Description:TECHNICAL FIELD
[0001] The embodiments of the present disclosure generally relate to real time clocks and, more particularly, is related to systems/apparatus and methods for calibrating real time clock (RTC) crystal in an electric meter, performed after an ultrasonic welding of meter enclosures, using a pulse output LED.

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] Real Time Clocks (RTC) are essential components of many electrical devices. RTCs utilize crystals for performing timing functions. The crystals oscillate at a predetermined frequency, and a counter is updated by one second after a predetermined number of oscillations. The frequency of oscillations varies with temperature, however, so the precision of the crystals will be affected when environmental conditions change. The quality of the crystals also affects the precision. This means that, in certain situations, the crystals will oscillate faster or slower than expected so the predetermined number of oscillations will not exactly equal one second and the clock timing becomes inaccurate. In these situations, calibration needs to be performed to correct for the timing errors.
[0004] An electronic electric energy meter comprises RTC, measuring control unit (MCU), nonvolatile memory, and communication interface, wherein the RTC clock accuracy plays a crucial role in billing. Because of the existence of the crystal inherent error of RTC in the electric energy meter at present, the output of the RTC device will offset when this error constantly accumulates, causing the RTC to drift significantly over a period.
[0005] Currently, at the last stage of production, the energy meter enclosure is welded using the Ultrasonic welding method, which leads to additional variation in the crystal error, and to address this error, this compensation method is developed to calibrate the crystal after ultrasonic welding.
[0006] Hence, to summarize the technical problems as recited above, there is a need for a simple, efficient and improved systems/apparatus and methods for calibrating real time clock (RTC) crystal in an electric meter, performed after an ultrasonic welding of meter enclosures, using a pulse output LED.

SUMMARY
[0007] This section is provided to introduce certain objects and aspects of the present invention in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0008] In order to overcome at least few problems associated with the known solutions as provided in the previous section, an object of the present disclosure is to provide systems/apparatus and methods for calibrating real time clock (RTC) crystal in an electric meter, performed after an ultrasonic welding of meter enclosures, using a pulse output LED.
[0009] The invention intends to solve the problem of providing a simple, efficient and improved capacitor drop power supply circuits with temperature management mechanism that reduce internal temperature and ultimately helps to increase life of meter.
[0010] Accordingly, an aspect of the present invention discloses a method of RTC Crystal Calibration after Ultrasonic Welding using Pulse LED in Energy Meter. The setup comprises a Photo Detector (receiver), a Frequency counter, a computing device, and a communication interface, which are connected in sequence.
[0011] The RTC Crystal Compensation is done by means of generating the clock signal from the microcontroller through the Pulse LED of the energy meter. The generated pulse is in the range of 32768Hz. The Frequency counter measures the Clock frequency of the signal outputted from the Pulse LED using the Photo Detector.
[0012] The communication interface is connected to the communication interface of the energy meter. The error caused by the initial Parts per Million (PPM) offset error of the crystal and the error created due to Ultrasonic welding of the Energy meter, at 25C is calculated and the corresponding compensation factor is calculated through the computing device.
[0013] The calculated factor is fed to the Energy meter through the communication interface for error compensation. This method can regulate the RTC crystal clock error and thereby solve the problem of the timing accuracy of the RTC in the electric energy meter.
[0014] 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
[0015] The accompanying drawings, which are incorporated herein, and constitute a part of this invention, illustrate exemplary embodiments of the disclosed methods and systems in which like reference numerals refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that invention of such drawings includes the invention of electrical components, electronic components or circuitry commonly used to implement such components.
[0016] FIG. 1 illustrates an apparatus for calibration of a crystal associated with a real time clock (RTC) of an energy meter, in accordance with an embodiment of the present disclosure.
[0017] FIG. 2 illustrates exemplary flowchart according to embodiments of the present disclosure, according to embodiments of the present disclosure.
[0018] The foregoing shall be more apparent from the following more detailed description of the invention.

