CA1194124A - Solid state watthour meter - Google Patents
Solid state watthour meterInfo
- Publication number
- CA1194124A CA1194124A CA000411053A CA411053A CA1194124A CA 1194124 A CA1194124 A CA 1194124A CA 000411053 A CA000411053 A CA 000411053A CA 411053 A CA411053 A CA 411053A CA 1194124 A CA1194124 A CA 1194124A
- Authority
- CA
- Canada
- Prior art keywords
- microprocessor
- power
- watt
- time
- consumer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R21/00—Arrangements for measuring electric power or power factor
- G01R21/08—Arrangements for measuring electric power or power factor by using galvanomagnetic-effect devices, e.g. Hall-effect devices
Abstract
ABSTRACT OF THE DISCLOSURE
The solid state watt-hour meter (10) comprises a watt-hour (16) sensor adapted to be coupled to a consumer's con-nection to a source of electric power for sensing the vol-tage supplied to, and the current drawn by, the consumer's total electric load and for producing an output signal in-dicative of a quantity of watt-hours of power utilized by the consumer. The meter (10) includes a microprocessor (22) coupled to the watt-hour sensor (16) for receiving output signals thereform. An electrically alterable ROM
(24) is coupled to the microprocessor (22). A power supply 18 having an input coupled to the consumer line voltage has an output coupled to the microprocessor (22) for sup-plying a regulated DC voltage thereto and includes means for supplying a 60 Hz clock signal to the microprocessor (22). A readout device (26) is coupled to the microprocessor for providing a readout of the power consumed since the last reading of the solid state watt-hour meter (10). A
load control circuit breaker (132) in a consumer's circuit line to a consumer load (130), is connected to a load con-trol output (123) of the microprocessor (22) and a micropro-cessor override switch (140) is coupled to the meter (10).
The microprocessor 22 and electrically alterable ROM (24) are connected and programmed:
(a) to sense the time of day as determined from an initial time of day and setting the 60 Hz clock signal;
(b) to sense and totalize signals from the sensor (16) indicating the total power used by the consumer;
(c) to provide a readout signal indicative of the total power consumed since the last reading of the meter;
(d) to automatically open circuit the circuit breaker (132) for a time period during the time of day (daytime) when power demand on the electric power source is high and/or the cost per kilowatt hour is high;
(e) to automatically close the circuit breaker (132) during the time of day (night-time) when the power demand on the source of electric power is low and/or the cost per kilowatt power is low;
(f) to allow a consumer to override the microprocessor (22) control of the circuit breaker (132) by operating the override switch (140) to close the circuit breaker (132);
and (g) to automatically reset the override switch (140) to the open position thereof when the microporcessor (22) is in the operating mode for automatically closing the cir-cuit breaker (132).
The solid state watt-hour meter (10) comprises a watt-hour (16) sensor adapted to be coupled to a consumer's con-nection to a source of electric power for sensing the vol-tage supplied to, and the current drawn by, the consumer's total electric load and for producing an output signal in-dicative of a quantity of watt-hours of power utilized by the consumer. The meter (10) includes a microprocessor (22) coupled to the watt-hour sensor (16) for receiving output signals thereform. An electrically alterable ROM
(24) is coupled to the microprocessor (22). A power supply 18 having an input coupled to the consumer line voltage has an output coupled to the microprocessor (22) for sup-plying a regulated DC voltage thereto and includes means for supplying a 60 Hz clock signal to the microprocessor (22). A readout device (26) is coupled to the microprocessor for providing a readout of the power consumed since the last reading of the solid state watt-hour meter (10). A
load control circuit breaker (132) in a consumer's circuit line to a consumer load (130), is connected to a load con-trol output (123) of the microprocessor (22) and a micropro-cessor override switch (140) is coupled to the meter (10).
The microprocessor 22 and electrically alterable ROM (24) are connected and programmed:
(a) to sense the time of day as determined from an initial time of day and setting the 60 Hz clock signal;
(b) to sense and totalize signals from the sensor (16) indicating the total power used by the consumer;
(c) to provide a readout signal indicative of the total power consumed since the last reading of the meter;
(d) to automatically open circuit the circuit breaker (132) for a time period during the time of day (daytime) when power demand on the electric power source is high and/or the cost per kilowatt hour is high;
(e) to automatically close the circuit breaker (132) during the time of day (night-time) when the power demand on the source of electric power is low and/or the cost per kilowatt power is low;
(f) to allow a consumer to override the microprocessor (22) control of the circuit breaker (132) by operating the override switch (140) to close the circuit breaker (132);
and (g) to automatically reset the override switch (140) to the open position thereof when the microporcessor (22) is in the operating mode for automatically closing the cir-cuit breaker (132).
Description
~1~4~Z4 SOLID STATE WATT-HOUP~ !`lETER
_ckaround of the Invention Field of the In~7ention The present invention relates to electronic watt-hour meters which include a solid state micro-processor coupled to a wat'-hour sensor.
DescriPtion of the Prior Art Heretofore, various electronic watt-hour meters incorporating a microprocessor therein have been proposed. Such electronic watt-hour meters have provided for monitoring of and storing of information rel2ted to power demand and power use by a consumer.
.lso, such meters have included circuitry, progr~mlming and switches connected to various consumer loads for enabling the microprocessor to switch off or de-energize certain consumer loads during high electric use periods, e.g., daytime, and to switch on or ene~rgize these loads during low electric use periods, e.g., ni~ht-time.
E~:amples of such previously proposed electronic watt-hour meters are disclosed in the follo~ing U.S.
patents:
U.S. Patent No. Patentee -3,505,508 Leyde 3,522,421 Miller 3,7~9,201 Carpenter, et al.
4,034,233 Leyde 4,059,747 Brody 4,075,699 Schneider, et al.
4,240,030 Bateman, et al.
4,241,237 Paraskevakos, et al.
4,253,151 Bouve 11~41Z4 See also European Patent Application Publica-tion No. 0015666 for: Apparatus for Controllins Elec,ric Power Consumption, filed by South Eas'ern Electricity Board, Queens ~ardens Hove, Sussex, England.
Still further, it has been proposed to utilize a Hall-effect sensor for monitoring and measuring the electric power consumption by a consumer in an elec-tronic watt-meter. E~:amples of such previously pro-posed Hall-effect sensors and watt-meters are dis- .
closed in the following U.S. patents:
U.S. Patent No. ~atentee 3,317,835 Dietz, et al .:
3,328,689 Raines, et al 3,343,084 Gambale 3,921,069 Milkovic g,283,643 Levin, et al As will be described in greater detail herein-after, the solid state watt-hour met~er of the present invention differs from the previously proposed electronic watt-hour meters by not only providing a solid state Hall-effect sensor and time/load -switching functions in the microprocessor of the _-meter but also by providing a reset function .-whenever there is a consumer-initiated over-ride of the time/load switching function of the microprocessor.
_ckaround of the Invention Field of the In~7ention The present invention relates to electronic watt-hour meters which include a solid state micro-processor coupled to a wat'-hour sensor.
DescriPtion of the Prior Art Heretofore, various electronic watt-hour meters incorporating a microprocessor therein have been proposed. Such electronic watt-hour meters have provided for monitoring of and storing of information rel2ted to power demand and power use by a consumer.
.lso, such meters have included circuitry, progr~mlming and switches connected to various consumer loads for enabling the microprocessor to switch off or de-energize certain consumer loads during high electric use periods, e.g., daytime, and to switch on or ene~rgize these loads during low electric use periods, e.g., ni~ht-time.
E~:amples of such previously proposed electronic watt-hour meters are disclosed in the follo~ing U.S.
patents:
U.S. Patent No. Patentee -3,505,508 Leyde 3,522,421 Miller 3,7~9,201 Carpenter, et al.
4,034,233 Leyde 4,059,747 Brody 4,075,699 Schneider, et al.
4,240,030 Bateman, et al.
4,241,237 Paraskevakos, et al.
4,253,151 Bouve 11~41Z4 See also European Patent Application Publica-tion No. 0015666 for: Apparatus for Controllins Elec,ric Power Consumption, filed by South Eas'ern Electricity Board, Queens ~ardens Hove, Sussex, England.
Still further, it has been proposed to utilize a Hall-effect sensor for monitoring and measuring the electric power consumption by a consumer in an elec-tronic watt-meter. E~:amples of such previously pro-posed Hall-effect sensors and watt-meters are dis- .
closed in the following U.S. patents:
U.S. Patent No. ~atentee 3,317,835 Dietz, et al .:
3,328,689 Raines, et al 3,343,084 Gambale 3,921,069 Milkovic g,283,643 Levin, et al As will be described in greater detail herein-after, the solid state watt-hour met~er of the present invention differs from the previously proposed electronic watt-hour meters by not only providing a solid state Hall-effect sensor and time/load -switching functions in the microprocessor of the _-meter but also by providing a reset function .-whenever there is a consumer-initiated over-ride of the time/load switching function of the microprocessor.
