EMC (Electro Magnetic Compatibility) test method for large LED display screen of smart venue

Abstract

The invention discloses an EMC test method for a large LED display screen of a smart venue, and the method comprises the steps: determining a test item needing to be completed according to the technical characteristics of a to-be-tested large LED display screen, determining the setting of a test environment, determining the parameters of a wireless signal, and designing an EMC test outline; the EMC test risk of the large LED display screen is evaluated, and a modification suggestion is provided; the electromagnetic environment of an outdoor test site is measured, and it is ensured that the test site is suitable for the EMC test of the large LED display screen; building a test environment; testing the large LED display screen according to an EMC test outline, assisting the test by the evaluation result in the step 2, and recording test data; storing test data, and removing the field; and summarizing test data, judging whether the EMC test is qualified or not according to analysis of the test data, and issuing an EMC test report.

Description

Technical Field

[0001] The present invention relates to the field of equipment detection technology, and in particular to an EMC (Electro Magnetic Compatibility) testing method for a large LED display screen in a smart venue. Background Art

[0002] With the widespread application of today's high electrification and electronics, electrical equipment systems have brought great convenience to production and life. When people watch games or performances in stadiums, they often need to watch live scores, playbacks, advertisements and interactions through LED screens. Stadium LED screens need to have high brightness, high contrast, high refresh rate and wide viewing angle to ensure clear visual effects under any lighting conditions. Considering the use environment, LED screens need to use durable materials to withstand the influence of harsh conditions such as sunlight, rain and dust; in addition, there are various installation methods, including center hanging, fence installation, etc., to adapt to different venue structures and audience viewing requirements.

[0003] Large LED screens improve the viewing experience of the audience in the venue, but also bring some problems. This kind of electrical equipment will be more or less interfered by the electromagnetic field inside and outside the system during operation. This electromagnetic interference will affect the performance of the system to a certain extent and reduce the reliability and safety of the system. At the same time, with the increase of electronic products in the venue and the influence of the surrounding environment, the electromagnetic compatibility issue becomes more and more important. Electromagnetic compatibility testing of the display helps to minimize the possibility of radiation or conducted radiation generated by the equipment interfering with other electronic products nearby. In addition, electromagnetic compatibility testing of the display can ensure that the display continues to operate as expected around other electromagnetic radiation sources, but due to the above-mentioned display level, material use, installation location and its own volume, the electromagnetic compatibility testing of large LED screens suitable for use in gymnasiums has more special requirements.

[0004] The existing detection methods are usually carried out under darkroom conditions. When conducting electromagnetic compatibility testing, the entire set of LED display screens including the control unit is placed in the darkroom, and the test signal is transmitted to the monitoring computer outside the darkroom via the CAN / USB bus, thereby testing the relevant electromagnetic compatibility of the LED display screen. On this basis, since the control unit will generate radiation signals, it will cause radiation effects on the LED display screen being tested, which is not conducive to troubleshooting the fault interference of the tested display screen. In addition, the traditional CAN (Controller Area Network) / USB (Universal Serial Bus) transmission rate is low and cannot meet the transmission of high-definition video signals. For high-definition LED displays similar to those mounted on vehicles, the test environment does not meet the daily use environment.

[0005] To solve the above problems, the prior art will place the display screen to be tested and the optical receiver in a dark room, and the control unit and the optical transmitter outside the dark room; the control unit is connected to the optical transmitter, and the optical transmitter is used to transmit the electromagnetic compatibility test signal provided by the control unit. By placing the control unit outside the dark room, it is possible to avoid the control unit from causing signal interference to the electromagnetic compatibility test. Both the optical transmitter and the optical receiver include APIX 3 (Automotive Pixel Link) photocouplers, which can improve the transmission efficiency of the test signal and meet the transmission of high-definition video signals, thereby improving the accuracy of the detection and the data transmission rate during the detection.

