CN211528519U - Digital multimeter with anti-electromagnetic interference performance - Google Patents

Abstract

The utility model discloses a digital multimeter with anti-electromagnetic interference performance, including the main shield casing, the main shield casing rotates and is connected with the shielding lid, and the internal fixation of main shield casing is equipped with signal conditioning circuit, low pass filter, microprocessor, measuring circuit and display device, fixed outside rotary switch and the root mean square converter of being equipped with on the shielding lid, the fixed inside wiring end that is equipped with of diapire in the main shield casing, inside wiring end and signal conditioning circuit electricity are connected, are equipped with the viewing aperture that corresponds with the display device position on the shielding lid, are equipped with the shielding display structure in the viewing aperture. The utility model discloses it is rational in infrastructure, for hole seam and opening for example: the display port, the gaps combined among the parts, the openings of various interfaces and the like have good shielding effects, and meanwhile, the universal meter is arranged in a circuit to filter the tested current and voltage by using a filtering technology, so that the strong electromagnetic interference in the transformer substation is enhanced by the universal meter.

Description

A digital multimeter with anti-electromagnetic interference performance

technical field

The utility model relates to the technical field of electric power maintenance, in particular to a digital multimeter with anti-electromagnetic interference performance.

Background technique

With the continuous expansion of the power grid, the electromagnetic environment and electromagnetic interference problems of substations have become more and more serious. The measurement results are incorrect, and the maintenance personnel cannot judge whether the crux is the problem of the circuit itself or the cause of electromagnetic interference. The traditional method of using a digital multimeter to test the direct resistance of the current loop in a strong electromagnetic interference environment is limited, which has a serious impact on the work efficiency of maintenance personnel.

For data acquisition in a strong electromagnetic field environment, the first problem to be solved is how to shield the interference caused by the strong electromagnetic field. The multimeter shielding box will have many holes and openings, such as: display ports, gaps between various parts, and various The opening of the interface, etc., and the current and voltage tested are filtered by filtering technology, so that the multimeter itself can enhance the strong electromagnetic interference in the substation.

To this end, we propose a digital multimeter with anti-electromagnetic interference performance to solve the above problems.

SUMMARY OF THE INVENTION

The purpose of the utility model is to propose a digital multimeter with anti-electromagnetic interference performance in order to solve the shortcomings existing in the prior art.

In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

A digital multimeter with anti-electromagnetic interference performance, comprising a main shielding shell, characterized in that a shielding cover body is rotatably connected to the main shielding shell, and a signal conditioning circuit, a low-pass A filter, a microprocessor, a measuring circuit and a display device, an external rotary switch and a rms converter are fixed on the shielding cover, internal terminals are fixed on the inner bottom wall of the main shielding shell, and the inner The terminal is electrically connected with the signal conditioning circuit, the internal terminal is communicated with the outside through the shielding connection structure, the shielding cover is provided with an observation port corresponding to the position of the display device, and the observation port is provided with a shielding display structure;

The signal conditioning circuit, the low-pass filter, the external rotary switch, the rms converter, the measuring circuit and the display device are electrically connected in sequence, the signal conditioning circuit and the external rotary switch are electrically connected, and the external rotary switch is electrically connected with the microprocessor The signal conditioning circuit, the measuring circuit and the display device are all electrically connected with the microprocessor.

Preferably, the shielding connection structure includes a bar-shaped opening fixedly arranged on the side wall of the main shielding shell, the bar-shaped opening is fixedly provided with an external wiring block, and the main shielding shell is provided with a shielding cover, so the The shielding cover body is covered on the external wiring block, the shielding cover body is fixedly connected with the main shielding shell, the shielding cover body corresponds to the position of the bar-shaped opening, and the external wiring block is electrically connected to the internal wiring terminal through the shielding wire. connect.

Preferably, the shielding display structure includes a shielding window sealed and fixedly connected in the observation port, and two strip-shaped blocks are symmetrically and fixedly connected on one side of the shielding cover body close to the main shielding shell, and the two strip-shaped blocks are distributed On the upper and lower sides of the observation port, a plurality of LED lights are evenly fixed on the end faces of the two bar-shaped blocks that are close to each other.

