Remote calibration method and system for digital metering system

Abstract

The invention discloses a remote calibration method and system for a digital metering system, and the system comprises a remote self-calibration server platform which is used for transmitting a calibration instruction; the remote self-calibration local client is connected with the calibrated equipment; a calibration result is uploaded to a remote self-calibration server platform; the remote self-calibration local module is used for analyzing the calibration instruction into a self-calibration control flow and controlling the clock self-standardization calibration module and the message dispersion error self-calibration module to complete calibration of the calibrated equipment; the clock error self-calibration module is used for measuring the clock stability and the relative error of the calibrated equipment according to the high-stability clock and correcting the error to complete clock calibration; the message dispersion self-calibration module is used for sending or receiving a sampling value message and measuring the dispersion of the message; and correcting the dispersion error according to the dispersion and the clock stability to complete message dispersion calibration. And remote calibration of the clock error and the message dispersion of the standard metering equipment is realized.

Description

Technical Field

[0001] The present invention relates to the field of power equipment calibration, and particularly to a remote calibration method and system for a digital metering system. Background Art

[0002] In daily quantity transfer work, the standard device can generally be calibrated only by the user submitting it for inspection or through on-site tests by the calibration unit. No matter which mode is used, a large amount of manpower and material resources are consumed. Especially for legal metrology institutions, restricted by the traditional calibration mode, they are often unable to complete the periodic calibration tasks of all metrological standards within their jurisdiction. Submitting for inspection can only be done in a rotating annual calibration manner, and the inspection period of the standard device is relatively long. Moreover, in the traditional calibration mode, during the transportation of the standard device, it is vulnerable to factors such as vibration, rain, temperature, and humidity, resulting in drift of the measured value and even the risk of being damaged.

[0003] Currently, the principle of message dispersion testing for digital metering devices mainly refers to DL / T 281-2012 "Combined Unit Testing Specification" and DL / T 282-2012 "Combined Unit Technical Conditions", and the main test object is the combined unit. Currently, the electronic current transformer calibrators and combined unit testers sold on the market all support message dispersion testing. Most of them control the MAC through a DSP or CPU processor, and the real-time performance of message capture is not high, and they can only measure devices with relatively low accuracy such as combined units. Summary of the Invention

[0004] In order to overcome the deficiencies in the prior art, the present invention provides a remote calibration method and system for a digital metering system. By using a synchronization pulse output synchronized with the message, it realizes the calibration of the message dispersion of the digital metering system, and at the same time realizes the traceability of the message sending time interval of the device itself; by remotely setting the time error and the preset value of the message dispersion, it calibrates the clock error and the message dispersion measurement function of the 0.02-level standard device. The system includes: a clock error self-calibration module, a message dispersion self-calibration module, a remote calibration local module, a remote self-calibration local client, and a remote self-calibration server platform; wherein,

[0005] The remote self-calibration server platform is used to send calibration instructions to the remote self-calibration local client;

[0006] The remote self-calibration local client is connected to the device to be calibrated, and is used to forward the calibration instructions to the remote calibration local module; receive the calibration results uploaded by the remote calibration local module or the device to be calibrated, and upload the calibration results to the remote self-calibration server platform;

[0007] The remote self-calibration local module is respectively connected to the clock error self-calibration module and the message dispersion self-calibration module; the remote self-calibration local module is used to parse the calibration instruction into a self-calibration control process, and control the clock self-normalization module and the message dispersion error self-calibration module to complete the calibration of the device to be calibrated according to the self-calibration control process;

[0008] The clock error self-calibration module is used to output a highly stable clock according to the self-calibration control process; measure the clock stability and relative error of the device to be calibrated based on the highly stable clock, and correct the error to complete the clock calibration;

[0009] The message dispersion self-calibration module is based on the highly stable clock and the self-calibration control process, sends or receives sampled value messages, and measures the dispersion of the messages; corrects the message dispersion error according to the dispersion and the clock stability to complete the message dispersion calibration.

[0010] Furthermore, the message dispersion self-calibration module includes: an FPGA-DSP communication interface, a pulse input / output interface, an Ethernet interface, a clock signal interface, and a power supply module;

[0011] The pulse input / output interface, the Ethernet interface, and the clock signal interface are respectively connected to the FPGA-DSP communication interface;

[0012] The FPGA-DSP communication interface is connected to the remote calibration local module;

[0013] The clock signal interface is connected to a Beidou / GPS receiver;

[0014] The pulse input / output interface performs clock output, clock input, and 4kHz input;

[0015] The Ethernet interface is used for message input and message output.

