A RS485 signal filter with lightning protection function

Abstract

The utility model relates to the technical field of filters, and discloses a RS485 signal filter with lightning protection, including a filter cavity, a two-core aviation connector base, a PCB circuit board, a grounding bolt, a conductive nut, a wire, a conductive column and epoxy resin. The filter cavity is matched with the two-core aviation connector base, and the wire is led out and soldered to the PCB circuit board using high-temperature solder. The PCB circuit board is provided with a ceramic gas discharge tube, a resistor, a semiconductor discharge tube, a monolithic capacitor, an inductor, a bypass capacitor, and a transient suppression diode to form a lightning surge electromagnetic protection and filtering circuit. Compared with the prior art, the utility model has the advantages of having two functions: signal filtering and protection against lightning surge electromagnetic pulses.

Description

Technical Field

[0001] The utility model relates to the technical field of filters, in particular to an RS485 signal filter with lightning protection function. Background Art

[0002] Lightning electromagnetic pulse is a very strong interference source. There are many interference transmission paths of lightning electromagnetic pulse. One of them is lightning strikes between clouds or lightning strikes nearby objects, which generates a strong electromagnetic field. It induces higher voltage and current in buildings and on conductors, and radiates outward along the conductive path.

[0003] RS485 bus is a serial communication standard interface widely used in the field of industrial automation. RS485 bus adopts differential signal transmission and can achieve a data transmission rate of up to 10Mbps. RS485 bus signal filter is a passive filtering network composed of capacitors, inductors and resistors. One end of the filter is connected to the input signal and the other end is connected to the telephone. The principle of the telephone signal filter is to filter out invalid signal interference and only retain valid signals for transmission. The main function of the RS485 bus signal filter is to solve the electromagnetic interference problem of spatial coupling into the wiring harness, such as electromagnetic interference of other equipment to RS485 communication equipment. The RS485 bus lightning surge protection module is a passive lightning protection network composed of ceramic gas discharge tubes, resistors, and semiconductor discharge tubes. This protection module has the function of solving the problem of super strong electromagnetic interference coupled into the wiring harness, such as lightning radiating strong electromagnetic interference to the RS485 wiring harness, causing damage to RS485 communication equipment.

[0004] Currently, the market only has single-function RS485 bus lightning surge protection modules or RS485 bus signal filters. How to develop RS485 bus signal filters with both signal filtering and lightning surge electromagnetic pulse protection functions is one of the research directions in the field of lightning arrester and filter technology. Utility Model Content

[0005] 1. Technical issues to be solved

[0006] The technical problem to be solved by the utility model is that lightning will generate strong electromagnetic interference radiation to the RS485 wiring harness, thereby causing damage to the RS485 communication equipment. Currently, there are only single-function RS485 bus lightning surge protection modules or RS485 bus signal filters.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the technical solution provided by the utility model is: a RS485 bus signal filter with lightning protection, including a filter cavity, a two-core aviation connector base, a PCB circuit board, a grounding bolt, a conductive nut, a wire, a conductive column and epoxy resin, the filter cavity is matched with the two-core aviation connector base, the wire is led out, and is soldered to the PCB circuit board end using high-temperature solder, the PCB circuit board is provided with a lightning surge electromagnetic protection and filtering circuit composed of a ceramic gas discharge tube, a resistor, a semiconductor discharge tube, a monolithic capacitor, an inductor, a bypass capacitor, and a transient suppression diode, the ground of the PCB circuit board is tightly connected to the bolt of the filter cavity, the filter cavity is tightly connected to the grounding bolt, wherein the grounding bolt is directly connected to the earth, and the filter cavity is encapsulated with epoxy resin.

[0009] As an improvement, the filter cavity is made of high-conductivity metal material.

[0010] As an improvement, the openings of the telephone signal input and output ends of the filter cavity match the size of the base of the two-core aviation connector.

[0011] As an improvement, the base terminal of the two-core aviation connector and the wire are welded using high-temperature solder.

[0012] As an improvement, the ground of the PCB circuit board is tightly connected to the conductive column of the filter cavity, and the PCB circuit board, the conductive nut and the conductive column are welded together using high-temperature solder, which can enhance the conductivity and further reduce the conductive impedance.

[0013] As an improvement, the filter cavity is potted with epoxy resin to avoid bubbles and holes in the epoxy resin.

[0014] (III) Beneficial effects

[0015] The advantages of the utility model compared with the prior art are: the RS485 bus signal filter of the utility model has both signal filtering and lightning surge electromagnetic pulse protection functions, has a simple structure, small size, light weight and good lightning surge electromagnetic pulse protection effect, and can be widely used in the RS485 bus communication field. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of a RS485 signal filter with lightning protection function in this utility model. Figure 1 .

