System and method for measuring response time of universal electric energy measuring equipment

Abstract

The invention provides a system and method for measuring response time of universal electric energy measuring equipment, and the system comprises an electric energy measuring device which is used for measuring current and is provided with an RS485 communication interface; the PC is connected with the electric energy measuring device through an RS485 communication bus and is used for sending a test command and receiving a test result; the first oscilloscope probe is connected with the RS485 communication bus in parallel and is used for monitoring a communication message on the communication bus; the primary frequency modulation signal source is connected with the electric energy measuring device and the PC and is used for generating a current jump signal; the CT sensor is connected in series on the single-phase power line between the signal source and the electric energy measuring device, consists of a signal loop consisting of a current transformer and a sampling resistor R, and is used for sensing current change and generating a corresponding voltage signal; and the second oscilloscope probe is connected with the CT sensor in parallel and is used for measuring the voltage change at the two ends of the sampling resistor R. The reliability and the accuracy of performance evaluation of the electric energy measuring equipment can be improved.

Description

Technical Field

[0001] The present invention relates to the field of performance testing of power measurement devices. More specifically, the present invention relates to a measurement system and method for the response time of a general-purpose power measurement device. Background Art

[0002] In the application of power measurement devices, accurately measuring the response time of the devices is very important. The response time refers to the time interval from when the device receives a signal to when it outputs a result. For power measurement devices, the length of the response time directly affects the accuracy of the measurement result and the real-time performance of the device. Existing methods for measuring the response time of power measurement devices usually rely on simple timing analysis or estimate the response time by manually observing the output changes of the device. These methods have certain limitations, such as low measurement accuracy and difficulty in real-time monitoring of the device's response. In addition, traditional measurement methods often require complex equipment and complex operation processes, increasing the difficulty and cost of measurement.

[0003] In the process of implementing the embodiments of the present invention, the inventors found that there are at least the following problems or defects in the prior art: insufficient measurement accuracy, difficult to meet the requirements of high-precision measurement; complex measurement process and inconvenient operation; inability to real-time monitor the response of the device, resulting in low reliability of the measurement result. Summary of the Invention

[0004] The present invention provides a measurement system and method for the response time of a general-purpose power measurement device.

[0005] In a first aspect of the present invention, a measurement system for the response time of a general-purpose power measurement device is provided, including:

[0006] A power measurement device for measuring current and having an RS485 communication interface;

[0007] A PC connected to the power measurement device through an RS485 communication bus, for sending test commands and receiving test results;

[0008] A first oscilloscope probe connected in parallel with the RS485 communication bus, for monitoring communication messages on the communication bus;

[0009] A primary frequency modulation signal source connected to the power measurement device and the PC, for generating a current jump signal;

[0010] A CT sensor connected in series on the single-phase power line between the signal source and the power measurement device, composed of a signal loop formed by a current transformer and a sampling resistor R, for sensing current changes and generating corresponding voltage signals;

[0011] A second oscilloscope probe, connected in parallel with the CT sensor, is used to measure the voltage change across the sampling resistor R.

[0012] Further, the ground clip of the first oscilloscope probe is connected to the ground wire of the RS485 communication bus, and the probe measurement end is connected to the A wire of the RS485 communication bus.

[0013] Further, the sampling resistor R is the recommended resistor of the current transformer, and this resistor is connected in parallel on the two output pins of the current transformer.

[0014] Further, the ground clip of the second oscilloscope probe is connected to one output pin of the current transformer, and the probe measurement end is connected to the other output pin.

[0015] Further, the primary frequency modulation signal source device has a single-phase current setting function, a timing multi-state switching function, and a communication control function.

[0016] Further, the PC uses an operating system above Windows7, installs serial port debugging software that can set the continuous transmission time and the number of transmissions, and the supporting control software of the primary frequency modulation signal source.

[0017] Further, the power measurement device has a current measurement function and has an RS485 communication interface, and can send the test results through communication.

[0018] Further, the current transformer of the CT sensor has a rated current of 5A and a turns ratio of 2000:1, and the sampling resistor R is 50Ω.

[0019] Further, both the first oscilloscope probe and the second oscilloscope probe have a bandwidth of at least 50MHz.

[0020] In the second aspect of the present invention, a method for measuring the response time of a general power measurement device is provided, including:

[0021] Set the response time of the power measurement device to the preset response time, with a default value of one hundred milliseconds, and the current range to the preset current range;

[0022] Set the primary frequency modulation signal source to the current source mode, and the current changes from 10% to 50% of the preset current range, and the state interval is set to fifty times the preset response time;

[0023] Install the CT sensor and calculate the voltage across the sampling resistor R;

[0024] Adjust the oscilloscope time resolution to half of the preset response time, use the first oscilloscope probe to monitor the communication message on the RS485 communication bus, and record the sending and receiving time points of the message.

