Verification system for digital multimeters

Abstract

A calibration system for digital multimeters includes a computer host, standard equipment, the device under test, and a calibration backend running on the host. The calibration backend includes a user interface module, a scheme management module, a task workflow module, a data upload module, a data management module, a task execution module, a status monitoring module, a unified equipment management module, an equipment driver module, and a database module. The user interface module allows operators to select a calibration scheme and the device under test and submit the calibration task to the task execution module, which then drives measurements on the standard equipment and the device under test and monitors the device status. The data management module processes data related to the digital multimeter calibration. This system enables automated calibration management, effectively improving calibration efficiency. Furthermore, it requires minimal human intervention during the calibration process, reducing human error and ensuring the reliability of the calibration results.

Description

Technical Field

[0001] This invention relates to the field of instrument calibration technology, and particularly to a calibration system for a digital multimeter. Background Technology

[0002] A digital multimeter is an instrument capable of performing precise electrical measurements and displaying the data digitally. It features functions such as AC / DC voltage, AC / DC current, DC resistance, frequency, period, continuity, and diode testing, and is widely used in defense, scientific research, factories, schools, and metrology and testing fields. Because its accuracy is crucial to the reliability of electronic measurement data in industries such as defense, energy and power, industrial production, metrology and testing, and scientific research, digital multimeters require periodic calibration and verification.

[0003] Currently, the calibration and verification of digital multimeters are mainly carried out manually by testing personnel, requiring manual data reading, recording, and error calculation. However, the number of digital multimeters in use is enormous, and the calibration and verification items are numerous and the calibration and verification points are complex, resulting in a large amount of repetitive work. This is not only time-consuming and labor-intensive, but also prone to significant errors due to human negligence, reducing the reliability of digital multimeter calibration and verification. Summary of the Invention

[0004] In view of this, and to address the above shortcomings, it is necessary to propose a calibration system for digital multimeters that can systematically and automatically perform metrological verification tests, thereby improving the efficiency and reliability of calibration and verification.

[0005] A calibration system for a digital multimeter, the system comprising: a computer host, standard equipment, a device under test, and a device calibration backend running on the host;

[0006] The computer host is connected to the standard device and the device under test through physical interfaces respectively. The device verification backend interacts with the standard device or the device under test according to the communication protocol adapted to the device connected to the computer host.

[0007] The equipment calibration backend includes a user interface module, a scheme management module, a task flow module, a data upload module, a data management module, a task execution module, a status monitoring module, a unified equipment management module, an equipment driver module, and a database module;

[0008] The user interface module allows direct interaction with the operator. After the operator selects the verification plan and the device under test, the verification task is submitted to the task execution module. The task execution module drives and measures the standard device and the device under test, and monitors their status. The data management module is connected to the database module. The task flow module, data upload module, and plan management module call the data management module to perform read and write operations on the database. The data management module also processes data related to the verification of the digital multimeter. The task execution module and the status monitoring module communicate with the standard device and the device under test by calling the unified device management module. The device driver module assembles and parses data during communication.

[0009] Preferably, the scheme management module provides an interface for converting data from the user interface module into a verification scheme structure, and a storage management interface for the user interface module's data to the lower layer; and the scheme management module is used to add, delete, modify, and query verification schemes; wherein, the verification scheme structure includes: equipment signal structure, equipment ledger structure, verification point structure, inspected scheme structure, verification scheme template structure, verification item template structure, verification task structure, and historical data structure.

[0010] Preferably, after the operator initiates the verification task through the user interface module, the task execution module controls the standard equipment and the equipment under test to execute operation instructions through the unified management module of the drive equipment to realize the relevant operations of the verification task; and the task execution module collects the data specified in the verification task and returns the execution result.

[0011] Preferably, the task execution module judges the validity and stability of the data during data collection.

[0012] Preferably, the data management module includes a data storage unit, a data processing unit, a data query and statistics unit, and a certificate and form printing unit;

[0013] The data query and statistics unit is used to query by one or more of the following: instrument name, submitting unit name, and submission date; the verification data retrieved by the data query and statistics unit includes: submitting unit, equipment type, specifications, and quantity of equipment.

