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US 4,335,447 AGranted
Power outage recovery method and apparatus for demand recorder with solid state memory
AssigneeSangamo Weston, Inc.
InventorJohn W. Jerrim
Life of this patent
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AssigneeSangamo Weston, Inc.
InventorJohn W. Jerrim
Estimating the term…
A demand recorder includes a microprocessor for receiving data pulses representative of measured events and formats the incoming data into demand intervals. After a predetermined number of demand intervals, called a collection period, the microprocessor transfers the data for more permanent storage to a solid state memory which may be removed for remote processing. The system has battery carryover during a power outage, but the microprocessor prevents data transfers to the solid state memory. At the end of a collection period in which a power outage occurred, the microprocessor transfers the current data to a secondary portion of random access memory. For subsequent demand intervals until power is restored and including any thermal recovery periods, the processor formats event data by assigning index numbers for demand intervals in order of occurrence and stores data only for those demand intervals in which power consumption was actually measured. After the system has returned to normal operation, the data temporarily stored in secondary RAM is transferred to the solid state memory and the data in primary RAM which is stored in compacted format is re-constructed into normal storage format in RAM with all intervals during which no event data was detected being zero-filled. As data is taken from primary RAM, converted into the original format and transferred to secondary RAM for storage in the solid state memory, the remaining data in primary RAM is advanced in memory, similar to the operation of a stack memory, so that as much space as possible is made available for data storage in the event of a subsequent power outage prior to the time all of the data in primary RAM is converted and stored in the solid state memory.
In a demand recorder including controller circuit means receiving data pulses representative of measured events and including random memory means having primary and secondary storage locations, said controller circuit means generating data words representative of received event data for predetermined demand intervals and storing the same in said primary storage locations of said random memory means for a collection period comprising a predetermined number of said demand intervals;
In a method for recording event data in a demand recorder including controller circuit means having random memory means with primary and secondary storage locations, providing temporary data storage, and a solid state memory, providing more permanent data storage, said method including transmitting data pulses to said controller circuit means representative of measured events causing said controller circuit means to respond to said data pulses and generate data words representative of received event data for predetermined demand intervals and to store the same in said primary storage locations of said random memory means for a collection period comprising a predetermined number of said demand intervals, causing said controller circuit means to transfer said event data from said random memory means to said solid state memory at the end of a collection period for more permanent storage in said solid state memory, and causing said controller circuit means to inhibit data transfers from said random memory means to said solid state memory during a power outage, the improvement comprising causing said controller circuit means to transfer the data from said primary storage locations of said random memory means to said secondary storage locations of said random memory means at the end of the first collection period during which a power outage has occurred, and when the power outage spans into the next collection period, causing said controller circuit means to store incoming event data in said primary storage locations of said random memory means in a compacted format comprising an index data word representative of the number of demand intervals of said next collection period for which the power outage lasts and event data representative of measured events which occurred during the demand interval of said next collection period during which restoration of power occurs.
Dependencies are inferred from the claim text.