[0025] Set the oscilloscope channel 2 to the level trigger mode, and set the trigger level value to 25% of the product of the preset current range and R;

[0026] After the PC subtracts 45 times the preset response time from the delay state interval of the serial port debugging software, it communicates with the device under test 20 times at an interval of half of the preset response time, queries the measured power value, and simultaneously sends a test start command to the primary frequency modulation signal source;

[0027] The oscilloscope is triggered at the moment of the level jump, records the waveforms before and after the current jump, and at least twelve transmitted and replied messages;

[0028] Analyze the content of the messages recorded by the PC serial port software to determine the message N that can correctly reflect the measured power value;

[0029] Identify the signal jump point of channel 1, the end moment of message N of channel 2, and the start time of the PC query message on the oscilloscope;

[0030] Calculate the measurement response time as the difference between the signal jump point and the end moment of message N, the communication response time as the difference between the end moment of message N and the start time of the PC query message, and determine the possible range of the response time as the minimum time to the maximum time, where the minimum time is the measurement response time minus half of the preset response time, and the maximum time is the measurement response time;

[0031] Use the bisection method to approximate and adjust the test time to the average of the maximum time and the minimum time;

[0032] Stop the iteration when the difference between the maximum time and the minimum time is less than or equal to 2 milliseconds;

[0033] Conduct ten tests with the minimum time, the minimum time plus 1 millisecond, and the maximum time as the response time respectively, and take the average of the ten test results as the final response time.

[0034] The above embodiments of the present invention have at least the following beneficial effects: By using an oscilloscope probe to monitor communication messages and current changes, the measurement system can achieve high-precision measurement of the response time of the power measurement device. The high bandwidth and precise time resolution of the oscilloscope probe enable accurate capture of the signal jump point and the sending and receiving time points of communication messages, providing a reliable data basis for calculating the response time. In addition, the system adopts the bisection method approximation test method, which can effectively narrow the measurement range of the response time, improve the measurement accuracy and reliability, and make the final response time measurement result more reliable.

[0035] The system also has good practicability and convenient operation. Through the serial port debugging software on the PC and the supporting control software of the primary frequency modulation signal source, the test parameters can be easily set and the test process can be controlled, reducing manual intervention and the complexity of operation. At the same time, the design of the system takes into account the compatibility and universality of the equipment, is applicable to the response time measurement of various power measurement devices, and has broad application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] By referring to the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present invention will become readily understood. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, wherein:

[0037] Figure 1 is a schematic structural diagram of a measurement system for the response time of a general-purpose power measurement device provided by an embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of a CT sensor provided by an embodiment of the present invention;

[0039] Figure 3 is a time parameter definition diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The principles and spirit of the present invention will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are provided only to enable those skilled in the art to better understand and implement the present invention, and do not limit the scope of the present invention in any way. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to be able to fully convey the scope of the present invention to those skilled in the art.

[0041] Those skilled in the art know that the embodiments of the present invention can be implemented as a system, apparatus, device, method, or computer program product. Therefore, the present invention can be specifically implemented in the following forms: completely hardware, completely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software.

[0042] It should be noted that any number of elements in the drawings is for illustration rather than limitation, and any naming is only for distinction and does not have any limiting meaning.

[0043] The following refers to Figure 1 , Figure 1 is a schematic structural diagram of a measurement system for the response time of a general-purpose power measurement device provided by an embodiment of the present invention. As Figure 1 shown, a measurement system for the response time of a general-purpose power measurement device includes:

[0044] An electric energy measurement device, which is used to measure current and has an RS485 communication interface;

[0045] A PC, which is connected to the electric energy measurement device through an RS485 communication bus, and is used to send test commands and receive test results;

[0046] A first oscilloscope probe, which is connected in parallel with the RS485 communication bus, and is used to monitor the communication messages on the communication bus;

[0047] A primary frequency modulation signal source, which is connected to the electric energy measurement device and the PC, and is used to generate a current jump signal;

[0048] A CT sensor, which is connected in series on a single-phase power line between the signal source and the electric energy measurement device, and is composed of a signal loop formed by a current transformer and a sampling resistor R, and is used to sense current changes and generate corresponding voltage signals;

[0049] A second oscilloscope probe, which is connected in parallel with the CT sensor, and is used to measure the voltage change across the sampling resistor R.

