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Description  |
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FIELD OF THE INVENTION
The present invention relates to utility monitoring apparatus and in
particular the present invention relates to utility monitor and
communication systems which monitor utility usage and transmit the utility
usage information to the utility via phone lines.
BACKGROUND OF THE INVENTION
Utility companies use utility usage meters to determine the amount of
utilities consumed at a customer site. A periodic reading of the utility
meter is necessary to determine the usage and to bill the customer for the
amount used. The need to send utility company employees to customer site
to read the meters is a costly and time consuming method of collecting
such information. Thus, automated means of recording and reporting the
utility usage at customer sites is rapidly replacing the manually-read
utility meters.
An example of a utility reporting system is described in the U.S. Pat. No.
4,086,434 to Bocchi entitled "Remote Condition Reporting System." This
prior art system records information on utility usage and periodically
dials into a central office to report the utility usage for recording and
billing purposes. The types of utilities described for this reporting
system are water, power, gas and the like. This prior art system connects
to the consumer's home telephone line to communicate to the central office
using a tone generator to send information over the telephone lines.
This and other prior art systems have several fundamental shortcomings.
When communicating on-line with the central office, the telephone
subscriber cannot use the residential phone for dialing out. Although the
prior art communication systems attempt their telephone connections in the
middle of the night, this is a serious shortcoming if the need arises to
dial an emergency number such as 911. In addition, many of the prior art
utility monitors operate using modems to communicate information between
300 and 2,400 baud or more. These modem-driven utility reporting
communication systems fail in many rural environments due to noisy lines,
interruption by call-waiting signals and the like. In addition, prior art
utility reporting communication systems suffer from a variety of data
errors in transmitting the information. The prior art is also lacking in
providing Timed Off-peak Usage (TOU) power metering in combination with a
utility meter reader and communication system.
SUMMARY OF THE INVENTION
These and other shortcomings of the prior art are solved by the present
invention. The present invention is a utility meter reading and
communications system which gathers data from utility meters and sends
that data to a utility company's central data collection point (host
computer) via telephone lines. The present invention places a call on the
user's telephone line at a specified time and date and transmits data
using dual-tone multifrequency (DTMF) format and ASCII encoding onto DTMF.
The use of DTMF format allows greater noise immunity on normally noisy
telephone lines and immunity from interruption by call-waiting signals and
the like. The present invention ensures that users still may use the
telephone line by sensing off-hook conditions initiated by a resident's
telephone and immediately dropping the line to reestablish dial tone for
the residential customer. The present invention uses a variety of
error-detection procedures and communications protocol to ensure a high
degree of reliability in communicating data to and from the central office
and the utility meter system. The present invention also uses
communications protocol and handshaking to ensure accurate data
communication and allow immediate interruptions of communications should
the customer attempt to use the telephone line.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a system diagram showing the present invention attached to a
utility meter and communicating with a host.
FIGS. 2-7 taken together comprise detailed electrical schematic diagram of
the present invention.
FIGS. 8A-8B are schematic keys to show how FIGS. 2-7 should be placed for
viewing together.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following detailed description of the preferred embodiment,
reference is made to the accompanying drawings which form a part hereof,
and in which is shown by way of illustration specific embodiments in which
the invention may be practiced. This embodiment is described in sufficient
detail to enable those skilled in the art to make and practice the
invention, and it is to be understood that other embodiments may be
utilized and that structural, electrical or logical changes may be made
without departing from the spirit and the scope of the present invention.
The following detailed description is, therefore, not to be taken in a
limiting sense, and the scope of the present invention is defined only by
the appended claims.
