Abstract: A ground fault detection system is provided where one current sensor is used to calibrate a second sensor in order to provide automatic zeroing of the difference measurement. The calibration is done gradually in order to differentiate between sensor drift and a transition in current due to a differential fault.

Abstract: A system that generates a dynamic trace of power consumption in a computer system. The system periodically polls current sensors and associated voltage sensors within the computer system to generate dynamic traces of currents and associated voltages for individual components within the computer system. The system then generates a dynamic trace of total power consumption for the computer system based on the dynamic traces of the currents and the associated voltages for the constituent components.

Abstract: A method for calibrating voltage sensors in a switchboard, using a communication bus which comprises the following steps: i. performing a measurement using a first voltage sensor; ii. transmitting an information derived from said measurement to an electronic device, through the communication bus; iii. using said information to calibrate a second voltage sensor.

Abstract: A portable calibration unit for calibrating test equipment is disclosed that may incorporate a communication interface for connecting to a computer embedded within the test equipment, a variable signal source for producing a test signal, a processor in communication with the computer for controlling the variable signal source, and a test interface for communicating the test signal to the test equipment.

Abstract: In accordance with the present invention, a method is provided whereby the transient voltages presented at the input to a watt-hour meter are suppressed to prevent damage to the watt-hour meter and to the electronic devices that are powered through the watt-hour meter. In addition to transient voltage protection, the method of the present invention also provides monitoring of the earth ground resistance, voltage and current of the earth ground conductor associated with the watt-hour meter. As such, voltage transients are suppressed when presented at the watt-hour meter through the power line input, ground resistance of the earth ground conductor in continuously monitored and the current and voltage conditions existing on the ground conductor are continuously monitored. Visual and audible indicators are provided to indicate quality issues with the grounding system and the effectiveness of the surge suppressor/arrestor.

Abstract: A measuring circuit arrangement (1) for an electricity meter for direct connection is respectively connected, to an input (3) for voltage measurement and an input (4) for current measurement of a measuring chip (2) for each phase of a three phase supply. Upstream of the input (3) for voltage measurement is a voltage divider (R1,R2) provided in order to match the voltage level, and upstream of the input (4) for current measurement is a voltage transformer (5) with measuring shunt (RSH) installed according to the invention. The voltage transformer (5) is so arranged that its ohmic resistance towards the measuring shunt (RSH) on the one hand sufficiently limits standard direct-current impingement of the voltage transformer (5) and on the other hand this ohmic resistance is also small enough so that, together with the inductance of the current transformer (5), it displays no more than standard angle error.

Abstract: A system operable to detect voltages within an electrical device and provide an output based on the voltages detected by the system. The electrical device may include an isolation switch adapted to selectively isolate the electrical device from an electrical bus. The system may be operable to detect voltage data in the electrical bus and the electrical device downstream of the isolation switch. The system may provide an indication that voltage is detected in the electrical bus, but that no hazardous voltages are detected within the electrical device downstream of the isolation switch. The system may be adapted to produce a plurality of outputs based on the voltage data detected on the electrical bus and in the electrical device downstream of the isolation switch.

Abstract: An electronic energy meter senses input voltage and current signals and processes the input voltage and current signals to generate measurements of multiple types of power. The meter comprises a processing system for selecting one of the multiple types of power and defining the same as the selected type of power. The processing system also generates a pulsed test signal representative of a magnitude of a measurement of the selected type of power for testing the operation of the meter. The meter further comprises a communications interface coupled to the processing system for transmitting the pulsed test signal from the meter and for receiving signals from sources external to the meter. Selection of one of the multiple types of power can be achieved by the meter receiving, via the communications interface and from a source external to the meter, a communications command identifying a selected one of the various types of power. The communications interface may comprise an optical communications port.

Abstract: A multimeter instrument for measuring variables, such as electrical current, voltage, or resistance includes touch-sensitive zones for selection of the variable to be measured. The measurement circuit associated with the variable selected with the aid of touch-sensitive selection zones is activated by the zone selected.

