Claims:1. A method for storing and updating data in a data flash memory of an Electronic Trip Unit, the method comprising steps of:
saving the data in a frame that incorporates Trip Record Data, Fault Counters, CRC Fault Counters and CRC Frame; and
clearing the Fault Counters and CRC Fault Counters by writing zeros when user wishes to clear the fault counters.
2. The method of claim 1, wherein the Trip Record Data includes type of fault and timestamp, and the Trip Record Data is generated by main controller and sent to display controller of the ETU.
3. The method of claim 2, wherein the display controller increments the Fault Counters based on source of trip and calculates CRC Fault Counters and appends it after Fault Counters in the frame.
4. The method of claim 2, wherein the display controller further calculates CRC Frame and appends it after CRC Fault Counters.
5. The method of claim 2, wherein the display controller receives command to clear the fault counter data via display navigation.
6. The method of claim 2, wherein the display controller on receipt of command to clear fault counter data clears only the Fault Counters and the CRC Fault Counters in the frame.
7. The method of claim 2, wherein the display controller, after clearing the Fault Counters and the CRC Fault Counters, calculates CRC Frame and appends it after CRC Counters. , Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of circuit breakers. In particular the present disclosure pertains to method of updating the data flash memory in the microcontroller of electronic trip units.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Traditionally circuit breakers were used to break the current passing through it in case the current goes above a certain threshold value. However, with introduction of microprocessors, Modern day circuit breakers or Electronic Trip Units (ETU) as they are often called now, provide a variety of protections using the microcontrollers for fault sensing and giving trip command such as current protection, voltage protection, frequency protection, power protection etc. Settings of the various protections offered can be done through rotary switches, dip switches, and display navigation.
[0004] The microcontrollers used in ETUs have non-volatile memories such as data flash for storing data that can be referred even after power down. Thus the ETUs besides fault sensing and tripping are also capable of recording metering data and storing records such as trip records, fault counters, and event records. Recording the data such as reason of trip when fault happens, has become an essential functionality of these ETUs so that user can view the reason of trip after power down to resolve the faulty condition which lead to breaker tripping. For example in case of current protections, when breaker trips in short circuit fault the trip time may be as less as 20ms.Therefore, before power down happens that is earlier than 20ms, the trip record data along with timestamp and tripping protection settings needs to be stored in the data flash memory. Also, the trip record fault counters that indicate the number of times breaker has tripped in a particular protection and total number of times the breaker has tripped, need to be updated.
[0005] The flash memories generally allow the reading and writing of the data according to the user defined size of bytes. However, before undertaking writing operation, data already stored in the flash needs to be erased. This erase operation is generally block wise (512 bytes/1024 bytes). Thus the data, once written in flash memory, if requiring modification, cannot be simply overwritten on the existing data. Modified data is stored at a new memory location and the memory location of the original data is subsequently marked as invalid and the memory location of the new database information is referenced for subsequent access. In case the data is already written at the new memory location, then the data flash needs to be erased before writing modified data at that location. In case only a part of the data needs to be modified then erasing the memory is an overhead and takes time as well as consumes power. Furthermore, the data flash have a fixed erase cycle (endurance) such as 10,000 or 1, 00,000. After this the data flash becomes corrupt. Therefore, more the number of erase operations, faster will be data flash corruption.
[0006] As can be seen, the conventional method of modifying the data in a flash memory requires frequent erase operations that reduces reliability and longevity of the device that has a finite number of write-erase cycles. Frequent erase operations also utilize processing resources and consume power.