[0050] It should be noted that the measurement system for the response time of the electric energy measurement device mainly includes the measured electric energy measurement device, PC, oscilloscope probe, primary frequency modulation signal source and CT sensor. The electric energy measurement device is a device for measuring current and usually has an RS485 communication interface for data exchange with the PC. The PC is connected to the electric energy measurement device through a communication bus and is used to send test commands and receive test results. The oscilloscope probe is used to monitor the communication messages on the communication bus, the primary frequency modulation signal source is used to generate a current jump signal, and the CT sensor is used to sense current changes and generate corresponding voltage signals. These components work together to enable accurate measurement of the response time of the electric energy measurement device.

[0051] Specifically, the electric energy measurement device can be an electric energy meter or other electric energy measurement equipment with current measurement function, and its RS485 communication interface is used for data communication with the PC. The PC can be a computer running an operating system above Windows 7, installed with serial port debugging software and supporting control software for the primary frequency modulation signal source, so as to facilitate setting test parameters and controlling the test process. The ground wire clip of the oscilloscope probe is connected to the ground wire of the communication bus, and the probe measurement end is connected to the A wire of the bus. The primary frequency modulation signal source has functions of single-phase current setting, timed multi-state switching, and communication control, and can flexibly set the amplitude and time interval of current jump. The CT sensor consists of a signal loop composed of a current transformer and a sampling resistor R. The current transformer is used to convert large current into small current for easy measurement and control, and the sampling resistor R is used to sense current changes and generate corresponding voltage signals. The oscilloscope probe is connected in parallel with the CT sensor and is used to measure the voltage change across the sampling resistor R.

[0052] Preferably, in order to improve the measurement accuracy and reliability, some parameters can be optimized during the measurement process. For example, the time resolution of the oscilloscope can be adjusted to half of the preset response time to more accurately capture the signal jump points and the sending and receiving time points of communication messages.

[0053] Furthermore, the current jump amplitude of the primary frequency modulation signal source can vary from 10% to 50% of the preset current range, and the state interval is set to 50 times the preset response time to ensure the stability and repeatability of the current jump signal. When installing the CT sensor, it should be ensured that the connection between it and the signal source and the electric energy measurement device is firm and reliable to avoid interference and errors during signal transmission. At the same time, an oscilloscope probe with a higher bandwidth can be used to meet the requirements of higher-precision measurement.

[0054] In some embodiments, the ground wire clip of the first oscilloscope probe is connected to the ground wire of the RS485 communication bus, and the probe measurement end is connected to the A wire of the RS485 communication bus.

[0055] It should be noted that the communication bus in this measurement system uses the RS485 communication bus. RS485 is a communication interface standard for differential signal transmission, widely used in industrial control systems, and has characteristics such as strong anti-interference ability, long transmission distance, and multi-device communication. In this system, the RS485 communication bus is used to connect the electric energy measurement device and the PC to ensure the reliable transmission of test commands and measurement results. Through the RS485 communication bus, the PC can send test commands to the electric energy measurement device and receive its measurement results, thereby realizing the measurement of the device response time.

[0056] Specifically, the connection of the RS485 communication bus needs to follow its standard specifications. The A and B lines of the RS485 interfaces of the power measurement device and the PC need to be correctly connected correspondingly. The A line is the positive signal line, and the B line is the negative signal line. Through differential signal transmission, the anti-interference ability of the signal can be improved. In addition, the communication rate of the RS485 communication bus can be set according to actual needs, usually selected between 9600 baud rate and 115200 baud rate to meet the communication requirements of different devices. In the system, the use of the RS485 communication bus needs to ensure the stability and reliability of the signal to guarantee the accuracy of the test data.

[0057] Preferably, in order to further improve the stability and reliability of communication, a terminating resistor can be added to the RS485 communication bus. The terminating resistor is usually set at both ends of the communication bus, and its resistance value is generally 120Ω, which matches the characteristic impedance of the RS485 communication interface, and can effectively reduce signal reflection and avoid signal distortion.

[0058] Furthermore, a shielding layer can also be added to the communication bus to further improve the anti-interference ability. In actual applications, the appropriate communication rate and transmission distance can also be selected according to the specific requirements of the device and environmental conditions to ensure the normal operation of the system and the accuracy of measurement.

[0059] In some embodiments, the sampling resistor R is the recommended resistor of the current transformer, and this resistor is connected in parallel on the two output pins of the current transformer.