Abstract: A modular electronic utility meter has a sensor portion that includes sensor devices and a memory device storing calibration and/or error information specific to the sensor devices. Such a sensor portion is designed for use with a corresponding measurement portion that extracts the calibration and/or error information from the memory in the sensor portion. The measurement module then employs the calibration and/or error information in its calculation of energy consumption information. The calibration information includes phase and magnitude error information for at least one of a current sensing device and/or a voltage-sensing device. That error information may include coefficients of a polynomial.

Abstract: A loss measurement system for measuring power, voltage and current losses in distribution transformers, medium power motors and turbines. The system has a sampling wattmeter that digitizes the voltage and current and performs appropriate calculations to determine power; and computer/controller and associated software/firmware and ancillary equipment that provide control, monitor, display and related functions.

Abstract: An apparatus for generating precision time signals includes a source of power line timing information, a source of precision time signals, and a timing circuit. The timing circuit is coupled to the source of precision time signals to receive a precision time signal there from, and is operable to generate clock information based on the precision time signal. The timing circuit is further operable to generate clock information based on the power line timing information.

Abstract: A field load tester for electric watt hour meters having a case enclosing an electrical circuit capable of carrying up to 240 volts of electricity, which circuit having at least a pair of connection leads, one of which is connected in series through a fuse, a thermostat, a circuit breaker, and an element with at least two terminals, one of the leads is connected to one of the terminals and the other lead is connectd to the element at the other terminal, with a light connected between the element terminals. Connecting the tester to the ground and load of a meter by use of clips or probes at the ends of the connection leads creates a load on the line causing the eddy current disc of the meter to turn if the meter is operational.

Abstract: A method is described for reprogramming a meter, including configuring the meter to accept user code reprogramming at meter power-up and, at power-up, providing user code reprogramming to the meter control program. The meter is configured to accept user code at power-up by executing processor boot loader code providing for optional loading of user code into the processor memory upon processor boot-up. The meter user thus can change metering functions and options without disassembling the meter or removing it from service.

Abstract: An electronic meter includes a sensing circuit for sensing voltage and current values of a waveform, an analog-to-digital converter for converting the sensed voltage and current values to digital voltage and current values, a digital filter for delaying one or both of the digital voltage and current values to compensate for a phase shift error in the sensing circuit, and a computation circuit for computing one or more parameters of the waveform in response to the phase compensated voltage and current values. The electronic meter may be calibrated by applying to the meter a test waveform having a known phase shift, measuring the phase shift using the electronic meter, determining a phase shift error based on the difference between the known phase shift and the measured phase shift and determining digital filter coefficients to produce a digital filter delay that corresponds to the phase shift error.

Abstract: An electricity meter performs a self-calibration operation. According to an exemplary embodiment, the meter includes a measurement circuit for generating power information representative of measured power. A controller is operably coupled to the measurement circuit and includes an input for receiving reference standard information. The controller compares the power information generated by the measurement circuit to the reference standard information and generates a compensation signal in dependence upon the comparison. The compensation signal is used to calibrate the measurement circuit. Preferably, the meter is capable of being electrically connected to, and calibrated concurrently with at least one other meter.

Abstract: Methods and apparatus for electronically displaying metered electrical energy are disclosed. A first processor receives voltage and current signals, determines electrical energy and generates an energy signal representative of the electrical energy determination. A second processor receives the energy signal and generates a display signal representative of electrical energy information. A display receives the display signal and displays the electrical energy information. In a first embodiment, it is preferred for the first processor to determine units of electrical energy and the rate at which the units are determined. The second processor generates a display signal representative of the units and the rate. The second processor may also generate a disk signal representative of an equivalent rate of disk rotation in relation to the rate at which the units are determined and energy flow direction information for display. A converter may also be provided for converting an electrical output signal to light.

Abstract: An electronic meter includes a sensing circuit for sensing voltage and current values of a waveform, an analog-to-digital converter for converting the sensed voltage and current values to digital voltage and current values, a digital filter for delaying one or both of the digital voltage and current values to compensate for a phase shift error in the sensing circuit, and a computation circuit for computing one or more parameters of the waveform in response to the phase compensated voltage and current values. The electronic meter may be calibrated by applying to the meter a test waveform having a known phase shift, measuring the phase shift using the electronic meter, determining a phase shift error based on the difference between the known phase shift and the measured phase shift and determining digital filter coefficients to produce a digital filter delay that corresponds to the phase shift error.

