EMS test method and system for PLC

Abstract

The invention relates to the field of automation, and discloses an EMS test method and system for a PLC, and the method comprises the steps: obtaining the basic EMS data and data fluctuation characteristics of a to-be-tested PLC according to the equipment parameters of the to-be-tested PLC; collecting electromagnetic interference data of the target environment, obtaining electromagnetic interference characteristics of the target environment according to the electromagnetic interference data, generating a target environment test case according to the electromagnetic interference characteristics of the target environment and the basic test case, and dividing the to-be-tested PLCs completing the basic test into an experiment test group and an environment test group; and if the use electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, obtaining the electromagnetic immunity of the to-be-tested PLC and the updated target environment test case. According to the method, the cloud database and the real-time electromagnetic interference data are combined to generate the customized test case for the target environment, so that the accuracy and practicability of the EMS test are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of industrial automation, and particularly to an EMS testing method and system for PLCs. Background Art

[0002] With the continuous improvement of industrial automation, as the core component of industrial control systems, the stability and reliability of PLCs are crucial for the operation of the entire production line. However, in the actual industrial environment, PLCs are often subject to various electromagnetic interferences, such as electrostatic discharge, electrical fast transient burst, lightning surge, etc. These interferences may cause abnormal operation of PLCs and even lead to system crashes, seriously affecting production efficiency and safety.

[0003] Traditional PLC EMS testing methods mainly rely on standard laboratory testing environments to evaluate the immunity of PLCs by simulating specific electromagnetic interference scenarios. However, this method has the following limitations: Large difference between the testing environment and the actual environment: It is difficult for the laboratory testing environment to fully reproduce the complex electromagnetic interference situations in the actual industrial environment, resulting in a large difference between the test results and the performance in actual applications.

[0004] Single test cases: Traditional test cases often rely on standard test specifications and lack customized tests for specific application environments, making it difficult to comprehensively reflect the immunity performance of PLCs in different environments.

[0005] Long testing cycle: Due to the need to manually adjust test parameters and repeat tests, the testing cycle of traditional methods is relatively long and the efficiency is low.

[0006] Lack of real-time feedback mechanism: Traditional testing methods usually analyze after the test is completed, lacking real-time monitoring and feedback mechanisms, making it difficult to discover and solve problems in a timely manner.

[0007] Unable to dynamically adapt to environmental changes: The electromagnetic interference in the actual industrial environment is dynamically changing. Traditional methods cannot automatically adjust test cases according to environmental changes, resulting in limited timeliness of test results.

[0008] Therefore, there is an urgent need for a PLC EMS testing method and system that can be closer to the actual industrial environment, efficient, flexible and have a real-time feedback mechanism to improve the accuracy and efficiency of PLC electromagnetic immunity testing and ensure the stable operation of PLCs in actual applications. Summary of the Invention

[0009] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an EMS testing method for PLCs, including the following steps: Step 1: According to the device parameters of the PLC to be tested, obtain the basic test cases from the reference test database. The test device performs self-calibration of the test device according to the test cases. After the self-calibration of the test device, the test device performs EMS tests on the PLC to be tested according to the test cases, obtains the EMS test data of the PLC to be tested, and obtains the basic EMS data and data fluctuation characteristics of the PLC to be tested based on the test data of the PLC to be tested. Step 2: Collect the electromagnetic interference data of the target environment, obtain the electromagnetic interference characteristics of the target environment based on the electromagnetic interference data, generate target environment test cases according to the electromagnetic interference characteristics of the target environment and the basic test cases, and divide the PLCs to be tested that have completed the basic test into an experimental test group and an environmental test group. Step 3: The test device performs EMS tests on the PLCs in the experimental test group according to the target environment test cases, obtains the EMS test data of the PLCs to be tested corresponding to the target environment, and obtains the experimental electromagnetic immunity of the PLCs to be tested in the target environment, then enter Step 5. Step 4: According to the set test cycle, obtain the EMS test data of the PLCs in the environmental test group through the target environment test cases, and obtain the service electromagnetic immunity of the PLCs to be tested in the target environment. Step 5: If the service electromagnetic immunity in the target environment is consistent with the experimental electromagnetic immunity in the target environment, enter Step 6; otherwise, update the target environment test cases according to the service electromagnetic immunity in the target environment, and return to Step 3 until the service electromagnetic immunity in the target environment is consistent with the experimental electromagnetic immunity in the target environment, then enter Step 6. Step 6: Obtain the electromagnetic immunity of the PLC to be tested and the updated target environment test cases.

