Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD ~OR COPYING DATA
FROM ONE ELECTRONIC DEMAND REGISTER TO ANOTHER
BACKGROUND OF THE INVENTION
The present invention relates to electric
meters and, more particularly, to electronic demand
registers of the type having volatile and
non-volatile memories, the non-volatile memories
being used for storing installation-specific and
billing data during periods when the integrity of
such data may be in danger.
Conventional electric meters employ an
aluminum disk driven as a rotor of a small induction
motor by an electric field at a speed which is
proportional to the electric power being consumed by
a load. Geared dials, or cyclometer discs, integrate
the disk rnotion to indicate the total energy
consurned, conventionally measured in kilowatt hours
(one kilowatt hour equals one thousand watts oE power
consumption for one hour).
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In addition to the above measurement of
consumption, some electric meters contain means for
separatirlg the consumption into those parts of
consumption occurring during peak and off-peak hours
S (howev~r defined) and for recording maximum demand
during a predetermined period of time in order to
adjust billing according to such parameters. In one
such demand meter disclosed in U. S. Patent
3,5~6,97~, a mechanical demand register records the
power usage during a predetermined period of time and
stores the value for reading. The predetermined
period of time may be, for example, the time between
meter readings, or a period of time corresponding to
the billing period of the utility providing the
power. A clockwork mechanism restarts the demand
register at the ends of regular demand intervals of,
for example, a fraction of an hour, so that, at the
end of the predetermined period, the stored value
represents the highest value of power usage occurring
during any one of the regular demand intervals in the
predetermined period.
Demand registers of the mechanical type, such
as disclosed in the above U. S. Patent, have limited
flexibility. Once their design is completed for a
particular meter physical configuration, the design
is not transferrable to a meter having a different
physical configuration. In addi.tion, the
demand-measurement functions cannot be redefined
without major mechanical redesign.
Greater flexibility may be obtainable using
electronic acquisition, integration and processing of
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power usage. ~n electronic processor such as, for
exarnple, a microprocessor may be employed to manage
the acquisition, storage, processing and display of
the usage and demand data. ~. S. Patents 4,17~,654;
4,197,582; 4,229,7g5; 4,283,772; 4,301,508; 4,361,872
and ~,36~,519, among others, illustrate the
fle~ibility that electronic processing brings to the
power and energy usage measurement. Each of these
electronic measurement devices includes means for
producing an electronic signal having a
characteristic such as, for example, a frequency or a
pulse repetition rate, which is related to the rate
of power usage. The electronic processor is
substituted for the mechanical demand register of the
prior art to ~eep track of the power usage during
defined periods of time.
An electronic processor of an electronic
demand register conventionally employs volatile
random access memory for the high speed and low power
consumption characteristics offered by such devices.
However, electronic devices occasionally fail and
require troubleshooting and repair or replacement of
defective parts. One convenient troubleshooting
method employs the substitution of a replaceable
module for a module which may be defective. Such a
troubleshooting method is foreseen for use with the
system of the present invention. Such a
troubleshooting method raises the_problem of defining
a practical way of copying the unique set of
programmed constants and billing data from a
non-volatile memory in a demand register being
replaced into a non-volatile memory of a replacement
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demand register.
OBJECTS A~D SUMMARY 0~ THE INVENTION
Accordingly, it is an object of the invention
to provide an electronic dernand register which
overcomes the drawbacks of the prior art.
It is a further object of the invention to
provide an electronic demand register of the type
employing a digital processor and a random access
memory which includes means for storing volatile data
in a non-volatile storage medium upon the occurrence
of a predetermined deviation from normal power
conditions and which further includes means for
cop}ing installation-specific and billing data from a
dernand register being removed from an electric meter
to a replacement demand register being installed in
the electric meter.
