Automatic utility meter monitor

A self-contained automated meter reader system for monitoring a plurality of channels for gas, electricity and water utilities, has additional channels dedicated to normally closed alarm signals for monitoring the integrity of the system. The system is installed at the site of a standard utility meter and is configured for monitoring and operation by a user via keyword command programming on a data terminal or personal computer. Externally entered programming communicates with a compiler in the automated meter reader unit. Pulse data is accepted from digital meter reader devices for gas and water systems and a photoelectric sensor reads the watt-hour electricity usage. Utility office communication is via telephone modem link to a computer and a lap-top computer for field setup and systems analysis. Computing electronics hardware is within the watt-hour meter housing and interfaces with utility service meters, DC power supply and telephone service through a connector on a weatherproof polycarbonate meter enclosure on a utility electric service box.

BACKGROUND OF THE INVENTION 
Field of the Invention 
The present invention relates generally to utility usage measurement 
systems, and more particularly to means for obtaining periodic readings of 
utility meters without the need for a personal meter reader to physically 
appear and read a meter periodically. A device according to the invention 
can totalize pulse signals from utility meters and remotely monitor system 
integrity status. 
Utility companies conventionally obtain periodic readings of utility meters 
by meter readers visiting each location to physically read the meters. An 
average of about $0.60 to $0.80 is the cost of each reading, depending on 
area and geographic location. In the U.S., the cost is about $864 million 
dollars to $1.152 billion annually to read electric meters. A comparable 
amount is involved in reading gas meters or water meters. The cumulative 
total for reading utility meters is about $2.6 to $3.45 billion annually. 
A number of utility companies have utilized automatic meter reading 
systems using wireless technology and 900 MHz radio transmitters. A meter 
can be read while riding in a vehicle while using a hand-held transceiver. 
A similar system may employ a Cellnet data system employing cellular phone 
technology. 
In the prior art, U.S. Pat. No. 4,804,957 to Selph et. al. discloses a 
utility meter and submetering system which is a microprocessor-based 
circuit using Hall Effect electric current sensors to measure power usage 
by customers. The microprocessor determines time of use information which 
is stored in random access memory, which may be remotely interrogated via 
a telephone line or serial communications link to effect a submetering 
configuration useful in apartment complexes and the like wherein a 
multiplicity of meters are multiplexed by a data collection computer, 
which is networked with other data collection computers to a central 
billing computer. 
U.S. Pat. No. 4,688,038 to Giammarese relates to a device for relaying the 
remote reading of a utility meter having circular dials, and includes an 
array of phototransistors for each circular dial of the utility meter. The 
face of the dial is illuminated selectively, when a reading of the dial is 
desired, by a light-emitting diode at the center of the array of 
phototransistors. The phototransistor which is shaded by a dial pointer 
indicates the highest value of the reading by the pointer, develops a 
signal indicative of the reading, which is output to a logic circuit for 
the development of the signal into usable form for generating the value at 
a remote display device on the outside of a building. Alternatively, the 
output from the logic circuit may be sent over a telephone transmission 
line to a remote computer center for storage and retrieval for billing 
customers. 
The prior art shows specific methods for reading meters, particularly dial 
indicator meters (such as gas meters) and some basic microprocessor based 
connection to a telephone line. However, the prior art does not present a 
practical, interactive data processing configuration that is required for 
monitoring the status of the service installation at any time to insure 
the integrity of the system and the accuracy of meter readings, nor does 
it teach the use of a photoelectric sensor for reading a watt-hour meter. 
The prior art does not teach the combination of a photoelectric watt hour 
meter with a pulse electric meter, such as a gas meter, and a water meter 
which are totalized and stored in an EEPROM data buffer or the like for 
further computation of status, records keeping, and billing. 
SUMMARY OF THE INVENTION 
In accordance with the invention, a self-contained microprocessor 
controlled system capable of monitoring a plurality of channels (gas, 
electricity and water) has a plurality of additional channels dedicated to 
normally closed alarm signals for monitoring the integrity of the system 
at all times. The automated meter reader (AMR) system device is installed 
at the site of the standard utility meter and configured for monitoring 
operation of the system by the utility via keyword command programming on 
a data terminal or personal computer. The system enables a utility company 
to selectively communicate by password with any home or industrial utility 
installation. Externally entered C programming is used to communicate with 
a C compiler resident in the automated meter reader (AMR) unit. 