[0016] Furthermore, the Beidou / GPS receiver outputs a high-precision 1PPS signal to the FPGA-DSP communication interface through the clock signal interface, and the FPGA-DSP communication interface generates a highly stable 100M clock.

[0017] Furthermore, the clock error self-calibration module includes: a remote calibration local time calibration program and an embedded mainboard;

[0018] The remote calibration local time calibration program includes data display, parameter configuration, calibration process control, and test result feedback;

[0019] The embedded mainboard includes two input clock terminals and two output clock terminals;

[0020] The embedded main board is communicatively connected to the remote calibration local module.

[0021] The present invention also provides a remote calibration method for a digital metering system, including:

[0022] Based on the high-precision 1PPS signal output by the satellite positioning system receiver, tame the FPGA digital phase-locked loop to multiply the frequency of the internal high-stability crystal and output a high-stability clock;

[0023] Use the high-stability clock signal to drive the MAC of the packet dispersion self-calibration module to send or receive sampled value packets, and at the same time drive the clock input or clock output;

[0024] When a packet header is sent or received, record the current time stamp and output a packet header synchronization signal at the same time;

[0025] Determine the dispersion of the packet header by measuring the period of the packet header synchronization signal.

[0026] Further, it also includes:

[0027] When there is a clock input or output, measure the transmission delay time of the packet by measuring the hardware time stamps of the second pulse and the packet sampled value header.

[0028] Further, when there is a clock input or output, measure the transmission delay time of the packet by measuring the hardware time stamps of the second pulse and the packet sampled value header, including:

[0029] When there is a clock input or output, record the current time stamp in the way of hardware time stamp;

[0030] Output a packet with adjustable delay time by controlling the delay time of the second pulse and the packet sampled value header;

[0031] Measure the transmission delay time of the packet by measuring the hardware time stamps of the second pulse and the packet sampled value header.

[0032] Further, determining the dispersion of the packet header by measuring the period of the packet header synchronization signal includes:

[0033] Measure the absolute value of the maximum value of the difference between the period of the packet header synchronization signal and the theoretical period of the sampled value packet to determine the dispersion of the packet header.

[0034] Further, the satellite positioning system is a Beidou or GPS positioning system.

[0035] Further, the high-stability clock has the same stability as the satellite positioning system clock. Description of the Drawings

[0036] Figure 1 It is the overall structure diagram of the remote calibration system for the digital metering system provided by the embodiment of the present invention;

[0037] Figure 2 It is the overall scheme diagram of clock calibration involved in the embodiment of the present invention;

[0038] Figure 3 It is the overall scheme block diagram of the message dispersion self-calibration of the digital metering system involved in the embodiment of the present invention;

[0039] Figure 4 It is the remote control schematic diagram of the remote calibration system of the digital metering system involved in the embodiment of the present invention;

[0040] Figure 5 It is a remote calibration method for a digital metering system provided by the embodiment of the present invention. Specific embodiments

[0041] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0042] As Figure 1 shown, the present invention provides a remote calibration method and system for a digital metering system, including: a clock error self-calibration module, a message dispersion self-calibration module, a remote calibration local module, a remote self-calibration local client, and a remote self-calibration server platform; wherein,

[0043] The remote self-calibration server platform is used to send calibration instructions to the remote self-calibration local client;

[0044] The remote self-calibration local client is connected to the device to be calibrated and is used to forward the calibration instructions to the remote calibration local module; receive the calibration results uploaded by the remote calibration local module or the device to be calibrated, and upload the calibration results to the remote self-calibration server platform;

[0045] The remote self-calibration local module is respectively connected to the clock error self-calibration module and the message dispersion self-calibration module; the remote self-calibration local module is used to parse the calibration instructions into a self-calibration control process, and control the clock self-standardization module and the message dispersion error self-calibration module to complete the calibration of the device to be calibrated according to the self-calibration control process;

[0046] The clock error self-calibration module is used to output a highly stable clock according to the self-calibration control process; measure the clock stability and relative error of the device to be calibrated according to the highly stable clock, and correct the error to complete the clock calibration;

[0047] The message dispersion self - calibration module, based on the high - stability clock and the self - calibration control process, sends or receives sampled - value messages and measures the dispersion of the messages; corrects the message dispersion error according to the dispersion and the clock stability to complete the message dispersion calibration.