[0006] In the prior art, the inventions of electromagnetic compatibility detection technology for LED display screens are all based on the premise of conventional testing in a darkroom and improving the accuracy of the test on this basis. However, nowadays, in order to be suitable for large venues, the size of LED display screens is also increasing. General darkrooms cannot meet the test space requirements. For businesses, renting a large darkroom to test only LED equipment is too expensive; if it is split into several small pieces for testing, it cannot meet the original usage scenario and the results are biased. Therefore, it is necessary to provide an EMC test method for large LED display screens in smart venues, which can solve the problem that darkrooms in the prior art cannot meet the test requirements of LED display screens for large outdoor use and there are deviations when split into small pieces for testing. Summary of the invention

[0007] The purpose of the present invention is to provide an EMC testing method for a large LED display screen in a smart venue, which can solve the problem in the prior art that a darkroom cannot meet the testing requirements of a large outdoor LED display screen and that there are deviations when the test is split into small pieces.

[0008] The present invention is achieved in that:

[0009] An EMC test method for a large LED display screen in a smart venue includes the following steps:

[0010] Step 1: According to the technical characteristics of the large LED display to be tested, determine the test items to be completed, determine the test environment settings, determine the parameters of the wireless signal, and design the EMC test outline;

[0011] Step 2: Evaluate the EMC test risks of large LED displays and propose modification suggestions;

[0012] Step 3: Measure the electromagnetic environment of the outdoor test site to ensure that the test site is suitable for EMC testing of large LED displays;

[0013] Step 4: Setting up the test environment;

[0014] Step 5: Test the large LED display screen according to the EMC test outline, and use the evaluation results in step 2 to assist the test, and record the test data;

[0015] Step 6: Save the test data and exit the site;

[0016] Step 7: Summarize the test data, determine whether the EMC test is qualified based on the test data analysis, and issue an EMC test report.

[0017] In the step 1, according to the technical characteristics of the large LED display screen to be tested, the corresponding national standards are selected to determine the test types of the EMC test: including emission test and immunity test; determine the environmental settings for the test, including: the location of the radiation source equipment and the location of the sensitive source equipment; determine the parameters of the wireless communication signal; design the EMC test outline, which includes: description of the LED display screen to be tested, test items and indicators, test methods, test equipment and test procedures.

[0018] The step 2 comprises the following steps:

[0019] Step 2.1: Before the formal test, for the large LED display to be tested, it is necessary to obtain its design schematics, including circuit principles, circuit boards and complete mechanical structure drawings, evaluate the EMC risks in the design, and provide modification suggestions;

[0020] Step 2.2: Combined with the test environment and test outline, evaluate the risk and pass rate of each test of the large LED display screen under test, and use the evaluation results to assist the formal test.

[0021] In the step 2, the risk assessment includes assisting where there are limitations during the actual test. Since the test environment is set up in an outdoor scene, some conditions cannot be met, resulting in the inability to test according to the test outline and relevant test standards. The risk points in the test are simulated and evaluated, and the test results are subsequently bidirectionally verified.

[0022] In step 2, when a test in the assessment passes and also passes during the actual test, it means that the assessment content is consistent with the actual test situation of the test; when the assessment passes but the actual test fails, a weighted analysis is performed on each risk to consider the risk factors that affect the failure of the test.

[0023] In step 3, the electromagnetic environment of the outdoor test site includes electromagnetic wave interference from radio broadcasting, mobile phone communications, walkie-talkies, radio stations, radars, and surrounding large industrial equipment.

[0024] The step 4 comprises the following sub-steps:

[0025] Step 4.1: Before testing begins, the outdoor test area should be cleaned;

[0026] Step 4.2: Debug the antenna positions of the radiation source equipment and the sensitive source equipment according to the drawings, and set up the antennas;

[0027] Step 4.3: Place the test instrument at a safe distance from the large LED display to be tested, and connect the cables between the instrument, antenna, and power supply according to the test outline;

[0028] Step 4.4: After the arrangement is completed, start and debug the test instruments and antennas to make the entire test system ready for working.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. Since the present invention performs an EMC test risk assessment before the formal test, it can make up for the defect that some test conditions cannot be met during outdoor test, and help to simplify the test process and improve test efficiency. At the same time, rectification is carried out according to the evaluation results and modification suggestions before the formal test, which helps to improve the pass rate during the formal test, reduce the number of repeated tests when the EMC test fails and the time required for project testing, and reduce project costs.

