Power meter having an auto-calibration feature and data acquisition capabilities

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.