[0048] In practical applications, the remote self - calibration server platform can be installed at the upper - level management terminal, the remote self - calibration local client and the remote calibration local module can be installed at the provincial detection centers, the remote self - calibration local client is connected to the device to be calibrated, and the remote calibration local module is respectively connected to the clock error self - calibration module and the message dispersion error self - calibration module.

[0049] Specifically, as Figure 2 shown, the clock error self - calibration module includes: a remote calibration local time - calibration program and an embedded mainboard; the remote calibration local time - calibration program includes data display, parameter configuration, calibration process control, and test result feedback; the embedded mainboard uses the high - precision 1PPS signal output by the Beidou / GPS receiver to tame the high - stability crystal inside the digital phase - locked loop for frequency multiplication and outputs a 100M high - precision clock, whose accuracy is consistent with the Beidou clock. It uses this clock signal to realize the transceiver of the external clock signal, the high - precision phase - shift output of the clock, and the high - precision measurement of the external clock phase. The measurement uncertainty of the clock error self - calibration module is better than 100ns; the embedded mainboard includes two input clock terminals and two output clock terminals; the embedded mainboard is communicatively connected to the remote calibration local module. The input interface of the clock error self - calibration module needs to be compatible with the requirements of 5 test modules, and each test mode will not be used simultaneously. Therefore, when designing the device, it is considered to reuse the input and output interfaces to reduce the number of input and output terminals. After adjustment, the input and output terminals can be optimized into two input clock terminals and two clock output terminals, which can be compatible with all calibration test requirements.

[0050] The embedded mainboard hardware solution is designed with the BF609 core board. Its core is a high-performance DSP processor, Blakefin, based on Analog Devices, Inc. The BF609 of Analog Devices' dual-core processor is a symmetric dual-core high-performance Blakefin processor, with a maximum operating frequency of 500Mhz per core. Each core has a built-in 148KB L1 SRAM memory with multi-parity protection function, and a 256KB L2 SRAM memory with ECC protection function. The dynamic memory controller provides a 16-bit interface and can be connected to a single set of DDR2 or LPDDR DRAM devices. It has 3 SPORT ports, 2 UART ports, 2 EMMC interfaces, 2 EMACs supporting IEEE1588, 2 SPIs, 2 TWIs, and 1 USB2.0 HS OTG. The clock circuit of the digital metering system time error self-calibration module mainly includes a CPU clock circuit with a highly stable temperature-controlled crystal oscillator, a satellite timing circuit based on Beidou / GPS, multiple external pulse input / output circuits and processing circuits. Through corresponding algorithms, functions such as measurement and verification of each clock are completed.

[0051] The message dispersion self-calibration module includes: an FPGA-DSP communication interface, a pulse input / output interface, an Ethernet interface, a clock signal interface, and a power supply module; the pulse input / output interface, the Ethernet interface, and the clock signal interface are respectively connected to the FPGA-DSP communication interface; the FPGA-DSP communication interface is connected to the remote calibration local module; the clock signal interface is connected to the Beidou / GPS receiver; the pulse input / output interface performs clock output, clock input, and 4kHz input; the Ethernet interface is used for message input and message output.

[0052] The Beidou / GPS receiver outputs a high-precision 1PPS signal to the FPGA-DSP communication interface through the clock signal interface, and the FPGA-DSP communication interface generates a highly stable 100M clock.

[0053] Based on the same inventive concept, the present invention also provides a remote calibration method for a digital metering system, as Figure 5 shown, including:

[0054] Step S501: Based on the high-precision 1PPS signal output by the satellite positioning system receiver, tame the FPGA digital phase-locked loop to multiply the frequency of the internal highly stable crystal and output a highly stable clock;

[0055] Step S502: Use the highly stable clock signal to drive the MAC of the device to be calibrated to send or receive sampled value messages, and at the same time drive clock input or clock output;

[0056] Step S503: When a message header is sent or received, record the current time stamp and output a message header synchronization signal simultaneously.

[0057] Step S504: Determine the dispersion of the message header by measuring the period of the message header synchronization signal.

[0058] Furthermore, it also includes: When there is clock input or output, measure the transmission delay time of the message by measuring the hardware time stamps of the second pulse and the message sample value header.

[0059] When there is clock input or output, measure the transmission delay time of the message by measuring the hardware time stamps of the second pulse and the message sample value header, including: When there is clock input or output, record the current time stamp in the hardware time stamp manner; output a message with adjustable delay time by controlling the delay times of the second pulse and the message sample value header; measure the transmission delay time of the message by measuring the hardware time stamps of the second pulse and the message sample value header.