[0031] 2. Since the present invention is tested in an outdoor test site, which is different from the relatively mature and stable darkroom test environment of small equipment indoors, the electromagnetic environment of the outdoor test site is relatively complex. The electromagnetic interference test of the environment is first performed to determine whether the outdoor test site is suitable for meeting the EMC test environment requirements of the large LED display. If not, the environment needs to be rectified or the test site needs to be replaced to ensure that the test environment of the large LED display meets the test requirements, thereby ensuring the accuracy of the EMC test results.

[0032] 3. Since the present invention conducts testing in an outdoor testing site with a wide area, it can be applied to test objects of large LED display screens, and there is no need to split the test objects into small pieces for testing. It gets rid of the need for a darkroom in a traditional LED display screen testing environment, and can be conducted in any outdoor site after the test environment has been inspected or rectified. The usage scenario is closer to the actual usage of large LED display screens, and there is a big difference between the EMC testing of conventional small LED devices and vehicle-mounted LED devices, thus filling the gap in the EMC testing solution for large LED display screens. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of the EMC testing method of the present invention for a large LED display screen in a smart venue. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] Please see attached Figure 1 , an EMC test method for a large LED display screen in a smart venue, comprising the following steps:

[0036] Step 1: According to the technical characteristics of the large LED display to be tested, determine the test items to be completed, determine the test environment settings, determine the parameters of the wireless signal, and design the EMC test outline.

[0037] In the step 1, according to the technical characteristics of the large LED display screen to be tested, the corresponding national standards are selected to determine the test type of EMC test: generally including emission test and immunity test; determine the environmental settings during the test, including: the location of the radiation source equipment and the location of the sensitive source equipment; determine the parameters of the wireless communication signal; design the EMC test outline, which includes: description of the LED display screen to be tested, test items and indicators, test methods, test equipment and test procedures, etc.

[0038] Step 2: Evaluate the EMC test risks of large LED displays and propose modification suggestions.

[0039] The step 2 comprises the following steps:

[0040] Step 2.1: Before the formal test, for the large LED display to be tested, it is necessary to obtain its design schematics, including circuit principles, circuit boards, and complete mechanical structure drawings, etc., to evaluate the EMC risks in the design and provide modification suggestions.

[0041] Since the large LED display screen to be tested may have EMC risks in its design, it is evaluated according to the standards and corresponding rectification suggestions are provided.

[0042] Step 2.2: Combined with the test environment and test outline, evaluate the risk and pass rate of each test of the large LED display screen under test, and use the evaluation results to assist the formal test.

[0043] Preferably, a computer equipped with an EMC risk assessment module of the prior art can be used to simulate the risk and pass rate of each test of the large LED display screen, which is used to evaluate the risk and pass rate of the test, which can reduce the complexity of field testing and provide a reference for electromagnetic compatibility testing of large-scale equipment of the same type. The specific test simulation content in the EMC risk assessment module can be set according to the adaptability of the EMC test outline of the large LED display screen to be tested.

[0044] Risk assessment includes assisting with limitations in actual testing. For example, since the test environment is set up in an outdoor scene, some conditions may not be met, resulting in the inability to test according to the test outline and relevant test standards. At this time, the risk points in the test are simulated and evaluated, and the test results are bidirectionally verified later.

[0045] When a test in the assessment passes and also passes during the actual test, it means that the assessment content is consistent with the actual test situation of the test; when the assessment passes but the actual test fails, the weighted analysis of each risk can be performed to consider the risk factors that affect the failure of the test.