2~
SU,~'IhRY O~ THE IN~7ENTION
According to the invention, there is provided a solid state watt-hour meter comprising a ~-att-hour sensor adapted to be coupled to a consumer's connection to a source of electric power ~or sensing the voltage supplied to, and the cu,rent drawn ~y, the consumerls total electric l.oad and for produ~ing an output signal indicative of a auantity of watt-hours of power utilized by the consumer; a microprocessor coupled to said watt-hour sensor for receiving said output signals;
an electrically alterable ROM coupled to said micro-pr~cessor; p~er supply means having an input couPled to the consumer line voltage and an output coupled to said microprocessor for supplying a regulated DC voltage 1~ thereto; clock signal generating means coupled between the consumer line voltage and said microprocessor for supplying a 60 Hz clock signal to said microprocessor;
readout means coupled to said microprocessor for pro-viding a readout of the power consumed since the last reading of said solid state watt-hour meter; at least one load control circuit breaker in a consumer's unit supply line to at least one consumer load, said micro-processor ha~ring at least one load control out-put coupled to said at least one circuit brea};er; an override s~itch coupled to said meter and said microprocessor and said electrically alterable RO~I being connected and programmed:
(a) to sense the time of day as determined from an initial time of day settins and the 6n Hz clock signal;
(b) to sense and totalize signals rrom said sensor indicating the total power used by the consumer;
~ c) to provide a readout signal indicative of the total power co~.s~ since the last reading of the meter;
(d) to auto~atically open said at least one circuit bre2}~er for a time period durins the time of day (daytime) when power demand on the electric power source is hish andfor the cost per ~;ilowa,t hour is high;
(e) to automatically close said at least one circuit brea};er during the time of day (night-time) when ~he power demand on the source of electric power is low and/or the cost per kilowatt power is lowi (f) to allow a consumer to override said microprocessor control of said at least one circuit breaker by operating said override switch to close said at least one circuit breaker; and (g) to automatically reset said override switch to the open position thereof when said micro-processor is in the operating mode for automatically closing said at least one circuit breaker.
B?~Ir~ Dr:SCPIP~ION OF THE DP~HINGS
FIG. 1 is a bloc~ diagram Or the solid state watt-hour meter of the present invention.
FIG. 2 is a perspective view of an idealized Hall cell ,e?resentins the Hall type sensor utilized in the ~211 multiplier sho~m in Fis. 1.
FIG. 3 is a perspective view of a current to flu~ generator including a yo~e having a gap for re~eiv-ins a Hall-effect chip.
10FIG. 4 is a perspective view of the solid state watt-hour meter and a meter reading unit.
FIG. 5 is a schematic circuit dias-am of the electrical circuit of the watt-hour meter shown in Fi~. 1.
15FIGS. 6-13 ~rP flow charts of routines performed by the microprocessor in the solid state watt-hour meter sho-vm in FIG. 1.
~J; ~
02 DESCRIPTlON OF THE__REFERRED EMBODI ENT
03 Referring now to Fig. 1, there is illustrated 04 therein a bloc]c diagram oE the solid s~ate wa-tt-hour 05 meter of the present inven-tion which is generally 06 identified by the reference numeral 10. The solid 07 state watt-hour meter 10 includes a current sensing 08 device (current source) 12 and a voltage sensing 09 device (voltage source) 14 which are coupled to a Hall-effect sensing and multiplying device (Elall 11 multiplier) 16. rrhe voltage source 1~ is also coupled 12 to a regulated power supply 18 which supplies DC
13 operating voltage through an information bus 20 to a 14 microprocessor (with RAM and ROM) 22.
As will be described in grea-ter detail herein-after 16 in connection with the description of Fig. 5, the 17 power supply 18 also supplies a 60Hz square wave clock 18 signal to the microprocessor 22.
19 The microprocessor 22 with built-in ROM memory contains the operation program and decision center for 21 the meter 10. The built-in RAM memory in the 22 microprocessor 22 is available fcr "scratchpad work".
23 Also connected to the bus 20 is a non-volatile 24 electrically alterable ROM (EAROM~ 24. This non-volatile memory 24 is available for storing 26 information that is changeable or changing and that 27 must be retained in the event of loss of power.
28 Typically, such information would include the content 29 of the watt-hour register, the demand register and related time, times related to time of day or time of 31 use periods, calibration constants, serial numbers, 32 account numbers, security numbers, etc.
33 The meter 10 further includes a readout device 26 34 which is coupled to the bus 20 and which is preferably a 6-digit seven-segmen-t LED display 26. The meter 10 36 can be factory preprogrammed -to display any 02 information in the meter 10. However, long running 03 displays would be difficult to follow even ~Dy a 04 trained and skilled observer and would be subject to 05 transcribing errors. Thus, to keep the clisplay 06 simple, two optical input/output (I/O) por-ts 28 and 30 07 (Fig.4~ are provided in a housing 31 (Fiy. 4) of the 08 meter 10. Behind one I/O port 28 is an 09 electro/optical device, namely, a phototransistor 32 (Fig. 5). The meter is then programmed so that a 11 light directed into the I/O port 28 by a customer will 12 cause the meter to present an output, such as total 13 watt hours used since the last reading, on the LED
14 display 26.
In addition to the phototransistor 32, an 16 electro/optical device, namely, an LED 34, is located 17 behind the I/O port 30 and forms an input/output pair 18 with the phototransistor 32 which input/output pair 19 are capable of transmitting data into or out oE the meter 10 at a relatively high rate.
21 As shown in Fig. 4, it will be apparent that a 22 meter reading unit 40, par~icularly adapted for use 23 with the meter 10 is provided with an optical plug, 24 terminal or wand 42 which is adapted to be placed over the I/O ports 28 and 30. Inside the unit 40 is a 26 microprocessor (not shown) and associated computer 27 components to form a microprocessor system which 28 includes an optical input/output pair identical to the 29 input/output pair 32 and 34 coupled by ~iber optics to the wand 42.
31 An important feature of the meter 10 is the optical 32 coupling available with the meter reading unit 40 33 which is effected by placing the wand 42 over the I/O
34 ports 28 and 30. Communication can then take place optically (and even -through a glass cover over -the
SU,~'IhRY O~ THE IN~7ENTION
According to the invention, there is provided a solid state watt-hour meter comprising a ~-att-hour sensor adapted to be coupled to a consumer's connection to a source of electric power ~or sensing the voltage supplied to, and the cu,rent drawn ~y, the consumerls total electric l.oad and for produ~ing an output signal indicative of a auantity of watt-hours of power utilized by the consumer; a microprocessor coupled to said watt-hour sensor for receiving said output signals;
an electrically alterable ROM coupled to said micro-pr~cessor; p~er supply means having an input couPled to the consumer line voltage and an output coupled to said microprocessor for supplying a regulated DC voltage 1~ thereto; clock signal generating means coupled between the consumer line voltage and said microprocessor for supplying a 60 Hz clock signal to said microprocessor;
readout means coupled to said microprocessor for pro-viding a readout of the power consumed since the last reading of said solid state watt-hour meter; at least one load control circuit breaker in a consumer's unit supply line to at least one consumer load, said micro-processor ha~ring at least one load control out-put coupled to said at least one circuit brea};er; an override s~itch coupled to said meter and said microprocessor and said electrically alterable RO~I being connected and programmed:
(a) to sense the time of day as determined from an initial time of day settins and the 6n Hz clock signal;
(b) to sense and totalize signals rrom said sensor indicating the total power used by the consumer;
~ c) to provide a readout signal indicative of the total power co~.s~ since the last reading of the meter;
(d) to auto~atically open said at least one circuit bre2}~er for a time period durins the time of day (daytime) when power demand on the electric power source is hish andfor the cost per ~;ilowa,t hour is high;
(e) to automatically close said at least one circuit brea};er during the time of day (night-time) when ~he power demand on the source of electric power is low and/or the cost per kilowatt power is lowi (f) to allow a consumer to override said microprocessor control of said at least one circuit breaker by operating said override switch to close said at least one circuit breaker; and (g) to automatically reset said override switch to the open position thereof when said micro-processor is in the operating mode for automatically closing said at least one circuit breaker.
B?~Ir~ Dr:SCPIP~ION OF THE DP~HINGS
FIG. 1 is a bloc~ diagram Or the solid state watt-hour meter of the present invention.
FIG. 2 is a perspective view of an idealized Hall cell ,e?resentins the Hall type sensor utilized in the ~211 multiplier sho~m in Fis. 1.
FIG. 3 is a perspective view of a current to flu~ generator including a yo~e having a gap for re~eiv-ins a Hall-effect chip.
10FIG. 4 is a perspective view of the solid state watt-hour meter and a meter reading unit.
FIG. 5 is a schematic circuit dias-am of the electrical circuit of the watt-hour meter shown in Fi~. 1.
15FIGS. 6-13 ~rP flow charts of routines performed by the microprocessor in the solid state watt-hour meter sho-vm in FIG. 1.