[0060] It should be noted that the ground clip of the first oscilloscope probe is connected to the ground wire of the 485 bus. If there is no ground wire, it is connected to the B line, and the probe measurement end is connected to the A line of the bus. The oscilloscope probe is a device used to measure voltage signals and can convert electrical signals into visual waveforms. In RS485 communication, the A and B lines are differential signal lines, and the ground wire is used to provide a reference point for the signal. By connecting the ground clip of the oscilloscope probe to the ground wire or the B line, the accurate measurement of the signal and the clear display of the waveform can be ensured, thus facilitating the monitoring of the communication messages on the communication bus.

[0061] Specifically, the connection method of the first oscilloscope probe needs to be set according to the specific configuration of the RS485 communication bus. When connecting, connect the ground clip of the oscilloscope probe to the ground wire of the 485 bus to provide a reference point for the signal. If the 485 bus has no ground wire, the ground clip can be connected to the B line to ensure the integrity of the signal. The probe measurement end is connected to the A line to measure the voltage signal on the A line. In this way, the oscilloscope probe can accurately capture the communication messages on the communication bus, including the signal sending and receiving time points, providing reliable data support for measuring the response time of the power measurement device.

[0062] Preferably, in order to improve the accuracy and reliability of the measurement, an oscilloscope probe with a high bandwidth can be selected. An oscilloscope probe with a high bandwidth can capture signal changes at higher speeds, ensuring the accuracy of the measurement results. For example, an oscilloscope probe with a bandwidth of more than 50 MHz can be selected to meet the measurement requirements for fast signal changes. In addition, when connecting the oscilloscope probe, ensure the firmness and stability of the connection to avoid signal distortion or measurement errors caused by poor contact.

[0063] In some embodiments, the ground clip of the second oscilloscope probe is connected to one output pin of the current transformer, and the probe measurement end is connected to the other output pin.

[0064] As Figure 2 shown. The sampling resistor in the CT sensor is the recommended resistor for the current transformer, and this resistor is connected in parallel to the two output pins of the current transformer. The CT sensor consists of a current transformer and a sampling resistor, and is used to sense current changes and convert them into voltage signals. The current transformer is a device for measuring current, which can convert a large current into a small current for easy measurement and control. The sampling resistor is a component used to sense current changes and generate corresponding voltage signals, and its resistance value is usually recommended by the manufacturer of the current transformer to ensure the accuracy and stability of the measurement.

[0065] Specifically, the current transformer of the CT sensor has a rated current of 5 A and a turns ratio of 2000:1, and the sampling resistor R is 50 Ω. This means that the current transformer can convert a current of 5 A into a smaller current signal, and the sampling resistor is used to convert the current signal into a voltage signal. The resistance value of the sampling resistor is 50 Ω, which is the recommended value of the current transformer, and can ensure the accurate conversion of the current signal and the stable output of the voltage signal during the measurement process. By connecting the sampling resistor in parallel to the two output pins of the current transformer, the current change can be effectively sensed and the corresponding voltage signal can be generated, providing reliable data support for measuring the response time of the power measurement device.

[0066] Preferably, in order to further improve the accuracy and reliability of the measurement, a sampling resistor with higher accuracy can be selected. For example, a sampling resistor with an accuracy of ±0.1% can be selected to ensure the accuracy of the measurement results.

[0067] Furthermore, when installing the CT sensor, ensure that its connection to the signal source and the power measurement device is firm and reliable to avoid interference and errors during signal transmission. At the same time, the sampling resistor can be calibrated and maintained regularly to maintain its good performance and measurement accuracy.

[0068] In some embodiments, the primary frequency modulation signal source device has a single-phase current setting function, a timing multi-state switching function, and a communication control function.

[0069] It should be noted that the ground clip of the second oscilloscope probe is connected to one of the output pins of the current transformer, and the probe measurement end is connected to the other output pin. The oscilloscope probe is used to measure the voltage signal to convert the electrical signal into a visual waveform. In the CT sensor, the output pins of the current transformer are the endpoints connected to the sampling resistor. Through the connection of the oscilloscope probe, the voltage change across the sampling resistor can be accurately measured. This connection method enables real-time monitoring of the voltage signal caused by the current change, thereby providing reliable data support for measuring the response time of the power measurement device.

[0070] Specifically, the connection method of the second oscilloscope probe needs to ensure that the voltage signal across the sampling resistor can be accurately measured. When connecting, connect the ground clip of the oscilloscope probe to one of the output pins of the current transformer, usually the pin connected to the ground wire, to provide a reference point for the signal. The probe measurement end is connected to the other output pin, usually the pin connected to the sampling resistor, to measure the voltage change across the sampling resistor. In this way, the oscilloscope probe can capture the voltage signal caused by the current change and convert it into a visual waveform for easy analysis and measurement.