Preferably, the shielding window comprises an inner layer, a middle layer and an outer layer, and the inner layer, the middle layer and the outer layer are a metal mesh layer, an acrylic layer and a black crystal glass layer, respectively.

Preferably, a frame-shaped shielding block is arranged in the main shielding shell, the shielding block is matched with the shielding cover, and the shielding block is fixedly connected with the main shielding shell.

Preferably, a sealing gasket is provided on the contact surface of the main shielding shell and the shielding cover, and a sound insulation layer is provided in both the main shielding shell and the shielding cover.

Compared with the prior art, the beneficial effects of the present utility model are:

1. By setting the shielding connection structure, at the same time installing a shielding window at the position of the observation display device, using LED lights to ensure the observation effect, and performing sound insulation processing and sealing processing on the shielding shell and shielding cover to ensure the shielding effect.

2. By adding a low-pass filter to the circuit, and then through the role of the root mean square converter and the microprocessor, the current and voltage tested can be filtered through the filtering technology, so that the multimeter itself can enhance the strong electromagnetic interference in the substation. .

Description of drawings

Fig. 1 is the structural representation of a kind of digital multimeter with anti-electromagnetic interference performance proposed by the utility model;

2 is a schematic structural diagram of a shielding window in a digital multimeter with anti-electromagnetic interference performance proposed by the utility model;

FIG. 3 is a circuit diagram of a digital multimeter with anti-electromagnetic interference performance proposed by the utility model.

In the figure: 1 main shielding shell, 2 shielding cover, 3 signal conditioning circuit, 4 low-pass filter, 5 microprocessor, 6 measuring circuit, 7 display device, 8 external rotary switch, 9 rms converter, 10 internal terminals, 11 external wiring blocks, 12 shielding enclosures, 13 shielding windows, 14 bar blocks, 15 LED lights, 16 shielding blocks.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example.

1-3, a digital multimeter with anti-electromagnetic interference performance includes a main shielding case 1, the main shielding case 1 is rotatably connected with a shielding cover 2, which can be opened, the main shielding case 1 and the shielding cover The contact surface of 2 is provided with a sealing gasket to ensure sealing. The main shielding shell 1 and the shielding cover 2 are provided with a sound insulation layer to ensure the sound insulation effect. The main shielding shell 1 is provided with a frame-shaped shielding block 16. The shielding block 16 is matched with the shielding cover body 2, and the shielding block 16 is fixedly connected with the main shielding shell 1. The main shielding shell 1 is fixedly provided with a signal conditioning circuit 3, a low-pass filter 4, a microprocessor 5, and a measuring circuit 6. And the display device 7, the external rotary switch 8 and the rms converter 9 are fixed on the shielding cover 2, the filtering technology is set in the circuit, the inner bottom wall of the main shielding shell 1 is fixedly provided with internal terminals 10, and the internal The terminal 10 is electrically connected to the signal conditioning circuit 3 .

The inner terminal 10 is communicated with the outside through a shielding connection structure. The shielding connection structure includes a bar-shaped opening fixed on the side wall of the main shielding shell 1, and an external wiring block 11 is fixed in the bar-shaped opening. The main shielding shell 1. There is a shielding cover 12 inside, the shielding cover 12 is covered on the external wiring block 11, the shielding cover 12 is fixedly connected with the main shielding shell 1, the shielding cover 12 corresponds to the position of the strip opening, and the external wiring block 11 The shielded wire is electrically connected to the internal terminal 10 , so that the wiring can be performed, and the shielding property of the wiring can be ensured at the same time.

Wherein, the observation port is provided with a shielding display structure, and the shielding display structure includes a shielding window 13 sealed and fixedly connected in the observation port. The shielding window 13 includes an inner layer, a middle layer and an outer layer, and the inner layer, the middle layer and the outer layer are metal mesh layers respectively. , acrylic layer and black crystal glass layer to ensure the shielding effect, the side of the shielding cover 2 close to the main shielding shell 1 is symmetrically and fixedly connected with two bar-shaped blocks 14, and the two bar-shaped blocks 14 are distributed on the upper and lower sides of the observation port. , a plurality of LED lights 15 are evenly fixed on the end surfaces of the two bar-shaped blocks 14 that are close to each other, and the LED lights 15 illuminate to assist in observation, thereby ensuring correct readings.