[0010] Further, the obtaining the basic test cases from the reference test database according to the device parameters of the PLC to be tested, and the test device performing self-calibration of the test device according to the test cases includes: Obtain the basic test cases from the cloud data server according to the device parameters of the PLC to be tested. The test device performs self-calibration of the test device according to the test environment parameters in the basic test cases. If the output data of the test device is consistent with the output data corresponding to the test environment parameters, the self-calibration of the test device is completed; otherwise, an alarm message is sent. The basic test cases include test environment parameters and PLC operation parameters.

[0011] Further, the obtaining the basic EMS data and data fluctuation characteristics of the PLC to be tested based on the test data of the PLC to be tested includes: The described basic EMS data is the output data of the PLC to be tested and the range of change in the difference between the output data of the PLC to be tested and the standard output data obtained under the basic test case. The range of change in the difference is the data fluctuation characteristic.

[0012] Further, collect the electromagnetic interference data of the target environment, obtain the electromagnetic interference characteristics of the target environment based on the electromagnetic interference data, and generate a test case for the target environment according to the electromagnetic interference characteristics of the target environment and the basic test case, including: The electromagnetic interference characteristics of the target environment include the frequency and intensity of characteristic electromagnetic interference within a set period. Adjust the test equipment parameters in the basic test case according to the frequency and intensity of the characteristic electromagnetic interference to generate a test case for the target environment; the characteristic electromagnetic interference includes electrostatic discharge and electrical fast transient pulses.

[0013] Further, obtaining the experimental electromagnetic immunity of the PLC to be tested in the target environment according to the EMS test data corresponding to the target environment includes: Obtain the environmental adaptability characteristics and stability characteristics of the PLC to be tested according to the obtained EMS test data corresponding to the target environment. The environmental adaptability characteristic is the test failure rate of the PLC to be tested; the stability characteristic of the PLC to be tested is the range of change in the difference between the output data of the PLC to be tested corresponding to the target environment and the standard output data according to the EMS test data corresponding to the target environment; according to the ratio of the range of change in the difference between the output data of the PLC to be tested corresponding to the target environment and the standard output data to the range of change in the difference between the output data of the PLC to be tested corresponding to the target environment and the standard output data; according to the sum of the products of the environmental adaptability characteristics and stability characteristics of the PLC to be tested and their respective weights, obtain the experimental electromagnetic immunity of the PLC to be tested in the target environment.

[0014] Further, obtaining the service electromagnetic immunity of the PLC to be tested in the target environment by obtaining the EMS test data of the PLC in the environmental test group through the test case for the target environment according to the set test period includes: According to the PLC operation parameters in the test case for the target environment, perform tests in the target environment according to the set test period to obtain the EMS test data of the PLC in the environmental test group, and obtain the service electromagnetic immunity of the PLC to be tested in the target environment according to the EMS test data of the PLC in the environmental test group.

[0015] Further, if the service electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, including: If the difference between the service electromagnetic immunity of the target environment and the experimental electromagnetic immunity of the target environment is within the set difference threshold range, then they are consistent; otherwise, they are inconsistent.

[0016] Further, updating the test cases for the target environment according to the electromagnetic immunity of the target environment for use includes: Adjust the test equipment parameters in the test cases for the target environment according to the difference between the electromagnetic immunity for use in the standard environment and the experimental electromagnetic immunity of the target environment until the experimental electromagnetic immunity of the target environment is consistent with the electromagnetic immunity for use in the target environment.

[0017] An EMS test system for PLCs, applying the EMS test method for PLCs described above, includes a cloud data server, an electromagnetic interference data acquisition module, test equipment, a communication module, an EMS test data acquisition device, and a data processing module; The test equipment and the communication module are respectively connected to the data processing module; the EMS test data acquisition device, the electromagnetic interference data acquisition module, and the cloud data server are respectively in communication connection with the communication module.

[0018] The beneficial effects of the present invention are: By combining the cloud database and real-time electromagnetic interference data, customized test cases for the target environment are generated, significantly improving the accuracy and practicality of EMS testing. Description of the Drawings

[0019] Figure 1 It is a schematic flowchart of an EMS test method for PLCs; Figure 2 It is a schematic flowchart of obtaining the experimental electromagnetic immunity of the target environment of the PLC to be tested. Detailed Embodiment

[0020] The technical solution of the present invention will be further described in detail below with reference to the drawings, but the protection scope of the present invention is not limited to the following.