[0071] Preferably, in order to improve the measurement accuracy and reliability, an oscilloscope probe with high bandwidth and high resolution can be selected. The oscilloscope probe with high bandwidth can capture higher-speed signal changes and ensure the accuracy of the measurement results. For example, an oscilloscope probe with a bandwidth of more than 50 MHz can be selected to meet the measurement requirements for fast signal changes. In addition, when connecting the oscilloscope probe, ensure the firmness and stability of the connection to avoid signal distortion or measurement errors caused by poor contact.

[0072] In some embodiments, the PC uses an operating system above Windows 7 and is installed with serial port debugging software that can set the continuous transmission time and the number of transmissions, as well as the supporting control software for the primary frequency modulation signal source.

[0073] It should be noted that the primary frequency modulation signal source device has a single-phase current setting function, a timing multi-state switching function, and a communication control function. The primary frequency modulation signal source is a device that can generate signals with specific frequencies and amplitudes, and is usually used for testing and calibrating circuits. The single-phase current setting function allows users to set the magnitude and phase of the current as needed. The timing multi-state switching function can switch between different current states at preset time intervals. The communication control function is used for data exchange and transmission of control instructions with external devices. These functions enable the primary frequency modulation signal source to flexibly generate current jump signals and meet the requirements for measuring the response time of power measurement devices.

[0074] Specifically, the single-phase current setting function of the primary frequency modulation signal source can be achieved by adjusting the current adjustment knob on the device or inputting the current value. For example, the current can be set to a certain percentage of the rated current of the power measurement device, such as 10% or 50%. The timing multi-state switching function can be achieved by setting the timer of the device. Users can set the switching time interval between different current states, such as 50 milliseconds or 100 milliseconds. The communication control function can be achieved by connecting to a PC. The PC can send control instructions to the primary frequency modulation signal source through serial port debugging software to start or stop the operation of the signal source or adjust the parameters of its output signal.

[0075] Preferably, in order to improve the accuracy and reliability of the measurement, a primary frequency modulation signal source device with high precision and high stability can be selected. For example, a device that can precisely control the current jump amplitude and time interval can be selected to ensure the stability and repeatability of the signal.

[0076] Furthermore, overload protection and short-circuit protection functions can also be added to the device to prevent damage to the device due to excessive current or circuit short-circuit during the measurement process. In practical applications, appropriate device models and parameter settings can also be selected according to specific measurement requirements and environmental conditions to meet the requirements for measurement accuracy and stability.

[0077] In some embodiments, the power measurement device has a current measurement function and an RS485 communication interface, and can send test results through communication.

[0078] It should be noted that the PC uses an operating system above Windows 7 and is installed with a serial port debugging software that can set the continuous transmission time and the number of transmissions, as well as the supporting control software for the primary frequency modulation signal source. The operating system above Windows 7 refers to the Windows operating system starting from the Windows 7 version, including Windows 8, Windows 10, etc. These operating systems provide good compatibility and stability and can support the operation of various application programs. The serial port debugging software is a software used to configure and test the serial port communication parameters. It can set parameters such as the transmission time interval and the number of transmissions to facilitate communication with the power measurement device. The supporting control software for the primary frequency modulation signal source is used to control the working state of the signal source, such as starting and stopping the signal source and setting the output parameters of the signal source.

[0079] Specifically, the operating system of the PC can choose a newer version such as Windows 10 or Windows 11. These operating systems have stronger performance and better user experience. The serial port debugging software can be set to continuous transmission mode. The user can set the transmission time interval according to needs, such as 50 milliseconds or 100 milliseconds, and the number of transmissions, such as 20 times or 50 times. The supporting control software for the primary frequency modulation signal source can be operated through a graphical interface or a command-line interface. The user can conveniently set parameters such as the output current magnitude and the switching time interval of the signal source and can start or stop the operation of the signal source through the software.

[0080] Preferably, in order to improve the stability and reliability of the system, a serial port debugging software and a supporting control software for the primary frequency modulation signal source with good compatibility and stability can be selected. For example, some software that has been widely tested and verified can be selected to ensure its stable operation in different operating systems and hardware environments.

[0081] Furthermore, error detection and exception handling functions can also be added to the software to prevent data loss or measurement errors caused by software failures during the measurement process. In practical applications, appropriate software versions and functional modules can also be selected according to specific measurement requirements and device configurations to meet the accuracy and stability requirements of the measurement.

[0082] In some embodiments, the current transformer of the CT sensor has the characteristics of a rated current of 5A and a turns ratio of 2000:1, and the sampling resistor R is 50Ω.