Abstract: A power meter is provided having an auto-calibration feature and a data acquisition node for measuring the power usage and power quality of electrical power in an electrical power distribution network. The auto-calibration feature calibrates the power meter at predetermined time increments and as a function of temperature changes.

Abstract: A metering module for use in a power circuit monitoring system including a circuit monitor having a processor for processing data related to power signals, said metering module comprising at least one sensor for sensing a predetermined property of a power signal and for producing a corresponding sensor signal, and a modular metering circuit for producing data corresponding to said sensor signal for input into said circuit monitor, wherein said metering module is selectively detachable and replaceable relative to said circuit monitor to permit one or more of testing, calibration and repair of said metering module thereby minimizing any interruption in operation of said circuit monitor.

Abstract: Methods and apparatus for electronically displaying metered electrical energy are disclosed. A first processor receives voltage and current signals and determines electrical energy. The first processor generates an energy signal representative of the electrical energy determination. A second processor, connected to said first processor, receives the energy signal and generates a display signal representative of electrical energy information. A display is connected to receive the display signal and displays the electrical energy information. In a first embodiment it is preferred for the first processor to determine units of electrical energy from the voltage and current signals and to generate an energy signal representative of the determination of such units and the rate at which the units are determined. In another embodiment the first processor meters multiple types of electrical energy and generates energy signals. A first converter is provided for converting an electrical output signal to light.

Abstract: A watthour meter testing device for testing watthour meters is provided that includes a measuring device, a switch, a transmitter and a receiver. The measuring device is in communication with the power measured by the watthour meter. The switch is operable to test electromechanical watthour meters in a first position and operable to test electronic watthour meters in a second position. The transmitter is operative to transmit a light signal to a consumption indicator on the watthour meter when the switch is in the first position for testing electromechanical watthour meter. The receiver is operative to detect the light signal transmitted from the transmitter and reflected from the consumption indicator on the watthour meter when the switch is in a first position. The receiver is further operative to detect a consumption light signal emanating from the electronic watthour meters when the switch is in a second position.

Abstract: An electronic energy meter senses input voltage and current signals and processes the input voltage and current signals to generate measurements of multiple types of power. The meter comprises a processing system for selecting one of the multiple types of power and defining the same as the selected type of power. The processing system also generates a pulsed test signal representative of a magnitude of a measurement of the selected type of power for testing the operation of the meter. The meter further comprises a communications interface coupled to the processing system for transmitting the pulsed test signal from the meter and for receiving signals from sources external to the meter. Selection of one of the multiple types of power can be achieved by the meter receiving, via the communications interface and from a source external to the meter, a communications command identifying a selected one of the various types of power. The communications interface may comprise an optical communications port.

Abstract: A system for improving accuracy of an intelligent electronic device operable to monitor electrical energy using metering sensors is disclosed. The metering sensors may be tested to determine characteristic curves by simulating operating conditions. The characteristic curves may be developed and transferred to the intelligent electronic device or may be developed by the intelligent electronic device through self-testing. The intelligent electronic device may apply the characteristic curves during operation of the intelligent electronic device.

Abstract: An electronic electricity meter includes voltage sensors configured to generate measurements of voltage at voltage elements, current sensors configured to generate measurements of current through current elements, a microcomputer coupled to the current and voltage sensors and configured to control operation of the meter, and a memory coupled to the microcomputer including calibration constants to compensate for instrument transformer ratio and phase angle errors. The microcomputer is configured to use the calibration constants, when so instructed, to correct for measurement errors that occur based upon instrument transformer ratios and phase angles and to correct metering quantities calculated by the microcomputer.

Abstract: An arrangement for adaptive time keeping in a utility meter includes a timing circuit and a controller. The timing circuit is operable to generate timing signals. The controller is operably coupled to the timing circuit to receive timing signals therefrom. Further, the controller is operable to: generate a first real-time value based at least in part on an externally generated first reference time value; derive a subsequent second real-time value, based at least in part on the first real-time value, the timing signals, and a timing circuit calibration value; obtain an externally generated second reference time value; determine a rate adjustment based at least in part on a difference between the second real-time value and the second reference time value; and generate a subsequent real-time value based at least in part on the timing signals, the timing circuit calibration value, and the rate adjustment.