The device accepts pulse data from prior art digital meter reader devices 
for gas and water systems, and utilizes a photoelectric sensor for reading 
the watt-hour indicator of electricity service usage. Communication with 
the utility office is via telephone modem link to a computer, and by a 
lap-top computer, such as an RS232 for field setup and analysis of the 
system. 
For electric meter pulse signals, a pulse divider is provided to produce a 
reading--i.e., a certain number of pulses equal to a counter reading, 
which depends on the type and model of the electric meters. For gas and 
water meters, pulses are direct counter reading. The system is capable of 
direct connection to a standard two-wire telephone. Thus the invention 
presents a practical and complete solution to the problem.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings, FIG. 1 shows an automated meter reader (AMR) 
invention, as including a self-contained microprocessor based control 
system capable of monitoring eight channels, inputs 1 through 8. The input 
channels comprise three pulse channels and five normally closed alarm 
channels, as shown. The system is integrated on a circuit board 20 (FIG. 
4) mounted in the electric meter housing, and is installed and configured 
for operation via key word command programming via a modem communicating 
with a data terminal or PC (not shown). The AMR has an internal resident 
compiler 19 to interpret the C-programming language. However, programming 
is not necessary for normal operation of the system, programming for 
normal operation being self-contained in the AMR. 
The system provides an internal modem connection for communication with the 
outside utility as well as an RS 232 serial port for lap-top access, and 
is provided with an automated dial-out/dial-in function for periodic and 
emergency data reporting. Access to AMR is through a secret AMR 
identification number. The unit 10 (FIG. 2) is designed for direct 
connection to any utility telephone network. 
Three pulse channels serve to receive pulse signals from domestic electric, 
gas and water meters. The pulse signals are totalized and stored in an 
EEPROM data buffer. One alarm channel 7 (FIG. 1) is used for a magnetic 
switch attached to the door of the AMR enclosure to activate an alarm when 
the AMR is tampered with or accessed illegally. The alarm may be 
overridden by the insertion of an RS 232 cable into serial port 15 during 
servicing or repair work on the AMR, after a one-minute delay. Three alarm 
channels 4, 5, 6 (FIG. 1) are provided to indicate loss of pulse signals 
from the meter pulse transmitter, and an alarm channel 8 is provided to 
indicate loss of AC power supply to the unit. Serial pulses from an 
electric meter, a gas meter, and a water meter are received, totalized and 
stored in the EEPROM data buffer. For electric meter pulse signals, a 
pulse divider is provided to produce a reading--i.e., a certain number of 
pulses equal to a counter reading, depending on the type and model of the 
utility meter. For gas and water meters, the pulses are direct counter 
readings. The AMR is capable of connection to a standard two-wire 
telephone using pulse or tone with loop start only. The AMR recognizes 
ringer frequencies from 10 to 60 Hz. The AMR is provided with a built-in 
300/2400 bps modem with a two-wire telephone connection, and an RS 232 
serial communications port for communications. The AMR is provided with an 
auto-dial circuitry to auto-dial up to eight telephone numbers, each 32 
digits long, during an alarm condition. Individual dial-out alarm 
selection may be programmed for each input channel to instruct the AMR to 
dial specific telephone numbers for certain alarms. In case an alarm is 
detected, the AMR will continue to call telephone numbers in succession 
until a positive acknowledgement of the alarm message is received. 
Acknowledgement is accomplished by a PC terminal. A circuit is provided to 
enable the AMR to wait for dial tones before dialing a number. Call 
detection insures that the alarm dial-out is not hindered by no-answers or 
busy signals. 
A circuit is provided to automatically pick up telephone inquiry calls 
using coded handshake signals, but hangs up if a third party pickup is 
sensed. The AMR is programmed to auto-dial a telephone number periodically 
for up to six telephone numbers to report meter input status. 
Referring to FIG. 1 and circuit board 20, and to FIG. 2, a memory with a 
96K non-volatile EEPROM 16 and 64K RAM 17 to store all resident programs 
and AMR information, are provided. The AMR board 20 includes a C-compiler 
19 to make it possible to write custom programs. The AMR can log and store 
the status of each input with a time stamp. The data is stored into the 
EEPROM data buffer 18. When the data buffer in the input/output management 
section 21 is full, the logger overrides the oldest data and adds the most 
recent. Time is kept by an on-board real-time clock which has its own 
battery backup. The time between logs can be programmed into any number of 
hours, minutes, and seconds. Historical files are stored in such manner as 
to be retrievable with a data base or a spread sheet program, using their 
file import function. 