[0014] Preferably, the data stored in the database module includes equipment ledger tables, scheme template tables, calibration process tables, and historical data tables;

[0015] The equipment ledger includes a standard equipment basic information table, a standard equipment indicator information table, and a tested equipment basic information table; wherein, the standard equipment basic information table stores common information of the standard instruments supported by the system for verification, the standard equipment indicator information table stores specific information of the standard instruments supported by the system, and the tested equipment basic information table stores customer equipment information;

[0016] The scheme template table includes a main scheme basic information table and a sub-scheme template table; wherein, the main scheme basic information table supports the creation of verification schemes based on different models of equipment, and the sub-scheme template table stores all verification items supported by the system;

[0017] The verification process table includes a verification task table, a verification plan table, a verification sub-item table, and a current verification result information table; wherein, the verification task table stores the verification tasks created by the operators, the verification plan table stores the specific verification task information of the customer, the verification sub-item table stores the verification items selected by the customer in the verification plan of the current verification task, and the current verification result information table stores the operation result information of each verification task and the tested equipment after verification;

[0018] The historical data table stores all the information from each of the customer's inspections.

[0019] Preferably, the unified device management module communicates with the device under test or the standard device through at least one of the following interfaces: serial port, Ethernet, GPIB, and VXI.

[0020] Preferably, the device driver module consists of several different types of driver devices, each type of driver device corresponding to a device driver program, which is used to provide the corresponding device driver program to the unified device management module; and the device driver module is also used to zero, set and output the range of the device under test.

[0021] Preferably, the system further includes a device scanning module that is communicatively connected to the device verification backend. This device scanning module is used to scan the electronic tags on the device under test or the standard device to obtain basic information about the device.

[0022] Preferably, the system also includes a mobile terminal loaded with a mini-program, which includes a registration module, a device information input module, and a processing module.

[0023] The entrustment registration module is used by customers to fill in information, including the entrusting unit, the entrusting contact person, and the entrustment category;

[0024] The device information input module is used for customers to input device information;

[0025] The entrustment processing module is used to modify, delete, and export entrustment information.

[0026] As can be seen from the above technical solution, the digital multimeter calibration system provided in this embodiment of the invention includes: a computer host, a standard device, a device under test, and a device calibration backend running on the host; the device calibration backend further includes a user interface module, a scheme management module, a task flow module, a data upload module, a data management module, a task execution module, a status monitoring module, a unified device management module, a device driver module, and a database module; the user interface module is used to directly interact with the operator. After the operator selects the calibration scheme and the device under test, the operator submits the calibration task to the task execution module, which drives and measures the standard device and the device under test, and monitors the status of the standard device and the device under test; the data management module is connected to the database module. The task flow module, the data upload module, and the scheme management module are used to call the data management module to perform read and write operations on the database, and the data management module is used to process data related to the digital multimeter calibration; the task execution module and the status monitoring module communicate with the standard device and the device under test by calling the unified device management module, and the device driver module is used to assemble and parse the data during communication. This invention enables the establishment of intelligent control and management of the tested equipment, as well as automated management of calibration information, achieving fully automated operation of the digital multimeter calibration process and effectively improving calibration efficiency. Furthermore, it requires minimal human intervention during the calibration process, thus reducing human error and ensuring the reliability and traceability of calibration results. Attached Figure Description

[0027] Figure 1 A schematic diagram of a digital multimeter calibration system provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of a device calibration backend provided in an embodiment of the present invention. Detailed Implementation

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] See Figure 1 This invention provides a verification system for a digital multimeter, which includes: a computer host, a standard device, a device under test, and a device verification backend running on the host.

[0031] The computer host is connected to the standard equipment and the equipment under test through physical interfaces. The equipment verification backend interacts with the standard equipment or the equipment under test according to the communication protocol adapted to the device connected to the computer host.

[0032] See Figure 2 The equipment calibration backend can include a user interface module, a scheme management module, a task flow module, a data upload module, a data management module, a task execution module, a status monitoring module, a unified equipment management module, an equipment driver module, and a database module.

[0033] The user interface module allows direct interaction with the operator. After the operator selects the verification plan and the device under test, they submit the verification task to the task execution module. The task execution module then drives and measures the standard device and the device under test, and monitors their status. The data management module connects to the database module. The task flow module, data upload module, and plan management module call the data management module to perform read and write operations on the database. The data management module also processes data related to the verification of the digital multimeter. The task execution module and status monitoring module communicate with the standard device and the device under test by calling the unified device management module. The device driver module assembles and parses the data during communication.

[0034] In one embodiment, the standard device can be a standard source. During calibration, the output value of the standard source is the displayed value. The system automatically controls the standard source to output a standard display value. The system automatically switches the various display states of the meter under test through the communication interface of the meter under test, reads the actual measured value of the meter under test as the display value of the meter under test, and thus calibrates the meter under test. Alternatively, the standard source can be manually adjusted until the display value of the meter under test meets the requirements, and the standard source reading is used to calibrate the meter under test.