~J; ~
02 DESCRIPTlON OF THE__REFERRED EMBODI ENT
03 Referring now to Fig. 1, there is illustrated 04 therein a bloc]c diagram oE the solid s~ate wa-tt-hour 05 meter of the present inven-tion which is generally 06 identified by the reference numeral 10. The solid 07 state watt-hour meter 10 includes a current sensing 08 device (current source) 12 and a voltage sensing 09 device (voltage source) 14 which are coupled to a Hall-effect sensing and multiplying device (Elall 11 multiplier) 16. rrhe voltage source 1~ is also coupled 12 to a regulated power supply 18 which supplies DC
13 operating voltage through an information bus 20 to a 14 microprocessor (with RAM and ROM) 22.
As will be described in grea-ter detail herein-after 16 in connection with the description of Fig. 5, the 17 power supply 18 also supplies a 60Hz square wave clock 18 signal to the microprocessor 22.
19 The microprocessor 22 with built-in ROM memory contains the operation program and decision center for 21 the meter 10. The built-in RAM memory in the 22 microprocessor 22 is available fcr "scratchpad work".
23 Also connected to the bus 20 is a non-volatile 24 electrically alterable ROM (EAROM~ 24. This non-volatile memory 24 is available for storing 26 information that is changeable or changing and that 27 must be retained in the event of loss of power.
28 Typically, such information would include the content 29 of the watt-hour register, the demand register and related time, times related to time of day or time of 31 use periods, calibration constants, serial numbers, 32 account numbers, security numbers, etc.
33 The meter 10 further includes a readout device 26 34 which is coupled to the bus 20 and which is preferably a 6-digit seven-segmen-t LED display 26. The meter 10 36 can be factory preprogrammed -to display any 02 information in the meter 10. However, long running 03 displays would be difficult to follow even ~Dy a 04 trained and skilled observer and would be subject to 05 transcribing errors. Thus, to keep the clisplay 06 simple, two optical input/output (I/O) por-ts 28 and 30 07 (Fig.4~ are provided in a housing 31 (Fiy. 4) of the 08 meter 10. Behind one I/O port 28 is an 09 electro/optical device, namely, a phototransistor 32 (Fig. 5). The meter is then programmed so that a 11 light directed into the I/O port 28 by a customer will 12 cause the meter to present an output, such as total 13 watt hours used since the last reading, on the LED
14 display 26.
In addition to the phototransistor 32, an 16 electro/optical device, namely, an LED 34, is located 17 behind the I/O port 30 and forms an input/output pair 18 with the phototransistor 32 which input/output pair 19 are capable of transmitting data into or out oE the meter 10 at a relatively high rate.
21 As shown in Fig. 4, it will be apparent that a 22 meter reading unit 40, par~icularly adapted for use 23 with the meter 10 is provided with an optical plug, 24 terminal or wand 42 which is adapted to be placed over the I/O ports 28 and 30. Inside the unit 40 is a 26 microprocessor (not shown) and associated computer 27 components to form a microprocessor system which 28 includes an optical input/output pair identical to the 29 input/output pair 32 and 34 coupled by ~iber optics to the wand 42.
31 An important feature of the meter 10 is the optical 32 coupling available with the meter reading unit 40 33 which is effected by placing the wand 42 over the I/O
34 ports 28 and 30. Communication can then take place optically (and even -through a glass cover over -the
3& housing 3l~ such that the large amount of informa-tion which can be senerated by the meter 10 can be quickly rea~ by the meter reading unit 40.
Eight load control in?u,~oulpu_ portC gener~lly ic~entified b~ reference nu.. leral 50 are cou?le~ 'o the 5 hus 2~ znd are available ior the cGntrol of specific customer loads such as water heaters, air conditioners, electric heating, etc., as will be described in greater det~il in connection with the description of Fig. 5.
Also, the meter 10 can be programmed so tha~ load con-trol can be asserted by the customer/consumer or bythe supplier/electric utili-y.
Finally, a power outage (105s 0~ voltage)timer 60 is coupled to the microprocessor 22 for supply-ins 2 sisnal, when power is restored after a poweroutage, to the ~.icroprocessor ~2. Such signal is indicative of the duration of the power outage so that the microp~ocessor 22 can update (correct~ the real time value stored in the ~A~OM 24. , ~n idealized Hall cell 70 is shown in rig. 2 and includes a Hall plate 71 which is located in a flu~: fiel-d~represented bv an arrow 72, that is estab-lished by line current _lowing through the irst and second phases of a two-phase power sup?l~- to the con-su..... ..,er.
A bias voltage directl~ related to the line volt2ge is supplied to opposite sides 73 and 74 of the plate 71. The Iall plate 71 output volta~e across the other two opposite sides 75 and 76 of the plate 71 is related to the instantaneous power, e.g. watts being supplied.
As shown in U.S. Patent No. 2,550,492 the Hall plate output voltage can be defined substantially as fol 10WS:
E;~ = [~I cos ~ - VI cos ~2wt + ~)]
~n which:
~, = Hall pla~e ouLput ~Toltage ~ = a constant V = voltage o_ source 1 = line current supplied by source ~ = ph~se angle between V and I
w = radius frequency = 2 ~ f t = time The direct current term (VI cos e) is propor-tional to real or active power. The average direct current in the output has a value of ~ero when no power is being transmitted.
Such a Hall ?late is formed on a chip 77 (Fig. 5) which is recei~ed in an air yap 78 (~ig. 3!, in a current transformer core or yoke 8~ having two legs (conductors) 81 and 82 of the two-phase voltage system su??lied to the customer/consumer passing therethrough as shown in Fig. 3. The yo};e 80 is mounted on a base plate 84 and a mounting plate 86 is provided for mount-ing the chip 77.
Alt~ough not shown in Fig. 4, it will be under-stood that a transparent (glass~ cover 88, a portion of which is shown in Fig. 5, is received over the housing 31 to ~eep dust and dirt from getting in the housing 31, particularly ports 28 and 30.
The meter 10 is preferably built on two main circuit boards (not shown), one for analog circuits and one for digital circuits, with two additional circuit boards, one for mounting transfo~mers, and or.e for mounting the Hall effect mul'Liplier 16 which functions as a watt-hour generator.
hlso, the m~ter 10, par'icula.lv t`ne houains 31 thereof, will be interchar,geable ~iith existins induc-ion watt-hour meters typic21 of those found in residen_i~l anc apar~-ent ins~allations - 5 ~e erring now to Fig 5, the-e is illus~ra_ed therein the schematic circuit ciaaram o_ .he me.er 10. .~â sho~ the vol~age source ( device ) 14 in-cludes a tranâfo~~le- 90 havins a primary coil 92, a secondarv windins94 for su?pl;ring voltage to the Hall ef ect device and multiplier 16 in the chip 77 and a secondary winding96 for supplying A C voltage to the A C to D C regulated power supply 18 The power supply 18 supplies a regulated D C voltage to a voltage bus 98 and 60 Hz clock signal via a conductor 100 to a cloc}: inpu~ 102 of the micro-processor 22 The chip 77 having the Hall multiplie- 16 is coupled via I/O ccnductors 104 to I/O ports of the microproceâsor 2 It will be understood that the 2G chip 77 has a plurality of Hall effect devices and multiplyins circuitry therein to provi~e a watt-hour sensor and generator 16 The inputs to the chip 77 are a flu~ 72 generated by the line current in conductor 81 and 82, line voltage from coil 94, and win~ing 94 a voltage signal via conductor lG5 connected to the voltage bus 98 and conductor 106 connectec to system co~or or ground 108 for timing and to control several self calibration features The output of this chip 77 is z sguare wave signal proportional 3G to ~Jatt-hours 11~4124 The chip 77 ic .,anu~actu.ec b~ Tei:as Ins~
ments and ~;ey additional external elements in the chip 77 ard circuitry thereG are: (1) RC inte-cr2to~- ?a--5 ccnsis ing o' a resistor Gf about 200 i ol~m5 2nd a ca?ac-to~ of 0.6 r~ mic-ofaraas, (2) a 2.2~; ohm ~eedbac}: resis.or, (3~ two 1 micr~~ara_ ca?acitorr, .o st2bliTe the circui~r~, (4) ~wo 100~;
oh~ esis~rs for bias, an-' (5) 2 po~entio~leter for bias adjust.
lG The basic calibration of the meter selecting a resistor of about 200~ ohms in the R-C
networ}~ Tris adjus~ment sets the ~h of the meter an~ compensates for such variables as the gap 7E in the flux generator 16, the gain in amplifiers in the chip 77, and .he accur2ciT o the 0.6~ microfarad ca?acitor. The po entiomeLer is used to eliminate the effect of an ur,wanted voltage-causea erfect on the chip 77.
An adcitional e-ror resulting from the Hall effect devi,ces in the chip 77 causes the circuitry to creep. The cree? can be "forward"~or "bac}.~.ard", and there is no stic}~tion to suppress this error.
The addi'.ion o a "tickler" coil on the current tr~nsduce- core or yo}:e &0 is use_ to add su'ficient 2~ arp _urns to negate an~T creep.
Variations in outputs from a nominal ambient te~perature over a tem~erature range be~.een -20C and +50C and up to 2.5%.
