MEMORY MANAGEMENT FOR AN INTELLIGENT ELECTRONIC DEVICE

• US 20080195794A1
• Filed: 12/28/2007
• Published: 08/14/2008
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: EI Electronics LLC (Hubbell, Inc.)
• Original Assignee: Electro Industries/Gaugetech
• Inventors: Banker, Patricia E.
• Granted Patent: US 9,063,181 B2
• Time in Patent Office: Days
• US Class Current: 711/100
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: G06F 2212/7211 Wear leveling

Abstract

A device and method are provided for managing flash memory of an intelligent electronic device (IED) to maximize the IED life. The IED includes at least one sensor for sensing at least one electrical parameter distributed to a load. At least one analog-to-digital converter is coupled to the at least one sensor for converting an analog signal output from the at least one sensor to digital data. A processing unit is coupled to the at least one analog-to-digital converter to receive the digital data and store the digital data in a memory. The memory includes sectors configured to store the digital data. The processing unit stores the digital data in each of the sectors and equalizes usage of each sector over time by equalizing a number of erases for each of the sectors over time.

Claims

1. An intelligent electronic device comprising:

at least one sensor configured for sensing at least one electrical parameter distributed to a load;

at least one analog-to-digital converter coupled to the at least one sensor and configured for converting an analog signal output from the at least one sensor to a digital data;

a processing unit coupled to the at least one analog-to-digital converter configured to receive the digital data and store the digital data in a memory, and

the memory including a plurality of sectors configured to store the digital data, wherein the processing unit stores the digital data in each of the plurality of sectors to equalize usage of each of the plurality of sectors over time.

2. The device as in claim 1, wherein the memory is a flash memory.

3. The device as in claim 1, wherein the memory is removable.

4. The device as in claim 1, wherein the processing unit is configured to manage wear of the plurality of sectors so that the number of erases for each of the plurality of sectors is equalized over time.

5. The device of claim 1, wherein each of the plurality of sectors includes data comprising a sector header.

6. The device as in claim 5, wherein the sector header includes erase count, assignment, sequence number, and at least one checksum.

7. The device as in claim 6, wherein the assignment comprises erased, available and in use.

8. The device as in claim 7, wherein the assignment comprises released and error, wherein the assignment of error is equivalent to an assignment of dead.

9. The device as in claim 8, wherein the at least one checksum includes a first checksum that is valid when the assignment is in use and a second checksum when the assignment is released.

10. The device as in claim 5, wherein the digital data forms at least one file and wherein every sector header is further configured to store a unique number, said unique number assigned in time sequence such that sorting the numbers for all sectors in a file arranges the sectors in correct time sequence.

11. The device of claim 5, wherein the sector header is further configured to store an assignment identifying the contents of that sector.

12. The device as in claim 11, wherein the assignment comprises erased, available and in use.

13. The device as in claim 12, wherein the assignment comprises released and error, wherein the assignment of error is equivalent to an assignment of dead and wherein the in use assignment includes a plurality of values distinguishing one use from another.

14. The device as in claim 13, wherein the processing unit is further configured to construct a sector directory for each of the plurality of sectors for determining the contents of each of the sectors and a file directory for determining each of the plurality of sectors associated with each of the at least one file.

15. The device as in claim 14, wherein the constructed sector and file directories are located in a different memory than the data the constructed sector and file directories are referencing.

16. The device as in claim 1, wherein the processing unit is configured to determine an error count for each of the plurality of sectors and selects the next sector for saving data from the available sectors based on the error count.

17. The device as in claim 16, wherein the determined error count is stored in non-volatile memory.

18. The device as in claim 1, wherein the processing unit is configured to determine an erase count for each of the plurality of sectors and selects the next sector for saving data from the available sectors based on the erase count.

19. The device as in claim 17, wherein the determined erase count is stored in non-volatile memory.

20. The device as in claim 1, wherein the processing unit is further configured to determine an error count for each of the plurality of sectors, determine an erase count for each of the plurality of sectors and selects from the available sectors the next sector for saving data based on the determined error and erase counts together.

21. The device as in claim 20, wherein the determined error count and determined erase count are stored in non-volatile memory.

22. The device as in claim 20, wherein the processing unit is further configured to store the digital data in at least one sector selected from a group of sectors with the lowest error counts and the sector having the lowest erase count of the group.

23. A method for managing a memory in an intelligent electronic device, the memory comprising a plurality of independently erasable sectors to be used as a set for storing data files, the method comprising the steps of:

generating at least one data file to be stored in the memory;

determining an erase count of at least one sector;

determining the at least one sector having the lowest erase count; and

storing the data in the determined at least one sector having the lowest erase count.

24. The method of claim 23, wherein at least one of the plurality of sectors includes a sector header.

25. The method as in claim 24, further comprising configuring the sector header to store an erase count of that sector.

26. The method as in claim 24, further comprising configuring the sector header to store an assignment of that sector.

27. The device as in claim 26, wherein the assignment comprises erased, available and in use.

28. The device as in claim 27, wherein the assignment comprises released and error, wherein the assignment of error is equivalent to an assignment of dead and wherein the in use assignment includes a plurality of values distinguishing one use from another.

29. The method as in claim 24, further comprising configuring at least one file of the generated data and wherein every sector header is further configured to store a unique number, said unique number assigned in time sequence such that sorting the numbers for all sectors in a file arranges the sectors in correct time sequence.

30. The method as in claim 29, further comprising determining the sector assignment and the sequence number for at least one of the plurality of sectors and generating a sector directory.

31. The method as in claim 30, further comprising generating a file directory including determining the sectors belonging to the file, sorting the sectors into oldest to newest order using the sequence numbers, and determining file sizes, wherein the file size is determined by searching for the end of the data.

32. The method of claim 30, wherein the sector directory comprises means for the intelligent electronic device to determine the contents of every sector.

33. The method of claim 31, wherein the sector and file directories are located in a different memory than the data the sector and file directories are referencing.

34. A method for managing a memory in an intelligent electronic device, the memory comprising a plurality of sectors, the method comprising the steps of:

generating data to be stored in the memory;

determining a quality of each of the plurality of sectors; and

storing the data in at least one sector having the highest determined quality.

35. The method as in claim 34, wherein the determining step further comprises determining an erase count for each of the plurality of sectors, wherein the at least one sector with the lowest erase count is determined to have the highest quality.

36. The method as in claim 34, wherein the determining step further comprises determining an error count for each of the plurality of sectors, wherein the at least one sector with the lowest error count is determined to have the highest quality.

37. The method as in claim 34, wherein the determining step further comprises determining an error count for each of the plurality of sectors, determining an erase count for a group of the plurality of sectors having the lowest error count, wherein the at least one sector with the lowest erase count from the group of the plurality of sectors having the lowest error count is determined to have the highest quality.