Briefly stated, the present invention
provides a non-volatile memory copy programmer which
includes apparatus for temporary storage into which
data can be read out from a non-volatile memory of an
electronic demand register of an electric meter. The
temporarily stored data csn then be written into a
replacement non-volatile memory. The non-volatile
memory copy pro~rammer also provides control signals
for controlling reading and writing in the
non-volatile memory. A power monitor circuit in the
demand register normally enables the storage of data
from a volatile memory to the non volatile memory in
the event of a loss of power and enables restoring
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S ll-ME-133
the data from the non-volatile to the volatile memory
when the power is restored. The power monitor
circuit recognizes loss of power resulting from the
rerno~al of the demand register from the electric
meter in the same manner as it recognizes a normal
power loss so that, when the demand register is
removed for service or troubleshooting, the
installation-specific data and the billing data are
safely transferred to the non-volatile memory. If
replacement of the demand register is required, the
non-volatile memory copy programmer enables the
copying of the data from tne non-volatile memory in
the removed demand register to a non-volatile memory
in a replacement demand register.
lS According to an embodiment of the invention,
there is provided apparatus for copying data from a
first electronic demand register to a second
electronic demand register, the first and second
electronic demand registers each containing a
processor having a volatile memory and a non-volatile
memory comprising means responsive to a loss of power
in the demand register for writing the data from the
volatile memory to the non-volatile memory, a
non-volatile memory copy programmer, first means in
the non-volatile memory copy programmer for
temporarily storing the data read out of the
non-volatile memory in the first electronic demand
register, second means in the no~-volatile memory
programmer for writing temporarily stored data from
the first means for temporarily storing into the
non-volatile memory in the second electronic demand
register, the second means including means for
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producing control signals for controlling at least a
read and a write operation of the non-volatile memory
in the first electronic demand register and the
non-volatile memory in the second electronic demand
register and means in the non-volatile memory copy
programmer for holding the volatile memory in the one
of the first and second demand registers being read
from and written to in a reset condition while the
data is being read from and written to the
non-volatile memory.
The above, and other objects, features and
advantages of the present invention will become
apparent from the following description read in
conjunction with the accompanying drawings, in which
like reference numerals designate the same elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l is a schematic diagram of an electric
meter to which the present invention may be applied.
Fig. 2 is a block diagram of a demand
register of Fig. 1 according to an embodiment of the
invention.
Fig. 3 is a schematic diagram of a processor
reset generator of the power supply and power monitor
of Fig. 2.
Fig. 4 is a graph showing the reset voltage
versus the regulated supply voltage of the power
supply and power monitor of Fig. 3.
Fig. 5 is a simplified block diagram of a
non-volatile memory copy programmer according to an
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embodiment of the invention.
DETAII,ED DESCRIPTION OF THE PREFERRED EMBODIMENT
Although the present invention may be adapted
to any suitable style of electric meter which employs
an element rotating at a speed proportional to power
consumption, including single phase meters with one
or more current windings and polyphase meters, for
concreteness, the detailed description which follows
is directed toward an illustrative example of a
2-wire single phase meter of the type having a single
current coil and a single voltage coil.
Referring now to Fig. 1, there is shown,
generally at 10, an electric meter which includes a
small induction motor 12 driving a register 14.
Induction motor 12 includes a stator 16 made up of a
voltage coil 18 and a current coil 20 disposed on
opposite sides of a disk 22. Voltage coil 18 employs
a core 24 upon which is wound a large number of turns
of fine wire. Voltage coil 18 is connected across
lines 26 and 28 which feed power to a load (not
shown). Current coil 20 employs a core 30 upon which
a small number of turns, typically one or two, of
heavy conductor are wound. Current coil 20 is
connected in series with the power being fed to the
load on line 26. ~
Disk 22 is affixed to a shaft 32 which is
supported on suitable bearings (not shown) to permit
concerted rotation of disk 22 and shaft 32 under the
influence of a rotating magnetic field produced by
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the combined influence of voltage coil 18 and current
coil 20. A permanent magnet 34, having its poles
disposed on opposite sides of disk 22, applies a
retarding ~orce which i9 proportional to the
rotational speed of disk 22. The rotational torque
produced by voltage coil 18 and current coil 20
combined with the retarding torgue produced by
permanent magnet 34 is effective to rotate disk 22 at
a speed which is proportional to the product of the
voltage and the current; that is, the power, consumed
by the load.