[0046] Step 3: Measure the electromagnetic environment of the outdoor test site to ensure that the test site is suitable for EMC testing of large LED displays.

[0047] Since the EMC test of large LED display screen equipment is conducted in an outdoor field environment, but considering the environment during normal use and the inevitable interference of various electromagnetic waves outdoors, such as radio broadcasting, mobile phone communications, walkie-talkies, radio stations, radars, and surrounding large industrial equipment, etc., it is necessary to measure the electromagnetic environment of the outdoor test site to determine whether the outdoor test site is suitable for EMC testing of large LED display screens. If outdoor interference cannot be avoided, appropriate treatment measures should be considered to avoid interference of the outdoor electromagnetic environment on the EMC test process, or even change the test site.

[0048] Step 4: Set up the test environment.

[0049] The step 4 comprises the following sub-steps:

[0050] Step 4.1: Before testing begins, the outdoor test area should be cleaned.

[0051] Step 4.2: Debug the antenna positions of the radiation source device and the sensitive source device according to the drawings, and set up the antennas.

[0052] Step 4.3: Place the test instrument at a safe distance from the large LED display to be tested. The cables connecting the instrument, antenna, and power supply must be arranged according to the test outline.

[0053] Step 4.4: After the arrangement is completed, start and debug the test instruments and antennas to make the entire test system ready for working.

[0054] Step 5: Test the large LED display according to the EMC test outline, and use the evaluation results in step 2 to assist the test.

[0055] During the test, the test shall be carried out according to the EMC test outline and the test data shall be recorded.

[0056] It should be noted that in some optional implementations, taking the external RF immunity test as an example, it is used to test the ability of all electronic devices in a large LED display screen and the cables connected between the electronic devices to resist external RF interference. Common external RF interference sources include radio broadcasting, mobile phone communications, walkie-talkies, radio stations, high-voltage lines, substations, and surrounding large industrial equipment. There are two main ways for external RF interference to enter a large LED display screen. One is spatial radiation coupling, that is, spatial interference waves enter the interior of the display screen through the shielding holes or poor shielding parts of the large LED display screen body and couple into the electronic equipment; the other is coupling cable conduction, that is, the interference waves are coupled into the antenna and cable of the large LED display screen, and then transmitted to the electronic equipment in the screen through the cable. When conducting an external RF sensitivity test, the body opening of the large LED display screen, the mounting plate of the electronic equipment, and the antenna seat are preset as external RF test points. The distance between the test antenna of the radiation source equipment and the external RF test point, the frequency increment, and the frequency range must be set according to the test outline and test standards, and the working frequency of the large LED display screen to be tested must be avoided. A test signal of predetermined intensity is generated through the radiation source device and radiated to the external RF test point. The test signal of predetermined intensity reaches the signal strength specified in the national standard to monitor whether the large LED display can operate normally. Then the test frequency, antenna polarization mode, and test points on the large LED display are continuously changed to complete the test plan.

[0057] Step 6: Save the test data and exit.

[0058] After saving the test data, the large LED display screen, radiation source equipment and sensitive source equipment were removed, and the outdoor test site was cleaned up.

[0059] Step 7: Summarize the test data, determine whether the EMC test is qualified based on the test data analysis, and issue an EMC test report.

[0060] Preferably, the EMC test method of the present invention can be composed of a test system consisting of a console, a communication management module, an anti-interference detector, a measuring receiver, an anti-interference three-phase power source, a signal generator and an isolation transformer, and the corresponding EMC test is performed on the large LED display screen under test; the console is wirelessly connected to other test equipment through the communication management module; the anti-interference detector can be used to apply interference signals to the large LED display screen under test, and is used to test the anti-interference ability of the large LED display screen under test, and the measuring receiver can be used to receive the transmitted interference signal; the anti-interference three-phase power source is connected to the voltage interface and the current interface of the large LED display screen under test, and is used to output voltage simulation signals and current simulation signals to the large LED display screen under test; the signal generator is connected to the input and output interface of the large LED display screen under test, and is used to output signals; the isolation transformer is connected to the power supply interface of the large LED display screen under test; during the test of the large LED display screen under test, the console monitors the operating status of the large LED display screen under test, detects various test indicators, and generates a test report based on the test data. In addition, before the formal test, a complete EMC risk assessment module can be used to conduct risk assessment on the test items to assist the formal test.