[0021] The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0022] As Figure 1 shown, an EMS test method for PLCs includes the following steps: Step 1, obtain basic test cases from the reference test database according to the device parameters of the PLC to be tested, and the test equipment performs self-calibration according to the test cases; after the test equipment is self-calibrated, perform EMS testing on the PLC to be tested according to the test cases, obtain the EMS test data of the PLC to be tested, and obtain the basic EMS data and data fluctuation characteristics of the PLC to be tested according to the test data of the PLC to be tested; Step 2: Collect the electromagnetic interference data of the target environment, obtain the electromagnetic interference characteristics of the target environment based on the electromagnetic interference data, generate the test cases for the target environment according to the electromagnetic interference characteristics of the target environment and the basic test cases, and divide the PLCs to be tested that have completed the basic test into an experimental test group and an environmental test group; Step 3: The testing equipment conducts EMS tests on the PLCs in the experimental test group according to the test cases for the target environment, obtains the EMS test data of the PLCs to be tested corresponding to the target environment, and obtains the experimental electromagnetic immunity of the PLCs to be tested in the target environment, then proceed to Step 5; Step 4: According to the set test cycle, obtain the EMS test data of the PLCs in the environmental test group through the test cases for the target environment, and obtain the service electromagnetic immunity of the PLCs to be tested in the target environment; Step 5: If the service electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, then proceed to Step 6; otherwise, update the test cases for the target environment according to the service electromagnetic immunity of the target environment, and return to Step 3 until the service electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, then proceed to Step 6; Step 6: Obtain the electromagnetic immunity of the PLCs to be tested and the updated test cases for the target environment.

[0023] Obtaining the basic test cases from the reference test database according to the device parameters of the PLCs to be tested, and the testing equipment performs self-calibration of the testing equipment according to the test cases, including: Obtain the basic test cases from the cloud data server according to the device parameters of the PLCs to be tested, and the testing equipment performs self-calibration of the testing equipment according to the test environment parameters in the basic test cases. If the output data of the testing equipment is consistent with the output data corresponding to the test environment parameters, then the self-calibration of the testing equipment is completed; otherwise, an alarm message is sent; the basic test cases include test environment parameters and PLC operation parameters.

[0024] Obtaining the basic EMS data and data fluctuation characteristics of the PLCs to be tested according to the test data of the PLCs to be tested, including: The basic EMS data is the output data of the PLCs to be tested obtained under the basic test cases, as well as the range of variation of the difference between the output data of the PLCs to be tested and the standard output data, and the range of variation of the difference is the data fluctuation characteristic.

[0025] Collecting the electromagnetic interference data of the target environment, obtaining the electromagnetic interference characteristics of the target environment based on the electromagnetic interference data, and generating the test cases for the target environment according to the electromagnetic interference characteristics of the target environment and the basic test cases, including: The electromagnetic interference characteristics of the target environment include the frequency and intensity of characteristic electromagnetic interference within a set period. According to the frequency and intensity of the characteristic electromagnetic interference, the test equipment parameters in the basic test cases are adjusted to generate target environment test cases; the characteristic electromagnetic interference includes electrostatic discharge and electrical fast transient pulses.

[0026] As Figure 2 shown, obtaining the experimental electromagnetic immunity of the PLC under test in the target environment according to the EMS test data corresponding to the target environment includes: According to the obtained EMS test data corresponding to the target environment, the environmental adaptability characteristics and stability characteristics of the PLC under test are obtained. The environmental adaptability characteristic is the test failure rate of the PLC under test; the stability characteristic of the PLC under test is the change range of the difference between the output data of the PLC under test corresponding to the target environment and the standard output data according to the EMS test data corresponding to the target environment; according to the ratio of the change range of the difference between the output data of the PLC under test corresponding to the target environment and the standard output data to the change range of the difference between the output data of the PLC under test corresponding to the target environment and the standard output data; according to the sum of the products of the environmental adaptability characteristics and stability characteristics of the PLC under test and their respective weights, the experimental electromagnetic immunity of the PLC under test in the target environment is obtained.

