EMC Test Fixture Dedicated to LRM Module

Abstract

The present invention provides a dedicated EMC test fixture for the LRM module, which relates to the field of electromagnetic compatibility testing. It includes a main structure box, a module mounting rack, cable accessories, and an LRM normal temperature test board. The main structure box is a metal shielding box body. One end of the main structure box is provided with module socket holes, and the other end of the main structure box is connected to a cable conduit. The inner wall of the cable conduit is filled with a layer of shielding copper mesh. An LRM socket is installed in the module socket holes. The LRM normal temperature test board is installed on the inner side wall of the main structure box. The LRM plug is adapted to the LRM socket, and the LRM plug is inserted into the LRM socket. The present invention can more comprehensively and deeply verify the electromagnetic compatibility ability of the LRM module, accurately analyze the problems encountered by the LRM module during testing, and avoid potential system failure hazards caused by electromagnetic compatibility problems. The main structure box adopts a metal shielding box body, the inner wall of the cable conduit is filled with shielding copper mesh, and shielding spring pieces are installed around the module socket holes, which can effectively shield external electromagnetic interference.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic compatibility testing, and particularly to a dedicated EMC test fixture for LRM modules. Background Art

[0002] In complex electronic systems such as aircraft, LRM modules such as power modules, communication modules, and clock modules are widely used. The electromagnetic compatibility performance of these LRM modules is crucial for the stable operation of the entire system. Taking an aircraft as an example, the power module is the core of the energy supply of the electronic system, and its stable output is crucial for maintaining the normal operation of each module. Once the electromagnetic compatibility performance of the power module has problems, the electromagnetic interference generated may cause unstable power supply to other modules, thereby triggering system failures and affecting the flight safety of the aircraft; the communication module is responsible for information transmission inside the aircraft and between the aircraft and the outside. Its electromagnetic compatibility performance is directly related to the quality and reliability of communication. If the communication module is subject to electromagnetic interference, problems such as signal loss and increased bit error rate may occur, and in severe cases, communication interruption may even occur, causing the aircraft to lose contact with the ground control center; the clock module provides an accurate time reference for the entire system. If the electromagnetic interference generated by it is not effectively controlled, it may affect the synchronous operation of other modules, resulting in system timing chaos and reducing the overall performance of the system.

[0003] However, there are many problems in the electromagnetic compatibility testing of LRM modules at present. On the one hand, existing test tools are difficult to fully verify the electromagnetic compatibility capabilities of the modules. In key test items such as electromagnetic compatibility conducted susceptibility, radiated susceptibility, radiated emission, and conducted emission, it is impossible to accurately verify the LRM modules specifically, and it is also difficult to quickly and accurately analyze the problems encountered by the modules during the test. This results in the electromagnetic compatibility problems of the modules being difficult to be fully discovered and solved in the early stage of system integration, laying hidden dangers for later delivery acceptance and system operation; on the other hand, there is a lack of test fixtures with strong general interchangeability. Different models of LRM modules often require customized special fixtures, which not only increases costs but also makes the test process cumbersome and complex, with low efficiency. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a dedicated EMC test fixture for LRM modules.

[0005] The dedicated EMC test fixture for LRM modules provided by the present invention includes a main structure box, a module mounting rack, cable accessories, and an LRM normal temperature test board;

[0006] The main structure box is a metal shielding box. One end of the main structure box is provided with module socket holes, and the other end of the main structure box is communicated with a cable threading pipe. The inner wall of the cable threading pipe is filled with a layer of shielding copper mesh. An LRM socket is installed in the module socket hole. The LRM normal temperature test board is installed on the inner side wall of the main structure box. An LRM plug is inserted into the LRM socket, and the LRM plug is adapted to the LRM socket;

[0007] The module mounting rack is fixedly connected to the side wall of one end of the main structure box where the module socket holes are provided;

[0008] The cable accessories include a test cable and a cable shielding wrapping cloth;

[0009] One end of the test cable is electrically connected to the LRM normal temperature test board, and the other end of the test cable is led out of the main structure box through the cable threading pipe.

[0010] The LRM normal temperature test board is arranged inside the main structure box.

