Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to energy meter calibration, and more specifically, relates to an auto-calibration process in energy meters.

BACKGROUND
[0002] Energy meters, irrespective of their class, must be calibrated before being sent to the customers. In this process, the gain values, with which the meter may be able to calculate and measure the energy accurately, can be set which, if done incorrectly, could lead to the meter accuracy going out of its desired class range. The conventional meter calibration process is lengthy and consumes a lot of time. Here, the gains are calculated by the master application by taking instantaneous uncalibrated data values from the meters and then the calculated gain values are fed back into the meter. It also requires a master application which monitors the entire process and the entire process is prone to a lot of issues which arise due to communication medium, and improper connection of the meter to the jig.
[0003] Conventionally, the calibration process is done using a master software which collects instantaneous uncalibrated data from the energy meter and then calculates the gains by taking the jig power source as a reference and the gains will then be fed back to the meter through a communication medium. This is a very time-consuming process and comes with a lot of issues which arise due to communication medium, and improper connection of the meter to the jig.
[0004] Therefore, it is desired to overcome the drawbacks, shortcomings, and limitations associated with existing solutions and solves all the above-mentioned issues in the following ways:
• A drastic reduction in the calibration process time without compromising accuracy.
• There is minimal communication required between the master software and the energy meters on the jig as the meter does most of the job which in turn reduces the errors due to the communication medium.
• The energy meters can now check the properness of their connection with the calibration jig which in turn removes the errors due to improper connection thereby making the energy meters more self-capable.
• In the long run, once implemented on a large scale, this invention can save a lot on operational costs.

OBJECTS OF THE PRESENT DISCLOSURE
[0005] An object of the present disclosure relates, in general, to energy meter calibration, and more specifically, relates to an auto-calibration process in an energy meter.
[0006] Another object of the present disclosure is to provide a calibration method that is capable of calculating and setting its gain values for energy measurement.
[0007] Another object of the present disclosure is to provide a calibration method that enables greater efficiency and accuracy in the calibration process.
[0008] Another object of the present disclosure is to provide a calibration method that allows for quicker detection of any flaws or improper connections, leading to improved calibration and accuracy.
[0009] Another object of the present disclosure is to provide a calibration method that is designed to work seamlessly with the current setup at the production center.
[0010] Another object of the present disclosure is to provide a calibration method that can be integrated into the existing infrastructure without major modifications or disruptions.
[0011] Another object of the present disclosure is to provide a calibration method that significantly reduces the overall process time by approximately five times while maintaining high accuracy.
[0012] Yet another object of the present disclosure is to provide a calibration method that is a time-saving benefit that translates into cost savings, especially when implemented on a larger scale.