[0060] Determine the dispersion of the message header by measuring the period of the message header synchronization signal, including: Measuring the absolute value of the maximum difference between the period of the message header synchronization signal and the theoretical period of the sampled value message to determine the dispersion of the message header.

[0061] The satellite positioning system is a Beidou or GPS positioning system.

[0062] A high-stability clock, whose stability is consistent with the satellite positioning system clock.

[0063] When self-calibration is required, the remote self-calibration server platform actively initiates a self-calibration instruction, which is sent to the remote self-calibration local client in the corresponding province through the network. After receiving the instruction, the remote self-calibration local client parses the instruction and then sends it to the remote calibration local module. After receiving the self-calibration instruction, the remote calibration local module parses the protocol into a self-calibration control process, and at the same time sends a serial port data frame to control the clock error self-calibration module or the message dispersion error self-calibration module to perform self-calibration; when the test is completed, the measurement results are centrally uploaded to the remote self-calibration local client through the remote calibration local module or the device to be calibrated, and finally uploaded to the remote self-calibration server platform through the remote self-calibration local client. The remote self-calibration server platform uniformly stores, manages, and traces the self-calibration data, and can remotely configure self-calibration parameters, such as message dispersion value setting, clock offset value setting, transmission delay time setting, etc., to achieve interoperability with the remote self-calibration local client.

[0064] To implement the functions of certificate reading, information management, and storage management, the remote self-calibration local client periodically and automatically reads the nameplate parameters and calibration certificate information of the standard device, saves them locally, and waits for the reading instruction from the remote self-calibration server platform. When the remote self-calibration local client receives the reading instruction, it uploads the information.

[0065] As Figure 3 shown, the clock remote calibration system of the digital metering system includes an FPGA-DSP communication interface, a pulse input / output interface interconnected with the FPGA-DSP communication interface, an Ethernet interface interconnected with the FPGA-DSP communication interface, a clock signal interface connected to the FPGA-DSP communication interface, and a power supply module; the clock signal interface is connected to a Beidou / GPS receiver, and there is a communication connection between the FPGA-DSP communication interface and the remote calibration local module. Message input and message output are performed through the Ethernet interface, and clock output, clock input, and 4kHz input are performed through the pulse input / output interface.

[0066] Using the high-precision 1PPS signal output by the Beidou / GPS receiver, the FPGA digital phase-locked loop is tamed to multiply the frequency of the internal high-stability crystal, and a high-stability clock of 100M is output, with the stability consistent with the Beidou clock; the relative error of the high-stability clock is 1.1×10 -7 , the setting range of the dispersion of the message header is -250μs to 250μs, the measurement uncertainty is 1μs, and the relative error is 1μs / 500μs = 2×10 -3 , the stability of the high-stability clock is much higher than the measurement relative error, meeting the test requirements; using the above high-stability clock signal to drive the MAC to send or receive sampled value messages, and at the same time drive clock input or clock output; when sending or receiving an SV message header, record the current time stamp in the hardware time stamp mode, and at the same time output a message header synchronization signal; measure the period of the above message header synchronization signal, and the absolute value of the maximum difference from the theoretical period of the sampled value message, that is, the dispersion of the message header, and connect for testing for 10 minutes; when there is clock input or output, record the current time stamp in the hardware time stamp mode, and by controlling the second pulse and the delay time of the message sampled value header, that is, output a message with adjustable output delay time; similarly, by measuring the hardware time stamps of the second pulse and the message sampled value header, that is, measuring the transmission delay time of the message.

[0067] To better be compatible with the devices of provincial metrology centers, the message dispersion self-calibration device of the digital metering system should include the following five functions:

[0068] (1) The device outputs sampled value messages to the device under test according to the set dispersion parameters to calibrate the message dispersion test function of the device under test.

[0069] (2) The device receives the sampled value message of the device under test and measures the dispersion of the message in real time to calibrate the message transmission dispersion of the device under test;

[0070] (3) The device outputs a synchronous clock and a sampled value message according to the set message transmission delay time parameter to calibrate the message transmission delay time test function of the device under test;

[0071] (4) The device outputs a synchronous clock and a sampled value message according to the set message transmission delay time parameter to calibrate the message transmission delay time test function of the device under test;

[0072] (5) The device receives the sampled value message and the message header synchronization signal of the device under test to calibrate the message time stamp accuracy of the device under test.

