Introduction The system uses an industrial control computer as its core, supplemented by some simple peripheral circuits. Existing measuring instruments are connected via GPIB, USB, and serial communication ports. Control software for the measurement process is developed by programmers. The user only needs to correctly connect the instrument to the equipment and issue simple operation commands to the computer to achieve the entire process of measurement, data analysis, processing, and recording. 1. Measuring Instruments as COM Components In software development, the instrument can be designed as a COM component. All the instrument's functions should be implemented in the COM component design, and corresponding interface functions should be provided. The virtual instrument software calls these components to operate the specific instrument. In this way, programmers can treat the specific instrument as a component when developing the virtual instrument control software, using the component's functions to complete the various command operations of the actual instrument. This not only makes it easier to troubleshoot potential hardware problems, but also allows developers to perform upgrades and maintenance only for the COM component once the hardware is updated. Taking a certain type of spectrum analyzer as an example, let's consider the process of measuring the spurious value of a signal within the control voltage variation range: 1) First, adjust the spectrum analyzer to a logarithmic coordinate system, and set the center frequency and appropriate bandwidth of the spectrum analyzer according to the signal variation range to ensure that the spectrum analyzer can capture the signal within the control voltage variation range. This realizes the sub-process of spurious value initialization; 2) Read all signals outside the main lobe of the signal within the bandwidth at different control voltage points, and take the largest side lobe value as the spurious value. To avoid the influence of white noise on the measurement of spurious values, the idea of ​​measuring several sets of signals at the same control voltage point and averaging them using software is adopted. This smooths the signal fluctuations caused by white noise, and takes the smoothed spurious value as the measurement result. This realizes the sub-process of measuring the spurious value of the current signal. Figure 1 Spurious value measurement flowchart. In the process of continuously measuring several sets of signals and averaging them, there is a communication time between the industrial control computer and the spectrum analyzer between two adjacent sets of data measurements, which weakens the time correlation of the signal and is not conducive to smoothing white noise. To improve measurement accuracy, a spectrum analyzer capable of averaging was introduced. The industrial control computer only needs to read the maximum value of all signals outside the main lobe after averaging as the current signal spurious value. Following this approach, the spectrum analyzer COM component was redesigned. The spurious value measurement process still follows the aforementioned measurement flowchart. The virtual instrument software calls the updated component, and the programmer doesn't even need to modify a single line of source code in the virtual instrument software. For the same signal, the spurious values ​​measured by the software before and after the improvement were -76.3dB and -78.2dB, respectively, while the value measured by the calibration equipment was -78.51dB. The improved software's measurement value is more accurate. 2. Real-time measurement archiving using an Access database During the measurement process, sometimes the equipment may experience unexpected interruptions due to sudden power outages, computer virus attacks, or other unforeseen malfunctions. However, the user's measurement may not have finished, and no measurement report has been submitted. All data in the system memory will be lost, which is very detrimental to the user. Therefore, it is essential to perform a real-time database backup of all user measurement results. The database that monitors the entire user measurement process uses in-memory variable storage, including user settings, measurement results, user operation steps, and automatic evaluation of measurement results, all of which have corresponding fields in the database. When a user operates the virtual instrument, a new measurement record is created for each new product measured, using the product number and measurement time entered by the user. During the operation, the user's actions and results are synchronously submitted to the database in real time. The record is only deleted after the user has completed all measurements and saved the report; otherwise, it is retained. The remaining record serves as the real-time measurement archive for a specific abnormal system exit. This is the process of real-time measurement archiving. When the user opens the virtual instrument software again, the software automatically loads the database. If the database contains data records, after loading the operation interface, the user will be prompted about unfinished tasks, allowing them to choose whether to continue the unfinished tasks or delete an incomplete test record. If they choose to continue, a list of unfinished tasks will be provided, allowing the user to select one to start. After the user's selection, the corresponding values ​​in the database will be automatically restored to the virtual instrument operation interface, restoring the results before the unexpected situation. This process of loading measurement archives is achieved through system queries and user selection. Of course, users can also choose to delete incomplete but unwanted test records to clean up the archived database, or choose to perform a new measurement and start a new operation. The workflow of the virtual instrument software is shown in Figure 2. Figure 2: Software Workflow Diagram with Database as the Core 3. System Performance Evaluation Using the solution presented in this paper, the virtual instrument software developed using the VB.NET programming language was successfully applied to the measurement of a product's specifications. The entire system has a short development cycle and is simple and convenient to maintain. The "real-time measurement archiving" adds a capability to resist external emergencies on top of the software's internal anomaly protection, effectively protecting the measurement data. The time required for each product measurement is only 1/3 to 1/4 of the original manual instrument measurement time (excluding subsequent data processing time), greatly improving production efficiency. The development cost of the entire system is very low; all measuring instruments utilize existing equipment, and the hardware investment is only an industrial control computer, a GPIB adapter card, and some cables.