supplying voltage to said electrical path, and means for selecting between a voltage derived from said power distribution system and a voltage corresponding to the output received from said line voltage sensor, the output of said selecting means supplying said signal representative of a derived voltage to said multiplying means.

68. A data communications system as in claim 67, wherein said voltage selecting means performs said selection in response to instructions received from said processor means.

69. A data communications system as in claim 60, wherein said multiplying means comprises a second analog to digital converter means for digitizing said signal representing derived voltage and a multiplier for multiplying said signal representative of the output of said current sensor by said digitized derived voltage signal.

70. A data communications system as in claim 60, wherein said multiplying means includes an automatic gain control circuit for amplifying said signal representing the output of said current sensor by an amount required to place the output of said multiplying means within a predetermined signal level range.

71. A data communications system as in claim 70, wherein said automatic gain control circuit comprises means for detecting whether the output of said multiplying means is within said predetermined signal level range, programmable amplifying means for amplifying said signal representing the output of said sensor by a factor determined by a value programmed therein, and means for repeatedly altering said programmed value until said detecting means indicates that the output of said multiplying means is within said predetermined signal level range.

72. A data communications system as in claim 71, wherein said altering means comprises a counter for counting a counting signal, means for repeatedly supplying a counting signal to said counter until said detector indicates the output of said multiplying means is within said predetermined signal level range, and means for decoding the contents of said counter to form said programmed value and supplying said programmed value to said programmable amplifying means.

73. A data communications system as in claim 72, further comprising means for supplying the output of said counter to said processor means when the output of said multiplying means is within said predetermined signal level range, said processor means storing said counter output.

74. A data communications system as in claim 60, wherein said processor means calculates from stored power value outputs of said multiplying means energy consumed through said electrical path and provides an output display of said energy consumption.

75. A data communications system as in claim 60, wherein said multiplying means produces an inherent D.C. offset voltage during operation, said multiplying means further comprising a capacitor means which is periodically charged to said D.C. offset voltage prior to the performance of a multiplying operation by said multiplying means by a periodically operated charging means, the charge on said capacitor means offsetting said offset voltage during operation of said multiplying means.

76. A data communications system as in claim 75, wherein said charging means is periodically operated by said processor means to charge said capacitor means.

77. A data communications system as in claim 60, further comprising means for supplying a test voltage to the derived voltage input of said multiplying means, said processor means storing the digital value of said test voltage.

78. A data communication system as in claim 77, wherein said test voltage supplying means is programmable to supply one of a plurality of test voltage to said analog to digital converter means in accordance with instructions from said processor means.

79. A data communications system as in claim 60, further comprising

at least one signal path in said central station;

and

a signal path selector means for selectively connecting said signal path to one of said communications channels, said signal path selector means comprising;

a plurality of input lines respectively connected to said plurality of communications channels, and a programmable line selector for connecting one of said input lines to said signal path.

80. A data communications system as in claim 79, further comprising a processor means for instructing said programmable line selector to connect one of said input lines to said signal path.

81. A data communication system as in claim 80, wherein said programmable line selector has at least two switching sections, each associated with a respective group of input lines, each section selectively connecting one of the input lines associated therewith to a respective ouput line of the section, means for coupling the output lines of said sections to respective signal paths in said central station, said signal path selector further comprising means operable by said processor means for selectively coupling the output lines of said sections together.

82. A data communications system as in claim 60, wherein said processor means controls said first analog to digitial converter means to digitize the power value output of said multiplying means and to store the digitized values by means of an interrupt program which is executed by said processor means in response to receipt of a first periodically generated interrupt signal.

83. A data communications system as in claim 82, wherein said periodically generated interrupt signal is generated by a frequency multiplier which is phase locked to the frequency of said derived voltage.

84. A data communications system as in claim 83, wherein said voltage deriving means is connected to and derives said voltage from a power distribution system supplying voltage to said electrical path, said power distribution system being a multi-phase distribution system having at least one set of multiple phase input power lines, said data communicating system further comprising means for selectively connecting one of said input power lines to said frequency multiplier.