Abstract: Disclosed an open type electricity meter having an open type communication module.

Abstract: The electronic calibration equipment for verifying the high frequency characteristics of electronic test equipment, including oscilloscopes arid time interval analyzers is provided.

Abstract: In order to obtain a simple construction of an electricity meter (1), the invention provides that the meter comprises a highly integrated input module (3a, 3b, 3c) in which an analog-digital converter (5a, 5b) and an output module (7a) are integrated. A multiplying means (21) can optionally be integrated. Such an input module (3a, 3b, 3c), in combination with conventional components, especially microprocessors, makes it possible to produce an electricity meter which comprises a simple construction and which is of a single-phase and multi-phase type (also for a plurality of consumers).

Abstract: An alternating current meter with photoelectric digital counter structure having a metal rotary disk, a light-emitting element, a photosensing element, and a signal line. The metal rotary disk is provided in a face plate thereof with a vertical through hole. The light-emitting element and the photosensing element are located at the positions corresponding to two opposite ends of the through hole of the metal rotary disk. As the metal rotary disk completes one revolution, one light signal emitted by the light-emitting element is received by the photosensing element. The light signal is then converted into a digital signal, which is transmitted to an electronic counter or a remote terminal via the signal line.

Abstract: High speed multifunction testing and calibration of electronic electricity meters comprises whole cycle synchronized testing. More specifically, start and end test commands defining a test interval synchronized to whole cycles of the pulsating a.c. potentials and currents are signaled by a meter under test (MUT) to a plurality of standard meters, during which multiple electrical quantities are accumulated by both the MUT and the standard meters. The MUT accumulated quantities and the accumulated quantities of the standard meters are communicated to the external test device for comparison. These comparisons may be used by the external test device to calculate coefficients for correcting or calibrating the MUT. The coefficients are transmitted to the MUT where they are incorporated into the algorithms for calculation of the desired electrical quantities.

Abstract: A method and apparatus for calibrating tester timing accuracy during testing of integrated circuits. An ATE tester measures itself through reference blocks that have the same relevant dimensions as the integrated circuits to be tested. The number of reference blocks required is equal to the number of signal terminals on an integrated circuit to be tested being subject to timing calibration. A signal trace electrically connects a different signal terminal to a common reference terminal on each reference block. Each signal trace used should be closely matched both physically and electrically to the other signal traces used in the set of reference blocks, so that the electrical path length associated with each trace is nearly identical. To perform the timing calibration, the reference blocks may be mounted on a single fixture one at a time, or using multi-site fixtures, multiple reference blocks may be used in parallel.

Abstract: A method for measuring electricity usage that includes steps of: coupling a sensor to a power source; converting a signal from the sensor to a digital measurement signal; using a microcomputer to determine quantities indicative of electricity consumption from the digital measurement signal; and using a nonvolatile, reprogrammable memory coupled to the microcomputer to control the microcomputer in determining the quantities indicative of electricity consumption.

Abstract: In order in a digital electricity meter (1) to permit flexibility in terms of user wishes, it is provided that, in addition to its basic meter (2) containing the basic metering functions, the electricity meter (1) includes an additional computing module (23) with which user-specific computations or functions can be implemented. In that way a virtual meter is formed within the electricity meter (1). Preferably the additional computing module (23) is accessible by way of an access module (20) and is freely programmable by the user without the calibrated function of the basic meter being violated.

Abstract: An apparatus for measuring electrical power consumption. An apparatus for measuring electrical power consumption is provided. The total power is obtained by multiplying the instantaneous voltage of the load by the instantaneous current of the load and summing the results of multiple phases. The total power voltage is calibrated to the full scale of the power meter for display to the operator. The power meter digitally displays the output in operator selectable measurement units and on a rapid response bar graph representing the proportion of full scale. Additionally, the power meter provides a current output and both scaled and unscaled voltage outputs representing the total power consumption, high and low trip settings, a peak power hold feature, and a scaling feature to allow precise measurements at for power levels less than the full scale rating of the power meter. Finally, the power meter can be connected to external devices for monitoring or control.