[0035] In another embodiment, the standard equipment may include a standard meter and a standard source. The calibration system automatically controls the standard source to output voltage and current to the standard meter via a communication interface, reads the measurement data as the standard indication value by communicating with the standard meter, and simultaneously communicates with the device under test to collect the measurement value as the indication value under test, thereby realizing the calibration of the device under test.

[0036] The user interface module provides a human-computer interaction window, receiving user operation commands to complete the visual operation process of the software. It is integrated with the main program interface, allowing access to business functions such as solution management, unified equipment management, task execution, and data management. The user interface module implements business functions by calling the solution management module, task execution module, and status monitoring module. The task execution module and status monitoring module require calls to the unified equipment management module.

[0037] In one embodiment, the scheme management module provides an interface for converting data from the user interface module into a verification scheme structure, and a storage management interface for the user interface module's data to the lower layer; the scheme management module is used to add, delete, modify, and query verification schemes; wherein, the verification scheme structure includes: equipment signal structure, equipment ledger structure, verification point structure, inspected scheme structure, verification scheme template structure, verification item template structure, verification task structure, and historical data structure.

[0038] In this embodiment, the scheme management module is the data processing center and core data structure of the system business layer. It is responsible for providing the relevant interfaces for converting user operation interface data into verification execution scheme structures, as well as the storage management interface for user interface data.

[0039] The scheme management module is responsible for maintaining the core execution data structure of this software system, namely the addition, deletion, modification, and query operations for verification execution schemes. Based on the execution schemes, it generates structures such as equipment model structure, equipment ledger structure, verification point structure, verification scheme structure, verification scheme template structure, verification project template structure, verification task structure, and historical data structure. In addition, the scheme management module can support users to perform addition, deletion, modification, and query operations on verification projects through the UI interface by calling the database module.

[0040] In one embodiment, after the operator initiates a verification task through the user interface module, the task execution module controls the standard equipment and the equipment under test to execute operation instructions through the unified management module of the driving equipment to realize the relevant operations of the verification task; and the task execution module collects the data specified in the verification task and returns the execution result.

[0041] The task execution module judges the validity and stability of the data during data collection.

[0042] In this embodiment, the task execution module is responsible for the execution logic of the verification task and the collection and output of verification data. The user interface module (UI) initiates the execution task, and the task execution module executes the specified task. The task execution module completes a series of operation instructions through the unified management module for driver devices, collects specified data, and returns the execution results.

[0043] Based on application layer requirements, the system's task execution module establishes data acquisition units for both the inspected device and the standard device. Their internal logic and processes are largely consistent. Once the data acquisition unit detects the data field sent by the protocol parser, it enters the data field processing logic. The data parser primarily performs logical control on the data in two ways: first, it determines whether the data is valid; second, it determines whether the data is authentic and stable.

[0044] Data validity is primarily determined based on principles such as whether the data is required for the current power level, the current data transmission requirement, or whether there are error indicators in the current data domain. Different device protocols may have some custom judgment requirements. For compatibility and scalability, the data collection and judgment process uses a JSON format configuration file to realize user customization needs.

[0045] The determination of data authenticity and stability mainly involves the system employing effective algorithms after the data acquisition device obtains valid data to ensure that the data is closer to the true measurement value. These algorithms include averaging multiple sets of data, moving averages, removing large amounts of data, and applying principles of stability over a certain period of time. This ensures that the data presented to users by the application layer meets the metrological traceability requirements in different experimental projects.

[0046] During data analysis, the protocol parser first determines whether the message structure conforms to the protocol requirements based on the protocol structure. The message structure type is determined according to the logical relationship of messages such as (header, trailer, length, address, terminator, and checksum). Messages conforming to the above logical rules are actively reported by the system as complete packets and enter the valid packet judgment. When no complete packet is found, the system buffer waits for the next message to be parsed. Valid packets structurally meet the requirements specified by the device protocol, but whether they can be used depends on the system comparing the internal information of the message, mainly by checking whether the address field and checksum meet the requirements. If the comparison is successful, the data field is reported to the data acquisition area; otherwise, it is discarded.

[0047] In one embodiment, the data management module includes a data storage unit, a data processing unit, a data query and statistics unit, and a certificate and form printing unit;

[0048] The data query and statistics unit is used to query by one or more of the following: instrument name, submitting unit name, and submission date. The verification data retrieved by the data query and statistics unit includes: submitting unit, equipment type, specifications, and quantity.