Three of the load control outputs identified by reference numerals 121, 122 and 123 are shown in Fis. 5 co~ing out of the microprocessor 22 for controlling customer/consumer 1O2ds. For exa~ple, the output 123 can be considered as connected to a w2ter heate~ load s`n.ol;~ in '.he blot~up in Fig. 5 ?5 a resistance loa~ 130. This load 130 is co~necte7 in serie- witll an SC.~ 132 across the ~..C su,7ply voi,-7ge. The scr. 137 fc~Jrlc a load circuit brea}e-. ~ cate 134 of th' SC~ 13~ is cou?led to the micro~)rocecsor load cGr.~rol output 123 so tha. the micro~rocessor 22 can control when the loac 130 is enerci~ed. Ty?ically, the loa~ 130 is enersized d~rins the early evening, nighttime and early morning Jnen the eost per KWH is low and de-ener~izec during the daytime when the cost per 7~l;H is high.
Aceording to the teachings of the ?resent invention, ar override switch ~40is provided coupled tc the microrjrocessor 22 to enable the customer to overri~7e the load con'rcl function of the mieroprocessor 22. In the illustrated embodiment the switeh 140 is also eoupled to the gate 134 via a eoncuctor 1~2. Thus, bv o?eratins the stiiteh 140,e.g. du~-ing the day, the eustomer ean energize his hot water heater ove riding the mieroproeessor 22.
~ lso, aecordins to the teachings of the present invention, the micro~rocessor 22 and E~ROr~ 24 are eonnec~ed and prograr~med to reset the switch 140 to the opern position thereof during the mode (time, e.g., nighttime) of opera-tion of the microprocessor 22 when an energizing signal is supplied via output 123 to the gate 134, if the switch 140 had been operated (closed) by the custo~er 10 to rest the s~iteh 140 to the open position.
The reterAhas no battery and derives its time froi, the po,7er ~ine, namely the 60 H~ clock signal. Since the me~cr 10 must accurately keep real time to support its time-of-day functions, loss of electrical power to the meter would destroy the time-of-day functions. To keep time without system voltage, the power outage timer(loss of voltage timer) 60 is included in the meter 10.
This timer 60 is based o~ an R-C net~ork, comprising resistor 150 connected across capacitor 152, ~here the recharge time is proportional to the outage time. If the recharge time indicates the outage has been greater than 6 hours then the time is not recoverable and default conditions must be used.
In that case the corrected time in the me e-- 10 is reloaded during the next meter reading opera-tion by the meter reading unit 40.
As shown in EIG. 5 the power outage timer 60 has other components ~hich will now be described and is one of several timers that can be used, such other timers being of the type disclosed in copending Canadian application Serial No. 411,602 filed ~epte~x~ 16, 1982, entitle~: PCWER OUTAGE TIMER, invented by Jim Hurley et al.
The timer 60 has a voltage supply line 154 from the microprocessor 22 which charges the capacitor 152 through a diode 156 and resistor 158 to a voltage level at junction 160 related to the supply voltage. The voltage at junction 160 is coupled to one input of a comparator 162.
Another voltage supply line 164 from the micro-processor 22 supplies a voltage through a diode 165 to a voltage divider 166, 167. A point (junction) 168 in the divider 166, 167 is coupled 02 to another input of the comparator 162 and has a 03 normal voltage which is equal to or slightly less than 04 the normal voltage on the capacitor 152. The output 05 of the comparator 162 is connected to the 06 microprocessor 22.
07 After a power outage, the time from the 08 reestablishment of the A.C. supply voltage to the time 09 the voltage at junction 160 equals or exceeds the voltage at point 168 is converted by the 11 microprocessor 22 to the real time elapsed and added 12 to the real time value in the EAROM 24 to correct the 13 real time value therein.
14 After the meter 10 is installed, the microprocessor 22 is designed to restart after power outages and to 16 be operating properly within about three seconds. The 17 arrival of A.C. power starts the power supply 18 that 18 causes the microprocessor 22 to initialize itself and 19 all related functions by calling data from its ROM and EAROM 24. It also counts each restart operation as 21 part of a power theft detection means.
22 One of the last steps in initialization is for the 23 microprocessor 22 to note the voltage on the 24 comparator 162 that looks at the capacitor voltage on timer capacitor 152. The microprocessor 22 then 26 causes the capacitor 152 to charge or discharge in 27 such a way that the comparator's output voltage will 28 change when its threshold voltage at point 168 is 29 crossed. The time to this change is measured. With this time and the polarity of the charge or discharge 31 operation the duration of the outage is calculated.
32 If the calculated outage exceeds 6 hours, 11~41.~i~
the micro~rocessor 22 then calls for a de-ault condition rat~er than tryins to es,a~'ish an unGependa~le 'ime.
The microprocessor 22 performs several interrupt routines, one of which is: ;~atthou.
Pulse Reception. Here, the microprocessor 22 watches for pulses from the chi? 77 indica.ing a fii:ed quantity of watthours has passed. The soft~are can trac}~ pulses at a ra,e up to 133 pulses per second, as well~as apply a preselected calibration factor. These features permit a large variation in manufacturing variations of the ~atthour sensor and generator chip 77.
Another interru?t routine is: Three l~1illi-second Timer. Lvery three milliseconds themicroprocessor checks to determine if (1) a sixty hertz (60 Hz) square wave has changed polarity for keepins up the real time ciock or (2~ the phototransistor 32 has changed state to note if a communication effort with,the meter 10 has been started. Further, the three milli-second clock is used to control the timing of the display function on display 26.
The third interrupt rou.ine is: i~ain Tas~
~oop. The };ey tas}: of the meter 10 is to count ~att hours into the proper time-of-use register.
The meter 10 will also calculate peak demands on a 15-minute running average and the time of the peak demand for each time-of-use period. The meter 10 must keep an accurate time-of-day clock to do these calculations. The ~lain Task Loop also controls the information that is ke?t in the EAP~0i~ 24 to insure that no important infor-mation is lost on a loss of voltage situation.
T~.~s function of the meter 24 also controls the data that is to be presented on tne display 26.
11~4~
From time tc time the meter ~ill be read by the Unit 40 and the battery-operated microprocessor the-ein. When the IJnit 40 sends its interrogation signal via wan~ 42 to the meter 10, the software program must identify this as a different signal than a chanse in lisht level used in manual readout.
Upon this determination the meter 10 sends a clock syr.chronizatior. pulse train to the meter-reading Vnit 40. ~^lith communication established and clocks synchronized,any amount of predetermined informa-tion can be exchanged.
The meter-reading ~nit 40 is a portable tool designed to read out the content of the meteI 10.
The Unit 40 microprocessor and the various other parts that relate to a microprocessor system are utilized to read out the meter 10 by placing the wand 42 properly centered on the face o~ cover 88 of the meter 10 and pushing a trigger on the wand 42. In about 2 seconds the unit 40 and meter 10 will: , 1. Establish contact and determine the communication frequency to use.
2. Read the serial number and/or the account into the Unit 40.
3. Check and correct (if necessary) the real time clock, noting if a correction was made.
Eight load control in?u,~oulpu_ portC gener~lly ic~entified b~ reference nu.. leral 50 are cou?le~ 'o the 5 hus 2~ znd are available ior the cGntrol of specific customer loads such as water heaters, air conditioners, electric heating, etc., as will be described in greater det~il in connection with the description of Fig. 5.
Also, the meter 10 can be programmed so tha~ load con-trol can be asserted by the customer/consumer or bythe supplier/electric utili-y.
Finally, a power outage (105s 0~ voltage)timer 60 is coupled to the microprocessor 22 for supply-ins 2 sisnal, when power is restored after a poweroutage, to the ~.icroprocessor ~2. Such signal is indicative of the duration of the power outage so that the microp~ocessor 22 can update (correct~ the real time value stored in the ~A~OM 24. , ~n idealized Hall cell 70 is shown in rig. 2 and includes a Hall plate 71 which is located in a flu~: fiel-d~represented bv an arrow 72, that is estab-lished by line current _lowing through the irst and second phases of a two-phase power sup?l~- to the con-su..... ..,er.
A bias voltage directl~ related to the line volt2ge is supplied to opposite sides 73 and 74 of the plate 71. The Iall plate 71 output volta~e across the other two opposite sides 75 and 76 of the plate 71 is related to the instantaneous power, e.g. watts being supplied.
As shown in U.S. Patent No. 2,550,492 the Hall plate output voltage can be defined substantially as fol 10WS:
E;~ = [~I cos ~ - VI cos ~2wt + ~)]
~n which:
~, = Hall pla~e ouLput ~Toltage ~ = a constant V = voltage o_ source 1 = line current supplied by source ~ = ph~se angle between V and I
w = radius frequency = 2 ~ f t = time The direct current term (VI cos e) is propor-tional to real or active power. The average direct current in the output has a value of ~ero when no power is being transmitted.
Such a Hall ?late is formed on a chip 77 (Fig. 5) which is recei~ed in an air yap 78 (~ig. 3!, in a current transformer core or yoke 8~ having two legs (conductors) 81 and 82 of the two-phase voltage system su??lied to the customer/consumer passing therethrough as shown in Fig. 3. The yo};e 80 is mounted on a base plate 84 and a mounting plate 86 is provided for mount-ing the chip 77.