[0011] Preferably, the top of the main structure box is open, and an upper cover plate is arranged corresponding to the opening at the top of the main structure box. One side of the upper cover plate is hinged to the box wall of the main structure box through a hinge, which is convenient for opening and closing the upper cover plate. A rotating handle is installed on the upper cover plate, and a clamping groove adapted to the rotating handle is arranged inside the main structure box. After rotating the rotating handle to make it correspond to and be clamped with the clamping groove inside the main structure box, the upper cover plate can be firmly fixed on the main structure box to prevent the upper cover plate from loosening during the test and affecting the shielding effect. Two handles are symmetrically and fixedly connected to both sides of the main structure box.

[0012] Preferably, shielding spring pieces are installed on the inner wall of the main structure box around the module socket holes. A shielding closed area is arranged on the back of the LRM normal temperature test board, and the shielding spring pieces are in close contact with the shielding closed area on the back of the LRM normal temperature test board to realize the overall shielding of the main structure box.

[0013] Preferably, the length of the cable threading pipe is 200 mm, the internal diameter of the cable threading pipe is 100 mm, and the dimensions of the main structure box are: length 500 - 600 mm, width 300 - 400 mm, height 300 mm.

[0014] Preferably, the LRM normal temperature test board is provided with a power interface, a CAN bus interface, an RS422 / RS485 interface, an RS232 interface, a BLVDS interface, and an SRIO interface.

[0015] Preferably, the cable shielding wrapping cloth has good flexibility and shielding performance and can tightly wrap the test cable.

[0016] Preferably, the differential signal impedance inside the test cable is 90 - 110 Ω, and the single - ended signal impedance is 50 Ω to ensure the accuracy and stability of signal transmission. The analog signal and power signal are thickened to meet the requirements of their power transmission. The low - speed differential signals in the test cable maintain differential equal - length and constant spacing inside the cable to avoid coupling interference between signals. The cable shielding wrap is wrapped outside the test cable to shield the cable signal and reduce the influence of external electromagnetic interference on signal transmission.

[0017] Compared with the related technologies, the LRM module - specific EMC test fixture provided by the present invention has the following beneficial effects:

[0018] In the present invention, the main structure box adopts a metal shielding box body, the inner wall of the cable through - tube is filled with shielding copper mesh, and shielding spring pieces are installed around the module socket holes. These designs enable the main structure box to have a shielding effectiveness of ≥40 dB in the frequency band of 10 kHz - 1 MHz and ≥50 dB in the frequency band of 1 MHz - 18 GHz, which can effectively shield external electromagnetic interference and create a stable electromagnetic environment for module testing. At the same time, the signal transmission between the LRM normal - temperature test board and the LRM module meets the integrity requirements. The high - speed signals are transmitted in a differential pair manner. The length between differential pairs is controlled within 50 mil, and the distance is greater than 3 times the line width. The differential signal impedance inside the test cable is 90 - 110 Ω, and the single - ended signal impedance is 50 Ω. The low - speed differential signals maintain differential equal - length and constant spacing. These optimized signal - transmission designs effectively reduce problems such as inconsistent signal - transmission delay, mutual interference, and reflection, ensuring the accuracy and stability of signal transmission, making the test data more accurate and reliable, being able to more comprehensively and deeply verify the electromagnetic compatibility of the LRM module, accurately analyze the problems encountered by the LRM module during testing, and avoiding potential system - failure hazards caused by electromagnetic - compatibility problems.

[0019] In the present invention, the LRM fixing rails and locking mechanisms on the module mounting rack adopt a modular design and can be quickly replaced and adjusted according to the structural differences of different models of LRM modules. When testing different models of power LRM modules and communication LRM modules, there is no need to re - customize the fixture. Directly replacing the adapted LRM fixing rails and locking mechanisms can complete the installation, greatly saving the fixture - customization cost and time, improving the test efficiency, and effectively solving the problem of the lack of general interchangeability of traditional test fixtures.

[0020] In the present invention, a power interface, a CAN bus interface, an RS422 / RS485 interface, an RS232 interface, a BLVDS interface, and an electrical SRIO interface are provided on the LRM normal temperature test board, and the quantity matches the number of external interfaces of the LRM module, which can meet the signal transmission requirements of different types of LRM modules, ensure accurate acquisition and transmission of various signals of the LRM module, and improve the adaptability and functionality of the test fixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall structure of the special EMC test fixture for the LRM module in the present invention;

[0022] Figure 2 is a schematic diagram of the structure at the main structure box in the present invention Figure 1 ;

[0023] Figure 3 is a schematic diagram of the structure at the main structure box in the present invention Figure 2 ;

[0024] Figure 4 is a schematic diagram of the LRM normal temperature test board installed in the main structure box in the present invention;

[0025] Figure 5 is a schematic diagram of the structure of the module mounting rack in the present invention.