[0027] Obtaining the service electromagnetic immunity of the PLC under test in the target environment according to the set test period through the target environment test cases includes: According to the PLC operation parameters in the target environment test cases, testing is carried out in the target environment according to the set test period to obtain the EMS test data of the PLC in the environmental test group. According to the EMS test data of the PLC in the environmental test group, the service electromagnetic immunity of the PLC under test in the target environment is obtained.

[0028] If the service electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, it includes: If the difference between the service electromagnetic immunity of the target environment and the experimental electromagnetic immunity of the target environment is within the set difference threshold range, then they are consistent; otherwise, they are inconsistent.

[0029] Updating the target environment test cases according to the service electromagnetic immunity of the target environment includes: According to the difference between the service electromagnetic immunity of the target environment and the experimental electromagnetic immunity of the target environment, the test equipment parameters in the target environment test cases are adjusted until the experimental electromagnetic immunity of the target environment is consistent with the service electromagnetic immunity of the target environment.

[0030] An EMS test system for PLC, applying the described EMS test method for PLC, includes a cloud data server, an electromagnetic interference data acquisition module, a test device, a communication module, an EMS test data acquisition device, and a data processing module; The described test device and communication module are respectively connected to the data processing module; the EMS test data acquisition device, the electromagnetic interference data acquisition module, and the cloud data server are respectively in communication connection with the communication module.

[0031] Specifically, the present invention provides an EMS test method for PLC, and this method includes the following steps: Step 1: Basic test and self - calibration Obtain basic test cases: According to the device parameters of the PLC to be tested (such as model, specification, expected working environment, etc.), retrieve and obtain the matching basic test cases in the benchmark test database of the cloud data server. These test cases contain standard test environment parameters and PLC operation parameters, which are the basis for testing.

[0032] Self - calibration of the test device: The test device self - calibrates according to the test environment parameters in the obtained basic test cases to ensure that the output data of the test device is consistent with the expected output data, thereby ensuring the accuracy of the test. If the calibration fails, an alarm message is issued to prompt the user to check the test device or recalibrate.

[0033] Execute the basic EMS test: After self - calibration is completed, the test device performs an EMS test on the PLC to be tested according to the basic test cases and records the test data.

[0034] Data analysis: According to the test data, calculate the basic EMS data of the PLC to be tested (such as the deviation range of the output data) and the data fluctuation characteristics, providing a benchmark for subsequent analysis.

[0035] Step 2: Generation of target environment test cases Collect electromagnetic interference data: Use the electromagnetic interference data acquisition module to collect electromagnetic interference data within a specific period in the target environment, including the frequency and intensity of characteristic electromagnetic interferences such as electrostatic discharge and electrical fast transient pulses.

[0036] Analyze electromagnetic interference characteristics: Based on the collected data, analyze the electromagnetic interference characteristics of the target environment and identify the interference sources that may have a significant impact on the operation of the PLC.

[0037] Generate target environment test cases: Combine the basic test cases and the electromagnetic interference characteristics of the target environment, adjust the parameters of the test device, and generate customized test cases for the target environment.

[0038] Group testing: Divide the PLCs to be tested that have completed the basic test into an experimental test group and an environmental test group for laboratory simulation testing and actual environmental testing respectively.

[0039] Step 3: EMS testing for the experimental test group Execute the EMS test for the target environment: The test equipment tests the PLCs in the experimental test group according to the target environment test cases and records the EMS test data corresponding to the target environment.

[0040] Calculate the experimental electromagnetic immunity: Analyze the test data to obtain the environmental adaptability characteristics (such as the test failure rate) and stability characteristics (such as the deviation change range and its ratio between the output data and the standard data) of the PLCs to be tested in the target environment, and comprehensively calculate the experimental electromagnetic immunity.

[0041] Step 4: EMS testing for the environmental test group Periodic testing: According to the set test cycle, conduct EMS testing on the PLCs in the environmental test group in the target environment and record the test data. Calculate the service electromagnetic immunity: Based on the environmental test data, evaluate the electromagnetic immunity of the PLCs to be tested during actual use in the target environment.

[0042] Step 5: Consistency verification and test case update Consistency judgment: Compare the service electromagnetic immunity and the experimental electromagnetic immunity of the target environment. If the difference between the two is within the set threshold range, it is considered consistent; otherwise, it is considered inconsistent.

[0043] Test case update: For inconsistent situations, adjust the test equipment parameters in the target environment test cases according to the feedback of the service electromagnetic immunity, and repeat Steps 3 to 5 until the two are consistent.

