Method and apparatus for storing electric power measurements

Abstract

An electronic instrument that records electric power measurements. The instrument contains two types of memories: the first type of memory can tolerate wide fluctuations in ambient temperature but is expensive per unit of storage capacity, and the second type of memory only operates in a narrow ambient temperature range but is inexpensive per unit of storage capacity. For example, the two types of memory may be static Random Access Memory (RAM) and a hard disk drive, respectively. The instrument contains more storage capacity of the second type than storage capacity of the first type. The instrument records all of its measurements in the first type of memory. It also monitors the ambient temperature. When it detects an ambient temperature that will permit the second type of memory to function properly, it flushes the first type of memory into the second type of memory, thus creating space for recording subsequent data in the first type of memory. The instrument contains sufficient memory of the first type to allow it to record at least twenty-four hours of data without employing the memory of the second type; consequently, as long as the ambient temperature passes through the acceptable range for the memory of the second type at least once during a day/night cycle, the instrument is able to record power measurements until the second type of memory is full.