Register 14 includes a watthour register 36
which may include, for example, a plurality OI dials
38 which are suitably geared and driven by a suitable
lS mechanical coupling 40 in proportion to the rotation
of shaft 32. In the embodiment shown, mechanical
coupling 40 includes a worm 42, which may be
integrall~ formed in shaft 32, which engages and
rotates a worm gear 44. Additional elements may be
present in mechanical coupling 40 for coupling the
rotation of worm gear 44 to watthour register 36 with
or without change in speed and direction according to
the design of the particular electric meter 10. As
is conventional, watthour register 36 totals the
nu~lber of revolutions of shaft 32, suitably scaled by
the gear ratios employed, for billing purposes.
A demand register 46, shown schematically as
a box in Fig. 1, is also connected by a suitable
coupling means 48 to respond to the rotation of shaft
32. In the prior art, demand register 46 is
conventionally a mechanical register having dials, or
other indicating devices (not shown), and coupling
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9 11-ME-133
means 48 is conventionally a mechanical arrangement
including shafts and gearing driven by rotation of
shaft 32. The dials, or indicating devices, in the
mechanical eMbodiment of demand register 46 are urged
forward for a fixed period of time by a pusher
mechanism (not shown). The pusher mechanism is reset
and restarted at the end of each of the fixed periods
of time, leaving the indicating devices with an
indicaticn proportional to the power usage (the
demand) during the fixed period of time. The
indication on the indicating devices at any time is,
therefore, the highest demand which has occurred
during any of the time periods since the last time
the indicating devices were reset. The recorded
demand is employed in billing. In the present
invention, demand register 46 is an electronic demand
register.
Referring now to Fig. 2, there is shown, a
simplified block diagram of a demand register 46
according to an embodiment of the invention. For
present purposes, it is sufficient to note that the
signal related to power usage fed from coupling means
48 to demand register 46 is an electronic signal
having a characteristic such as, for example, a
frequency, which is variable in dependence on the
rate of power usage. Any suitable electronic signal
generating apparatus, such ss disclosed in the
referenced prior patents, may be~employed to produce a
power usage signal which ls applied on a line 50 to a
processor 52 in demand register 46. Processor 52
appropriately performs calculations on the usage data
to derive desired demand parameters and stores the
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ll-ME-133
result. In addition, processor 52 may provide an
output on a line 54 suitable for driving a display
56. In addition, the stored data may be transmitted
on a line 58 to a remote location (not shown) for
further analysis and/or billing.
~ ue to the extremes of environment in which
electric meters may be used, display 56 mag need
special compensation for environmental parameters.
Such special compensation may include a display
temperature compensator 60 whose detailed structure
and function are not of interest to the present
disclosure.
The data which processor 52 transmits for
display and/or the manner in which processor 52
operates on the input data to produce internally
stored values may be modified according to a manual
input 62 which is not of concern to the present
disclosure.
As previously noted, processor 52
conventionally ernploys volatile random access memory
elements which lose any data stored in them in the
event of a power outage. This is usually not
acceptable in an electric meter where such loss of
usage and/or demand data has a negative financial
impact on the utility supplying the electric power.
Non-volatile storage elements such as, for example,
electrically erasable programmable read only memory
elements, are well known for use with processor 52.
However, such non-volatile storage elements normally
have relatively slow erase and write times on the
order of 10 or 20 milliseconds. This is too slow for
most applications. In addition to this drawback, the
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11 11-ME-133
power required to write such memory elements is quite
high compared to that required by volatile memor~
elements of processor 52. Finally, a wear-out
mechanism in electrically erasable programmable read
S only memory cells limits the number of times they can
be erased and re-recorded. About 10,~00 cycles of
write and erase brings such a memory element to the
end of its reliable useful life. Memory elements in
processor 52 must, of course, be written and erased
many thousands of times a day. Thus, an electrically
erasable programmable read only memory would have a
very short life as the operating memory for processor
52. In its role in non-volatile memory 64, however,
electrically erasable programmable read only memory
elements are erased and rewritten only when a
relatively serious power outage occurs and possibly
during a relatively small number of test cycles.