[0044] Step 6: Output results Final electromagnetic immunity assessment: When the experimental electromagnetic immunity is consistent with the service electromagnetic immunity, output the final electromagnetic immunity assessment results of the PLCs to be tested in the target environment. Update the test case library: Update the verified and effective target environment test cases to the cloud data server to provide reference for future PLC testing in similar environments.

[0045] According to the device parameters of the PLCs to be tested, obtain basic test cases from the benchmark test database, and the test equipment performs self-calibration according to the test cases, specifically including: Device parameter matching: Match the device parameters of the PLCs to be tested with the records in the cloud database through an algorithm and select the most similar basic test cases.

[0046] Self - calibration process: The test equipment is automatically configured according to the environmental settings (such as temperature, humidity, electromagnetic background noise, etc.) in the selected basic test cases, and the equipment output is verified through a preset calibration program to ensure test accuracy.

[0047] Based on the test data of the PLC to be tested, obtain the basic EMS data and data fluctuation characteristics of the PLC to be tested, specifically including: Calculation of basic EMS data: Compare the output of the PLC to be tested under standard test conditions with the expected standard output, and calculate the deviation value as the basic EMS data.

[0048] Analysis of data fluctuation characteristics: Statistically analyze the fluctuation conditions in the test data, such as the maximum value, minimum value, standard deviation, etc., as data fluctuation characteristics for evaluating the stability of the PLC.

[0049] Collect the electromagnetic interference data of the target environment, obtain the electromagnetic interference characteristics of the target environment based on the electromagnetic interference data, and generate the test cases for the target environment according to the electromagnetic interference characteristics of the target environment and the basic test cases, specifically including: Real - time data collection: Use a high - precision electromagnetic interference data collection module to continuously monitor the electromagnetic interference situation of the target environment.

[0050] Feature extraction: Through signal processing technology, extract key parameters such as the frequency, intensity, and duration of the characteristic electromagnetic interference.

[0051] Test case customization: According to the extracted electromagnetic interference characteristics, adjust the test parameters in the basic test cases, such as adding interference signals of specific frequencies to simulate the target environment.

[0052] Based on the EMS test data of the corresponding target environment, obtain the experimental electromagnetic immunity of the PLC to be tested in the target environment, specifically including: Environmental adaptability assessment: Evaluate its adaptability to the electromagnetic interference of the target environment by analyzing the failure rate of the PLC during the test process.

[0053] Stability assessment: Calculate the deviation change range and its ratio between the PLC output data and the standard data to reflect the output stability of the PLC under interference.

[0054] Comprehensive assessment: Combine the environmental adaptability and stability assessment results, and calculate the experimental electromagnetic immunity according to their respective weights.

[0055] Based on the set test cycle, obtain the EMS test data of the PLC in the environmental test group through the test cases of the target environment, and obtain the service electromagnetic immunity of the PLC to be tested in the target environment, specifically including: Periodic Test Plan: Develop a detailed test plan, including test time, frequency, duration, etc. Field Test Execution: In the target environment, conduct EMS tests on the PLC of the environmental test group according to the plan and record the actual operation data. Calculation of Operational Electromagnetic Immunity: Based on the field test data, use the same evaluation method as the experimental test to calculate the operational electromagnetic immunity.

[0056] The situation where the operational electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment specifically includes: Consistency Judgment Criterion: Set an acceptable difference threshold range to determine whether the two immunity values are consistent.

[0057] Judgment Process: Compare the two immunity values. If the difference is within the threshold range, they are considered consistent; otherwise, further analyze the reasons and adjust the test cases.

[0058] Updating the test cases for the target environment according to the operational electromagnetic immunity of the target environment specifically includes: Difference Analysis: Analyze in detail the difference between the experimental and operational electromagnetic immunity and identify the factors that may cause the difference.

[0059] Adjustment of Test Cases: According to the analysis results, adjust the relevant parameters in the test cases for the target environment, such as increasing or decreasing specific types of electromagnetic interference, to be closer to the actual usage environment.

[0060] Iterative Verification: Retest using the adjusted test cases until the experimental and operational electromagnetic immunity are consistent.

[0061] To implement the above test method, the present invention also provides an EMS test system for PLC, which includes: Cloud Data Server: Store a large number of basic test cases, support quick retrieval and matching of cases according to PLC device parameters, and provide remote calibration support for test equipment.