[0083] It should be noted that the measured power measurement device has a current measurement function and is equipped with an RS485 communication interface, and can send the test results through communication. The current measurement function means that the power measurement device can accurately measure the magnitude of the current and convert it into a corresponding electrical signal. The RS485 communication interface is a communication interface standard for differential signal transmission, which is widely used in industrial control systems and has the characteristics of strong anti-interference ability, long transmission distance and multi-device communication. Through the RS485 communication interface, the power measurement device can send the measured current data to a PC or other devices for further processing and analysis.

[0084] Specifically, the current measurement function of the power measurement device can be realized by an internal current sensor. The current sensor can be of types such as Hall effect sensors and current transformers, and can convert the current signal into a voltage signal or a digital signal. The connection method of the RS485 communication interface needs to conform to its standard specifications. The A line and B line of the RS485 interface of the power measurement device need to be correctly connected to the communication bus to ensure the stable transmission of signals. During the communication process, the power measurement device can send the measured current data to the PC in a certain format and rate according to the preset communication protocol. For example, the MODBUS protocol is used for data transmission.

[0085] Preferably, in order to improve the measurement accuracy and reliability, a current sensor with high precision and high stability can be selected, and the power measurement device can be calibrated and maintained regularly to ensure the accuracy of its measurement results.

[0086] Furthermore, a data checksum and error detection function can also be added to the power measurement device to prevent data loss or measurement errors caused by signal interference or transmission errors during the communication process. In actual applications, the appropriate type of current sensor and communication protocol can also be selected according to specific measurement requirements and environmental conditions to meet the requirements of measurement accuracy and stability.

[0087] In some embodiments, both the first oscilloscope probe and the second oscilloscope probe have a bandwidth of at least 50 MHz. In some embodiments,

[0088] It should be noted that this measurement method accurately measures the response time of the power measurement device by setting the response time of the power measurement device, configuring the primary frequency modulation signal source and oscilloscope parameters, and using the bisection method approximation. The response time refers to the time interval from when the device receives a signal to when it outputs a result, and is one of the important indicators to measure the performance of the device. The primary frequency modulation signal source is used to generate a current jump signal, and the oscilloscope is used to monitor the signal changes and communication messages. The bisection method approximation is a numerical approximation method that improves the measurement accuracy by continuously narrowing the measurement range and is suitable for occasions that require high-precision measurement.

[0089] As Figure 3 shown, first, set the response time of the power measurement device to a preset response time, usually 100 milliseconds, and the current range to the rated current of the device. Then configure the primary frequency modulation signal source to the current source mode, set the current to vary from 10% to 50% of the current range, and the state interval to 50 times the preset response time. Next, install the CT sensor and calculate the voltage across the sampling resistor. Adjust the time resolution of the oscilloscope to half of the preset response time. Channel 1 is used to monitor the communication messages on the communication bus, and channel 2 is set to the level trigger mode with the trigger level value set to 25% of the product of the preset current range and the sampling resistor. After the PC delays by the state interval minus 45 times the preset response time through the serial port debugging software, it communicates with the device under test, queries the measured power value, and sends a test start command. The oscilloscope is triggered at the moment of the level jump, and records the waveforms and communication messages before and after the current jump. By analyzing the content of the messages recorded by the PC, determine the message N that can correctly reflect the measured power value, identify the signal jump point and the message end moment on the oscilloscope, and calculate the measurement response time and the communication response time.

[0090] Preferably, in order to improve the measurement accuracy and reliability, some parameters can be optimized during the measurement process. For example, the time resolution of the oscilloscope can be further improved to more accurately capture the signal jump point and the time point of the communication message.

[0091] Furthermore, a data checksum and error detection function can be added during the measurement process to prevent measurement errors caused by signal interference or transmission errors. When using the bisection method to approximate, the iteration step size and stop condition can be adjusted according to the actual situation to ensure the accuracy and stability of the measurement results. For example, stop the iteration when the difference between the maximum time and the minimum time is less than or equal to 1 millisecond to improve the measurement accuracy.

[0092] The above-mentioned embodiments of the present invention have the following beneficial effects: The measurement system described in the present invention can accurately measure the response time of the power measurement device by integrating components such as a power measurement device, a PC, an oscilloscope probe, a primary frequency modulation signal source, and a CT sensor. The power measurement device has an RS485 communication interface, which can efficiently exchange data with the PC to ensure the accurate transmission of test commands and results. The configuration of the current transformer and sampling resistor of the CT sensor enables accurate induction of current changes and generation of corresponding voltage signals, providing a reliable basis for measuring the response time. The high bandwidth and precise time resolution of the oscilloscope probe can capture the subtle changes in communication messages and current jumps, thus providing accurate data support for calculating the response time. In addition, the multi-functional design of the primary frequency modulation signal source, including single-phase current setting, timed multi-state switching, and communication control functions, enables flexible setting of test conditions to meet different measurement requirements.

