Electronic watthour meter.

摘要

An electronic watthour meter is digitally configurable to operate as several different types of watthour meters for metering electrical energy from a variety of different electric utility services Automatic scaling of line input currents is provided to scale the voltage input to an analog to digital converter over selected ranges such that low level and high level input signals are measured in an optimum range. A digital signal processor is employed to calculate values for metered electrical energy and output pulses, each proportional to a guantum of energy flowing in the circuit being metered The processor calculates the value of DC offset errors inherent in the various analog circuits of the meter and uses that value in the calculation of metered electrical energy to compensate for such offset errors The meter employs automatic and manually initiated test functions for testing the operation of the processor and other critical circuits in the meter