Such operations are not expected to occur on a
frequent enough basis in the register of an electric
meter to represent a limit on the life of the
register.
In order to provide safe storage for data
and/or programmed constants during a power outage, a
conventional non-volatile memory 64 is provided into
which such data and constants can be written in the
event of a power outage and from which the data and
constants can be again read upon restoration of
normal conditions.
A power supply and power monitor 66 receives
AC power from lines 26 and 28 for the production of a
regulated DC voltage which is applied on a line 68 to
all circuits in demand register 46 requiring such
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12 ll-ME-133
po~er. In addition to producing regulated DC power,
power supply and power monitor 66 also monitors the
condi.ion of the AC power on lines 26 and 28 and, in
response to certain detected conditions, applies
control signals on a line 70 to processor 52 which
controls the transfer of data from processor 52 to
non-volatile memory 64 in the event of an apparent
power outage and resets processor 52 in the event of
an actual power outage,
In summary, when a momentary power outage on
lines 26 and 28 causes the voltage of the unregulated
DC voltage to fall below a first threshold value, a
timer is started. If the unregulated DC voltage does
not rise above a second threshold, slightly higher
than the first threshold before the timer times out,
processor 52 is commanded to transfer billing data
and programmed constants to non-volatile memory 64.
A capacitor in power supply and power monitor 66
stores sufficient energy to maintain operation of
demand register 46 for the duration of the timer
delay, and to then have sufficient energy remaining
therein to write the billing data and programmed
constants to non-volatile memory 64.
The length of the timing cycle in power
supply and power monitor 66 is established at a value
which is long enough to ensure that a reduction in
the supply voltage probably results from a serious
power outage rather than from sur-ges, noise or a
purely momentary power outage,
When demand register 46 is removed from
electric rneter 10, or when electric meter 10 is
removed from connection to line 26 and line 28, power
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13 11-ME-133
supply and power monitor 66 recognizes the loss of
supply voltage as an impending power outage and
executes the process of writing the data from
volatile memory in processor 52 to non-volatile
memory in non-volatile memory 64. Thus, the
installation-specific data which is contained in the
programmed constants and the billing data are stored
in non-volatile memory 64 and may be made available
for writing to a non-volatile memory 6~ in a
replacement demand register 46 if provision is made
of a suitable memory programmer which permits copying
of such data from the previous non-volatile me~ory 64
to the replacement non-volatile memory 64. A full
disclosure of the apparatus and function of power
supply and power monitor 66 is contained in
Canadian ~atent Application Serial Number ~6a~ ,
W. R. Germer, which application was
filed Jv~e ~ q~ , and is assigned to assignee
of this application.
Referring now to Fig. 3, there is shown a
processor reset generator 71 which is an element of
power supply and power monitor 66 having particular
relevance to the present invention. It is the
function of processor reset generator 71 during
normal operation to monitor the regulated DC voltage
on line 68 and to apply a reset signal to processor
52 whenever the regulated DC voltage falls below a
predetermined value that is no loDger high enough to
maintain the regulated DC voltage at about its
operating value. It is also convenient for processor
reset generator 71 to produce a reset signal for
processor 52 during normal power-up as the re~ulated
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DC voltage rises from zero to its normal value.
Processor reset generator 71 contains
a switchiny transistor Ql whose base is connected
-to the regula-ted DC supply through a Zener
diode Dl in series with a resistor Rl. A second
resistor R2 is connected between the base of
switching transistor Ql and ground. In the
preferred embodiment, breakdown diode Dl has
a breakdown voltaye of about 2.7 volts and
resistors Rl and R2 have equal resis-tance
values.