[0017] Figure 2 This is a schematic diagram of the structure of a RS485 signal filter with lightning protection function in this utility model. Figure 2 .

[0018] Figure 3The utility model discloses a PCB circuit board circuit diagram of an RS485 signal filter with lightning protection function.

[0019] As shown in the figure: 1. Filter cavity; 2. Two-core aviation connector base; 3. PCB circuit board; 4. Grounding bolt; 5. Conductive nut; 6. High-temperature solder; 7. Wire; 8. Conductive column; 9. Epoxy resin. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments; based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0021] When the utility model is implemented, Figure 1 and Figure 3 As shown, a RS485 signal filter with lightning protection function includes a filter cavity 1, a two-core aviation connector base 2, a PCB circuit board 3, a grounding bolt 4, a conductive nut 5, a wire 7, a conductive column 8 and an epoxy resin 9. The filter cavity 1 is made of a high-conductivity metal material. The filter cavity 1 cooperates with the two-core aviation connector base 2, the grounding bolt 4 and the conductive column 8. The two-core aviation connector base 2 is connected to the PCB circuit board 3 by a wire 7. The PCB circuit board 3 is fixed by the conductive column 8 and the conductive nut 5 of the filter cavity 1. The PCB circuit board 3 is welded with the conductive nut 5 and the conductive column 8 by using a high-temperature solder 6. The filter cavity 1 is potted with an epoxy resin 9 to avoid bubbles and holes in the epoxy resin 9.

[0022] Through the above structure, the PCB circuit board 3 adopts SMT welding, that is, the electronic components are directly welded on the PCB circuit board 3 by reflow soldering, and the PCB circuit board 3 replaces the wires 7 of each component.

[0023] like Figure 3 As shown, A_In and B_In of the utility model are connected to the two-core aviation connector base 2 of the input signal, A_Out and B_Out are connected to the two-core aviation connector base 2 of the output signal, PE is connected to the grounding bolt 4 through the conductive column 8, the conductive nut, the high-temperature solder 6, and the filter cavity 1, and the grounding bolt 4 is connected to the ground.

[0024] Through the above structure, the ceramic gas discharge tube (GDT) constitutes the first-level lightning protection circuit, the semiconductor discharge tube (TSS) constitutes the second-level lightning protection circuit, the transient suppression diode (TVS) constitutes the third-level lightning protection circuit, the monolithic capacitor, inductor, and bypass capacitor in the utility model constitute a first-level filter, and the capacitors and inductors in the PCB circuit board 3 are placed alternately in sequence to constitute a multi-stage filter, which has the functions of signal filtering and protection against lightning surge electromagnetic pulses.

[0025] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0027] The above description of the utility model and its implementation methods is not restrictive. The drawings show only one implementation method of the utility model, and the actual structure is not limited thereto. In short, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention of the utility model, they should all fall within the protection scope of the utility model.

Claims

1. A RS485 signal filter with lightning protection, characterized in that: A lightning protection RS485 bus signal filter comprises a filter cavity (1), a two-core aviation connector base (2), a PCB circuit board (3), a grounding bolt (4), a conductive nut (5), a wire (7), a conductive column (8) and an epoxy resin (9). The filter cavity (1) is matched with the two-core aviation connector base (2), the wire (7) is led out and soldered to the PCB circuit board (3) using high-temperature solder, and the PCB circuit board (3) is provided with a lightning surge electromagnetic protection and filtering circuit composed of a ceramic gas discharge tube, a resistor, a semiconductor discharge tube, a monolithic capacitor, an inductor, a bypass capacitor and a transient suppression diode.

2. The RS485 signal filter with lightning protection according to claim 1, characterized in that: The filter cavity (1) is made of a high-conductivity metal material.

3. The RS485 signal filter with lightning protection according to claim 1, characterized in that: The openings at the telephone signal input end and the output end of the filter cavity (1) match the size of the two-core aviation connector base (2).

4. The RS485 signal filter with lightning protection according to claim 1, characterized in that: The connection terminals of the two-core aviation connector base (2) and the wires (7) are welded using high-temperature solder (6).

5. The RS485 signal filter with lightning protection according to claim 1, characterized in that: The ground of the PCB circuit board (3) is tightly connected to the conductive column (8) of the filter cavity (1), and the PCB circuit board (3), the conductive nut (5) and the conductive column (8) are welded together using high-temperature solder (6).

6. The RS485 signal filter with lightning protection according to claim 1, characterized in that: The filter cavity (1) is potted with epoxy resin (9).

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