Alt~ough not shown in Fig. 4, it will be under-stood that a transparent (glass~ cover 88, a portion of which is shown in Fig. 5, is received over the housing 31 to ~eep dust and dirt from getting in the housing 31, particularly ports 28 and 30.
The meter 10 is preferably built on two main circuit boards (not shown), one for analog circuits and one for digital circuits, with two additional circuit boards, one for mounting transfo~mers, and or.e for mounting the Hall effect mul'Liplier 16 which functions as a watt-hour generator.
hlso, the m~ter 10, par'icula.lv t`ne houains 31 thereof, will be interchar,geable ~iith existins induc-ion watt-hour meters typic21 of those found in residen_i~l anc apar~-ent ins~allations - 5 ~e erring now to Fig 5, the-e is illus~ra_ed therein the schematic circuit ciaaram o_ .he me.er 10. .~â sho~ the vol~age source ( device ) 14 in-cludes a tranâfo~~le- 90 havins a primary coil 92, a secondarv windins94 for su?pl;ring voltage to the Hall ef ect device and multiplier 16 in the chip 77 and a secondary winding96 for supplying A C voltage to the A C to D C regulated power supply 18 The power supply 18 supplies a regulated D C voltage to a voltage bus 98 and 60 Hz clock signal via a conductor 100 to a cloc}: inpu~ 102 of the micro-processor 22 The chip 77 having the Hall multiplie- 16 is coupled via I/O ccnductors 104 to I/O ports of the microproceâsor 2 It will be understood that the 2G chip 77 has a plurality of Hall effect devices and multiplyins circuitry therein to provi~e a watt-hour sensor and generator 16 The inputs to the chip 77 are a flu~ 72 generated by the line current in conductor 81 and 82, line voltage from coil 94, and win~ing 94 a voltage signal via conductor lG5 connected to the voltage bus 98 and conductor 106 connectec to system co~or or ground 108 for timing and to control several self calibration features The output of this chip 77 is z sguare wave signal proportional 3G to ~Jatt-hours 11~4124 The chip 77 ic .,anu~actu.ec b~ Tei:as Ins~
ments and ~;ey additional external elements in the chip 77 ard circuitry thereG are: (1) RC inte-cr2to~- ?a--5 ccnsis ing o' a resistor Gf about 200 i ol~m5 2nd a ca?ac-to~ of 0.6 r~ mic-ofaraas, (2) a 2.2~; ohm ~eedbac}: resis.or, (3~ two 1 micr~~ara_ ca?acitorr, .o st2bliTe the circui~r~, (4) ~wo 100~;
oh~ esis~rs for bias, an-' (5) 2 po~entio~leter for bias adjust.
lG The basic calibration of the meter selecting a resistor of about 200~ ohms in the R-C
networ}~ Tris adjus~ment sets the ~h of the meter an~ compensates for such variables as the gap 7E in the flux generator 16, the gain in amplifiers in the chip 77, and .he accur2ciT o the 0.6~ microfarad ca?acitor. The po entiomeLer is used to eliminate the effect of an ur,wanted voltage-causea erfect on the chip 77.
An adcitional e-ror resulting from the Hall effect devi,ces in the chip 77 causes the circuitry to creep. The cree? can be "forward"~or "bac}.~.ard", and there is no stic}~tion to suppress this error.
The addi'.ion o a "tickler" coil on the current tr~nsduce- core or yo}:e &0 is use_ to add su'ficient 2~ arp _urns to negate an~T creep.
Variations in outputs from a nominal ambient te~perature over a tem~erature range be~.een -20C and +50C and up to 2.5%.
Three of the load control outputs identified by reference numerals 121, 122 and 123 are shown in Fis. 5 co~ing out of the microprocessor 22 for controlling customer/consumer 1O2ds. For exa~ple, the output 123 can be considered as connected to a w2ter heate~ load s`n.ol;~ in '.he blot~up in Fig. 5 ?5 a resistance loa~ 130. This load 130 is co~necte7 in serie- witll an SC.~ 132 across the ~..C su,7ply voi,-7ge. The scr. 137 fc~Jrlc a load circuit brea}e-. ~ cate 134 of th' SC~ 13~ is cou?led to the micro~)rocecsor load cGr.~rol output 123 so tha. the micro~rocessor 22 can control when the loac 130 is enerci~ed. Ty?ically, the loa~ 130 is enersized d~rins the early evening, nighttime and early morning Jnen the eost per KWH is low and de-ener~izec during the daytime when the cost per 7~l;H is high.
Aceording to the teachings of the ?resent invention, ar override switch ~40is provided coupled tc the microrjrocessor 22 to enable the customer to overri~7e the load con'rcl function of the mieroprocessor 22. In the illustrated embodiment the switeh 140 is also eoupled to the gate 134 via a eoncuctor 1~2. Thus, bv o?eratins the stiiteh 140,e.g. du~-ing the day, the eustomer ean energize his hot water heater ove riding the mieroproeessor 22.
~ lso, aecordins to the teachings of the present invention, the micro~rocessor 22 and E~ROr~ 24 are eonnec~ed and prograr~med to reset the switch 140 to the opern position thereof during the mode (time, e.g., nighttime) of opera-tion of the microprocessor 22 when an energizing signal is supplied via output 123 to the gate 134, if the switch 140 had been operated (closed) by the custo~er 10 to rest the s~iteh 140 to the open position.
The reterAhas no battery and derives its time froi, the po,7er ~ine, namely the 60 H~ clock signal. Since the me~cr 10 must accurately keep real time to support its time-of-day functions, loss of electrical power to the meter would destroy the time-of-day functions. To keep time without system voltage, the power outage timer(loss of voltage timer) 60 is included in the meter 10.
This timer 60 is based o~ an R-C net~ork, comprising resistor 150 connected across capacitor 152, ~here the recharge time is proportional to the outage time. If the recharge time indicates the outage has been greater than 6 hours then the time is not recoverable and default conditions must be used.
In that case the corrected time in the me e-- 10 is reloaded during the next meter reading opera-tion by the meter reading unit 40.
As shown in EIG. 5 the power outage timer 60 has other components ~hich will now be described and is one of several timers that can be used, such other timers being of the type disclosed in copending Canadian application Serial No. 411,602 filed ~epte~x~ 16, 1982, entitle~: PCWER OUTAGE TIMER, invented by Jim Hurley et al.
The timer 60 has a voltage supply line 154 from the microprocessor 22 which charges the capacitor 152 through a diode 156 and resistor 158 to a voltage level at junction 160 related to the supply voltage. The voltage at junction 160 is coupled to one input of a comparator 162.
Another voltage supply line 164 from the micro-processor 22 supplies a voltage through a diode 165 to a voltage divider 166, 167. A point (junction) 168 in the divider 166, 167 is coupled 02 to another input of the comparator 162 and has a 03 normal voltage which is equal to or slightly less than 04 the normal voltage on the capacitor 152. The output 05 of the comparator 162 is connected to the 06 microprocessor 22.
07 After a power outage, the time from the 08 reestablishment of the A.C. supply voltage to the time 09 the voltage at junction 160 equals or exceeds the voltage at point 168 is converted by the 11 microprocessor 22 to the real time elapsed and added 12 to the real time value in the EAROM 24 to correct the 13 real time value therein.
14 After the meter 10 is installed, the microprocessor 22 is designed to restart after power outages and to 16 be operating properly within about three seconds. The 17 arrival of A.C. power starts the power supply 18 that 18 causes the microprocessor 22 to initialize itself and 19 all related functions by calling data from its ROM and EAROM 24. It also counts each restart operation as 21 part of a power theft detection means.
22 One of the last steps in initialization is for the 23 microprocessor 22 to note the voltage on the 24 comparator 162 that looks at the capacitor voltage on timer capacitor 152. The microprocessor 22 then 26 causes the capacitor 152 to charge or discharge in 27 such a way that the comparator's output voltage will 28 change when its threshold voltage at point 168 is 29 crossed. The time to this change is measured. With this time and the polarity of the charge or discharge 31 operation the duration of the outage is calculated.
32 If the calculated outage exceeds 6 hours, 11~41.~i~
the micro~rocessor 22 then calls for a de-ault condition rat~er than tryins to es,a~'ish an unGependa~le 'ime.
The microprocessor 22 performs several interrupt routines, one of which is: ;~atthou.
Pulse Reception. Here, the microprocessor 22 watches for pulses from the chi? 77 indica.ing a fii:ed quantity of watthours has passed. The soft~are can trac}~ pulses at a ra,e up to 133 pulses per second, as well~as apply a preselected calibration factor. These features permit a large variation in manufacturing variations of the ~atthour sensor and generator chip 77.
Another interru?t routine is: Three l~1illi-second Timer. Lvery three milliseconds themicroprocessor checks to determine if (1) a sixty hertz (60 Hz) square wave has changed polarity for keepins up the real time ciock or (2~ the phototransistor 32 has changed state to note if a communication effort with,the meter 10 has been started. Further, the three milli-second clock is used to control the timing of the display function on display 26.