[0007] Efforts have been made in the art to overcome above drawbacks and enhance endurance of the flash memory. For example United States Patent number 8,131,915 B1 discloses a methodology for flash memory stored data modification and provides a memory controller that manages data Write and erase operations to the Flash memory. The flash memory includes a first flash memory region of single-Write flash memory cells that are each configured for a data Write operation and a corresponding erase operation before a subsequent data Write operation. The flash memory also includes a second flash memory region of multiple-Write flash memory cells that are each configured for multiple data Write operations before an erase operation. Thus the referred prior art document maintains separate regions for single write memory region and multiple write memory regions. But many times it may be required to store the data of multiple write and single write at the same location, since that data is related to each other, for example the data of trip records and fault counters. Data of fault counters is derived from trip record and needs to be saved in the same region with trip records. However, at the time of modification, only the counters data needs to be modified, keeping the records data intact.
[0008] Another prior art reference WO 9510083A1endeavours to solve the problem by reducing the number of memory erase in data flash by incorporating two algorithms. According to first algorithm, erase cycles are avoided by programming the altered data file into an empty mass storage block rather than over itself after an erase cycle of that block as done on conventional block. Periodically, the mass storage will fill up as no erase has been performed, at such times the multi sectors erase needs to be done. The second algorithm provides means for even use of all the blocks in mass storage. A counter tracks the number of times each blocks needs to be erased. A programmable maximum value for the counter is also provided. As the number of erase cycles for a block becomes one less than maximum, the block is erased one last time and written with another file having a then smallest number of erase cycles. As can be seen the referred prior art reference merely tries to ensure even use of all blocks and thus can at best avoid early corruption of part of the flash memory without actually improving its life.
[0009] There is, therefore, a need in the art for a more efficient methodology for modification of data in flash memory that does not cause undesirable stress on the flash memory reducing reliability and longevity of the device and does not require processing resources and power for erase operations.
[0010] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0011] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0012] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0013] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0014] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0015] A general object of the present disclosure is to provide a method for updating data in flash memory that overcomes drawbacks of the conventional methods.
[0016] An object of the present disclosure is to provide method for updating data in flash memory that preserves the memory endurance by reducing memory erase operations.
[0017] Another object of the present disclosure is to provide a method to reset certain region of data flash without performing memory erase.
[0018] Yet another object of the present disclosure is to provide time efficient method to modify only a part of the data frame without making copy of the entire frame, thus saving the entire frame from becoming invalid.

SUMMARY
[0019] Aspects of the present disclosure relate to the updating data in a flash memory of an Electronic Trip Unit in power distribution systems. In an aspect, the disclosure provides a methodology for overwriting the modified data on the existing data in the flash memory thus doing away the need of writing the modified data at new location and making the earlier data invalid and erasing it subsequently.
[0020] In an aspect, the method of the present disclosure can be applied when only certain bytes of data flash frame needs to be modified keeping rest of the frame unchanged. In an aspect, when the ETU receives input from user to clear certain data of the frame written in the data flash keeping rest of the data unchanged, those bytes of data is made zero in the same data flash frame. As can be seen the proposed method resets a region of the data flash and saves time which would otherwise be required for memory erase operation. Furthermore, writing zeroes instead of erasing the memory provides benefits of preserving memory endurance by reducing memory erase operations and saving time and resources from performing memory erase operations.
[0021] In an aspect, the disclosed method proposes to save the data in a frame that incorporates Trip Record Data, Fault Counters, CRC Fault Counters and CRC Frame. If user wishes to clear fault counters then only the fault counters and its CRC can be cleared (by writing zeros) with the CRC of the frame remaining unchanged. Since the data and its CRC are written in the same frame, they cancel out each other. Thus when the user views the new modified data, he will see the cleared fault counters but intact trip record.
[0022] Thus the disclosed method provides a time efficient method to modify only a part of the data frame without making copy of the entire frame, thus saving the entire frame from becoming invalid.
[0023] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components

BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0025] FIG. 1 illustrates an exemplary block diagram of a typical Electronic trip unit (ETU) with LCD display.
[0026] FIG. 2 illustrates a typical data frame format used for saving different types of data such as ETU settings in data flash.
[0027] FIG. 3 illustrates an exemplary frame format for saving fault counters data along with trip record in data flash in accordance with an embodiment of the present disclosure.