FIG. 1 is a block diagram of the environment in which the present invention
is used. The utility meter reader terminal 100 contains the preferred
embodiment of the present invention as a means for receiving and recording
utility usage and communicating that information to the host computer. The
utility meter reader terminal 100 is located at the user/customer premises
and is connected on the telephone line between the user premises telephone
equipment 102 and the telephone line connection to the telephone company
105. It is essential that the customer's telephone equipment 102 all be
located downstream from the present invention so that user-initiated
off-hook conditions can be sensed. Meter reader terminal 100 also accepts
inputs from a plurality of utility meters exemplified by utility meters
101A through 101H shown in FIG. 1.
The meter reader terminal periodically dials the telephone number of the
host computer at a predetermined time and date and downloads information
from the utility meters over the telephone line to the host computer. The
host computer includes a host interface to the telephone lines which
receives the telephone calls from the field installed meter reading
terminals. The host computer then compiles the information and prepares
utility usage bills which are then sent to the customer to pay for the
utilities used.
OPERATION OF THE PRESENT INVENTION
The present invention uses Dual Tone Multi-Frequency (DTMF) dialing tones
for communicating to and from the host computer. DTMF dialing tones are
preferable to all types of modem communications since they are more immune
to distortion and interruption. In many rural environments modem
communication rates as low as 300 baud cannot effectively communicate
information. The standard noise level on rural communication lines however
is still low enough to allow effective DTMF tone transmissions and
reception.
The present invention places a call on the user's telephone line at a
specified time and date and transmits data using DTMF format and ASCII
encoding onto DTMF. In the preferred embodiment of the present invention,
the use of the DTMF format allows greater noise immunity on normally noisy
telephone lines and immunity from interruption by call-waiting signals.
The present invention ensures that users still may use the telephone line
by the terminal sensing off-hook conditions initiated by a resident's
telephone and immediately dropping the line to reestablish dial tone for
the residential customer. The present invention uses a variety of
error-detection procedures and communications protocol to ensure a high
degree of reliability in communicating data to and from the central office
and the utility meter system. The present invention also uses
communications protocols and handshaking to ensure accurate data
communication and allow immediate interruptions of communications should
the customer attempt to use the telephone line.
In the preferred embodiment of the present invention, communicating a burst
of information to a central site to the host computer has been measured at
approximately 13 seconds for the total phone call. A 1200 baud modem
communicating the same amount of information takes about 11 seconds,
including all connection and synch times. A 300 baud modem communicating
the same information takes 22 seconds, including all connection and synch
times. Thus, the present invention does not appreciably add to the
communication time that the utility meter reader needs to be on-line for
communications yet it appreciably contributes to the noise immunity of its
data transmission.
The present invention provides a wide variety of features to the utility
company for sensing, recording and transmitting utility usage information.
This information can be used to tailor services to their customers and
detect potential problems before they occur. For example, in the
application of the present invention to electric power utility reading,
average kilowatt hours used per day and average power used per hour at
specific times of day can be recorded and down-loaded to the utility.
Usage averaging can also be fed back to the consumer so that they can
review their power usage habits and find cost-saving alternatives to their
current habits.
A popular way of reducing peak loads and offering consumers reduced prices
on utilities is the concept of timed off-peak usage (TOU). Traditionally,
a second kilowatt hour meter is used as a separate AC mains line for
distributing and measuring TOU power at a consumer's site. For example,
some pumping and power usages in rural environments can be done at any
time and so a cost savings is realized by the farmers by doing the
majority of their power consumption and usage at night when rates are
cheaper via TOU metering. The present invention supports TOU metering by
means of an auxiliary input. No additional meter is needed to record the
utility usage since the user simply indicates to the present invention
that TOU power is being requested and the TOU status is invoked by the
present invention.
The present invention is also designed with a nonvolatile memory which is
used to control and store usage information for later down-loading to the
host computer. An Analog-to-Digital converter is also an integral portion
of the present invention which is available to measure line voltage
variations for later reporting to the host.