[0026] Reference numerals in the figure: 1, main structure box; 2, module mounting rack; 22, LRM fixed guide rail; 23, locking mechanism; 3, cable accessory; 31, test cable; 32, cable shielding wrapping cloth; 4, LRM normal temperature test board; 5, cable threading pipe; 6, shielding filling copper mesh; 7, LRM socket; 8, LRM plug; 9, rotating handle; 10, handle; 11, upper cover plate; 12, module socket hole; 122, shielding reed. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present invention will be further described below with reference to the drawings and embodiments.

[0028] Embodiment 1

[0029] Please refer to Figures 1 to 5, a dedicated EMC test fixture for the LRM module, includes a main structure box 1, a module mounting bracket 2, a cable accessory 3, and an LRM normal temperature test board 4; the main structure box 1 is a metal shielding box, one end of the main structure box 1 is provided with a module socket hole 12, the other end of the main structure box 1 is connected to a cable conduit 5, the inner wall of the cable conduit 5 is filled with a layer of shielding copper mesh 6, an LRM socket 7 is installed in the module socket hole 12, the LRM normal temperature test board 4 is installed on the inner side wall of the main structure box 1, an LRM plug 8 is plugged into the LRM socket 7, the LRM plug 8 is adapted to the LRM socket 7, and the LRM plug 8 is electrically connected to the LRM module; the module mounting bracket 2 is fixedly connected to the side wall of one end of the main structure box 1 where the module socket hole 12 is located; the cable accessory 3 includes a test cable 31 and a cable shielding wrap 32; one end of the test cable 31 is electrically connected to the LRM normal temperature test board 4, and the other end of the test cable 31 is led out of the main structure box 1 through the cable conduit 5 and then electrically connected to a power source / test equipment; the LRM normal temperature test board 4 is arranged inside the main structure box 1, and the LRM normal temperature test board 4 is electrically connected to the LRM module through the LRM socket 7 and the LRM plug 8.

[0030] In the above, when the module socket hole 12 is completely closed and the cable conduit 5 is filled with the shielding copper mesh 6, the shielding effectiveness of the main structure box 1 in the frequency band of 10 kHz - 1 MHz is ≥ 40 dB, and in the frequency band of 1 MHz - 18 GHz is ≥ 50 dB, thus meeting the electromagnetic shielding requirements under different frequency bands.

[0031] In the above, the module mounting bracket 2 is made of a non-metallic material or a small amount of metal that has been insulated to reduce interference with the electromagnetic environment.

[0032] In the above, the test cable 31 includes a power cable, an RS232 cross-test cable, a CAN test cable, and an Ethernet cable. The power cable is 5 meters long and uses FF46 series high-temperature resistant wire FF46 - 1 - 1.5 mm² to meet the current and voltage drop requirements that the maximum power consumption of the 12V power supply of the module does not exceed 45W; the RS232 cross-test cable is 5 meters long, and the two ends are in a DB9 female head wiring relationship: 2 is connected to 3, 3 is connected to 2, 5 is connected to 5, and a single-core wire FF46 - 1 - 0.2 mm² is selected; the CAN test cable is 5 meters long, and the two ends are in a DB9 female head wiring relationship: 7 is connected to 7, 2 is connected to 2, 5 is connected to 5, and a twisted pair shielded wire 24AWG×2C is selected; the Ethernet cable is 5 meters long, and the two ends are RJ45 connectors, and a super category 5 shielded Ethernet cable is selected to ensure the signal integrity of each signal after being transmitted through the cable.

[0033] In the above, a signal shielding layer and a grounding wire are provided inside the test cable 31. The signal shielding layer adopts a composite structure of a metal braided mesh and aluminum foil. The grounding wire is connected to the grounding system of the main structure box 1, further improving the shielding effect of the test cable 31 and reducing signal interference.