SUMMARY
[0013] The present disclosure relates in general, to energy meter calibration, and more specifically, relates to the auto-calibration process in energy meters. The main objective of the present disclosure is to overcome the drawback, limitations, and shortcomings of the existing process and solution, by enabling energy meters to achieve efficient self-calibration, resulting in reduced time requirements for the calibration process while ensuring high accuracy. The invention utilizes calibration jigs and incorporates multiple calibration points to facilitate adjustments in the meter's measurements. Additionally, it involves the storage of calibration parameters within the meter for future utilization.
[0014] The present disclosure relates to a method for auto-calibration in energy meters, the method includes placing uncalibrated energy meters onto a calibration jig, sending, by a processor, a command from a master application through a communication medium to initiate the calibration process, performing a jig check process, wherein each meter takes a set of its uncalibrated current readings and compares to identify any improper connection with the jig, flagging any improper connections and returning to normal operation for meters that are not properly connected, awaiting re-initiation of the process by the master application. Further, the method initiates a point-1 calibration for the meters with proper jig connections, enters a point-2 calibration phase when the jigs are set to point-2, enters a point-3 calibration phase, when the jigs are set to point-3, wherein the pre-loaders are calculated and set in the point-2 calibration and point-3 calibration and store all calculated gains and pre-loaders in the memory of the meter for future calculations.
[0015] In an aspect, the point-1 calibration is performed sequentially by calculating and setting voltage gains, current gains, and power gains based on the reference provided by the jig source. The completion of the point-1 calibration, point-2 calibration and point-3 calibration is verified. The verification process in each calibration point includes comparing the calculated gains and pre-loaders with predetermined criteria to determine the successful completion of calibration.
[0016] Further, the memory of the energy meter comprises electrically erasable programmable read-only memory (EEPROM), non-volatile memory (NVM) and any combination thereof. The calibration process is exited and returned into normal operation mode after storing gains and pre-loaders. The calibration process is repeated for multiple meters placed on the calibration jig simultaneously.
[0017] 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
[0018] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0019] FIG. 1 illustrates an exemplary flow chart of the calibration procedure for uncalibrated meters using a calibration jig and a master application, in accordance with an embodiment of the present disclosure.
[0020] FIG. 2 illustrates exemplary functional components of the proposed system, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0021] 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. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0022] 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.
[0023] The present disclosure relates, in general, to energy meter calibration, and more specifically, relates to the auto-calibration process in energy meters. The proposed process disclosed in the present disclosure overcomes the drawbacks, shortcomings, and limitations associated with the conventional process by providing energy meters that possess the capability to autonomously calibrate themselves by comparing the input from a calibration jig source with the meter's data.
[0024] The present disclosure relates to a method for auto-calibration in energy meters, the method includes placing uncalibrated energy meters onto a calibration jig, sending, by a processor, a command from a master application through a communication medium to initiate the calibration process, performing a jig check process, wherein each meter takes a set of its uncalibrated current readings and compares to identify any improper connection with the jig, flagging any improper connections and returning to normal operation for meters that are not properly connected, awaiting reinitiation of the process by the master application. Further, the method initiates a point-1 calibration for the meters with proper jig connections, enters a point-2 calibration phase when the jigs are set to point-2, enters a point-3 calibration phase, when the jigs are set to point-3, wherein the pre-loaders are calculated and set in the point-2 calibration and point-3 calibration and store all calculated gains and pre-loaders in memory of the meter for future calculations. The memory of the energy meter comprises electrically erasable programmable read-only memory (EEPROM), non-volatile memory (NVM) and any combination thereof.
[0025] The point-1 calibration is performed sequentially by calculating and setting voltage gains, current gains, and power gains based on the reference provided by the jig source. The completion of the point-1 calibration, point-2 calibration and point-3 calibration is verified. The verification process in each calibration point includes comparing the calculated gains and pre-loaders with predetermined criteria to determine the successful completion of calibration.
[0026] Further, the calibration process is exited and returned into normal operation mode after storing gains and pre-loaders. The calibration process is repeated for multiple meters placed on the calibration jig simultaneously. The present disclosure can be described in enabling detail in the following examples, which may represent more than one embodiment of the present disclosure.
[0027] The advantages achieved by the process of the present disclosure can be clear from the embodiments provided herein. The calibration method is capable of calculating and setting its own gain values for energy measurement. This enables greater efficiency and accuracy in the calibration process. The process allows for quicker detection of any flaws or improper connections, leading to improved calibration and accuracy. The process is designed to work seamlessly with the current setup at the production center. It can be integrated into the existing infrastructure without major modifications or disruptions. Further, the calibration method significantly reduces the overall process time by approximately five times while maintaining high accuracy. This time-saving benefit translates into cost savings, especially when implemented on a larger scale. The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0028] FIG. 1 illustrates an exemplary flow chart of the calibration procedure for uncalibrated meters using a calibration jig and a master application, in accordance with an embodiment of the present disclosure.
[0029] Referring to FIG. 1, the method 100 outlines the calibration procedure for uncalibrated energy meters using a calibration jig and a master application. The present disclosure presents a method for energy meters to perform self-calibration, reducing the calibration time without compromising accuracy and minimizing the chances of failures caused by connection issues. The energy meter employs a processor having an associated memory for receiving an input of analog voltage, power and current signals and for processing these signals to generate data representative of electrical measurements and related information. The memory is coupled to the processor for storing calibration constants and energy formulas associated with various meter forms.
[0030] The calibration jigs used in production centers are essential for this process, as the invention is designed to work with existing setups. Minor modifications to the master software, the main controlling application, are required to handle the data exchange and commands with the energy meters in the calibration jig. The jigs need to be set at three points, each representing a combination of voltage, current, and power factor levels.
[0031] The invention comes into play during the calibration phase of meter production. Once the meters are placed on the jig and the jig is set to "Point-1," an initialize command initiates the calibration process. The meters then check the quality of their connection with the jig by collecting multiple samples of instantaneous data (uncalibrated data) and comparing them. Once the connection is deemed satisfactory, the self-calibration process begins. The meters gather uncalibrated values for voltage, current (phase and neutral), and power (phase and neutral) and calculate the gains by comparing them with pre-set values in the meter firmware.
[0032] After completing the "point-1 calibration," the meter returns to normal operation until the jig is set to "point-2." Once set, the meters enter "point-2 calibration," where phase correction of the ADC measurement occurs through the setting of a preloader value representing the number of degrees of phase shift. Following "point-2 calibration," the meter resumes normal operation until the jig is set to "Point-3." At this stage, the preloader for higher currents is set, and the calibration process concludes with the meter returning to the normal operation mode. The gains and preloaders calculated during calibration are stored in the meter's permanent memory, such as EEPROM, for future energy calculations.
[0033] Thus, the present disclosure enables energy meters to perform efficient self-calibration, reducing time requirements while maintaining accuracy. It relies on calibration jigs and involves multiple calibration points, allowing meters to adjust their measurements and store calibration parameters for future use.
[0034] As depicted in FIG. 1, Initially, at block 102, the uncalibrated meters are placed onto a calibration jig at the production center and powered on. At block 104, the master application sends a command through a communication medium to initiate the calibration process. At block 106, the "Jig Check" process begins, where each meter takes its own set of uncalibrated current readings. These readings are then compared among themselves to identify any issues or improper connections with the jig.