Communications to the host computer is by telephone line connections
connected in series with the customer-premises equipment. Two relays and
an off-hook detect circuit are included in the present invention to allow
a telephone user immediate access to the line if the present invention is
currently using the phone line. The present invention automatically
disconnects and gives the line back to the user within approximately one
second after downstream pick-up of a telephone to ensure that the user
gets an immediately dial tone. Also the present invention will not try to
connect to the telephone line if the user is already on the line.
The programming of the present invention is designed to use normally quiet
nighttime hours for transmitting data to the host computer. For example,
the clock/calendar of the present invention will cause an interrupt of the
microcontroller at 3:00 a.m. on Monday nights to transmit data either once
a week or once a month to the host computer. If the present invention
fails to connect to the host computer, the call will be repeated within
approximately four minutes and five successive attempts will be tried. If
the present invention fails to report within a given period of time, a
service person is sent to the customer's residence to repair and maintain
the present invention.
In addition to the above-listed features, the present invention is equipped
with tamper-detection circuits which will initiate an immediate call to
the host computer upon detection of tampering. Moving, tilting or jarring
the present invention will cause a motion detector to force an interrupt
on the microcontroller which in turn will cause a call to the host. Also,
a loop-back circuit is wired through the utility meter such that
disconnection of the present invention from the utility meter will cause
an immediate call to the host. The present invention is also programmed to
detect whether metering pulses have been received within the last hour and
within the last day. An insufficient or lack of metering pulses from the
meter indicates the disconnection of the present invention from the
utility meter which is also invoke a call to the host.
The host computer and communication systems which interface to the present
invention are very much like the present invention in the way in which
they interface to the telephone lines. A microcomputer or a personal
computer is used with peripheral storage systems to record the large
volume of calls and data recorded on a daily basis of the utility meter
reader devices installed in the field. A personal computer can also be
used for recording power usage averages throughout the power grid for
detecting and predicting peak loading and potential breakdowns.
DETAILED ELECTRICAL SCHEMATIC DIAGRAMS
FIGS. 2-7 comprise detailed electrical schematic diagrams which describe
the present invention and which should be viewed together. Specifically,
FIGS. 2 and 3 are to be view side-by-side (left and right, respectively)
to line up the electrical lines passing therebetween, as shown in the
schematic key of FIG. 8A. FIGS. 4-7 are to be viewed together to form the
second schematic diagram to line up the electrical lines passing
therebetween, and are to be placed in counterclockwise positions starting
with FIG. 3 in the lower left position, as shown in schematic key of FIG.
8B.
The present invention is based on a microprocessor configured in a
bus-structured architecture to control the operations and functions of the
present invention. FIG. 2 shows a portion of the microprocessor circuitry
including microcontroller U7. In the preferred embodiment of the present
invention, microcontroller U7 is part number 80C31 which is a single-chip,
8 bit microcomputer with on-chip RAM and I/O available from Intel and
other semiconductor manufacturers. This preferred microcontroller includes
a 128 bites of RAM, 32 I/O lines and two 16-bit timer/counters internal to
the chip. The 32 I/O lines are multiplexed on the chip pins for multiple
uses such as address, data, and I/O use. Not all 32 of the I/O lines are
used in this preferred embodiment of the present invention. Those skilled
in the art will readily recognize that a wide variety of microprocessor or
microcontroller implementations could be used to support the present
invention other than the Intel 80C31 shown here.
The low-ordered address lines (8 bits) A0-A7 and 8 data lines (D0-D7) are
multiplexed on pins 32-39 as a combined address/data bus. This bus
originates on FIG. 2 and extends to FIGS. 3, 4, 6, and 7. The high-ordered
address bits are multiplexed out of pins 21-28 (A8-A15) with address lines
A14 and A15 being used for special dedicated control as described below.
The high-ordered address bus originates on FIG. 2 and extends to FIG. 3.