The third interrupt rou.ine is: i~ain Tas~
~oop. The };ey tas}: of the meter 10 is to count ~att hours into the proper time-of-use register.
The meter 10 will also calculate peak demands on a 15-minute running average and the time of the peak demand for each time-of-use period. The meter 10 must keep an accurate time-of-day clock to do these calculations. The ~lain Task Loop also controls the information that is ke?t in the EAP~0i~ 24 to insure that no important infor-mation is lost on a loss of voltage situation.
T~.~s function of the meter 24 also controls the data that is to be presented on tne display 26.
11~4~
From time tc time the meter ~ill be read by the Unit 40 and the battery-operated microprocessor the-ein. When the IJnit 40 sends its interrogation signal via wan~ 42 to the meter 10, the software program must identify this as a different signal than a chanse in lisht level used in manual readout.
Upon this determination the meter 10 sends a clock syr.chronizatior. pulse train to the meter-reading Vnit 40. ~^lith communication established and clocks synchronized,any amount of predetermined informa-tion can be exchanged.
The meter-reading ~nit 40 is a portable tool designed to read out the content of the meteI 10.
The Unit 40 microprocessor and the various other parts that relate to a microprocessor system are utilized to read out the meter 10 by placing the wand 42 properly centered on the face o~ cover 88 of the meter 10 and pushing a trigger on the wand 42. In about 2 seconds the unit 40 and meter 10 will: , 1. Establish contact and determine the communication frequency to use.
2. Read the serial number and/or the account into the Unit 40.
3. Check and correct (if necessary) the real time clock, noting if a correction was made.
4. Check and correct (if necessary) the time-of-use times, noting if a correction was made.
S. Read the main register and the time-of-use registers.
6. Read counters or registers (and reset if proper) other indicatorSon the meter 10.
When all elements of the readout have finished, a tone or other indication ~ill be given the operator ~y the ~nit 40 indicating that the read-out is finished. ~fter finishing a readout at one meter 10, the operator proceeds to the ne~ meter 10 and repeats the procedure. After completion of a day's rou-e, the operator returns the meter-reading Vnit 40 to a central location where it is cou?led to a host computer that re~ds out the Unit4 0 for higher level data processing. The host computer can also load new data for the next day's route.
1`he meter-reading Uni~ 40 can also have an on~oard keyboard and display to permit operator control of the Unit 40 and thus the ability to do selective ~odifications of meter 10 and readout of a meter 10 through the display 26 thereof.
Various routines which can be programmed into and performed by the microprocessor 22 system are 5 described below with reference to ~igs. 6-]4.
B~.SIC START-UP ROUTINE
In Fig. 6 there is shown a Basic Start~Up Routine in which, at Step l primary housekeeping routines are performed, such as settins an inter-rupt mas}; for the microprocessor 22, setting up astack pointer and input/output default- conditions ar.d neutralizing the system address.
At Step 2, a Power Failure Time Routine is perfo-med as described in further detail herein-below in connec.ion with the description of Fig. 7.
At Step 3, secondary housekeeping routinesare perfor~ed such asreal time clock setup, serial communications f a~ set, interrupt mask clear, system updates, flag clear, flag check and ini-tialization-configuration setup.
At Step 4 the microprocessor 22 system is initialized.
At Steps 5 and 6 self-diagnostic routines are performed.
~5 Comrlunications are performed at Step 7.
At Step 8 a clear interrupt mas~. is performed, 11~41Z4 which allows upàatin~ on interrupts from the -watt-hour sensor 16 or real time cloc~:.
If the system is flagged, a s~stem up~ate routine is performed at Step 9 and then returned to self-diasnostics at Step 6. --PO~R FAILURE RO~TINE
In Figs. 7 and 8 the Power Failure ~imer Routine is illustrated in which,at Step 1, the microprocessor 22 system determines whether a power fail timer error flag is set and if so, the system proceeds to ~ at Fig. 8.
If not, at Step 2 the po~er fail timer error flag of EAROM 24 is set. At Step 3 the system clears the timing loop cycle counter of the micro-processor 22.
The system then enters a delay A at Step 4.
At Step 5 it is determined whether the timer flag is set, which is a hardware flag.
If so, the system goes to ~ of Fig. 8, and if notl an internal cycle counter is incremented at Step 6.
If the cycle counter is at its limit at Step 7, the system goes to ~ of Fig. 7, and if not, a second delay B is entered at Step 8 before the 2~ system routine returns to Step 5.
Continuin~ the routine at ~ in Fig. 8 at ;
Step 9, the system obtains the time correction from a lool; up table is pointed out by the cycle counter at Step 7.
At Step 10, the system updates the real time clock and calendar.
At Step 11 the system clears the EARO~I power ail timer error flag.
Continuing the routine at ~ in Fig. 8, at 3~ Step 12,the EARO~ power fail timer limit error flag is set after which the system is ready for 1~41Z4 the Communications/Meter Read Routine in Pig. 9.
CO`L~IUI~ICATIOI~S/rlETEP~ PEAD ROU~INE
In Fig. ~ is illustrated the Communica'ions/
Meter Read Routine in whic~4 at Step l,the s~ste~
accesses the serial input to the meter 10.
~ t Step 2 a determination is made whether the input is at a constant level, which is an indication that a customer or meter reader is attempting access.
If the input is at a constant level, the system yoes to Step 3 to determine whether the input is different from the last access which checks the serial communication level flag in the random access memory (RP~).
If the access is not different at Step 3, the system contineus.
If it is different, the system at Step 4 will show allowable registers for an LED display .
A t Step 5 the system sets zero co~unications leval flag which is a "1" if a serial input is high and a "0" if the zero input is low.
At Step 2, if the input level is not con-stant, the system goes to Step 6, which is a meter reader routine and which is sus?ended if ; more than 200 watt~hour interrupts occur.
SYST~M UPDATE ROUTINE
In Figs. 10, ll, 12 a System Update Routine is illustrated.
At Step 1 the system e~amines the ~att-hour update counter (WHUC).
At Step 2, if the W~IUC is greater than zero, the system goes to an Override Reset Subroutine, and if not to Step 3.
At Step 3 the system increments the R~M watt-hour accumulating register.
11~4~
At Step 9 the system increments the R~
accurulatins register.
At S~ep 5 the system incremen.s the R~M
pea~; }~ilo~J~tt derl~nd reqister.
At S-e? 6 the s~stem de-rements the watt-hour update counter (~HUC) after which the system returns to Step 2.
If l~JC is greater than zero, the system ~-:
goes to the O~erride Reset Subrou~ine which begins at Step 7 where the question is asked:
Is the right flag set? for causing energization of a con,rolled customer load, e.g. a water heater for energizing the water heater.
If the ans~er is ye~, the system knows that it is nighttime and goes on to Setp 8, -the reset privilege flag step where .he override switch is reset to the open position.
If the answer is no, then at Step 9 the question is as}~ed: Is the meter re~uest flag set? and if not, the system goes to Ste~ 8, and if yes, to Step 10.
At Step 10 the questior. is as~ed, Is the thermostat closed? If not, the system again goes to Step 8 and if yes, to ~ in Pig. 11 and Step 11.
At Step 11 the system examines the real time update counter.
At step 12 the real time update counter is - examined to see if the count is greater than zero.
If the counter is greater than zero, the routine ends at Step 13 ~here the system goes to a neutral condition.
If not, at Ste? 14 the system increments the E~RO15 updating clock.
After that at Step lS the EA~O`1 upd2te clock is e~amined to see ~hether it is greater or equal t~ 15.
II not, the system goes to ~ in Fis. 12.
If yes, tne system goes to step 16, in which t~e EARO; updating cloc}; is cleared.
At ste? 17, the system adds the R~ watt-hour accumulator register to the E~.ROM ~att-hour ac~umu-latGr register and goes to step 1~, which chec~.s the EAROM error flass.
At ste~ 19, the EAROM data error or power fail timer error is checked, and if there is an error, the system goes to ~ in Fig. 12.
If not, the system goes to step 20, in which the EAROM real time clock is updated.
From the input ~ in Fig. 12, the system, at step 21, checks the EAROM error flass as at Step 18.
At Step 22, a check is made for an EAROM data error or power fail timer error as at Step 19.
If there is, the system goes to Step 23 to check if a data error has occurred as it does at ~ from Step 19. If there are no data er_ors at Step 24, the address register is updated by default and the system goes to Step 25. If there is a data error at Step 23, the systemStill goes to Step 25 where the real time update counter is decremented and the system returns to ~ in FIG. 11 where it repeats Step 12 and checks to see if the real time upd~te counter is greater than zero and if so, the system goes to neutral at~Step 13.
Returning to ~ from FIG. 11 back to ~ in FIG. 12 at the next Step 26, the system updates the EAROM
watt-hour accumulating register.
At Step 27 the EAROM peak kilowatt demand register is updated, if required.
. .
`' 119~
2~
At Step 2E the real time clo-l is inc~e~.ented.
