Automatic meter reading system using locally communicating utility meters

• US 6,737,984 B1
• Filed: 03/10/2000
• Issued: 05/18/2004
• Est. Priority Date: 08/15/1997
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Welles, Kenneth Brakeley II, Daum, Wolfgang
• Primary Examiner(s): EDWARDS JR, TIMOTHY
• Application Number:
  US09/522,383
• Time in Patent Office: 1,530 Days
• Field of Search: 340/870.02, 340/870.03, 340/310.01, 340/310.03, 340/310.06, 340/870.18, 455/3.3
• US Class Current: 340/870.02
• CPC Class Codes: H04Q 2209/30 using a wired architecture
• CPC Class Codes: H04Q 2209/60 for transmitting utility meters data, i.e. transmission of data from the reader of the utility meter
• CPC Class Codes: H04Q 2209/823 where the data is sent when the measured values exceed a threshold, e.g. sending an alarm
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A low cost frequency shift keying communications system for communication between utility meters within a local area network and for communication with a central database. Transmitters coupled to the utility meters transmit utility meter data measurements over power lines to at least one power line receiver associated with another utility meter within the local area network. The power line receiver communicates the data measurements from each utility meter to the central database via telephone or radio frequency transmitter.

Claims

1. A system for transmitting and receiving utility meter data via a power line, said system comprising:

a plurality of utility meters adapted to measure utility usage of respective customers and to provide utility meter data based on said usage;

a power line extending between said customers so as to form a local area network;

a plurality of transceivers, each of said transceivers coupled to a corresponding utility meter and to said power line, said transceivers adapted to receive utility meter data provided by said utility meters and to transmit said utility meter data over said power line;

said transceiver including a receiver, said receiver adapted to receive said utility meter data from said power line and wherein said receiver is further adapted to monitor said power line for the presence of radio frequency transmissions, said receiver including at least one narrow band pass filter for filtering signals on said power line and wherein the center frequency of said band pass filter is selectable.

2. The system recited in claim 1 wherein said receiver is adapted to detect utility meter data being transmitted over said power line.

3. The system of claim 1 wherein said transceiver is a Frequency Shift Keyed (FSK) transceiver.

4. The system as recited in claim 1 wherein said utility meters are selected from the group including a electric utility meter, a gas utility meter, and a water utility meter.

5. A method of communicating data over a power line comprising the steps of:

scanning said power line to identify clear frequency bands; and

,

transmitting said data utilizing said clear frequency bands

wherein the step of scanning includes the step of selecting successive passbands of a selectable band pass filter such that said band pass filter passes selected frequency bands to a receiver;

determining and storing noise levels corresponding to said passed selected frequency bands;

selecting a clear frequency band based upon said stored noise levels.

6. The method of claim 5 wherein said data is utility meter data.

7. The method of claim 5 wherein said transmitting step is accomplished using a frequency shift keying (FSK) modulation technique.

8. A method of receiving data from a power line comprising the steps of:

coupling said power line to a receiver by means of a selectable band pass filter;

scanning said power line to identify at least one frequency band by which a signal including said data is being transmitted via said power line; and

setting the passband of said selectable band pass filter to include the frequency band identified in the previous step.

9. The method of claim 8 wherein the step of scanning includes the steps of:

selecting successive passbands of said selectable band pass filter such that said band pass filter passes selected frequency bands to said receiver;

determining, for each successive passed frequency band, if a signal including said data is being transmitted via said passed frequency band.

10. The communications module as recited in claim 8, wherein said module further comprises a radio frequency antenna coupled to said power amplifier.

11. The communications module as recited in claim 10, wherein said module further comprises a level detector coupled to said low frequency amplifier and adapted to generate a detection signal when the signal generated by said low pass filter is above a predetermined voltage threshold.

12. The communications module as recited in claim 8, wherein said module further comprises a radio frequency amplifier coupled to said voltage controlled oscillator, wherein said radio frequency amplifier is adapted to generate a radio frequency signal for transmission over said antenna.

13. The communications module as recited in claim 12, wherein said predetermined voltage threshold is about five volts.

14. The communications module as recited in claim 8, wherein said module further comprises at least one divider coupled to said power amplifier and adapted to reduce the frequency of said voltage controlled oscillator frequency signal so as to enable the external computer to measure the frequency of said voltage controlled oscillator frequency signal.

15. The communications module as recited in claim 14, wherein said voltage controlled oscillator is controlled by a pseudo random signal so as to generate a spread spectrum voltage control oscillator frequency signal.

16. An amplitude modulated communications module coupled to a utility meter and coupled to an external computer, said communications module comprising:

a power amplifier, said power amplifier adapted to generate a data signal;

a voltage controlled oscillator coupled to the external computer, wherein said voltage controlled oscillator is adapted to generate a voltage controlled oscillator frequency signal in correspondence with a frequency code generated by the external computer;

a modulator coupled to said power amplifier and coupled to said voltage controlled oscillator, wherein said modulator is adapted to generate a modulated signal corresponding to said data signal and having a modulation frequency equal to the frequency of said voltage controlled oscillator frequency signal;

a low pass filter coupled to said modulator, wherein said low pass filter is adapted to generate a low pass signal in correspondence with the modulated signal.

17. A power line transceiver utilizing frequency shift keying for communicating utility meter data from a respective building to a remote database comprising:

at least one pair of variable dividers for generating a adjustable center frequency signal and an adjustable non center frequency signal wherein said center frequency signal is greater than said non center frequency signal by a fixed ratio;

a power amplifier coupled to said at least one pair of variable dividers for generating a power amplifier signal having a frequency in correspondence with said center frequency signal and in correspondence with said non center frequency signal; and

at least one pair of adjustable narrow bandpass filters coupled to said power amplifier and adapted to detect said center frequency signal and said non center frequency signal.

18. The power line transceiver as recited in claim 17, wherein said transceiver further comprises a reference voltage source, wherein said reference voltage source is adapted to generate a reference signal.

19. The power line transceiver as recited in claim 17, wherein said transceiver further comprises at least one pair of variable gain amplifiers coupled to said pair of narrow bandpass filters for adjusting the gain of said pair of narrow band pass filters.

20. The power line transceiver as recited in claim 19, wherein said transceiver further comprises a first envelope detector, and a second envelope detector, wherein each envelope detector is coupled to one of said pair of variable gain amplifiers, and wherein said first envelope detector is adapted to generate a first band pass filter signal, and wherein said second envelope detector is adapted to generate a second band pass filter signal.

21. The power line transceiver as recited in claim 19, wherein said transceiver further comprises a gain adjust comparator coupled to each of said first envelope detector, said second envelope detector, and said reference voltage source, wherein said gain adjust comparator is adapted to generate a gain adjust signal when the first band pass signal is greater than the reference signal, and alternatively when said second band pass signal is greater than the reference signal.

22. The power line transceiver as recited in claim 21, wherein said transceiver further comprises a signal quality comparator coupled to each of said first envelope detector, said second envelope detector, and said reference voltage source, wherein said signal quality comparator is adapted to generate a signal quality signal when the first band pass signal and the second band pass signal is greater than the reference signal.

23. The power line transceiver as recited in claim 22, wherein said transceiver further comprises a serial data comparator coupled to each of said first envelope detector and said second envelope detector, wherein said serial data comparator is adapted to generate a serial data signal which comprises the first band pass signal and the second band pass signal.