Also attached to microcontroller U7 is a crystal connected to dedicated
crystal inputs for crystal-controlled timing of the internal functions of
the microcontroller. Transmit TXD and receive RXD lines on microcontroller
U7 are used for an RS-232 port which may be used to program the present
invention with a hand-held microcomputer or the like on site. The inputs
on connector J4 labeled TX and RX are opto-isolated by optical couplers
U1A and U1B.
An integral part of the present invention and a necessary component of the
circuitry is clock/calendar chip U8. This is a battery backed-up real-time
clock chip part number NJU6355 available from New Japan Radio Co. Ltd. of
Mountain View, Calif. This chip contains an internal oscillator (with
external quartz crystal), counter, shift register, voltage regulator,
voltage detector and interface controller for presenting accurate time and
date in a serial fashion on data pin 7. This clock/calendar chip U8 is
battery backed up and controlled by a separate crystal X2 for accuracy and
nonvolatility of the current time and date. The battery for backing up the
clock calendar chip and also for ensuring battery back-up of the RAM chip
shown in FIG. 3 is also shown in FIG. 3 as a 3.0 volt lithium battery. A
low-voltage threshold detector Q9 is used to detect a low voltage
condition on the battery B1 and alert the microprocessor to a failing
condition.
FIG. 3 shows a portion of the detailed electrical schematic diagram
including the random-access memory (RAM) chip U14 and the programmable
read-only memory (PROM) U13. RAM chip U14 is in the preferred embodiment a
2K by 8 bit CMOS static RAM chip for low-power, high-speed operation. This
chip in the preferred embodiment is part number HY6116A available from
Hyundai Semiconductor of Korea having U.S. headquarters in Santa Clara,
Calif. This RAM chip is battery backed up with the lithium battery B1 also
shown in FIG. 3. An important feature of this particular type of RAM chip
is the reduced power consumption in standby mode allowing very low battery
drain from lithium battery B1 during power outages. Although the present
invention is powered by a 12 volt DC source deriving its power from the AC
mains, a loss of power on the AC mains means loss of power to the present
invention. The lithium battery ensures that the current status of data
recorded in RAM U14 in not lost. Those skilled in the art will readily
recognize that a wide variety of nonvolatile memory could be used and
substituted for the RAM chip U14 of the present invention.
RAM chip U14 contains all current operating data and information
accumulated from the utility meters. In addition, current command modes
are stored in RAM U14 in conjunction with the on-chip RAM of
microcontroller U7 of FIG. 2. The low-ordered eight bits of multiplex
data/address bus are connected for storing and retrieving data from RAM
chip U14 on pins 9-17 (pin 12 being chip ground). The address lines on
pins 1-8 (not shown) are connected in parallel with the low-ordered
address lines of PROM chip U13.
Programmable read-only memory (PROM) chip U13 is used in the preferred
embodiment to store the operating programs of the present invention. PROM
chip U13 is in the preferred embodiment part number 27C128 available from
Intel and other semiconductor vendors. This chip in the preferred
embodiment is 128 Kbits arranged as 16K by 8. This is a standard EPROM
which is field programmable and erasable using ultraviolet light. Those
skilled in the art will readily recognize that a wide variety of PROM
chips may be used in the present invention and substituted for the type
named without departing from spirit and scope of the present invention.
The combined address and data bus originating from microcontroller U7 on
FIG. 2 is demultiplexed onto dedicated address and data lines by
octal-transparent latch chip U11. This chip combines eight latches in a
single package and provides three state outputs for bus interfacing. This
chip is in the preferred embodiment part number 74LS373 available from
National Semiconductor and many other vendors as a standard 7400 Series
TTL part. The three state outputs of chip U11 allow for disconnecting the
address lines connected to RAM chip U14 and PROM chip U13 during the data
transfer mode of operation of the combined data/address bus.
The high-ordered address bits of PROM chip U13 are connected in a dedicated
fashion to high-ordered address pins 21-26 of microcontroller chip U7
shown in FIG. 2.
