Method and apparatus for remote measurement

• US 4,783,748 A
• Filed: 03/04/1987
• Issued: 11/08/1988
• Est. Priority Date: 12/09/1983
• Status: Expired due to Term

• Current Assignee: Quadlogic Controls Corp.
• Original Assignee: Quadlogic Controls Corp.
• Inventors: Swarztrauber, Sayre, Stern, Mark C., Newsome, Michael R.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): COSIMANO, EDWARD R
• Application Number:
  US07/022,554
• Time in Patent Office: 615 Days
• Field of Search: 324/142, 340/310 A, 340/825.08, 364/483, 364/492
• US Class Current: 702/62
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

A method and apparatus are disclosed for sensing, sampling and performing calculations on a parameter of a physical quantity at a plurality of remote locations comprising a plurality of remote sensing units and at least one processing unit linked to said plurality of remote sensing units via a two way communication link. Parameters of a physical quantity are sensed and sampled, calculations are performed and accumulated and transmitted, on demand, provided to the processing unit using a plurality of frequency bands one of which is identified as having valid data.

Claims

1. A remote sensing system comprising:

a plurality of remote sensing digital meters comprising;

means for sensing one or more parameters of a physical quantity as a measure thereof,

means for taking a plurality of samples of a function of the parameters sensed by said sensing means,

means for calculating from the samples taken by said sampling means one or more numerical values representative of said physical quantity,

means for accumulating the magnitude of the numerical value or values calculated by said calculating means,

means for providing the accumulated value to a remote location, and

at least one processing unit linked to said plurality of remote sensing meters via AC power lines, said processing unit comprising;

a central processing unit,

means for storing accumulated values received from said remote sensing meters, and

means for communicating with said remote sensing meters, said means comprising;

means for transmitting identical signals to said remote sensing meters on a plurality of spaced apart frequency bands and means for receiving signals from said remote sensing meters on one of said frequency bands.

2. The apparatus of claim 1 wherein said providing means in said remote sensing meter comprises:

means for receiving from said processing unit signals transmitted from the processing unit on the spaced apart frequency bands,

means for testing the validity of the signals received to locate a frequency band on which valid data is present, and

means for transmitting signals representative of the accumulated values to said processing unit using the frequency band on which said data was received.

3. The apparatus of claim 2 wherein:

the receiving means of said providing means comprises a mixer and a local oscillator, said local oscillator having an adjustable output to provide for the demodulation of signals transmitted in any one of the different frequency bands transmitted by the processing unit; and

the transmitting means of said providing means comprises a mixer and said local oscillator, said local oscillator applying the same output signal to the mixer of the transmitting means as is applied to the mixer of the receiving means.

4. The apparatus of claim 1 wherein the physical quantity to be measured is energy transmitted through the electric power line over which the remote sensing meter and the processing unit communicate, and wherein the parameters measured are current and voltage in the power line.

5. The apparatus of claim 4 wherein the parameters are samples at a frequency which does not exceed twice the highest harmonic frequency present in the parameter that said remote sensing meter is capable of sensing.

6. A remote sensing digital meter comprising:

means for sensing one or more parameters of a physical quantity as a measure thereof,

means for taking a plurality of samples of a function of the parameters sensed by said sensing means

means for calculating from the samples taken by said sampling means one or more numerical values representative of said physical quantity,

means for accumulating the magnitude of the numerical value or values calculated by said calculating means, and

means for providing the accumulated values to another location, said providing means comprising;

means for receiving from said another location a plurality of signals at different frequency bands,

means for testing the validity of the signals received to locate a frequency band on which valid data is present, and

means for transmitting signals representative of the accumulated values to said another location using the frequency band on which said valid data was received.

7. The apparatus of claim 6 wherein:

the receiving means of said providing means comprises a mixer and a local oscillator, said local oscillator having an adjustable output to provide for the demodulation of siganls transmitted in any one of the different frequency bands transmitted by said another location; and

the transmitting means of said providing means comprising a mixer and said local oscillator, said local oscillator applying the same output signal to the mixer of the transmitting means as it applied to the mixer of the receiving means.

8. The apparatus of claim 6 wherein the physical quantity meaured is energy transmitted through an electric power line over which the remote sensing meter and said another location communicate, and wherein the parameters measured are current and voltage in the power line.

9. The apparatus of claim 8 wherein the parameters are sampled at a frequency:

having a value not equal to the frequency of the electric power carried by said electric power line;

having harmonics which are not equal to any harmonic below the fifth harmonic of the frequency of said electric power; and

having a value no more than three and one-half times the frequency of said electric power.

10. A remote sensing digital meter comprising:

means for sensing the current and voltage in an alternating current power line,

means for taking a plurality of samples of current and voltage values sensed by said sensing means,

means for calculating from the samples taken by said sampling means energy transmitted by said power line, and

means for accumulating the magnitude of the energy transmission calculated by said calculating means and means for providing the accumulated value to another location, said providing means comprising;

means for receiving from said another location a plurality of identical signals at different frequency bands,

means for testing the validity of the signals received to locate a frequency band on which valid data is transmitted, and

means for transmitting signals representative of the accumulated values to said another location using the frequency band on which said valid data was received.

11. A remote sensing digital meter comprising:

means for sensing the current and voltage in an alternating current power line,

means for taking a plurality of samples of current and voltage values sensed by said sensing means,

means for calculating from the samples taken by said sampling means energy transmitted by said power line, and

12. means for accumulating said magnitude of the energy transmission calculated by the calculating means and means for providing the accumulated value to another location, said sampling means samples said power line at a frequency:

having a value not equal to the frequency of said alternating current;

having a harmonics which are not equal to any harmonic below the fifth harmonic of the frequency of said alternating current; and

having no more than three and one-half times the frequency of said alternating current.

13. A remote sensing system comprising:

at least one remote digital station comprising;

means for sensing one or more parameters of a physical quantity as a measure thereof,

means for taking a plurality of samples of a function of the parameters sensed by said sensing means and for storing data representative of such samples,

means for providing the stored data to a remote location, and

at least one processing unit linked via AC power lines to said at least one remote digital station, said processing unit comprising;

a central processing unit,

means for storing data received from said at least one remote digital station, and

means for communicating with said at least one remote digital station, said means comprising;

means for transmitting address signals to said at least one remote digital station over said AC power lines on a plurality of spaced apart frequency bands, and means for receiving signals from said at least one remote digital station over said AC power lines on one of said frequency bands.

15. The method according to claim 13 in which the address signals are transmitted substantially simultaneously on the plurality of frequency bands by the central digital station.

16. The method according to claim 13 in which address signals are transmitted from the central digital station over the AC power lines on at least six spaced apart frequency bands.

14. A method for communication between a central digital station and a plurality of remote digital stations over AC power lines to which the central digital station and the remote digital stations are connected, comprising the steps of:

(a) transmitting address signals from said central digital station over said AC power lines to said remote digital stations on a plurality of spaced apart frequency bands, said address signals identifying at least one of said remote digital stations;

(b) receiving at each or tne remote digital stations address siganls form said central digital station over said AC power lines on one of said frequency bands and testing the received address signals to determine it they constitute a valid address signal identifying the respective remote digital station; and

(c) transmitting response signals from the remote digital station identified by said address signals over said AC power lines to said central digital station on a frequency band on which the remote digital station received valid address signals identifying the station.

17. The method according to claim 14 in which the spaced apart frequency bands are in the range of from about 30 kHz to about 50 kHz.