[0049] In this embodiment, the data management module mainly performs the main business tasks of data storage, data management, data query and statistics, as well as printing certificates and various forms, etc.

[0050] Data query supports searching by single items such as measuring instrument name and submitting unit name; it also supports searching by combined conditions. The statistics submodule summarizes the verification information retrieved according to the search conditions, including submitting unit, type, specifications, and quantity of measuring instruments. The data management module serves as the system's data center, a bridge between the database and upper-layer applications, providing data storage and management interfaces for the task execution module and the scheme management module, as well as interfaces for mutual conversion between database data and upper-layer data structures.

[0051] In one embodiment, the data stored in the database module includes an equipment ledger table, a scheme template table, a calibration process table, and a historical data table;

[0052] The equipment ledger includes a standard equipment basic information table, a standard equipment specification information table, and a tested equipment basic information table. The standard equipment basic information table stores common information about the standard instruments supported by the system for verification, the standard equipment specification information table stores specific information about the standard instruments supported by the system, and the tested equipment basic information table stores the customer's equipment information.

[0053] The scheme template table includes a main scheme basic information table and a sub-scheme template table; the main scheme basic information table supports the creation of verification schemes based on different equipment models, and the sub-scheme template table stores all verification items supported by the system.

[0054] The verification process table includes a verification task table, a verification plan table, a verification sub-item table, and a current verification result information table. Among them, the verification task table stores the verification tasks created by the operators, the verification plan table stores the specific verification task information of the customer, the verification sub-item table stores the verification items selected by the customer in the verification plan of the current verification task, and the current verification result information table stores the operation result information of each verification task and the equipment under test after verification.

[0055] The historical data table stores all the information from each of the customer's inspections.

[0056] In this embodiment, the database tables designed by the system are divided into four main categories: equipment ledger table, scheme template table, verification process table, and historical data table.

[0057] (1) Equipment ledger

[0058] The equipment ledger is categorized by the inspection object and includes: the basic information table of standard equipment, the index information table of standard equipment, and the basic information table of the inspected equipment.

[0059] Standard Equipment Basic Information Table: Stores common information about standard instruments supported by the system for verification. Field names include: model, grade, name, manufacturer, verification cycle, type, etc.

[0060] Standard Equipment Specifications Table: Stores information specific to the standard instruments supported by the system for verification, including power commands, range, settling time, resolution, and different error calculation parameters;

[0061] Basic Information Table of the Equipment Under Inspection: Stores user equipment information, including model name, equipment level, communication parameters, factory code, and submitting unit.

[0062] (2) Proposal Template Table

[0063] The scheme templates are categorized by the verification items supported by the system and serve as reference templates for the verification process. They include: the main scheme basic information table and the sub-scheme template table.

[0064] Main scheme basic information table: Users can create verification schemes according to different models of equipment. This table includes the scheme name, the procedures referenced in this verification, and the associated verification sub-items, etc.

[0065] Sub-scheme template table: Stores all verification items supported by the system, such as DC voltage, DC current, resistance and other verification functions. Fields include power name, power code, wire unwinding method, influencing factor, verification mode, retrieval index, number of measurements, etc.

[0066] (3) Verification process table

[0067] The verification process is divided according to the system's business logic, including: verification task table, verification plan table, verification sub-item table, and current verification result information table.

[0068] Verification Task Table: Stores verification tasks created by users, including tasks issued by third parties or tasks created directly in the system. Fields include: verification result, verification personnel, verification date, associated verification plan, etc.

[0069] Verification Plan Table: Stores user-specific verification task information, including associated standards and equipment under test, verification items, etc.

[0070] Verification Sub-item Table: Stores the verification items selected by the customer in the current task plan, as well as the associated verification equipment, verification results, retrieval indicators, calculation result formulas and parameters, and other information required for the current task to run.

[0071] Verification Result Information Table: Stores the running result information after verification of different tasks and equipment. Fields include standard average value, standard rounded value, standard maximum value, standard minimum value, tested average value, tested rounded value, tested maximum value, tested minimum value, value display unit, accuracy, stability, relative error, absolute error, original error data, conclusion, etc.

[0072] (4) Historical data table

[0073] Historical data stores all information from each user's verification process, including verification equipment information, scheme information, and verification process result data. It is divided into two tables: a main historical information table and a historical verification task details table. Users retrieve data from the historical data module each time they print or export data.