[0062] Electromagnetic Interference Data Acquisition Module: Deployed in the target environment, responsible for real-time collection of electromagnetic interference data, providing a data basis for generating test cases for the target environment.

[0063] Test Equipment: The core equipment for performing EMS tests, capable of automatically configuring the test environment according to the test cases and accurately testing the PLC.

[0064] Communication Module: Realize data transmission between the test system, the cloud server, and the electromagnetic interference data acquisition module to ensure smooth information flow.

[0065] EMS Test Data Acquisition Device: Responsible for collecting various data during the test process, providing raw materials for subsequent analysis.

[0066] Data processing module: Process and analyze the collected test data, calculate key indicators such as basic EMS data, data fluctuation characteristics, experimental and operational electromagnetic immunity, etc., and support dynamic update of test cases. Embodiment

[0067] A certain industrial plant plans to deploy a new PLC system. To ensure its stable operation in a complex electromagnetic environment, the technical method of this application is used for PLC testing, including: According to the model, specifications, and expected working environment (such as temperature, humidity, electromagnetic background, etc.) of the PLC to be tested, retrieve and obtain matching basic test cases from the cloud data server. The test equipment self-calibrates according to the environmental settings in the basic test cases to ensure the accuracy of the output data. After successful calibration, conduct a basic EMS test on the PLC and record the test data.

[0068] Calculate the basic EMS data (such as deviation range) and data fluctuation characteristics of the PLC to provide a benchmark for subsequent analysis.

[0069] Deploy an electromagnetic interference data acquisition module inside the industrial plant to continuously monitor and record electromagnetic interference data within a specific period. Identify significant interference sources such as electrostatic discharge and electrical fast transient pulses. Combine the basic test cases and electromagnetic interference characteristics to adjust the parameters of the test equipment and generate customized test cases for the industrial plant.

[0070] Divide the PLC into an experimental test group and an environmental test group: Experimental test group: Test the PLC in the experimental test group according to the customized test cases. Analyze the test data to obtain the environmental adaptability characteristics and stability characteristics of the PLC in the industrial plant environment, and comprehensively calculate the experimental electromagnetic immunity.

[0071] Environmental test group: Conduct EMS tests on the PLC in the environmental test group in the industrial plant according to the set test cycle. Based on the on-site test data, evaluate the electromagnetic immunity of the PLC during actual use.

[0072] Compare the experimental electromagnetic immunity with the operational electromagnetic immunity to confirm their consistency. For inconsistent situations, adjust the test cases according to the feedback of the operational electromagnetic immunity and repeat the test until they are consistent.

[0073] Output the final electromagnetic immunity evaluation result of the PLC in the industrial plant environment. Update the verified and effective target environmental test cases to the cloud data server.

Claims

1. An EMS testing method for PLC, characterized in that: The steps include: Step 1: According to the device parameters of the PLC to be tested, basic test cases are obtained from the benchmark test database, and the test equipment performs self-calibration of the test equipment according to the test cases; after the test equipment is self-calibrated, an EMS test is performed on the PLC to be tested according to the test cases to obtain EMS test data of the PLC to be tested, and basic EMS data and data fluctuation characteristics of the PLC to be tested are obtained according to the test data of the PLC to be tested; Step 2: Collect electromagnetic interference data of the target environment, obtain electromagnetic interference characteristics of the target environment according to the electromagnetic interference data, generate target environment test cases according to the electromagnetic interference characteristics of the target environment and basic test cases, and divide the PLCs to be tested that have completed the basic test into an experimental test group and an environmental test group; Step 3: The test equipment performs EMS test on the PLC of the experimental test group according to the target environment test case, obtains the EMS test data of the PLC to be tested corresponding to the target environment, and obtains the experimental electromagnetic immunity of the target environment of the PLC to be tested according to the EMS test data corresponding to the target environment, and then proceeds to step 5; Step 4: According to the set test cycle, the EMS test data of the PLC of the environmental test group is obtained through the target environment test case, and the electromagnetic immunity of the target environment of the PLC to be tested is obtained; Step 5: If the electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, proceed to step 6; otherwise, update the target environment test case according to the electromagnetic immunity of the target environment, and return to step 3 until the electromagnetic immunity of the target environment is consistent with the experimental electromagnetic immunity of the target environment, and proceed to step 6; Step 6: Obtain the electromagnetic immunity of the PLC to be tested and the updated target environment test case.