DETAILED DESCRIPTION
[0019] Various example embodiments will now be described more fully with reference to the accompanying drawings in which only some example embodiments are shown. Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. The present invention, however, may be embodied in many alternate forms and should not be construed as limited to only the example embodiments set forth herein.
[0020] Accordingly, while example embodiments of the invention are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments of the present invention to the particular forms disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the invention. Like numbers refer to like elements throughout the description of the figures.
[0021] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items.
[0022] It will be understood that when an element is referred to as being “connected,” or “coupled,” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” or “directly coupled,” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between,” versus “directly between,” “adjacent,” versus “directly adjacent,” etc.).
[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0024] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0025] Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly.
[0026] Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present invention.
[0027] As recited above, in order to overcome at least few problems associated with the known solutions as provided in the previous section, an object of the present disclosure is to provide systems/apparatus and methods for calibrating real time clock (RTC) crystal in an electric meter, performed after an ultrasonic welding of meter enclosures, using a pulse output LED.
[0028] The invention intends to solve the problem of providing a simple, efficient and improved capacitor drop power supply circuits with temperature management mechanism that reduce internal temperature and ultimately helps to increase life of meter.
[0029] Accordingly, an aspect of the present invention discloses a method of RTC Crystal Calibration after Ultrasonic Welding using Pulse LED in Energy Meter. The setup comprises a Photo Detector (receiver), a Frequency counter, a computing device, and a communication interface, which are connected in sequence.
[0030] The RTC Crystal Compensation is done by means of generating the clock signal from the microcontroller through the Pulse LED of the energy meter. The generated pulse is in the range of 32768Hz. The Frequency counter measures the Clock frequency of the signal outputted from the Pulse LED using the Photo Detector.
[0031] The communication interface is connected to the communication interface of the energy meter. The error caused by the initial Parts per Million (PPM) offset error of the crystal and the error created due to Ultrasonic welding of the Energy meter, at 25C is calculated and the corresponding compensation factor is calculated through the computing device.
[0032] The calculated factor is fed to the Energy meter through the communication interface for error compensation. This method can regulate the RTC crystal clock error and thereby solve the problem of the timing accuracy of the RTC in the electric energy meter.
[0033] FIG. 1 illustrates an apparatus for calibration of a crystal associated with a real time clock (RTC) of an energy meter, in accordance with an embodiment of the present disclosure.
[0034] In an embodiment, an apparatus (100) for calibration of a crystal (204) associated with a real time clock (RTC) (202) of an energy meter (200) is provided. The apparatus includes a microcontroller (102) configured to generate a clock signal through a pulse output (208) of the energy meter, a transceiver (104) configured to detect the generated clock signal, a frequency counter (106) coupled to the transceiver (104) that measures a clock frequency of the generated clock signal based on the detected clock signal, a communication interface (108) connected to the energy meter communication interface (210), and a computing device (110) of the apparatus.
[0035] The computing device (110) retrieves the measured clock frequency, determine a first error caused by an initial part per million (PPM) offset error of the crystal based on the retrieves clock frequency and a second error created due to an ultrasonic welding of the energy meter and obtains a corresponding compensation factor based on the retrieved first error and the second error.
[0036] The obtained corresponding compensation factor is fed to the energy meter through the communication interface for error compensation and for calibrating the crystal associated with the real time clock (RTC), the error compensation is performed by a controller (206) of the energy meter (200).
[0037] In an exemplary embodiment, the pulse output is an optical output indicated through a diode (LED).
[0038] In an exemplary embodiment, the pulse output is an electrical output (called S0).
[0039] In an exemplary embodiment, the generated pulse output is in a range of 32768 Hz.
[0040] In an exemplary embodiment, the transceiver is a receiver.
[0041] In an exemplary embodiment, the transceiver is a photo detector.
[0042] In an exemplary embodiment, the first error and the second error are determined at 25o C.
[0043] In an exemplary embodiment, the pulse output of the energy meter is obtained as an optically encoded signal and is decoded by the frequency counter or the computing device.
[0044] FIG. 2 illustrates exemplary flowchart according to embodiments of the present disclosure, according to embodiments of the present disclosure.
[0045] In an embodiment, the method shows the procedural flow of firmware/software logical activities. It provides sequence of steps for how to verify the drift in clock signal and subsequently how to compensate/adjust the clock to make it precise and correct.
[0046] At step 302, a clock signal through a pulse output of the energy meter is generated by a microcontroller of an apparatus.
[0047] At step 304, the generated clock signal is detected by a transceiver of the apparatus. A clock frequency of the generated clock signal is measured based on the detected clock signal by a frequency counter coupled to the transceiver.
[0048] At step 306, the measured clock frequency is retrieved by a computing device through a communication interface of the apparatus. A first error caused by an initial part per million (PPM) offset error of the crystal based on the retrieves clock frequency and a second error created due to an ultrasonic welding of the energy meter are determined by the computing device. Further, a corresponding compensation factor based on the retrieved first error and the second error is obtained by the computing device.
At step 308, the obtained corresponding compensation factor is fed to the energy meter through the communication interface for error compensation and for calibrating the crystal associated with the real time clock (RTC). The error compensation is performed by a controller of the energy meter at step 310.
[0049] What are described above are merely preferred embodiments of the present invention, and are not to limit the present invention; any modification, equivalent replacement and improvement within the principle of the present invention should be included in the protection scope of the present invention.
[0050] The example embodiment or each example embodiment should not be understood as a restriction of the invention. Rather, numerous variations and modifications are possible in the context of the present disclosure, in particular those variants and combinations which can be inferred by the person skilled in the art with regard to achieving the object for example by combination or modification of individual features or elements or method steps that are described in connection with the general or specific part of the description and are contained in the claims and/or the drawings, and, by way of combinable features, lead to a new subject matter or to new method steps or sequences of method steps, including insofar as they concern production, testing and operating methods.
[0051] References back that are used in dependent claims indicate the further embodiment of the subject matter of the main claim by way of the features of the respective dependent claim; they should not be understood as dispensing with obtaining independent protection of the subject matter for the combinations of features in the referred-back dependent claims. Furthermore, with regard to interpreting the claims, where a feature is concretized in more specific detail in a subordinate claim, it should be assumed that such a restriction is not present in the respective preceding claims.
[0052] Since the subject matter of the dependent claims in relation to the prior art on the priority date may form separate and independent inventions, the applicant reserves the right to make them the subject matter of independent claims or divisional declarations. They may furthermore also contain independent inventions which have a configuration that is independent of the subject matters of the preceding dependent claims.
[0053] Further, elements and/or features of different example embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.
[0054] Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