[0093] The design of the system also takes into account the convenience of operation and the compatibility of the system. The PC uses an operating system above Windows 7 and is installed with serial port debugging software and supporting control software for the primary frequency modulation signal source, enabling users to conveniently set test parameters and control the test process, reducing the complexity of manual operation. At the same time, the component design of the system has good versatility and compatibility, is applicable to the response time measurement of various power measurement devices, and has broad application prospects and market potential.

[0094] In some embodiments, a method for measuring the response time of a general power measurement device is provided, and the method includes the following steps:

[0095] Set the response time of the power measurement device to a preset response time, with a default value of one hundred milliseconds and a current range set to a preset current range;

[0096] Set the primary frequency modulation signal source to the current source mode, with the current changing from 10% to 50% of the preset current range, and the state interval set to fifty times the preset response time;

[0097] Install a CT sensor and calculate the voltage across the sampling resistor R;

[0098] Adjust the oscilloscope time resolution to half of the preset response time, use the first oscilloscope probe to monitor the communication messages on the RS485 communication bus, and record the sending and receiving time points of the messages;

[0099] Set oscilloscope channel 2 to the level trigger mode, and set the trigger level value to 25% of the product of the preset current range and R;

[0100] After the PC delays for (state interval minus forty-five times the preset response time) seconds through the serial port debugging software, communicate with the device under test twenty times at an interval of half of the preset response time, query the measured power value, and simultaneously send a test start command to the primary frequency modulation signal source;

[0101] The oscilloscope is triggered at the moment of the level jump, and the waveforms before and after the current jump, as well as at least twelve sent and replied messages, are recorded;

[0102] Analyze the content of the messages recorded by the PC serial port software to determine the message N that can correctly reflect the measured power value;

[0103] Identify the signal jump point of channel 1, the end moment of message N on channel 2, and the start time of the PC query message on the oscilloscope;

[0104] The calculation of the measurement response time is the difference between the signal jump point and the end time of message N, and the communication response time is the difference between the end time of message N and the start time of the PC query message. The possible range of the response time is determined to be from the minimum time to the maximum time, where the minimum time is the measurement response time minus half of the preset response time, and the maximum time is the measurement response time.

[0105] Use the bisection method to approximate, and adjust the test time to the average of the maximum time and the minimum time.

[0106] Stop the iteration when the difference between the maximum time and the minimum time is less than or equal to two milliseconds.

[0107] Conduct ten tests with the minimum time, the minimum time plus one millisecond, and the maximum time as the response time respectively, and take the average of the ten test results as the final response time.

[0108] It should be noted that the response time includes the measurement response time and the communication response time. The measurement response time refers to the time interval from when the power measurement device receives the current change signal to when it outputs the measurement result, while the communication response time refers to the time interval from when the device receives the communication command to when it sends the measurement result. These two response times jointly determine the overall response performance of the power measurement device. The measurement response time is mainly affected by the internal signal processing speed and accuracy of the device, while the communication response time is related to the transmission speed and stability of the communication interface.

[0109] Specifically, the measurement response time can be determined by recording the time difference between the current jump signal and the device output signal with an oscilloscope. For example, when the current jumps, the oscilloscope can capture the moment of the current change and record the time point of the device output signal. The communication response time can be determined by recording the time difference between when the device receives the communication command and when it sends the measurement result.

[0110] More specifically, in actual measurement, by setting the time resolution and trigger conditions of the oscilloscope, the time points of the signals can be accurately captured, and combined with the time points of the communication messages recorded by the PC, the measurement response time and the communication response time can be calculated.

[0111] Preferably, in order to improve the measurement accuracy and reliability, some parameters can be optimized during the measurement. For example, the time resolution of the oscilloscope can be increased to capture the time points of the signals more accurately.

[0112] Furthermore, a data verification and error detection function can be added during the measurement to prevent measurement errors caused by signal interference or transmission errors. When calculating the response time, the method of taking the average of multiple measurements can be used to improve the stability and accuracy of the results. For example, conduct multiple measurements and take the average to eliminate the influence of accidental errors and thus obtain a more accurate response time.