[0035] At block 108, if the meters are connected properly to the jig after the "Jig Check" process, they proceed to start the "Point-1 Calibration." However, if the connection is deemed improper, the meters take the following actions:
• Flag the connection as improper.
• Return to the normal operation mode (uncalibrated state) and wait for the reinitiation of the process through a command from the master application.
[0036] At block 110, once the meters sense a proper connection with the jig, they commence the "Point-1 Calibration." This calibration step involves comparing and calculating gains by using the jig source as a reference. The meters calculate and set the voltage gains first, followed by current gains and power gains.
[0037] At block `112, after completing the "Point-1 Calibration," a verification is performed to ensure the calibration process is completed correctly. If the verification is successful, the meters return to normal operation mode until the jig is set to "Point-2."
[0038] At block 114, when the jigs are set to "Point-2," the meters enter the "Point-2 Calibration" phase. At block 116, the preloaders (phase shift) are calculated and set. At block 118, the verification is conducted after the "Point-2 Calibration" to ensure the calibration process is successful. If the verification is successful, the meters resume normal operation. However, if the verification fails, the meters go back to the "Point-2 Calibration" step.
[0039] At block 120, if "Point-3 Calibration" is required, the meters enter this calibration phase once the jigs are set to "Point-3 at block 122. If "Point-3 Calibration" is not needed, all the previously calculated gains and preloaders are stored in the meter's permanent memory, such as EEPROM, for future calculations.
[0040] At block, 124 once the meters enter the "Point-3 Calibration," the preloaders (phase shift) are calculated and set. At block 126, after completing the "Point-3 Calibration," a verification is conducted to ensure the calibration process is completed accurately. At block 128, if the verification is successful, the meters store all the previously calculated gains and preloaders in the non-volatile memory (NVM) of the meter for future calculations. However, if the verification fails, the meters return to the "Point-3 Calibration" step.
[0041] At block 130, the calibration process concludes with the storing of gains and preloaders. The meters then enter back into normal operation mode. Overall, this process ensures that uncalibrated meters are calibrated using a calibration jig and appropriate calibration points. Verification steps are performed throughout the process to ensure the accuracy of the calibration, and the calibrated values are stored for future use.
[0042] The conventional calibration process for energy meters involves using master software to collect data from the meter and calculate the gains. These gains are then communicated back to the meter via a communication medium i.e., an optical port. To overcome the above limitation, the present process offers several advantages:
• Self-calculation of gains: The meter is capable of calculating and setting its own gain values for energy measurement. This enables greater efficiency and accuracy in the calibration process.
• Proper connection detection: The meter has the ability to determine the quality of its connection with the calibration jig. This allows for quicker detection of any flaws or improper connections, leading to improved calibration and accuracy.
• Compatibility with the existing setup: The process is designed to work seamlessly with the current setup at the production center. It can be integrated into the existing infrastructure without major modifications or disruptions.
• Reduced process time: The new calibration method significantly reduces the overall process time by approximately five times while maintaining high accuracy. This time-saving benefit translates into cost savings, especially when implemented on a larger scale.
[0043] Thus, the present invention overcomes the drawbacks, shortcomings, and limitations associated with existing solutions, and provides the described process that brings automation and efficiency to the calibration of energy meters, allowing for faster and more accurate calibration while minimizing operational costs.
[0044] FIG. 2 illustrates exemplary functional components 200 of the proposed system in accordance with an embodiment of the present disclosure.
[0045] In an aspect, the system may comprise one or more processor(s) 202. The one or more processor(s) 202 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and/or any devices that manipulate data based on operational instructions. Among other capabilities, the one or more processor(s) 202 are configured to fetch and execute computer-readable instructions stored in a memory 204 of the system. The memory 204 may store one or more computer-readable instructions or routines, which may be fetched and executed to create or share the data units over a network service. The memory 204 may comprise any non-transitory storage device including, for example, volatile memory such as RAM, or non-volatile memory such as EPROM, flash memory, and the like.
[0046] The system may also comprise an interface(s) 206. The interface(s) 206 may comprise a variety of interfaces, for example, interfaces for data input and output devices, referred to as I/O devices, storage devices, and the like. The interface(s) 206 may facilitate communication of system . The interface(s) 206 may also provide a communication pathway for one or more components of the system. Examples of such components include, but are not limited to, processing engine(s) 208 and database 210.
[0047] The processing engine(s) 208 may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the processing engine(s) 208. In examples described herein, such combinations of hardware and programming may be implemented in several different ways. For example, the programming for the processing engine(s) 208 may be processor executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the processing engine(s) 208 may comprise a processing resource (for example, one or more processors), to execute such instructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the processing engine(s) 208. In such examples, the system may comprise the machine-readable storage medium storing the instructions and the processing resource to execute the instructions, or the machine-readable storage medium may be separate but accessible to system and the processing resource. In other examples, the processing engine(s) 208 may be implemented by electronic circuitry.
[0048] The database 210 may comprise data that is either stored or generated as a result of functionalities implemented by any of the components of the processing engine(s) 208 or the system.
[0049] The energy meter can include the processor 202 coupled to the memory 204, the memory 204 storing instructions executable by the processor to send a command from a master application through a communication medium to initiate the calibration process, perform a jig check process, wherein each meter takes a set of its own uncalibrated current readings and compares to identify any improper connection with the jig. The processor can flag any improper connections and returning to normal operation for meters that are not properly connected, awaiting reinitiation of the process by the master application, initiate a point-1 calibration for the meters with proper jig connections, enter a point-2 calibration phase when the jigs are set to point-2, enter a point-3 calibration phase, when the jigs are set to point-3, wherein the pre-loaders are calculated and set in the point-2 calibration and point-3 calibration and store all calculated gains and pre-loaders in the memory of the meter for future calculations.
[0050] It will be apparent to those skilled in the art that the process 100 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT INVENTION
[0051] The present invention provides a calibration method that is capable of calculating and setting its gain values for energy measurement.
[0052] The present invention provides a calibration method that enables greater efficiency and accuracy in the calibration process.
[0053] The present invention provides a calibration method that allows for quicker detection of any flaws or improper connections, leading to improved calibration and accuracy.
[0054] The present invention provides a calibration method that is designed to work seamlessly with the current setup at the production center.
[0055] The present invention provides a calibration method that can be integrated into the existing infrastructure without major modifications or disruptions.
[0056] The present invention provides a calibration method that significantly reduces the overall process time by approximately five times while maintaining high accuracy.
[0057] The present invention provides a calibration method that is a time-saving benefit translates into cost savings, especially when implemented on a larger scale.
, Claims:1. A method (100) for auto-calibration in energy meters, the method comprising:
placing (102) uncalibrated energy meters onto a calibration jig;
sending (104), by a processor, a command from a master application through a communication medium to initiate the calibration process;
performing (106) a jig check process, wherein each meter takes a set of its own uncalibrated current readings and compares to identify any improper connection with the jig;
flagging (108) any improper connections and returning to normal operation for meters that are not properly connected, awaiting reinitiation of the process by the master application;
initiating (112) a point-1 calibration for the meters with proper jig connections;
entering (114) a point-2 calibration phase when the jigs are set to point-2;
entering (122) a point-3 calibration phase, when the jigs are set to point-3, wherein the pre-loaders are calculated and set in the point-2 calibration and point-3 calibration;
storing (128) all calculated gains and pre-loaders in the memory of the meter for future calculations.