FIG. 4 shows the dual-tone multifrequency (DTMF) transceiver chip U18. This
chip in the preferred embodiment of the present invention is part number
CM8880/8888 which is a CMOS integrated DTMF transceiver available from
California Micro Devices. This DTMF transceiver chip is a complete DTMF
transmitter/receiver within a single chip. The timing and frequency
control of DTMF transceiver chip U18 is controlled by crystal X3 which is
a 3.579545 megahertz crystal selected for its availability (a common NTSC
color-burst frequency). Control of DTMF transceiver U18 is from lines 1.5,
1.3 and 1.2 from the microcontroller chip U8 of FIG. 2. The read-write
control lines control chip U18 for transmitting data along the combined
data and address bus using data bits D0-D3 on pins 14-17 of chip U18.
DTMF transceiver chip U18 communicates by transmitting DTMF tones out pin 8
through a operational amplifier network onto impedance-matching
transformer T1. Transformer T1 is connected through the telephone network
interface shown on FIG. 5 for transmitting DTMF tones onto the telephone
line. In a parallel arrangement, tones received from the telephone line
are transmitted through impedance-matching transformer T1 and on through
an operational amplifier network to drive the tone inputs to DTMF
transceiver chip U18. Operational amplifier U19A of the transmitting
network is configured for a gain of approximately 7 while operational
amplifier U19B is configured to receive tones with an approximate gain of
unity.
The telephone network interface is shown in FIG. 5. The customer premises
telephones must all be passed through the present invention in order for
the present invention to detect when an upstream telephone goes off hook.
By detecting an off-hook condition on an upstream telephone, the present
invention can drop the telephone and relinquish it to the telephone
subscriber for use. The time delay in dropping the communication line and
restoring dial tone is approximately one second delay. This is hardly
noticeable to the customer and allows for transparent operation of the
present invention while concurrently allowing the customer to use the
telephone at any time of day or night.
Standard RJ-11 connectors are shown in FIG. 5 for connection of the present
invention. Only the tip and ring wires 3 and 4 respectively of the RJ-11
jacks are used for communicating. In the Telco standards, pins 3 and 4
correspond to the tip and ring wires of line 1 in that connector. The
other wires in the RJ-11 jack are passed through without interruption. It
is essential that the customer's telephone equipment all be connected
downstream from the present invention so that user-initiated off-hook
conditions can be sensed by sensor U6.
Phone relays RLY1 and RLY2 are used to control the seizure of the telephone
line and the communication over it. Relays RLY1 and RLY2 are controlled
via lines 2.1 and 2.0 from the microcontroller U7 of FIG. 2. Relay RLY1 is
normally closed and is used to momentarily open the telephone line to
break the terminal-to-host connection and to get a dial tone when detector
U6 detects the user's downstream telephone going off-hook. Relay RLY2 is
normally open and is used to connect to the telephone line when a
terminal-to-host connection is required. When detector U6 detects the
user's downstream telephone equipment going off-hook, relay RLY2 is
immediately opened drop the terminal-to-host connection. The
communications protocol and heavy dependance upon bidirectional
handshaking (described more fully below) allows immediate interruption of
the terminal-to-host connection without detriment. The reporting
communication session of the utility monitor terminal of the present
invention can be restarted after the user is finished with the telephone
call.
When connected to the telephone, impedance-matching transformer T1 and the
electronic circuits connected to it are protected from surges and
overvoltage conditions by metal oxide varister MOV and fuse F1. Also, back
to back zener diodes on the tone-chip side of impedance-matching
transformer T1 are also used to shunt surges (see FIG. 4).
Tamper resistance is also an integral feature of the present invention.
Tamper-detection circuits are shown in. FIG. 5 which sense the tilting or
movement of the present invention or detect the disconnection or loop-back
connections through the meter cables. Either tilting the box or
disconnecting the meter cable will cause and interrupt condition on
microcontroller U8 which in turn will cause the present invention to alert
the central office as to a tampering condition.