[0074] In one embodiment, the unified device management module communicates with the device under test or the standard device through at least one of the following interfaces: serial port, Ethernet, GPIB, and VXI.

[0075] In this embodiment, the task execution module and the status monitoring module are implemented by calling the unified device management module. The unified device management module communicates with the device through interfaces such as serial port, Ethernet, GPIB, and VXI. In this way, the unified device management layer reduces the coupling between the interface layer, task management layer, and specific hardware; the interface layer only needs to use an abstract interface to configure and control the device. Furthermore, the unified device management provides a unified device driver calling interface for task execution and the UI interface, achieving isolation between the upper-layer application and the actual device, thereby enabling standardized calls to device drivers.

[0076] In one embodiment, the device driver module consists of several different types of driver devices, each type of driver device corresponding to a device driver program, which is used to provide the corresponding device driver program to the unified device management module; and the device driver module is also used to zero, set and output the range of the device under test.

[0077] In this embodiment, the device driver module consists of several devices, and each model of device corresponds to a device driver, which is responsible for providing the driver of the actual device to the unified device management service.

[0078] The device driver module has the following features:

[0079] 1) Supports multiple communication methods: serial port, Ethernet, GPIB, VXI, etc., and reserves space for future expansion to other interface types such as Bluetooth.

[0080] 2) Communication parameters can be customized, such as serial port baud rate.

[0081] 3) Device communication protocol parsing supports text configuration files and CSScript scripting language, so adding device driver configuration does not require software modification and is convenient for debugging.

[0082]

[0083] 4) For some devices that require manual range switching, the device driver layer can realize the entire process of zeroing, setting the range, and outputting.

[0084] Furthermore, the device driver employs an object-oriented design approach, implementing the most comprehensive base class. Specific devices implement specific instructions based on their functions; functions that are not available are left empty and do not execute any actual instructions.

[0085] In one embodiment, the system further includes a device scanning module that is communicatively connected to the device verification backend. The device scanning module is used to scan electronic tags on the device under test or standard device to obtain basic information about the device.

[0086] In this embodiment, the device scanning module scans the electronic tag information of the submitted instrument to establish a link with the system database, automatically reading the basic information of the submitted instrument and realizing the management of electronic tags for the submitted instruments. The practical application of electronic tags results in a large amount of basic information being stored in the electronic tag system. This solution can achieve this through a barcode scanner, allowing the system to receive scanned information instantly. The barcode scanner facilitates the complete automation of data input into the system, reducing the tedious operations and human errors caused by manual data entry and comparison, improving work efficiency, and meeting the requirements of this project.

[0087] The device scanning module can be used in the following scenarios:

[0088] 1) Used when adding new equipment, the system quickly reads the basic information of the equipment by scanning the electronic tag to establish the verification ledger system.

[0089] 2) Used when locating equipment: By scanning the electronic tag, the corresponding equipment calibration information can be quickly found in the calibration log.

[0090] 3) When calibrating equipment, the corresponding calibration plan for the equipment can be found directly by scanning the electronic tag.

[0091] In one embodiment, the system further includes a mobile terminal loaded with a mini-program, which includes a registration module, a device information input module, and a processing module.

[0092] The entrustment registration module is used by customers to fill in information, including the entrusting unit, the contact person, and the type of entrustment;

[0093] The equipment information entry module is used by customers to enter equipment information;

[0094] The delegation processing module is used to modify, delete, and export delegation information.

[0095] In this embodiment, the project uses a mini-program to implement user registration and management of entrustments, achieving paperless office operations in the entrustment receipt and dispatch management process. This mini-program is an application that can be used without downloading; users can open and use it by scanning a QR code or searching for the application. It embodies the concept of "use and go," allowing users to complete the required functions without installing an application. This meets the needs of the user group of this project.

[0096] This project utilizes the APIs provided by WeChat Cloud for development. When developing core business logic using WeChat Cloud's APIs, there's no need to build your own servers, databases, storage, or CDN, enabling rapid iterative development that perfectly suits the project's application scenario.

[0097] For example, in some use cases, users can scan a QR code to enter the entrustment registration module and enter information such as the entruster and the entrusted equipment; for the equipment information entry module, users can enter multiple equipment at once; for the entrustment processing module, only administrators can enter, and administrators can modify or delete entrustment information, as well as export entrustment information to a WORD template.

[0098] The task flow module can reserve an external interface for connecting to external devices that can issue verification tasks.