[0113] Furthermore, the storage medium of the embodiment of the present application stores program instructions capable of implementing all the above methods. Among them, the program instructions can be stored in the above storage medium in the form of a software product, including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in various embodiments of the present application. The aforementioned storage medium includes: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs, or terminal devices such as computers, servers, mobile phones, and tablets.

[0114] The above description is only some preferred embodiments of the present invention and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above inventive concept. For example, the technical solutions formed by mutually replacing the above features with (but not limited to) technical features having similar functions disclosed in the embodiments of the present invention.

Claims

1. A measurement system for the response time of a general-purpose power measurement device, characterized in that Comprising: An electric energy measurement device for measuring current and having an RS485 communication interface; A PC connected to the electric energy measurement device via an RS485 communication bus, for sending test commands and receiving test results; A first oscilloscope probe connected in parallel with the RS485 communication bus, for monitoring communication messages on the communication bus; A primary frequency modulation signal source connected to the electric energy measurement device and the PC, for generating current jump signals; A CT sensor connected in series on a single-phase power line between the signal source and the electric energy measurement device, composed of a signal loop formed by a current transformer and a sampling resistor R, for sensing current changes and generating corresponding voltage signals; A second oscilloscope probe connected in parallel with the CT sensor, for measuring voltage changes across the sampling resistor R.

2. The measurement system according to claim 1, wherein the ground clip of the first oscilloscope probe is connected to the ground wire of the RS485 communication bus, and the probe measurement end is connected to the A wire of the RS485 communication bus.

3. The measurement system according to claim 2, wherein the sampling resistor R is the recommended resistor of the current transformer and is connected in parallel on two output pins of the current transformer.

4. The measurement system according to claim 3, wherein the ground clip of the second oscilloscope probe is connected to one output pin of the current transformer, and the probe measurement end is connected to the other output pin.

5. The measurement system according to claim 4, wherein the primary frequency modulation signal source device has a single-phase current setting function, a timing multi-state switching function, and a communication control function.

6. The measurement system according to claim 5, wherein the PC uses an operating system above Windows 7, installs serial port debugging software for setting the continuous transmission time and the number of transmissions, and supporting control software for the primary frequency modulation signal source.

7. The measurement system according to claim 6, wherein the electric energy measurement device has a current measurement function and an RS485 communication interface, and can send test results through communication.

8. The measurement system according to claim 7, wherein the current transformer of the CT sensor has a rated current of 5A, a turns ratio of 2000:1, and the sampling resistor R is 50Ω.

9. The measurement system according to claim 8, wherein the bandwidths of both the first oscilloscope probe and the second oscilloscope probe are greater than or equal to 50MHz.

10. A method for measuring the response time of an electrical energy measurement device using the measurement system according to any one of claims 1 to 9, characterized in that, Including the following steps: Set the response time of the electric energy measurement device to a preset response time, with a default value of one hundred milliseconds, and the current range to a preset current range; Set the primary frequency modulation signal source to the current source mode, with the current changing from 10% to 50% of the preset current range, and the state interval set to fifty times the preset response time; Install the CT sensor and calculate the voltage across the sampling resistor R; Adjust the oscilloscope time resolution to half of the preset response time, use the first oscilloscope probe to monitor the communication messages on the RS485 communication bus, and record the sending and receiving time points of the messages; Set the oscilloscope channel 2 to the level trigger mode, and set the trigger level value to 25% of the product of the preset current range and R. After the PC delays the state interval through the serial port debugging software and subtracts 45 times the preset response time in seconds, it communicates with the device under test 20 times at an interval of half of the preset response time, queries the measured power value, and simultaneously sends a test start command to the primary frequency modulation signal source; The oscilloscope is triggered at the moment of the level jump, records the waveforms before and after the current jump, and at least twelve sent and replied messages; Analyze the message content recorded by the PC serial port software to determine the message N that can correctly reflect the measured power value; Identify the signal jump point of channel 1, the end moment of message N of channel 2, and the start time of the PC query message on the oscilloscope; Calculate the measurement response time as the difference between the signal jump point and the end moment of message N, the communication response time as the difference between the end moment of message N and the start time of the PC query message, and determine the possible interval of the response time as the minimum time to the maximum time, where the minimum time is the measurement response time minus half of the preset response time, and the maximum time is the measurement response time; Adopt the bisection method to approximate and adjust the test time to the average of the maximum time and the minimum time; Stop the iteration when the difference between the maximum time and the minimum time is less than or equal to 2 milliseconds; Conduct ten tests with the minimum time, the minimum time plus 1 millisecond, and the maximum time as the response time respectively, and take the average of the ten test results as the final response time.

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