[0034] In the above, the LRM normal temperature test board 4 selects an FR4 dielectric multi-layer circuit board, and is laid out and routed according to the types and characteristics of the module signals to achieve signal hierarchical design, optimize the routing quality, meet the signal integrity requirements. High-speed signals are transmitted in differential pair mode, and the length between differential pairs is controlled within 50 mil. The distance between differential pairs is greater than 3 times the line width rule; a 120Ω matching resistor in 0603 package is reserved near the VPX connector end of the CAN bus to improve the stability and accuracy of signal transmission.

[0035] Further, the top of the main structure box 1 is open. A top cover plate 11 is provided corresponding to the opening at the top of the main structure box 1. One side of the top cover plate 11 is hinged to the box wall of the main structure box 1 through a hinge, facilitating the opening and closing of the top cover plate 11. A rotating handle 9 is installed on the top cover plate 11. A clamping groove adapted to the rotating handle 9 is provided inside the main structure box 1. After rotating the rotating handle 9 to be correspondingly clamped with the clamping groove inside the main structure box 1, the top cover plate 11 can be firmly fixed on the main structure box 1 to prevent the top cover plate 11 from loosening during the test and affecting the shielding effect. Two handles 10 are symmetrically and fixedly connected to both sides of the main structure box 1. By holding the handles 10, it is convenient to carry and move the test fixture.

[0036] Embodiment 2

[0037] Further, please refer to Figures 1 to 5 , on the basis of Embodiment 1, shielding spring pieces 122 are installed on the inner wall of the main structure box 1 around the module socket holes 12. A shielding closed area is provided on the back of the LRM normal temperature test board 4. The shielding spring pieces 122 are in close contact with the shielding closed area on the back of the LRM normal temperature test board 4 to achieve the overall shielding of the main structure box 1.

[0038] Further, the signal transmission between the LRM normal temperature test board 4 and the LRM module needs to meet the integrity requirements. High-speed signals are transmitted in differential pair mode, and the length between differential pairs is controlled within 50 mil, and the distance between differential pairs is greater than 3 times the line width. This is because if the length difference of the differential pairs is too large or the spacing is too small, it will cause inconsistent signal transmission delays and mutual interference between signals, thereby causing signal reflection and affecting the accuracy and stability of signal transmission.

[0039] Furthermore, the length of the cable conduit 5 is 200 mm, the inner diameter of the cable conduit 5 is 100 mm, and the dimensions of the main structure box 1 are: length 500 - 600 mm, width 300 - 400 mm, height 300 mm. This dimension setting is determined by comprehensively considering factors such as the size of the LRM module, the cable routing space, and ensuring a good shielding effect. Within this dimension range, it can not only meet the installation requirements of various LRM modules but also effectively reduce the impact of external electromagnetic interference on internal signal transmission.

[0040] Furthermore, the LRM fixed guide rails 22 and the locking mechanism 23 are installed on the module mounting rack 2. The structures of the LRM fixed guide rails 22 and the locking mechanism 23 are adapted to the structure of the LRM module. The LRM fixed guide rails 22 and the locking mechanism 23 on the module mounting rack 2 adopt a modular design, which can be quickly replaced and adjusted according to the structural differences of different models of LRM modules to adapt to the installation requirements of various LRM modules and improve the versatility and flexibility of the test fixture.

[0041] Furthermore, the LRM normal temperature test board 4 is provided with a power supply interface, a CAN bus interface, an RS422 / RS485 interface, an RS232 interface, a BLVDS interface, and an electrical SRIO interface. The quantities of the power supply interface, the CAN bus interface, the RS422 / RS485 interface, the RS232 interface, the BLVDS interface, and the electrical SRIO interface match the number of external interfaces of the LRM module. Among them, the power supply interface is used to provide a stable power supply for the LRM module; the CAN bus interface realizes high-speed data communication between the LRM module and external devices; the RS422 / RS485 interface is used for reliable data transmission over long distances and multiple nodes; the RS232 interface is suitable for short-distance and low-speed device communication connections; the BLVDS interface is used to meet specific high-speed differential signal transmission requirements; the electrical SRIO interface can realize high-speed serial input and output data communication to ensure the accurate acquisition and transmission of various signals of the LRM module.

[0042] Furthermore, the cable shielding wrap 32 has good flexibility and shielding performance, can tightly wrap the test cable 31, and is not easily damaged or detached, ensuring the stability of the shielding effect.

