Redundant pulse monitoring in electric energy metering system

Abstract

Redundant pulses generated by independently operable pulse sources in an electricity meter are accumulated as pulse counts in a pair of channels of a multi-channel recorder. The pulse counts are compared to verify the accuracy of the pulses counted by each channel. If the difference between the values of the pulse counts exceeds a predetermined threshold value, a trouble indicator is turned on and a telephone call is initiated by the recorder to notify a data center that a system malfunction has occurred which is disrupting the accumulation of pulses in one of the channels of the recorder. The pulse counts are stored in the recorder as substantially duplicate independent measures of energy usage by a load connected to the electricity meter, to be thereafter retrieved from the recorder to obtain energy survey and billing data. The recorder also maintains a system status error log which records the time and date of each malfunction and the identification of the channel pair where the malfunction occurred. In one embodiment, the operation of the recorder is controlled by a programmable microprocessor. Combinations of independent power sources for powering the recorder and the pulse sources are employed to enhance system reliability by making each of the pulse sources and the recorder substantially independently operable.