Sensing and control of the metering conditions is shown in FIG. 6. The
multiplex data and address bus is shown connected to octal-transparent
latch chip U12 which is in the preferred embodiment part number 74373
available from a wide variety of vendors. This standard TTL chip is used
to interface sense and control wires to microcontroller U8 of FIG. 2. The
combined data and address bus is also connected to chip U15 which is in
the preferred embodiment and octal-D-type flip-flop part number 74374 also
available from a wide variety of semiconductor vendors. This additional
latch chip is also used as an interface to control auxiliary outputs.
Chip U15 receives data from the combined data and address bus when the bus
is in the data mode. The only connections interfaced to chip U15 are two
auxiliary outputs labeled OUT1 and OUT2. These are external control lines
which can be used, for example, for controlling power disconnects or main
disconnects. Thus, when the present invention is alert a condition in
which the power should be removed (such as nonpayment of utility bills),
the present invention can shut off selected circuits, alert the consumer
or shut off the mains. An indicator LED CR19 is also shown as an optional
means of alerting the user as to a problem condition.
As described above, the present invention can be used in a timed off-peak
usage meter. Line TOU IN is used as a user input to request TOU power.
This line is interfaced through latch chip U12 which can be read from the
combined data and address bus when in data mode. Chip U12 and U13 is also
connected through lines D and E to the loop-back sense circuit and
tilt-sense circuits respectively.
An optional battery power pack can be installed with the present invention
to enable full power operation during loss of AC mains. When an external
NiCad battery is used to back up the plus 12 volt supply for the present
invention, line 7 of auxiliary connector J3 is tied low to indicate that
battery backed-up power is not available. If such power is available, the
present invention will operate normally and can continue to communicate
with the central office even during loss of mains. Without such battery
backup, the present invention can not attempt to communicate with the
central office during loss of AC mains power (no power).
Terminal block TB1 is used to connect to the utility meters. In the case of
an electrical meter, for example, logic pulses are received from meter 1
on line 5 and logic pulses indicating utility usage for meter 2 are
received on line 4. These lines are optically isolated with photocouplers
U1A and U1B shown in FIG. 6. The outputs from these opto-isolators are
received by microcontroller chip U8 for counting and recording as an
indicator of utility usage. Those skilled in the art will readily
recognize that a wide variety of utility meters can be interfaced to the
present invention for recording utility usage. The logic pulses from an
electrical meter, for example, could be received from an optical coupler
sensing the rotation of the kilowatt hour disk in a conventional power
meter.
Line 3 of terminal block TB1 is used to force a call to the central office
at this time. This line could be used by operator maintenance or user
requests. Main power is supplied to operate the present invention through
pins 1 and 2 of terminal block 1. Pin 2 is system ground and pin 1
receives plus 12 volt DC from an appropriate DC power supply connected to
AC mains. The optional battery backup also supplies plus 12 volt DC to pin
1 of terminal block TB1.
The operating voltage for the circuits of the present invention is 5 volts
DC. 5 volt DC regulated power is controlled by monolithic regulator chip
U16 which in the preferred embodiment is a National part number LM340T-5.
12 volts DC is used in special situations to, for example, control the
coils of relays RLY1 and RLY2 shown in FIG. 5.
A key feature of the present invention is the ability to detect if the
phone line is in use before seizing the line. As shown in FIG. 5, an
opto-isolator chip U6 is placed in series with the tip conductor of the
telephone line. Current flow through the tip conductor on the telephone
line indicates on off-hook condition upstream from the present invention
and that condition is sensed by microcontroller chip U8. In such a
condition the present invention will not attempt to seize the line until
an on-hook condition is once again restored.