Abstract: A device and a method of metering and displaying immediate and/or accumulated energy consumption at a place of consumption, such as electricity, water or heating consumption in a household, said device comprising a recording unit which records and sums an immediate energy consumption on the basis of regular measurements and stores there measurements for the calculation of an average consumption, a display comprising at least one display unit capable of displaying the relationship between an accumulated energy consumption and the calculated average consumption for a selected period of time on a percentage scale.

Abstract: There are provided a timing calibration apparatus and a timing calibration method capable of carrying out the calibration of timing on an IC tester with high accuracy. There is provided a probe to be sequentially contacted with pins of an IC socket on which an IC under test is to be mounted, and a calibration pulse supplied to the IC socket from the IC tester is taken in the probe. The calibration pulse is compared with the reference timing, thereby to calibrate the timing on a driver included signal path. In the probe a calibration pulse is generated, which is sequentially supplied to the pins of the IC socket, thereby to calibrate the timing on a comparator included signal path in each of channels. There are provided in the probe an optical modulator for converting an electric signal into an optical signal and an optically driven type driver. An optical cable couples between a calibration controller provided in the IC tester and the probe.

Abstract: A digital meter is designed for measuring alternating current and is formed of a metal rotary disk, a light-emitting element, a light-sensing element, a signal wire, and a signal conversion display. The metal rotary disk is provided with a through hole located at an appropriate position thereof The light-emitting element and the light-sensing element are corresponding in location to each other such that they are located on a rotational path of the through hole. As the metal rotary disk completes one revolution, the light-sensing element receives once a light signal is transmitted via the signal wire into the signal conversion display by which the signal is converted into a numerical value of power consumtion. The numerical value of power consumption by a power user is thus attained by a terminal located in the power company without the use of a meter-person.

Abstract: A circuit testing device includes a handle with a hollow interior, a conductive probe projecting from one end and a removable cap with a wire and clamp projecting from the opposite end A subassembly retained within a counterbore in the handle includes a polarity sensitive buzzer and light in a parallel circuit configuration whereby the device is useful for determining polarity, circuit continuity, and battery drain.

Abstract: An electronic power meter for metering the consumption of electrical energy on power lines includes phase compensation on current transformers, whereby the acquisition of one of the two samples for the current signals is delayed and time shifted averaged, such that the average of the two signals provides a compensated signal. The amount of delay is determined from the phase lag the current transformers exhibit during the process of calibration for phase compensation. The amount of compensation that is applied varies with current, thus compensation for the non-linearity in the phase shift for the current transformers. The degree of non-linearity is computed which results in only two variables that define the phase lag at higher current and the degree of non-linearity. The technique helps in using inexpensive current transformers in the meter.

Abstract: Disclosed an open type electricity meter having an open type communication module.

Abstract: In order in a digital electricity meter (1) to permit flexibility in terms of user wishes, it is provided that, in addition to its basic meter (2) containing the basic metering functions, the electricity meter (1) includes an additional computing module (23) with which user-specific computations or functions can be implemented. In that way a virtual meter is formed within the electricity meter (1). Preferably the additional computing module (23) is accessible by way of an access module (20) and is freely programmable by the user without the calibrated function of the basic meter being violated.

Abstract: A scale control method provides fine scale control in a measurement instrument and also provides scale control spanning wide adjustment ranges. The method detects the presence of the user input to a control sensor and establishes an acceleration factor for the input based on a rate at which events are generated by the control sensor. The acceleration factor modifies a defined scale step size that has a correspondence to the events generated by the control sensor. The defined scale step size, as modified by the acceleration factor, is added to a prior scale to establish a present scale. The present scale and prior scale are used to select a detent value from a series of detent values and to determine if a detent is applicable. When a detent is applicable, the present scale is set to the selected detent value and control of the scale parameters is then determined by this detent value.

Abstract: A portable energy meter test system for testing energy meters and other related instrumentation on-site is disclosed. The test system utilizes waveform generating circuitry to generate and transmit electrical waveforms to an energy meter to be tested, and sensing circuitry for sensing electrical characteristics corresponding to the transmitted electrical waveform. The test system includes a processor for evaluation and control of the testing procedure. A graphic touch screen is coupled to the processor for displaying information about the energy meter and for displaying test options to the user and allowing the user to control the testing process by touching the screen.