[0099] The modules or units in the device of this invention can be merged, divided, or deleted according to actual needs.

[0100] The modules or units in the device of this invention can be merged, divided, and deleted according to actual needs. The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this invention still fall within the scope of the invention.

Claims

1. A calibration system for a digital multimeter, characterized in that, The system includes: a computer host, standard equipment, the equipment under test, and an equipment verification backend running on the host; The computer host is connected to the standard device and the device under test through physical interfaces respectively. The device verification backend interacts with the standard device or the device under test according to the communication protocol adapted to the device connected to the computer host. The equipment calibration backend includes a user interface module, a scheme management module, a task flow module, a data upload module, a data management module, a task execution module, a status monitoring module, a unified equipment management module, an equipment driver module, and a database module; The user interface module allows direct interaction with the operator. After the operator selects the verification plan and the device under test, the verification task is submitted to the task execution module. The task execution module drives and measures the standard device and the device under test, and monitors their status. The data management module is connected to the database module. The task flow module, data upload module, and plan management module call the data management module to perform read and write operations on the database. The data management module also processes data related to the verification of the digital multimeter. The task execution module and the status monitoring module communicate with the standard device and the device under test by calling the unified device management module. The device driver module assembles and parses data during communication. The scheme management module provides interfaces for converting data from the user interface module into a verification scheme structure, and a storage management interface for the user interface module's data to the lower layer; the scheme management module is used to add, delete, modify, and query verification schemes; wherein, the verification scheme structure includes: equipment signal structure, equipment ledger structure, verification point structure, inspected scheme structure, verification scheme template structure, verification item template structure, verification task structure, and historical data structure; After the operator initiates a verification task through the user interface module, the task execution module controls the standard equipment and the equipment under test to execute operation instructions through the unified management module of the drive equipment to realize the relevant operations of the verification task; and the task execution module collects the data specified in the verification task and returns the execution results. The data management module includes a data storage unit, a data processing unit, a data query and statistics unit, and a certificate and form printing unit; wherein, the data query and statistics unit is used to query by one or more of the following: instrument name, submitting unit name, and submission date; the verification data queried by the data query and statistics unit includes: submitting unit, equipment type, specifications, and quantity of equipment; The database module stores data including equipment ledger tables, scheme template tables, calibration process tables, and historical data tables. The equipment ledger includes a standard equipment basic information table, a standard equipment indicator information table, and a tested equipment basic information table; wherein, the standard equipment basic information table stores common information of the standard instruments supported by the system for verification, the standard equipment indicator information table stores specific information of the standard instruments supported by the system, and the tested equipment basic information table stores customer equipment information; The scheme template table includes a main scheme basic information table and a sub-scheme template table; wherein, the main scheme basic information table supports the creation of verification schemes based on different models of equipment, and the sub-scheme template table stores all verification items supported by the system; The verification process table includes a verification task table, a verification plan table, a verification sub-item table, and a current verification result information table; wherein, the verification task table stores the verification tasks created by the operators, the verification plan table stores the verification task information of the customers, the verification sub-item table stores the verification items selected by the customers in the verification plan of the current verification task, and the current verification result information table stores the operation result information of each verification task and the equipment under test after verification; The historical data table stores all the information from each of the customer's inspections.

2. The calibration system for a digital multimeter according to claim 1, characterized in that, The task execution module judges the validity and stability of the data during data collection.

3. The calibration system for a digital multimeter according to claim 1, characterized in that, The unified device management module communicates with the device under test or standard device through at least one of the following interfaces: serial port, Ethernet, GPIB, and VXI.

4. The calibration system for a digital multimeter according to claim 3, characterized in that, The device driver module consists of several different types of driver devices, each type of driver device corresponding to a device driver program, which is used to provide the corresponding device driver program to the unified device management module; and the device driver module is also used to zero, set and output the range of the device under test.

5. The calibration system for a digital multimeter according to claim 1, characterized in that, The system also includes a device scanning module that is connected to the device verification backend. This device scanning module is used to scan the electronic tags on the device under test or the standard device to obtain the basic information of the device.

6. The calibration system for a digital multimeter according to any one of claims 1 to 5, characterized in that, The system also includes a mobile terminal loaded with a mini-program, which includes a registration module, a device information input module, and a processing module. The entrustment registration module is used by customers to fill in information, including the entrusting unit, the entrusting contact person, and the entrustment category; The device information input module is used for customers to input device information; The entrustment processing module is used to modify, delete, and export entrustment information.

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