2. The EMS testing method for PLC according to claim 1, characterized in that: The method of obtaining basic test cases in a benchmark test database according to the device parameters of the PLC to be tested, and the test device performing self-calibration of the test device according to the test cases, includes: According to the device parameters of the PLC to be tested, basic test cases are obtained from the cloud data server. The test equipment performs self-calibration of the test equipment according to the test environment parameters in the basic test cases. If the output data of the test equipment is consistent with the output data corresponding to the test environment parameters, the self-calibration of the test equipment is completed, otherwise, an alarm message is issued; the basic test cases include test environment parameters and PLC operating parameters.

3. The EMS testing method for PLC according to claim 2, characterized in that: The method of obtaining the basic EMS data and data fluctuation characteristics of the PLC to be tested according to the test data of the PLC to be tested includes: The basic EMS data is the PLC output data to be tested, and the difference range between the PLC output data to be tested and the standard output data, obtained under the basic test case. The difference range is the data fluctuation characteristic.

4. The EMS testing method for PLC according to claim 3, characterized in that: The collecting of electromagnetic interference data of the target environment, obtaining electromagnetic interference characteristics of the target environment according to the electromagnetic interference data, and generating target environment test cases according to the electromagnetic interference characteristics of the target environment and basic test cases include: The electromagnetic interference characteristics of the target environment include the frequency and intensity of the characteristic electromagnetic interference within a set period. According to the frequency and intensity of the characteristic electromagnetic interference, the test equipment parameters in the basic test case are adjusted to generate the target environment test case; the characteristic electromagnetic interference includes electrostatic discharge and electrical fast transient pulses.

5. The EMS testing method for PLC according to claim 4, characterized in that: The method of obtaining the experimental electromagnetic immunity of the target environment of the PLC to be tested according to the EMS test data of the corresponding target environment includes: According to the obtained EMS test data of the corresponding target environment, the environmental adaptability characteristics and stability characteristics of the PLC to be tested are obtained, and the environmental adaptability characteristics are the test failure rate of the PLC to be tested; the stability characteristics of the PLC to be tested are the difference variation range between the output data of the PLC to be tested corresponding to the target environment and the standard output data obtained according to the EMS test data of the corresponding target environment; according to the ratio of the difference variation range between the output data of the PLC to be tested corresponding to the target environment and the standard output data to the difference variation range between the output data of the PLC to be tested corresponding to the target environment and the standard output data; according to the sum of the products of the environmental adaptability characteristics and stability characteristics of the PLC to be tested and their respective weights, the experimental electromagnetic immunity of the target environment of the PLC to be tested is obtained.

6. The EMS testing method for PLC according to claim 4, characterized in that: The method of obtaining the EMS test data of the PLC of the environmental test group according to the set test cycle through the target environment test case and obtaining the electromagnetic interference immunity of the target environment of the PLC to be tested includes: According to the PLC operating parameters in the target environment test case and the set test cycle, the test is performed in the target environment to obtain the EMS test data of the environmental test group PLC. Based on the EMS test data of the environmental test group PLC, the electromagnetic immunity of the target environment of the PLC to be tested is obtained.

7. The EMS testing method for PLC according to claim 6, characterized in that: If the electromagnetic interference immunity of the target environment is consistent with the experimental electromagnetic interference immunity of the target environment, it includes: If the difference between the target environment's use electromagnetic immunity level and the target environment's experimental electromagnetic immunity level is within the set difference threshold range, they are consistent; otherwise, they are inconsistent.

8. The EMS testing method for PLC according to claim 7, characterized in that: The target environment test case is updated according to the electromagnetic immunity of the target environment, including: According to the difference between the electromagnetic immunity level of the standard environment and the experimental electromagnetic immunity level of the target environment, adjust the test equipment parameters in the target environment test case until the experimental electromagnetic immunity level of the target environment is consistent with the electromagnetic immunity level of the target environment.

9. An EMS test system for PLC, characterized in that: An EMS test method for PLC according to any one of claims 1 to 8 is applied, comprising a cloud data server, an electromagnetic interference data acquisition module, a test device, a communication module, an EMS test data acquisition device and a data processing module; The test equipment and communication module are respectively connected to the data processing module; the EMS test data acquisition device, electromagnetic interference data acquisition module, and cloud data server are respectively connected to the communication module for communication.

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