Abstract: An apparatus for determining loss of reference voltage (indicating possible tampering) in a 2-element electronic meter that includes a processor for determining electrical power from voltage and current signals, and a display for indicating an operating status of the meter. To determine if the reference voltage of the meter in a 3-wire delta or network installation has been lost, a measurement of the phase angle difference between the two phases is made. If the phase difference is equal to a predetermined value, the meter indicates on the display that loss of reference voltage and possible tampering has taken place. The apparatus may further be adapted to determine a length of time that this condition has occurred such that the appropriate enforcement and billing agencies may be informed.

Abstract: A secondary service conductor tester includes a housing. A set of at least two wires suitable for detachably engaging a meter base are electrically connected to the secondary electrical service of a power utility. A plurality of electrical loads each of which includes a fan unit are capable of drawing approximately 80 amps or more current when activated. A switch is electrically connected to at least one of the at least two wires and the plurality of electrical loads to select respective pairs of the three wires through which the current is drawn. A display indicates the electrical voltage drop when one of the respective pairs of wires are electrically connected to the meter base and the plurality of electrical loads are activated. The electrical loads and the switch enclosed within the housing and at least one of the at least two wires at least periodically electrically connected to the plurality of electrical loads in response to switching the switch.

Abstract: A variable threshold comparator receiving, on an input node, an input signal having a voltage, and providing an output signal on an output node when the voltage of the input signal exceeds a selectable threshold voltage of the comparator. The comparator includes a transistor coupled by way of its source and drain between a power supply and an output node, and having its gate coupled to the input node. Also included are a plurality of pairs of transistors coupled together by a source of a first one of the pair of transistors and drain a drain of a second one of the pair of transistors, and coupled in series between the output node and a ground, a gate of the first one of the transistors coupled to the input node, and a gate of the second one of the transistors coupled to a control signal specific to the second one of the transistors. The threshold voltage of the comparator is selectable by the application of one or more of the control signals to a respective one or more of the second ones of said transistors.

Abstract: High speed multifunction testing and calibration of electronic electricity meters comprises whole cycle synchronized testing. More specifically, start and end test commands defining a test interval synchronized to whole cycles of the pulsating a.c. potentials and currents are signaled by a meter under test (MUT) to a plurality of standard meters, during which multiple electrical quantities are accumulated by both the MUT and the standard meters. The MUT accumulated quantities and the accumulated quantities of the standard meters are communicated to the external test device for comparison. These comparisons may be used by the external test device to calculate coefficients for correcting or calibrating the MUT. The coefficients are transmitted to the MUT where they are incorporated into the algorithms for calculation of the desired electrical quantities.

Abstract: A calibration apparatus for a programmable comparator is provided which does not need circuits for offset adjustment and gain adjustment or high precision parts makes possible inexpensive construction of the apparatus itself, and at the same has a wide adjustment range and can carry out high precision calibration. The programmable comparator compares the analog voltage value corresponding to a supplied digital code and the voltage value corresponding to the electric current value of an electric current supplied by a predetermined power supply point, and outputs the result. In the calibration apparatus, the power supply means supplies to a power supply point an electric current having an electric current value indicated, and an electric current detection means converts the electric current value of the electric current flowing through the power supply point to a voltage value, and this value is output to the programmable comparator.

Abstract: The present invention includes an electrical utility meter operable to measure power consumption. The method detects and compensates for one or more wiring errors that affects the power consumption measurement of the electrical utility meter. The method includes the steps of: obtaining measured phase angle data for a plurality of phases in a polyphase electrical system; periodically performing one or more diagnostic tests using the measured phase angle data to determine whether a wiring error is present, automatically adjusting the operation of the electrical utility meter to effect a compensation for the wiring error, said compensation increasing an accuracy of power consumption measurement of the electrical utility meter. The meter is operable to detect and compensate for wiring errors including polarity errors and cross phasing errors. According to another method of the present invention, the meter is operable to determine automatically the service type to which it is connected.