2. The method according to claim 1, wherein the point-1 calibration is performed sequentially by calculating and setting voltage gains, current gains, and power gains based on the reference provided by jig source.

3. The method as claimed in claim 1, wherein completion of the point-1 calibration, point-2 calibration and point-3 calibration is verified.
4. The method as claimed in claim 1, wherein the memory of the energy meter comprises electrically erasable programmable read-only memory (EEPROM), non-volatile memory (NVM) and any combination thereof.

5. The method as claimed in claim 1, wherein the verification process in each calibration point includes comparing the calculated gains and pre-loaders with predetermined criteria to determine the successful completion of calibration.

6. The method as claimed in claim 1, wherein the calibration process is exited and returned into normal operation mode after storing gains and pre-loaders.

7. The method as claimed in claim 1, wherein the calibration process is repeated for multiple meters placed on the calibration jig simultaneously.

8. An energy meter (200) for auto-calibration, the energy meter comprising:
a processor (202) coupled to a memory (204), the memory storing instructions executable by the processor to:
send a command from a master application through a communication medium to initiate the calibration process by placing uncalibrated energy meters onto a calibration jig;
perform a jig check process, wherein each meter takes a set of its own uncalibrated current readings and compares to identify any improper connection with the jig;
flag any improper connections and return to normal operation for meters that are not properly connected, awaiting reinitiation of the process by the master application;
initiate a point-1 calibration for the meters with proper jig connections;
enter a point-2 calibration phase when the jigs are set to point-2;
enter a point-3 calibration phase, when the jigs are set to point-3, wherein the pre-loaders are calculated and set in the point-2 calibration and point-3 calibration; and
store all calculated gains and pre-loaders in the memory of the meter for future calculations.