[0043] Furthermore, the internal differential signal impedance of the test cable 31 is 90 - 110 Ω, and the single-ended signal impedance is 50 Ω to ensure the accuracy and stability of signal transmission. The analog signals and power supply signals are thickened to meet the requirements of their power transmission. The low-speed differential signals in the test cable 31 maintain differential equal length and constant spacing within the cable to avoid coupling interference between signals. The cable shielding wrap 32 is wrapped outside the test cable 31 to achieve shielding of the cable signals and reduce the impact of external electromagnetic interference on signal transmission.

[0044] Furthermore, the dedicated EMC test fixture for the LRM module is also provided with a power interface. A power filter connector is used as the power supply input port, and an independent switch is equipped to achieve effective control and filtering of the power supply, reducing the impact of power interference on the test results. The test fixture is also provided with an RJ45 interface, a DB9 male interface, a PHY transformer, a J30J interface, and a VPX connector. Among them, the VPX connector is used to achieve mechanical and electrical connections with the LRM module, leading out the control and communication interfaces of the LRM module to the corresponding external interfaces, facilitating connection and communication with external power supplies / test equipment.

[0045] Furthermore, a self-loop plug is provided on the dedicated EMC test fixture for the LRM module to perform loopback tests on low-frequency signals. Signals such as RS422 / RS485 bus signals and LVCMOS_UART signals are led to the J30J interface, and the loopback head is used to complete the loopback test of the same-group signal transmission and reception; high-speed signals such as 1x_GTX electrical signals and 1x_RIO electrical signals are looped back at the self-loop plug to detect the signal transmission quality and the communication function of the module.

[0046] Furthermore, the LRM module in the present invention is the abbreviation of "Line Replaceable Module", which means "field replaceable module". In complex electronic systems such as airplanes, the LRM module is a type of standardized module with specific functions and can be replaced on-site. The LRM module can be a power module, a communication module, a clock module, etc.; Power module: As the core of the energy supply of the electronic system, stable output is crucial for maintaining the normal operation of each module. If there are problems with its electromagnetic compatibility performance, the electromagnetic interference generated may cause unstable power supply to other modules, and then lead to system failures. For example, in an airplane, a power module failure will affect flight safety; Communication module: Responsible for information transmission inside the airplane and between the airplane and the outside. Its electromagnetic compatibility performance is directly related to the quality and reliability of communication. When affected by electromagnetic interference, problems such as signal loss and increased bit error rate may occur, and in severe cases, communication interruption may occur, causing the airplane to lose contact with the ground control center; Clock module: Provides an accurate time reference for the entire system. If the electromagnetic interference generated by it is not effectively controlled, it may affect the synchronous operation of other modules, resulting in system timing chaos and reducing the overall performance of the system.

[0047] Please refer to Figures 1 to 5 , the working principle of the dedicated EMC test fixture for the LRM module provided by the present invention is as follows:

[0048] The LRM module is connected by inserting it into the LRM socket 7 through the LRM plug 8. The LRM fixing guide rail 22 and the locking mechanism 23 on the module mounting bracket 2 are adapted to the structure of the LRM module, and can firmly fix the LRM module, facilitating subsequent test operations and ensuring the stability of the module during the test. Various signals of the LRM module are transmitted to the LRM normal temperature test board 4 through the LRM plug 8 and the LRM socket 7. One end of the test cable 31 is electrically connected to the LRM normal temperature test board 4, and the other end is led out of the main structure box 1 through the cable threading pipe 5 and connected to the power supply / test equipment to achieve signal transmission. The self-loop plug on the test fixture can lead low-frequency signals such as RS422 / RS485 bus signals and LVCMOS_UART signals to the J30J interface, and complete the self-loop test of the same-group signal transceiver through the loop-back head. High-speed signals such as 1x_GTX electrical signals and 1x_RIO electrical signals are self-loop received and transmitted at the self-loop plug to detect the signal transmission quality and the module communication function. The power supply of the LRM module uses MOS transistors to implement an anti-reverse connection circuit to prevent damage to the equipment due to reverse power supply polarity. A passive overvoltage protection circuit is composed of a zener diode. When the power supply voltage is too high, it protects the LRM module and the power supply / test equipment. The power supply interface uses a power filter connector as the power supply input port, equipped with an independent switch, which effectively controls and filters the power supply, reducing the influence of power supply interference on the test results. The main structure box 1 is a metal shielding box body. The shielding spring pieces 122 around the module socket hole 12 are in close contact with the shielding closed area on the back of the LRM normal temperature test board 4. The inner wall of the cable threading pipe 5 is filled with a shielding copper mesh 6. The test cable 31 is internally provided with a signal shielding layer and a grounding wire. The signal shielding layer adopts a composite structure of a metal braided mesh and aluminum foil. The grounding wire is connected to the grounding system of the main structure box 1. The cable shielding wrapping cloth 32 wraps the test cable 31. These measures work together to reduce the influence of external electromagnetic interference on signal transmission and meet the electromagnetic shielding requirements in different frequency bands.