P.t Step 2~ a de.ermination is made if .he -eal ti~e cloc}. is sreater than or equal to 1440.
If so, the system goes to Step 30 which updates ~ the Ei~O.~ calender.
At Ste~ 31, 1440 is subtracte~ from the real ti~e cloc};.
At Step 32, the time related registers an~
flass are initialized and the system goes to Step 33 as does the NO ?ath from Step 29.
.~t Step 33 an ou.put latch is updated, and from there the system goes to Step.s 29, 1~ c-d 13 and ends.
INTERRUPT ROUTINE
In Fig. 13, an interrupt routine is shown in which, at Step 1, the watt-hour generator inputs 104 are checked for interrupt.
If so, at Step 2 the system increments the watt-hour update counter and at Step 3, clears the interrupt flag before going on to Step 4.
At S.ep 4, or if there is no interrupt at Step 1, the system checks an interrupt from the real time clock.
If there is an interrupt, at Step 5 the system increments the real time update counter and then at Step 6 clears the interrupt flag and returns to normal.
~ lso, if there is no interrupt at Step ~, the system returns to normal.
From the foregoing description, it is ap?arent that the solid state watt-hour meter 10 of the present invention has a number of advantages, some of which have been described above and others of which are inherent in the invention. For example, the meter 10 has no ~oving parts, being based on Hall effect technolog~ and can replace the conventional ,, ~ ...... . . . . .
41~ `
industion watt-hour m.eters. Additionally, the meter lO is a "smart" meter incor?orating a microprocessor and related parts which can measure watt-hours and pea~. watts with res?ec, to time and store this 5 information in a7apropriate time-of-use reg7isters so that electric power is used only ~lhen it is most economical to do so. Moreover, the override switch and reset function make it very at.ractive to consumer customers.
The features of manual readout by eye or automatic readout with the meter reading unit 40, constitute further advantages.
It will also be apparent that many modifications can be made to the meter lO without departing from the teachings of the present inven~ion. For example, an optical or conventional induction 2isk watt-hour sensor can be used in place of the Hall effect watt-hour sensor and generator 16. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims.
S. Read the main register and the time-of-use registers.
6. Read counters or registers (and reset if proper) other indicatorSon the meter 10.
When all elements of the readout have finished, a tone or other indication ~ill be given the operator ~y the ~nit 40 indicating that the read-out is finished. ~fter finishing a readout at one meter 10, the operator proceeds to the ne~ meter 10 and repeats the procedure. After completion of a day's rou-e, the operator returns the meter-reading Vnit 40 to a central location where it is cou?led to a host computer that re~ds out the Unit4 0 for higher level data processing. The host computer can also load new data for the next day's route.
1`he meter-reading Uni~ 40 can also have an on~oard keyboard and display to permit operator control of the Unit 40 and thus the ability to do selective ~odifications of meter 10 and readout of a meter 10 through the display 26 thereof.
Various routines which can be programmed into and performed by the microprocessor 22 system are 5 described below with reference to ~igs. 6-]4.
B~.SIC START-UP ROUTINE
In Fig. 6 there is shown a Basic Start~Up Routine in which, at Step l primary housekeeping routines are performed, such as settins an inter-rupt mas}; for the microprocessor 22, setting up astack pointer and input/output default- conditions ar.d neutralizing the system address.
At Step 2, a Power Failure Time Routine is perfo-med as described in further detail herein-below in connec.ion with the description of Fig. 7.
At Step 3, secondary housekeeping routinesare perfor~ed such asreal time clock setup, serial communications f a~ set, interrupt mask clear, system updates, flag clear, flag check and ini-tialization-configuration setup.
At Step 4 the microprocessor 22 system is initialized.
At Steps 5 and 6 self-diagnostic routines are performed.
~5 Comrlunications are performed at Step 7.
At Step 8 a clear interrupt mas~. is performed, 11~41Z4 which allows upàatin~ on interrupts from the -watt-hour sensor 16 or real time cloc~:.
If the system is flagged, a s~stem up~ate routine is performed at Step 9 and then returned to self-diasnostics at Step 6. --PO~R FAILURE RO~TINE
In Figs. 7 and 8 the Power Failure ~imer Routine is illustrated in which,at Step 1, the microprocessor 22 system determines whether a power fail timer error flag is set and if so, the system proceeds to ~ at Fig. 8.
If not, at Step 2 the po~er fail timer error flag of EAROM 24 is set. At Step 3 the system clears the timing loop cycle counter of the micro-processor 22.
The system then enters a delay A at Step 4.
At Step 5 it is determined whether the timer flag is set, which is a hardware flag.
If so, the system goes to ~ of Fig. 8, and if notl an internal cycle counter is incremented at Step 6.
If the cycle counter is at its limit at Step 7, the system goes to ~ of Fig. 7, and if not, a second delay B is entered at Step 8 before the 2~ system routine returns to Step 5.
Continuin~ the routine at ~ in Fig. 8 at ;
Step 9, the system obtains the time correction from a lool; up table is pointed out by the cycle counter at Step 7.
At Step 10, the system updates the real time clock and calendar.
At Step 11 the system clears the EARO~I power ail timer error flag.
Continuing the routine at ~ in Fig. 8, at 3~ Step 12,the EARO~ power fail timer limit error flag is set after which the system is ready for 1~41Z4 the Communications/Meter Read Routine in Pig. 9.
CO`L~IUI~ICATIOI~S/rlETEP~ PEAD ROU~INE
In Fig. ~ is illustrated the Communica'ions/
Meter Read Routine in whic~4 at Step l,the s~ste~
accesses the serial input to the meter 10.
~ t Step 2 a determination is made whether the input is at a constant level, which is an indication that a customer or meter reader is attempting access.
If the input is at a constant level, the system yoes to Step 3 to determine whether the input is different from the last access which checks the serial communication level flag in the random access memory (RP~).
If the access is not different at Step 3, the system contineus.
If it is different, the system at Step 4 will show allowable registers for an LED display .
A t Step 5 the system sets zero co~unications leval flag which is a "1" if a serial input is high and a "0" if the zero input is low.
At Step 2, if the input level is not con-stant, the system goes to Step 6, which is a meter reader routine and which is sus?ended if ; more than 200 watt~hour interrupts occur.
SYST~M UPDATE ROUTINE
In Figs. 10, ll, 12 a System Update Routine is illustrated.
At Step 1 the system e~amines the ~att-hour update counter (WHUC).
At Step 2, if the W~IUC is greater than zero, the system goes to an Override Reset Subroutine, and if not to Step 3.
At Step 3 the system increments the R~M watt-hour accumulating register.
11~4~
At Step 9 the system increments the R~
accurulatins register.
At S~ep 5 the system incremen.s the R~M
pea~; }~ilo~J~tt derl~nd reqister.
At S-e? 6 the s~stem de-rements the watt-hour update counter (~HUC) after which the system returns to Step 2.
If l~JC is greater than zero, the system ~-:
goes to the O~erride Reset Subrou~ine which begins at Step 7 where the question is asked:
Is the right flag set? for causing energization of a con,rolled customer load, e.g. a water heater for energizing the water heater.
If the ans~er is ye~, the system knows that it is nighttime and goes on to Setp 8, -the reset privilege flag step where .he override switch is reset to the open position.
If the answer is no, then at Step 9 the question is as}~ed: Is the meter re~uest flag set? and if not, the system goes to Ste~ 8, and if yes, to Step 10.
At Step 10 the questior. is as~ed, Is the thermostat closed? If not, the system again goes to Step 8 and if yes, to ~ in Pig. 11 and Step 11.
At Step 11 the system examines the real time update counter.
At step 12 the real time update counter is - examined to see if the count is greater than zero.
If the counter is greater than zero, the routine ends at Step 13 ~here the system goes to a neutral condition.
If not, at Ste? 14 the system increments the E~RO15 updating clock.
After that at Step lS the EA~O`1 upd2te clock is e~amined to see ~hether it is greater or equal t~ 15.
II not, the system goes to ~ in Fis. 12.
If yes, tne system goes to step 16, in which t~e EARO; updating cloc}; is cleared.
At ste? 17, the system adds the R~ watt-hour accumulator register to the E~.ROM ~att-hour ac~umu-latGr register and goes to step 1~, which chec~.s the EAROM error flass.
At ste~ 19, the EAROM data error or power fail timer error is checked, and if there is an error, the system goes to ~ in Fig. 12.
If not, the system goes to step 20, in which the EAROM real time clock is updated.
From the input ~ in Fig. 12, the system, at step 21, checks the EAROM error flass as at Step 18.
At Step 22, a check is made for an EAROM data error or power fail timer error as at Step 19.
If there is, the system goes to Step 23 to check if a data error has occurred as it does at ~ from Step 19. If there are no data er_ors at Step 24, the address register is updated by default and the system goes to Step 25. If there is a data error at Step 23, the systemStill goes to Step 25 where the real time update counter is decremented and the system returns to ~ in FIG. 11 where it repeats Step 12 and checks to see if the real time upd~te counter is greater than zero and if so, the system goes to neutral at~Step 13.