FIG. 7 describes additional control and sense logic used to support
additional features of the present invention. Analog to digital (A/D)
converter chip U5 is in the preferred embodiment a National part number
ADC0804 8 bit A/D converter. An analog input signal is received from pin 2
of an auxiliary connector J3. This analog input is used for sensing the
line voltage at the customer premises. The line voltage is sensed with an
external circuit which produces a 0-5 volt DC value corresponding to the
AC main's voltage. This 0-5 volt DC value is sensed by the V.sub.IN +
input to A/D converter chip U5 for long-term averaging and sensing of the
condition of the AC main's voltage. This type of data gathering of AC
main's voltage, power usages and the like at remote customer sites for
later down-loading and use by the utility is extremely useful in
controlling and predicting utility usage, loading and problems at remote
locations. The utility can then use this information for better service to
their customers.
Some additional interface logic is shown in FIG. 7. These interface lines
make logical decisions of chip read and write signals for assisting in
demultiplexing the combined data and address but for chips U12 and U15
shown in FIG. 6.
FIRMWARE
The main software which controls the present invention is stored in PROM
chip U13. The main loop of the software is described here.
Main Loop
On Power Up the two auxiliary outputs are turned off. This loop checks for
changes to these outputs. The options for these two outputs are stored as
8 bits as follows:
______________________________________
1 = Outputs #1 & #2 OFF
2 = Output #2 ON
4 = Output #2 Toggles ON/OFF every 2 secs
8 = Output #1 Toggles ON/OFF every Hour
16 = Output #1 ON @Time-of-day
32 = Output #1 OFF @Time-of-day
64 = Output #1 ON Immediately
128 = Output #1 OFF-Immediately
______________________________________
If a Time-of-Day option is ON, Read the calendar clock and compare with the
output #1 Time-of-Day. If the Hours and Minutes are =, perform the desired
output #1 change.
If a toggle function is ON, check if 2 seconds or 1 hour has elapsed. If
so, perform output function.
If a valid meter pulse has occurred (Interrupt), then check if rotation
pulse time=0, add current pulse time to total, increment number of times
saved in total. Repeat for number of active meters.
A meter pulse interrupt also can flag a new minimum rotation pulse time. If
so, the current date/time is stored with the new minimum pulse time.
A fail-safe check is done to see if there was a meter pulse in the last
hour. If not, a call is made with a transaction code sending this
information.
A fail-safe check is also done at midnight to tell if there were any KWH
increments during the day. If not, a call with a transaction code is made.
Both the Rev/Hour and KWH Inc/Day are checked for each active meter. These
fail-safe conditions could be used, for example, to monitor the heating
equipment in a home in the winter to detect failure of power usage due to
a tripped breaker.
TOU meter mode is used to swap meter readings. TOU mode can switch meter
readings by an external input or Time-of-Day, except for Saturday and
Sunday which optionally can force the meter readings on meter 1.
Auto dial is then checked (Month/Day/Hours/Minutes) only if off the phone
line.
The Tilt and Loop fail-safes are then checked. This ca be disabled and
bypassed. If not, it is checked to see if Tilt or Loop has been
interrupted. If yes, a call is made and a transaction code is sent.
Host command tones are checked only when on line. If a command tone is
found, then dispatches to command function which will return to loop.
Check if an RS232 command has come in. If so, dispatch to function, then
return to loop.
TERMINAL COMMANDS
In following descriptions, Tones flagged w/"H" are sent by the HOST & those
flagged w/"T" are sent by the Utility Meter Reader Residential Terminal.
Host to Terminal Commands
All commands are 2 Tones. First Tone # is never [*] or [#]. First tone
selects function category:
[0]=NO Commands
[1]=NO Commands
[2]=NO Commands
[3]=NO Commands
[4]=Transmit Data From Terminal
[5]=NO Commands
[6]=DownLoad Data to Terminal
[7]=Reset/Transmit KWH Parameters Commands
[8]=Utility Meter Reader Specific Commands
[9]=Utility Commands
[#],[*]=Tones are never used
Utility Meter Reader [0][n]-[3][n] Commands
No commands yet implement | | |