In opera-tion, when the regulated DC
supply voltage i5 below a -threshold value,
switching transistor Ql is cut off and the
reset signal on line 70b follows the regulated
DC supply voltage. At and above the threshold
voltage, switching transistor Ql is turned on and
thus holds line 70b low. This relationship is
illustrated in Fig. 4. ~hen the regulated DC
supply voltage decreases from its nominal
value of 5 volts to a threshold value of about
3.9 volts the voltage on line 70b jumps from
about zero to about 3.9 volts and follows
the supply voltage as it decreases. The reset
signal as shown in Fig. 4 therefore provides a
reset signal both when the regulated DC supply
vol-tage decays below the threshold as well as
when the regulated DC supply voltage comes up
following a power outaye or duriny a normal
turn-on. ~ processor reset hold signal line 72
is mainta:ined in a floatiny condit:ion duriny
normal operation but may be grounded Eor purposes
to be described when demand reyister 46 is removed
from electric meter 10.
~eferring now to Fig. 5, a non-volatile
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11-ME-133
meli)ory copy programmer 74 is capable of being
connected to a removed demand register 46 to receive
serial input read from non-volatile memory 64 on a
line 76. The serial input is temporarily stored in a
5 temporary storage 78. The data temporarily stored in
temporary storage 78 may be copied into a replacement
non-volatile rneMOry 64'. In order to enable the
above reading and copying operations, a control
signal generator 80 is provided to apply an
10 appropriate chip select signal on a line 82 to
non-volatile meMory 64 or a replacement non-volatile
memory 64'. While reading or copying data, control
- signal generator 80 is effective to place a ground on
processor reset generator 71. This holds the base of
15 transistor Ql (Fig. 3) at ground potential and
maintains processor 52 in the reset condition.
Control signal generator 80 may employ an~
convenient devices to produce the appropriate logic
level signals for controlling non-volatile memory 64
20 (or a replacement non-volatile memory 64') such as,
for example, mechanically or electrically controlled
switches. Temporary storage 78 may also be any
convenient apparatus for formatting an appropriate
output message and for decoding an input message
25 prior to storage. Temporary storage 78 may include,
for example, a microprocessor with appropriate
communications buffers. For example, non-volatile
memory 64 rray be a type NMC9306 non-volatile memory
and yrocessor 52 may be a type N~C 7503
30 microprocessor, both of which are commercially
available at the time of filing of the present
application. This is the same combination of
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equipment disclo~ed in Canadian Patent Applicati~n
5erial Number ~j ~ , F. Y. Simon, which
application was filed on /~ 0~ IY~ ,
and whieh appli~ation is assi~ned to assig~ee of this
applic~tion.
As noted in the above-referenced patent
application, problems may be encountered in passing
data back and forth between non-volatile MemOry 64
and the particular microprocessor employed in
processor 52 because of differences in the da~a
formats for the two communicating devices. The
solution described in the referenced application,
which may be employed in non-volatile memory copy
prog}ammer 74, includes providing a communications
l~ buffer in temporary storage 78 which is effective for
formatting a data message for transmission to
non-volatile memory 64 (or a replacement non-volatile
memory 64') which fools non-volatile memory 64 into
recognizing a portion of the data message having an
acceptable protocol. Similarly, the communications
buffer performs selective shift and ignore operations
on data received from non-volatile memory 64 to
convert the data protocol into one which a
microprocessor in temporary storage 78 is capable of
accepting.
After the data read out from non-volatile
memory 64 into temporary storage in temporary storage
78 has been copied into a replacement non-volatile
memory 64', the ground signal on processor reset hold
signal line 72 may be removed. This permits
processor reset generator 71 to generate a reset
signal which, among other things, reads the copied
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17 11-ME-133
contents of non-volatile memory 64 into processor 52
in order to enable testing of demand register 46.
When demand register 46 is physically removed from
non-volatile rnemory copy programmer 74 and power is
thereby cut off from demand register 46, the apparent
power outage is effective in the manner described to
ersse non-volatile memory 64 and store the data
therein. When demand register 46 is installed in an
electric meter, and the voltage applied thereto rises
above a predetermined value, the stored content of
non-volatile memory 64 is returned to processor 52.
~ aving described preferred embodiments of the
invention with reference to the accompanying
drawings, it is to be understood that the invention
-~ not li~ited LO those precise embodiments, and that
various changes and modifications may be effected
therein by one skilled in the art without departing
from the scope or spirit of the invention as defined
in the appended claims.