Returning to ~ from FIG. 11 back to ~ in FIG. 12 at the next Step 26, the system updates the EAROM
watt-hour accumulating register.
At Step 27 the EAROM peak kilowatt demand register is updated, if required.
. .
`' 119~
2~
At Step 2E the real time clo-l is inc~e~.ented.
P.t Step 2~ a de.ermination is made if .he -eal ti~e cloc}. is sreater than or equal to 1440.
If so, the system goes to Step 30 which updates ~ the Ei~O.~ calender.
At Ste~ 31, 1440 is subtracte~ from the real ti~e cloc};.
At Step 32, the time related registers an~
flass are initialized and the system goes to Step 33 as does the NO ?ath from Step 29.
.~t Step 33 an ou.put latch is updated, and from there the system goes to Step.s 29, 1~ c-d 13 and ends.
INTERRUPT ROUTINE
In Fig. 13, an interrupt routine is shown in which, at Step 1, the watt-hour generator inputs 104 are checked for interrupt.
If so, at Step 2 the system increments the watt-hour update counter and at Step 3, clears the interrupt flag before going on to Step 4.
At S.ep 4, or if there is no interrupt at Step 1, the system checks an interrupt from the real time clock.
If there is an interrupt, at Step 5 the system increments the real time update counter and then at Step 6 clears the interrupt flag and returns to normal.
~ lso, if there is no interrupt at Step ~, the system returns to normal.
From the foregoing description, it is ap?arent that the solid state watt-hour meter 10 of the present invention has a number of advantages, some of which have been described above and others of which are inherent in the invention. For example, the meter 10 has no ~oving parts, being based on Hall effect technolog~ and can replace the conventional ,, ~ ...... . . . . .
41~ `
industion watt-hour m.eters. Additionally, the meter lO is a "smart" meter incor?orating a microprocessor and related parts which can measure watt-hours and pea~. watts with res?ec, to time and store this 5 information in a7apropriate time-of-use reg7isters so that electric power is used only ~lhen it is most economical to do so. Moreover, the override switch and reset function make it very at.ractive to consumer customers.
The features of manual readout by eye or automatic readout with the meter reading unit 40, constitute further advantages.
It will also be apparent that many modifications can be made to the meter lO without departing from the teachings of the present inven~ion. For example, an optical or conventional induction 2isk watt-hour sensor can be used in place of the Hall effect watt-hour sensor and generator 16. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims.
Claims (14)
1. A solid state watt-hour meter comprising a watt-hour sensor adapted to be coupled to a consumer's connection to a source of electric power for sensing the voltage supplied to, and the current drawn by, the consumer's total electric load and for producing an output signal indicative of a quantity of watt-hours of power utilized by the consumer; a microprocessor coupled to said watt-hour sensor for receiving said output signals; an electrically alterable ROM coupled to said microprocessor; power supply means having an input coupled to the consumer line voltage and an output coupled to said microprocessor for supplying a regulated DC voltage thereto; clock signal generating means coupled between the consumer line voltage and said microprocessor for supplying a 60 Hz clock signal to said microprocessor;
readout means coupled to said microprocessor for providing a readout of the power consumed since the last reading of said solid state watt-hour meter; at least one load control circuit breaker in a consumer's circuit line to at least one consumer load, said microprocessor having at least one load control output coupled to said at least one circuit breaker; an override switch coupled to said micrometer and said microprocessor and said electrically alterable ROM
being connected and programmed:
(a) to sense the time of day as determined from an initial time of day setting and the 60 Hz clock signal;
(b) to sense and totalize signals from said sensor indicating the total power used by the consumer;
(c) to provide a readout signal indicative of the total power consumed since the last reading of the meter;
(d) to automatically open said at least one circuit breaker for a time period during the time of day (daytime) when power demand on the electric power source is high and/or the cost per kilowatt hour is high;
(e) to automatically close said at least one circuit breaker during the time of day (night-time) when the power demand on the source of electric power is low and/or the cost per kilowatt power is low;
(f) to allow a consumer to override said microprocessor control of said at least one circuit breaker by operating said override switch to close said at least one circuit breaker; and (g) to automatically reset said override switch to the open position thereof when said micro-processor is in the operating mode for automatically closing said at least one circuit breaker.
readout means coupled to said microprocessor for providing a readout of the power consumed since the last reading of said solid state watt-hour meter; at least one load control circuit breaker in a consumer's circuit line to at least one consumer load, said microprocessor having at least one load control output coupled to said at least one circuit breaker; an override switch coupled to said micrometer and said microprocessor and said electrically alterable ROM
being connected and programmed:
(a) to sense the time of day as determined from an initial time of day setting and the 60 Hz clock signal;
(b) to sense and totalize signals from said sensor indicating the total power used by the consumer;
(c) to provide a readout signal indicative of the total power consumed since the last reading of the meter;
(d) to automatically open said at least one circuit breaker for a time period during the time of day (daytime) when power demand on the electric power source is high and/or the cost per kilowatt hour is high;
(e) to automatically close said at least one circuit breaker during the time of day (night-time) when the power demand on the source of electric power is low and/or the cost per kilowatt power is low;
(f) to allow a consumer to override said microprocessor control of said at least one circuit breaker by operating said override switch to close said at least one circuit breaker; and (g) to automatically reset said override switch to the open position thereof when said micro-processor is in the operating mode for automatically closing said at least one circuit breaker.
2. The solid state watt-hour meter according to claim 1 wherein said sensor is a Hall-effect sensor.
3. The solid state watt-hour meter according to claim 2 wherein said Hall-effect sensor comprises a Hall-effect chip including Hall-effect devices and multiplying circuitry.
4. The solid state watt-hour meter according to claim 1 wherein said readout means includes a visual display device.
5. The solid state watt-hour meter according to claim 1 wherein said visual display device is a seven-segment numeric display for showing the watt-hours consumed since the last reading of said meter.
6. The solid state watt-hour meter according to claim 1 wherein said readout means comprises signal producing and receiving means for facilitating meter readout.
7. The solid state watt-hour meter according to claim 6 wherein said signal producing and receiving means are optical.
8. The solid state watt-hour meter according to claim 7 wherein said signal producing and receiving means comprise at least one light emitting diode and at least one phototransistor.
9. The solid state watt-hour meter according to claim 1 including power outage timing means for generating a signal when, after a power outage, power is restored, such signal being indicative of the time duration of the power outage and being input to said microprocessor when the power is restored so that said microprocessor can update the real time value in the memory thereof to reflect the correct real time.
10. The solid state watt-hour meter according to claim 9 wherein said power outage timing means include a capacitor.
11. The solid state watt-hour meter according to claim 10 wherein said capacitor is charged by the power supply voltage wherein a shunt resistor is connected across said capacitor, and wherein said power outage timing means include a comparator having a first input connected to said capacitor, a second input connected to a reference voltage related to the power supply voltage and an output coupled to the micro-processor, the reference voltage normally being at or just below the normal voltage on said capacitor;
and the output of said comparator being coupled to said microprocessor, which is operable:
(h) to sense a first point in time when power is restored after a power outage;
(i) to sense a second point in time when the output of said comparator changes indicating said capacitor has recharged (after having discharged through said shunt resistor during a power outage) back to its normal value;
(j) to calculate the real time represented by the time or count made between said first and second points in time added to the real time value in the memory; and (k) to update the real time value in the memory to the correct real time value.
and the output of said comparator being coupled to said microprocessor, which is operable:
(h) to sense a first point in time when power is restored after a power outage;
(i) to sense a second point in time when the output of said comparator changes indicating said capacitor has recharged (after having discharged through said shunt resistor during a power outage) back to its normal value;
(j) to calculate the real time represented by the time or count made between said first and second points in time added to the real time value in the memory; and (k) to update the real time value in the memory to the correct real time value.
12. The solid state watt-hour meter according to claim 11 wherein said microprocessor is operable:
(1) to determine if the time or count made between the first and second points in time is equal to the maximum time or count to charge said capacitor with the supply voltage; and (m) when equality is determined to abort the load control function and to raise an alarm flag indicating that the real time value needs to be corrected and updated.
(1) to determine if the time or count made between the first and second points in time is equal to the maximum time or count to charge said capacitor with the supply voltage; and (m) when equality is determined to abort the load control function and to raise an alarm flag indicating that the real time value needs to be corrected and updated.
13. The solid state watt-hour meter according to claim 12 wherein said maximum time or count is equivalent to six hours of real time.
14. The solid state watt-hour meter according to claim 9 wherein said power outage timing means can sense and record a power outage of up to six hours.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US303,627 | 1981-09-18 | ||
| US06/303,627 US4467434A (en) | 1981-09-18 | 1981-09-18 | Solid state watt-hour meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1194124A true CA1194124A (en) | 1985-09-24 |
Family
ID=23172970
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000411053A Expired CA1194124A (en) | 1981-09-18 | 1982-09-09 | Solid state watthour meter |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4467434A (en) |
| CA (1) | CA1194124A (en) |
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Also Published As
| Publication number | Publication date |
|---|---|
| US4467434A (en) | 1984-08-21 |
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