, Claims:1. An apparatus (100) for calibration of a crystal (204) associated with a real time clock (RTC) (202) of an energy meter (200), the apparatus comprising:
a microcontroller (102) configured to generate a clock signal through a pulse output (208) of the energy meter;
a transceiver (104) configured to detect the generated clock signal;
a frequency counter (106) coupled to the transceiver (104), wherein the frequency counter configured to measure a clock frequency of the generated clock signal based on the detected clock signal;
a communication interface (108) connected to the energy meter communication interface (210) such that a computing device (110):
retrieves the measured clock frequency;
determine a first error caused by an initial part per million (PPM) offset error of the crystal based on the retrieves clock frequency and a second error created due to an ultrasonic welding of the energy meter; and
obtains a corresponding compensation factor based on the retrieved first error and the second error;
wherein the obtained corresponding compensation factor is fed to the energy meter through the communication interface for error compensation and for calibrating the crystal associated with the real time clock (RTC), the error compensation is performed by a controller (206) of the energy meter (200).

2. The apparatus as claimed in claim 1, wherein the pulse output is an optical output indicated through a diode (LED).

3. The apparatus as claimed in claim 1, wherein the pulse output is an electrical output (called S0).

4. The apparatus as claimed in claim 1, wherein the generated pulse output is in a range of 32768 Hz.
5. The apparatus as claimed in claim 1, wherein the transceiver is a receiver.

6. The apparatus as claimed in claim 1, wherein the transceiver is a photo detector.

7. The apparatus as claimed in claim 1, wherein the first error and the second error are determined at 25o C.

8. The apparatus as claimed in claim 1, wherein the pulse output of the energy meter is obtained as an optically encoded signal and is decoded by the frequency counter or the computing device.

9. A method for calibrating a crystal associated with a real time clock (RTC) of an energy meter, the method comprising:
generating (302), by a microcontroller of an apparatus, a clock signal through a pulse output of the energy meter;
detecting (304), by a transceiver of the apparatus, the generated clock signal;
measuring (304), by a frequency counter coupled to the transceiver, a clock frequency of the generated clock signal based on the detected clock signal;
retrieving (306), by a computing device through a communication interface of the apparatus, the measured clock frequency;
determining (306), by the computing device, a first error caused by an initial part per million (PPM) offset error of the crystal based on the retrieves clock frequency and a second error created due to an ultrasonic welding of the energy meter; and
obtaining (306), by the computing device, a corresponding compensation factor based on the retrieved first error and the second error;
wherein the obtained corresponding compensation factor is fed (308) to the energy meter through the communication interface for error compensation and for calibrating the crystal associated with the real time clock (RTC), the error compensation is performed by a controller of the energy meter (310).

10. The method as claimed in claim 9, further includes obtaining the pulse output of the energy meter as an optically encoded signal and decoding the pulse output by the frequency counter or the computing device.