[0073] Furthermore, the FPGA uses the ProASIC3 device A3P1000 of Actel Corporation. It is based on a flash architecture and supports the implementation of a soft ARM7 processor. It has 1 million system gates, 24,576 logic resources, 1 PLL, 32 ARM blocks of 4068 bits, 144 kbits of dual-port SRAM, 300 user I / Os and many other resources, with a maximum system main frequency of 350 MHz. In this embodiment, the main frequency of A3P1000 is designed to be 120M, which respectively controls the pulse signal and the control of the digital input / output signals, and uses a high-speed parallel bus to interact with the DSP. The DSP selects the high-performance DSP processor BF609 of the Blakefin processor of ADI Corporation. The FPGA is mainly used to process tasks with extremely high real-time requirements such as optical Ethernet, message sending with dispersion changes, message header time stamp and synchronous pulse output, and synchronous clock processing. BF609 is mainly used to process tasks with relatively low real-time requirements, such as data display, parameter configuration, calibration process control and communication tasks.

[0074] As Figure 4 shown, after the remote self-calibration server platform issues a calibration command, it is remotely transmitted through the network to the remote self-calibration local client for data processing, and the calibration instruction is sent to the remote calibration local module. The remote calibration local module parses the calibration fingerprint into a calibration process, and controls the clock error self-calibration module and the message dispersion error self-calibration module to complete the calibration of the device under test step by step according to the process instructions. The calibration results are centralized to the remote self-calibration local client, and after all tests are completed, the final all calibration results are uploaded to the remote self-calibration server platform as required. Structurally, the remote calibration local module can be integrated with the clock error self-calibration module and the message dispersion error self-calibration module according to actual needs; or the remote calibration local module can be integrated with the remote self-calibration local client.

[0075] Clock error calibration:

[0076] The electronic current transformer detection platform is used to detect the time synchronization error performance of the merging unit. In this test, the clock error remote calibration device simulates the time synchronization function of the merging unit to connect with the electronic current transformer detection platform. The electronic current transformer detection platform outputs a standard 1PPS optical second pulse signal and sends it to the clock error remote calibration device. The clock error remote calibration device generates an optical second pulse signal with an adjustable delay time according to the rising edge of the 1PPS optical second pulse signal, and this pulse signal is fed back to the electronic current transformer detection platform. The electronic current transformer detection platform compares the phase difference between the two signals to complete the calibration of the time synchronization error. By setting the test mode of the time error remote calibration device on the remote server, a pulse signal with a delay time of 0 is output.

[0077] The delay times of the time error remote calibration device are preset to 0 μs, 1 μs, and 5 μs respectively, and the test results of the electronic current transformer detection platform are shown in Table 1.

[0078] Table 1: Time synchronization error test data

[0079] Remote calibration device preset value (μs) Measured value of the detection platform (μs) Error (μs) Variation (μs) 0 0.130 0.130 0.050 1 1.155 0.155 0.025 5 5.180 0.180 0.050

[0080] It can be seen from Table 1 that all test results do not exceed 0.3 μs, and the electronic current transformer detection platform passes the test. At the same time, it can be seen from the variation difference of the data that the maximum variation is 0.05 μs, which can directly show that the jitter of the time synchronization signal output by the clock error remote calibration device is very small, meeting the expected goal.

[0081] When the delay time is 0 μs, the time synchronization error is 0.13 μs. This error comes from the lack of delay time compensation for the externally connected optical fiber loop. Perform the transceiver loop delay time test, and then deduct this delay time from the test results to make the final test results closer to the true value. Since the electronic current transformer detection platform is a 0.05-level standard device, the requirement for the measurement uncertainty of the time synchronization error is not less than 0.3 μs, and the requirement is relatively low. The delay time of the optical fiber loop can be ignored. However, for standard devices of 0.02 level and above, the delay time test of the optical fiber loop must be carried out first, and then the standard test.

[0082] Message dispersion calibration:

[0083] The electronic transformer detection platform is used to detect the message dispersion performance of the merged unit output. In this test, the clock error remote calibration device simulates the SV message output by the merged unit, and the electronic transformer detection platform measures the dispersion of this SV message. By setting the test mode and parameters of the clock error remote calibration device on the remote server, SV messages with dispersions of 0 μs, 5 μs, and 10 μs are output respectively.

[0084] The maximum error between the maximum value of all test results and the preset value is 0.125 μs, which is much smaller than the required 3 μs, and the electronic transformer detection platform passes the detection. At the same time, it can be seen from the variation value of the data that the maximum variation is 0.125 μs, which can directly indicate that the jitter of the SV message output by the time error remote calibration device is very small and meets the expected goal.