[0028] FIG. 4 illustrates an exemplary flow diagram for process of saving trip record frame along with fault counters data in data flash memory in accordance with an embodiment of the present disclosure.
[0029] FIG. 5 illustrates an exemplary flow diagram for process of clearing fault counters and saving trip record frame along with fault counters data in data flash memory in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0030] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0031] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0032] Various terms as used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0033] The present disclosure relates to updating data in a flash memory of an Electronic Trip Unit in power distribution systems. In an aspect, the disclosure provides a methodology for overwriting the modified data on the existing data in the flash memory thus doing away the need of writing the modified data at new location and making the earlier data invalid and erasing it subsequently.
[0034] In an aspect, the method of the present disclosure can be applied when only certain bytes of data flash frame needs to be modified keeping rest of the frame unchanged. In an aspect, when the ETU receives input from user to clear certain data of the frame written in the data flash keeping rest of the data unchanged, those bytes of data is made zero in the same data flash frame. As can be seen the proposed method resets a region of the data flash and saves time which would otherwise be required for memory erase operation. Furthermore, writing zeroes instead of erasing the memory provides benefits of preserving memory endurance by reducing memory erase operations and saving time and resources from performing memory erase operations.
[0035] In an aspect, the disclosed method proposes to save the data in a frame that incorporates Trip Record Data, Fault Counters, CRC Fault Counters and CRC Frame. If user wishes to clear fault counters then only the fault counters and its CRC can be cleared (by writing zeros) with the CRC of the frame remaining unchanged. Since the data and its CRC are written in the same frame, they cancel out each other. Thus when the user views the new modified data, he will see the cleared fault counters but intact trip record.
[0036] Thus the disclosed method provides a time efficient method to modify only a part of the data frame without making copy of the entire frame, thus saving the entire frame from becoming invalid.
[0037] It is to be appreciated that though the embodiments of the present disclosure have been explained with reference to clearing data in respect of fault counters in an ETU, the disclosed method can be applied to any data stored in flash memory of any device without any limitations with similar benefits and all such applications are well within the scope of the present disclosure.
[0038] Referring now to FIG. 1 wherein an exemplary block diagram 100 of a typical Electronic trip unit (ETU) is illustrated. The ETU can incorporate a main controller 102, a display controller 104 and a LCD display 106 for user interface. They can have serial communication 108 between them through driver and bus interface. An ETU is an intelligent module of the circuit breakers which are configured to sense the current flowing through the breaker and in case of occurrence of a fault current, break the current by issuing a trip command. It becomes very important to store the trip record which gives the information of source of trip, time of trip, current flowing through breaker etc. Furthermore, because of use of microcontrollers for sensing the fault, breakers now provide multiple types of protections. Therefore, counters for each of various types of faults are also stored along with the trip record. These counters provide useful information on number of times the breaker has tripped on account of a particular fault such as short circuit or overload fault. The display controller 104 incorporates data flash memory for storing the trip record received from the main controller 102. Before storing the trip record received from the main controller 102 in the data flash memory the fault counters are incremented based on the fault occurred
[0039] The fault counters not only give information regarding the total number of trips on account of a particular fault but also help in planned maintenance of the breaker. For example, if the breaker has tripped three times in instantaneous fault, then the breakers arc shuts needs to be checked and cleaned. After the maintenance activity user may wish to clear the fault counters stored in the flash memory, but may not wish to clear the entire trip record, since trip record gives an indication of reason for last breaker tripping. Therefore, there is no requirement of making a new copy of the previously stored trip record with cleared fault counters which would result in one invalid trip record. Requirement can be met by only clearing the fault counters data in the same trip record.
[0040] The data that needs to be stored in the flash memory such as ETU settings, event records etc. are typically stored in a frame format as illustrated in FIG. 2. The frame format 200 may consist of a start of frame, data 202 and CRC of the data 204. Start of frame is required to identify the presence of the data in a memory block during search mechanism. CRC of the data is used to check authenticity of the data on reading the stored data.