[0049] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. The EMC test fixture dedicated to the LRM module, characterized in that, It includes a main structure box (1), a module mounting bracket (2), a cable accessory (3), and an LRM normal temperature test board (4); The main structure box (1) is a metal shielding box body. One end of the main structure box (1) is provided with a module socket hole (12). The other end of the main structure box (1) is communicated with a cable threading pipe (5). The inner wall of the cable threading pipe (5) is filled with a layer of shielding filling copper mesh (6). An LRM socket (7) is installed in the module socket hole (12). The LRM normal temperature test board (4) is installed on the inner side wall of the main structure box (1). An LRM plug (8) is plugged into the LRM socket (7), and the LRM plug (8) is adapted to the LRM socket (7); The module mounting bracket (2) is fixedly connected to the side wall of one end of the main structure box (1) where the module socket hole (12) is provided; The cable accessory (3) includes a test cable (31) and a cable shielding wrapping cloth (32); One end of the test cable (31) is electrically connected to the LRM normal temperature test board (4), and the other end of the test cable (31) is led out of the main structure box (1) through the cable threading pipe (5); the internal differential signal impedance of the test cable (31) is 90 - 110Ω, and the single - end signal impedance is 50Ω; The LRM normal temperature test board (4) is arranged inside the main structure box (1).

2. The dedicated EMC test fixture for the LRM module according to claim 1, characterized in that, The top of the main structure box (1) is open. A top cover plate (11) is provided corresponding to the opening at the top of the main structure box (1). One side of the top cover plate (11) is hinged to the box wall of the main structure box (1) through a hinge, which facilitates the opening and closing of the top cover plate (11). A rotating handle (9) is installed on the top cover plate (11). A clamping groove adapted to the rotating handle (9) is arranged inside the main structure box (1). After rotating the rotating handle (9) to make it correspond and be clamped with the clamping groove inside the main structure box (1), the top cover plate (11) can be firmly fixed on the main structure box (1) to prevent the top cover plate (11) from loosening during the test and affecting the shielding effect. Two handle grips (10) are symmetrically and fixedly connected to both sides of the main structure box (1).

3. The dedicated EMC test fixture for the LRM module according to claim 1, wherein Shielding spring pieces (122) are installed on the inner wall of the main structure box (1) around the module socket hole (12). The back of the LRM normal temperature test board (4) is provided with a shielding closed area. The shielding spring pieces (122) are in close contact with the back shielding closed area of the LRM normal temperature test board (4) to achieve the overall shielding of the main structure box (1).

4. The dedicated EMC test fixture for the LRM module according to claim 1, characterized in that, The length of the cable threading pipe (5) is 200mm, the internal diameter of the cable threading pipe (5) is 100mm, and the dimensions of the main structure box (1) are: length 500 - 600mm, width 300 - 400mm, height 300mm.

5. The dedicated EMC test fixture for the LRM module according to claim 1, wherein, An LRM fixed guide rail (22) and a locking mechanism (23) are installed on the module mounting bracket (2), and the LRM fixed guide rail (22) and the locking mechanism (23) on the module mounting bracket (2) adopt a modular design.

6. The dedicated EMC test fixture for the LRM module according to claim 1, characterized in that, The LRM normal temperature test board (4) is provided with a power interface, a CAN bus interface, an RS422 / RS485 interface, an RS232 interface, a BLVDS interface and an SRIO interface.

7. The dedicated EMC test fixture for the LRM module according to claim 1, characterized in that The cable shielding wrapping cloth (32) has good flexibility and shielding performance and can tightly wrap the test cable (31).

Images