The meter pulse transmitters 23, 24 and 30 (FIG. 2) provide local and 
remote power failure indication to a memory which stores the number of 
kilowatt hours of electricity usage, cubic feet of gas, or units of water 
usage in the microprocessor-associated memories above described. These 
measurement signals are introduced through the input-output management 
circuits 21 associated with the microprocessor. The communications 
interface circuits 25 associated with the microprocessor handle the modem 
and RS 232 ports to the outside, for utility company use only, and any 
illegal access or tampering is reported by the AMR to the utility company 
when the magnetic door switch 26 (FIG. 4) is open. Power failure can also 
open this magnetic switch, giving the utility company a measure of outages 
in an area having AMRs installed throughout. 
The pulse computer totalizer circuits 28 associated with the microprocessor 
20A provide totals in digital form of the final usage values in a 
designated period, for storage in memory through memory management 
function 29. 
Referring to FIG. 3, the photoelectric sensor 30 circuit and mechanism 
comprising an infrared LED-modulated light source 31, light sensitive 
phototransistor 32 and amplifier circuit 33, to amplify the reflective 
signals to turn on or off a relay switch, is provided. The sensor 30 
senses the black mark or an aperture 34 at the bottom side of the 
watt-hour meter disk, against the white background. An infrared light on 
the bottom surface of the rotating disk in a watt-hour meter is projected 
as by a diode laser. A watt-hour meter is based on proportional eddy 
currents induced in the disk to rotate the disk in proportion to the 
current. The light is reflected by a metallic or white surface of the 
disk, and is sensed by the light sensitive phototransistor, which may be 
no more than 50 mm distant, thereby completing a circuit. When the 
infrared light is projected against the black mark at the bottom of the 
rotating disk or an aperture in the disk, the light is not reflected from 
the black mark or aperture. The phototransistor senses no light, thereby 
cutting off the circuit, opening the relay switch and sending a pulse to 
indicate a full rotation of the disk. The opening and closing of the 
switch is sent as a pulse input signal to the AMR to be totalized and 
stored in the EEPROM. 
FIG. 4 shows an assembled meter reader and monitor in accordance with the 
invention. An electric utility watt-hour meter illustrates the relative 
positions, of the elements of the invention to the elements of the 
standard meter, shown face down and mounted on a chassis in the electrical 
utility service box 10, with readout control switching circuitry and 
connection to communications facilities together with other utility 
service meters. All computing elements of the monitor system are contained 
within the utility watt-hour meter housing. A polycarbonate cover 40 with 
a screw-in top 42 encloses the watt-hour meter, replacing the glass cover 
thereof which may be removed. A system interface circuitry connector 41 
for connection to communications facilities and other utility service 
meters, includes connections for a telephone 2-wire connector, a 220 AC/24 
VDC power supply transformer, a terminal connector for a gas meter pulse 
transmitter, and a terminal connector for water meter pulse transmitter. 
The polycarbonate cover makes the automatic utility meter reader and 
monitor weather proof. 
The present invention provides for quick and economical installation. For 
example, $100 might be involved for a conversion of a standard service 
meter installation to an automated system. Such cost is justified in view 
of the annual 30% or more savings over non-automatic meter reading. 
Referring to FIG. 5, there is shown an embodiment of the sensor for the 
watt-hour meter in the form of a simple clip-on photoelectric device 30, 
in accordance with the invention. This sensor implementation is shown in 
FIG. 7, which shows the front and back mounting clips 61, 61, and the 
position of the light source 31 and phototransistor 32 in block 62. 
FIG. 6 shows a watt-hour meter electrical service box connection, and the 
rapid-installation clip-on connectors 71, 72 of the sensor circuitry to 
the power service at the meter. 
Thus there has been shown and described a novel automatic utility meter 
monitor which fulfills all the objects and advantages sought therefor. 
Many changes, modifications, variations and other uses and applications of 
the subject invention will, however, become apparent to those skilled in 
the art after considering this specification together with the 
accompanying drawings and claims. All such changes, modifications, 
variations and other uses and applications which do not depart from the 
spirit and scope of the invention are deemed to be covered by the 
invention which is limited only by the claims which follow.