| 摘要 |
An electronic demand register includes a processor for calculating a demand in a demand subinterval. At the end of each demand subinterval, the calculated demand is summed with the demand in the preceding N-1 subintervals to derive an interval demand over N contiguous subintervals. The interval demand is compared to a previously recorded maximum demand and, if the interval demand exceeds the maximum demand, its value is substituted for the maximum demand for use in subsequent comparisons. The processor employs volatile memory. A non-volatile memory is provided for storing the billing data and programmed constants in the event of an impending power outage. A power monitor detects the possibility of an impending power outage and, operating on stored energy, both enables and powers the transfer of data to the non-volatile memory. When power is resumed, the power monitor enables resetting the processor and retransferring the data from the non-volatile to the volatile memory for resumption of demand metering. A grace period is provided after the resumption of power before beginning demand metering to permit the energy user's starting loads to pass before demand metering begins. Provision is made for treating the beginning and ending of a test operating mode similar to a power outage. In addition, the demand register responds to its removal from, and its replacement in, the electric meter in a manner similar to its response to a power outage.
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