[0061] There is currently no relatively complete test system for EMC testing of large LED display screens. The present invention can make up for this gap and take both reliability and economy into consideration. Therefore, facing the ever-increasing market size, the present invention has broad commercial prospects.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An EMC test method for large LED display screens in smart venues, characterized by: The following steps are involved: Step 1: According to the technical characteristics of the large LED display to be tested, determine the test items to be completed, determine the test environment settings, determine the parameters of the wireless signal, and design the EMC test outline; Step 2: Evaluate the EMC test risks of large LED displays and propose modification suggestions; Step 3: Measure the electromagnetic environment of the outdoor test site to ensure that the test site is suitable for EMC testing of large LED displays; Step 4: Setting up the test environment; Step 5: Test the large LED display screen according to the EMC test outline, and use the evaluation results in step 2 to assist the test, and record the test data; Step 6: Save the test data and exit the site; Step 7: Summarize the test data, determine whether the EMC test is qualified based on the test data analysis, and issue an EMC test report.

2. The EMC test method for a large LED display screen in a smart venue according to claim 1 is characterized in that: In the step 1, according to the technical characteristics of the large LED display screen to be tested, the corresponding national standard is selected to determine the test type of EMC test: including emission test and anti-interference test; Determine the environmental settings for the test, including: the location of the radiation source equipment and the location of the sensitive source equipment; determine the parameters of the wireless communication signal; design the EMC test outline, which includes: description of the LED display screen to be tested, test items and indicators, test methods, test equipment and test process.

3. The EMC test method for a large LED display screen in a smart venue according to claim 1 is characterized in that: The step 2 comprises the following steps: Step 2.1: Before the formal test, for the large LED display to be tested, it is necessary to obtain its design schematics, including circuit principles, circuit boards and complete mechanical structure drawings, evaluate the EMC risks in the design, and provide modification suggestions; Step 2.2: Combined with the test environment and test outline, evaluate the risk and pass rate of each test of the large LED display screen under test, and use the evaluation results to assist the formal test.

4. The EMC test method for a large LED display screen in a smart venue according to claim 3 is characterized in that: In the step 2, the risk assessment includes assisting where there are limitations during the actual test. Since the test environment is set up in an outdoor scene, some conditions cannot be met, resulting in the inability to test according to the test outline and relevant test standards. The risk points in the test are simulated and evaluated, and the test results are subsequently bidirectionally verified.

5. The EMC test method for a large LED display screen in a smart venue according to claim 3 is characterized in that: In step 2, when a test in the assessment passes and also passes during the actual test, it means that the assessment content is consistent with the actual test situation of the test; when the assessment passes but the actual test fails, a weighted analysis is performed on each risk to consider the risk factors that affect the failure of the test.

6. The EMC test method for a large LED display screen in a smart venue according to claim 1 is characterized in that: In step 3, the electromagnetic environment of the outdoor test site includes electromagnetic wave interference from radio broadcasting, mobile phone communications, walkie-talkies, radio stations, radars, and surrounding large industrial equipment.

7. The EMC test method for a large LED display screen in a smart venue according to claim 1 is characterized in that: The step 4 comprises the following sub-steps: ； Step 4.1: Before testing begins, the outdoor test area should be cleaned; Step 4.2: Debug the antenna positions of the radiation source equipment and the sensitive source equipment according to the drawings, and set up the antennas; Step 4.3: Place the test instrument at a safe distance from the large LED display to be tested, and connect the cables between the instrument, antenna, and power supply according to the test outline; Step 4.4: After the arrangement is completed, start and debug the test instruments and antennas to make the entire test system ready for working.

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