[0085] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the processes or multiple processes and / or blocks Figure 1 one or more of the blocks or multiple blocks.

[0087] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in Figure 1 one or more of the processes or multiple processes and / or blocks Figure 1 one or more of the blocks or multiple blocks.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are executed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the process Figure 1 in one process or multiple processes and / or blocks Figure 1 steps for the functions specified in one block or multiple blocks.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that modifications or equivalent replacements can still be made to the specific embodiments of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A remote calibration system for a digital metering system, characterized in that Comprising: A clock error self - calibration module, a message dispersion self - calibration module, a remote calibration local module, a remote self - calibration local client, and a remote self - calibration server platform; wherein, The remote self - calibration server platform is used to send calibration instructions to the remote self - calibration local client; The remote self - calibration local client is connected to the device to be calibrated and is used to forward the calibration instructions to the remote calibration local module; receive the calibration results uploaded by the remote calibration local module or the device to be calibrated, and upload the calibration results to the remote self - calibration server platform; The remote calibration local module is respectively connected to the clock error self - calibration module and the message dispersion self - calibration module; the remote calibration local module is used to parse the calibration instructions into a self - calibration control process, and control the clock self - calibration module and the message dispersion error self - calibration module to complete the calibration of the device to be calibrated according to the self - calibration control process; The clock error self - calibration module is used to output a high - stability clock according to the self - calibration control process; measure the clock stability and relative error of the device to be calibrated based on the high - stability clock, and correct the error to complete clock calibration; The message dispersion self - calibration module is based on the high - stability clock and the self - calibration control process, sends or receives sampled - value messages, and measures the dispersion of the messages; corrects the message dispersion error according to the dispersion and clock stability to complete message dispersion calibration.

2. The system according to claim 1, wherein The message dispersion self - calibration module includes: an FPGA - DSP communication interface, a pulse input / output interface, an Ethernet interface, a clock signal interface, and a power supply module; The pulse input / output interface, the Ethernet interface, and the clock signal interface are respectively connected to the FPGA - DSP communication interface; The FPGA - DSP communication interface is connected to the remote calibration local module; The clock signal interface is connected to a Beidou / GPS receiver; The pulse input / output interface performs clock output, clock input, and 4kHz input; The Ethernet interface is used for message input and message output.

3. The system according to claim 2, characterized in that, The Beidou / GPS receiver outputs a high - precision 1PPS signal to the FPGA - DSP communication interface through the clock signal interface, and the FPGA - DSP communication interface generates a 100M high - stability clock.

4. The system according to claim 1, characterized in that, The clock error self - calibration module includes: a remote calibration local time calibration program and an embedded main board; The remote calibration local time calibration program includes data display, parameter configuration, calibration process control, and test result feedback; The embedded main board includes two input clock terminals and two output clock terminals; The embedded main board is communicatively connected to the remote calibration local module.

5. A remote calibration method for a digital metering system, characterized in that, Comprising: Based on the high - precision 1PPS signal output by the satellite positioning system receiver, taming the FPGA digital phase - locked loop to multiply the frequency of the internal high - stability crystal and output a high - stability clock; Using the high - stability clock signal to drive the MAC of the device to be calibrated to send or receive sampled - value messages, and at the same time drive clock input or clock output; When a message header is sent or received, record the current time stamp and output a message - header synchronization signal at the same time; Determine the dispersion of the message header by measuring the period of the message header synchronization signal.

6. The method according to claim 5, characterized in that, It further includes: When there is clock input or output, measure the transmission delay time of the message by measuring the second pulse and the hardware time stamp of the message sample value header.

7. The method according to claim 6, characterized in that, When there is clock input or output, measure the transmission delay time of the message by measuring the second pulse and the hardware time stamp of the message sample value header, including: When there is clock input or output, record the current time stamp in the form of hardware time stamp. Output a message with adjustable delay time by controlling the delay time of the second pulse and the message sample value header. Measure the transmission delay time of the message by measuring the second pulse and the hardware time stamp of the message sample value header.

8. The method according to claim 5, characterized in that, Determine the dispersion of the message header by measuring the period of the message header synchronization signal, including: Measure the absolute value of the maximum difference between the period of the message header synchronization signal and the theoretical period of the sampled value message to determine the dispersion of the message header.

9. The method according to claim 5, wherein The satellite positioning system is a Beidou or GPS positioning system.

10. The method according to claim 5, characterized in that A highly stable clock, whose stability is consistent with the satellite positioning system clock.

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