| 摘要 |
An electricity billing recorder has a controller for processing pulses from an electric meter. The resulting data is temporarily stored in random access memory as data words representative of energy consumed in predetermined time ("demand") intervals. The accumulated measurement ("event") data and time data are transferred to a non-volatile, solid state memory module after relatively long collection periods comprising a number of demand intervals. The solid state memory is energized only during data transfers. The entire memory module is replaceable for processing at a central location. During replacement the controller writes a special Removal Record in predetermined locations on the memory module being removed, and prepares a special Insertion Record for the new module. The cumulative counts recorded on these special records in addition to the normal records establish reliable data continuity. After any collection period in which a power outage has occurred, the controller transfers the current data to a secondary portion of RAM. Subsequent demand intervals, until power is restored and including any memory thermal recovery periods, are assigned chronological index numbers and event data is stored only for those demand intervals in which power consumption actually occurs. After return to normal operation, the data in secondary RAM is transferred to the solid state memory and the compact format data in primary RAM is reconstructed into normal storage format with all intervals during which no event data was stored being zero filled. As this data is transferred to secondary RAM for storage in the solid state memory, the remaining data in primary RAM is re-located to provide as much space as possible for data storage should another power outage occur before conversion of all the compact format data. |