[0041] In an embodiment, the disclosure provides for memory frame that can consist of start of frame, trip record data, fault counters data, CRC of fault counters data, and CRC of entire frame. Traditionally trip record and fault counters are stored in separate frames in separate blocks of data flash along with their CRC since they can be accessed by the user independently. But this requires minimum two blocks of data flash memory for saving trip record and counters separately. Also when trip record is updated, both the memory blocks will have to be erased and updated. Thus the frame format suggested in the embodiment will not only save the data flash memory but also gives user the flexibility to view as well as clear the counters independently.
[0042] FIG. 3 illustrates an exemplary frame format 300 for saving fault counters data along with trip record in data flash in accordance with an embodiment of the present disclosure. The memory frame can consist of start of frame, trip record data 302, fault counters data 304, CRC of fault counters data 306, and CRC of entire frame 308 as illustrated in FIG. 3.In an aspect, the proposed structure of the memory frame to store the data can enable overwriting of a new frame over the existing frame after user has decided to clear the fault counters as would be explained in succeeding paragraphs.
[0043] FIG. 4 illustrates an exemplary flow diagram 400 for process of saving trip record frame along with fault counters data in data flash memory in accordance with an embodiment of the present disclosure. As shown at step 402 of the flow diagram 400, the main controller 102 generates the trip record data based on type of fault with time stamp and sends it to the display controller 104. At step 404, the display controller 104 receives the trip record data sent by the main controller 102 and increments the fault counter based on source of trip. The display controller 104, at step 406, can calculate CRC of the incremented fault counter and append it after the counter data. At step 408, the display controller 104 can calculate CRC of the trip frame and append the calculated CRC after CRC counters. The updated frame can be saved in the data flash memory as shown at step 410. In an embodiment, CRC used is Kermit CRC 16.
[0044] When the user wishes to view trip record data the entire trip frame can be read, CRC can be calculated and checked with the stored frame CRC for data validation, and then the trip record can be displayed to the user. In case the user wants to view the fault counters data, then fault counters are read from the latest trip record frame, the CRC is calculated and compared with the stored fault counters CRC and information is displayed to the user.
[0045] In an embodiment, if the user wishes to clear fault counters, in the latest trip record only the fault counters and its CRC can be cleared without any change in the CRC of the frame since in case of Kermit CRC 16when data and its CRC is written in the same frame, they cancel out each other. Therefore, when the user views the modified data he will see the cleared fault counters but intact trip record.
[0046] FIG. 5 illustrates an exemplary flow diagram 500 for process of clearing fault counters and saving trip record frame along with fault counters data in data flash memory in accordance with an embodiment of the present disclosure. As shown at step 502 of the flow diagram 500, an instruction for clearing the fault counter data can be received via display navigation. At step 504, the data can be read from the trip record frame of the data flash memory and CRC of the frame can be verified. At step 506, the fault counters data in the trip frame can be cleared by writing zeros and CRC of the trip counter calculated. At step 508, CRC of the trip frame can be calculated and the calculated CRC can be appended after CRC counters. At step 510 the frame can be saved in the data flash memory.
[0047] Thus only the fault counter data is modified in the same trip record frame preserving not only the trip record but also saving unnecessary memory erase operation which reduces memory endurance ,consumes time and power.
[0048] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0049] The present disclosure provides a method for updating data in flash memory that overcomes drawbacks of the conventional methods.
[0050] The present disclosure provides method for updating data in flash memory that preserves the memory endurance by reducing memory erase operations.
[0051] The present disclosure provides a method to reset certain region of data flash without performing memory erase.
[0052] The present disclosure provides a time efficient method to modify only a part of the data frame without making copy of the entire frame, thus saving the entire frame from becoming invalid.