Power meter having an auto-calibration feature and data acquisition capabilities
First Claim
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1. An auto-calibrating power meter comprising:
- circuitry configured to receive a plurality of voltage and current inputs including analog conditioning circuitry, which includes a plurality of optical isolators for receiving the plurality of analog voltage inputs and a plurality of current transformers for receiving the plurality of current inputs, and sample and hold circuitry for sampling and holding the plurality of voltage and current inputs to be individually converted from analog to digital signals; and
processing circuitry configured to measure at least one parameter of the received digitized plurality of voltage and current inputs, to select at least one reference voltage during a calibration mode for calibrating a range of measurements for the at least one measured parameter of the received digitized plurality of voltage and current inputs, and to compute at least one calibration factor, which corrects drift errors occurring in the analog voltage inputs from the optical isolators, for the range of measurements for calibrating at least one parameter of the received digitized plurality of voltage and current inputs;
wherein the processing circuitry executes several routines for computing the at least one calibration factor in a hierarchical order of a 0.1 second routine having a highest priority, a 1.0 second routine having a next highest priority, and a main routine having a lowest priority.
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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.
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Citations
18 Claims
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1. An auto-calibrating power meter comprising:
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circuitry configured to receive a plurality of voltage and current inputs including analog conditioning circuitry, which includes a plurality of optical isolators for receiving the plurality of analog voltage inputs and a plurality of current transformers for receiving the plurality of current inputs, and sample and hold circuitry for sampling and holding the plurality of voltage and current inputs to be individually converted from analog to digital signals; and
processing circuitry configured to measure at least one parameter of the received digitized plurality of voltage and current inputs, to select at least one reference voltage during a calibration mode for calibrating a range of measurements for the at least one measured parameter of the received digitized plurality of voltage and current inputs, and to compute at least one calibration factor, which corrects drift errors occurring in the analog voltage inputs from the optical isolators, for the range of measurements for calibrating at least one parameter of the received digitized plurality of voltage and current inputs;
wherein the processing circuitry executes several routines for computing the at least one calibration factor in a hierarchical order of a 0.1 second routine having a highest priority, a 1.0 second routine having a next highest priority, and a main routine having a lowest priority. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18)
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16. A method for auto-calibrating at least one parameter of a received plurality of voltage and current inputs in a power meter, the method comprising the steps of:
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receiving the plurality of analog voltage inputs and the current inputs by the power meter;
performing analog conditioning of the plurality of analog voltage inputs and the current inputs utilizing a plurality of optical isolators;
sampling and holding the plurality of inputs to be individually converted from analog to digital signals;
measuring at least one parameter of the digitized plurality of voltage and current inputs;
selecting at least one reference voltage for calibrating a range of measurements for the at least one measured parameter; and
computing at least one calibration factor, which corrects drift errors occurring in the analog voltage inputs from the optical isolators, for the range of measurements for calibrating the at least one parameter of the digitized plurality of voltage and current inputs;
wherein the at least one calibration factor is computed in a hierarchical order of a 0.1 second routine having a highest priority, a 1.0 second routine having a next highest priority, and a main routine having a lowest priority. - View Dependent Claims (17)
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Specification