The signal conditioning circuit 3, the low-pass filter 4, the external rotary switch 8, the rms converter 9, the measuring circuit 6 and the display device 7 are electrically connected in sequence, the signal conditioning circuit 3 is electrically connected with the external rotary switch 8, and the external rotary switch 8 Electrically connected to the microprocessor 5 , the signal conditioning circuit 3 , the measuring circuit 6 and the display device 7 are all electrically connected to the microprocessor 5 .

In the utility model, when using the device, the external wiring block 11 is used for plugging, and then the signal is transmitted to the internal wiring terminal 10 through the shielded wire, and then the electrical signal is adjusted by the signal conditioning circuit 3, and then the micro-processing is performed. The sensor 5 is transmitted to the measuring circuit 6, and finally displayed through the display device 7, the external rotary switch 8 is turned on and off, and the rms converter 9 is assisted at the same time, so as to use the filtering technology, the observation port corresponding to the display device 7 is provided with a shielding window 13 , The electromagnetic shield is shielded by the metal mesh layer, the acrylic layer and the black crystal glass layer, and the LED light 15 is used to assist the observation to ensure the accuracy of the observation.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Equivalent replacement or modification of the new technical solution and its utility model concept shall be included within the protection scope of the present utility model.

Claims (6)

1. A digital multimeter with anti-electromagnetic interference performance, comprising a main shielding shell (1), characterized in that the main shielding shell (1) is rotatably connected with a shielding cover (2), and the main shielding A signal conditioning circuit (3), a low-pass filter (4), a microprocessor (5), a measuring circuit (6) and a display device (7) are fixedly arranged in the casing (1), and the shielding cover (2) ) is fixedly provided with an external rotary switch (8) and an RMS converter (9), the inner bottom wall of the main shielding shell (1) is fixedly provided with an internal terminal (10), the internal terminal (10) ) is electrically connected to the signal conditioning circuit (3), the internal terminal (10) communicates with the outside through a shielding connection structure, and the shielding cover (2) is provided with an observation port corresponding to the position of the display device (7), The observation port is provided with a shielding display structure; The signal conditioning circuit (3), the low-pass filter (4), the external rotary switch (8), the rms converter (9), the measuring circuit (6) and the display device (7) are electrically connected in sequence, and the The signal conditioning circuit (3) is electrically connected with an external rotary switch (8), the external rotary switch (8) is electrically connected with the microprocessor (5), the signal conditioning circuit (3), the measuring circuit (6) and the display The devices (7) are all electrically connected to the microprocessor (5). 2. A digital multimeter with anti-electromagnetic interference performance according to claim 1, characterized in that the shielding connection structure comprises a bar-shaped opening fixedly arranged on the side wall of the main shielding shell (1), so An external wiring block (11) is fixed in the strip-shaped opening, and a shielding cover (12) is provided in the main shielding shell (1), and the shielding cover (12) is covered on the external wiring block (11). ), the shielding case (12) is fixedly connected to the main shielding case (1), the shielding case (12) corresponds to the position of the bar-shaped opening, and the external connection block (11) is connected to the internal The terminal (10) is electrically connected. 3. The digital multimeter with anti-electromagnetic interference performance according to claim 1, wherein the shielding display structure comprises a shielding window (13) sealed and fixedly connected in the observation port, and the shielding cover (13) 2) Two bar-shaped blocks (14) are symmetrically and fixedly connected on the side close to the main shielding shell (1), and the two bar-shaped blocks (14) are distributed on the upper and lower sides of the observation port. A plurality of LED lights (15) are uniformly fixed on the end faces of the blocks (14) that are close to each other. 4. A digital multimeter with anti-electromagnetic interference performance according to claim 3, characterized in that the shielding window (13) comprises an inner layer, a middle layer and an outer layer, and the inner layer, the middle layer and the outer layer They are metal mesh layer, acrylic layer and black crystal glass layer respectively. 5. A digital multimeter with anti-electromagnetic interference performance according to claim 1, characterized in that a frame-shaped shielding block (16) is arranged in the main shielding shell (1), and the shielding block (16) is matched with the shielding cover (2), and the shielding block (16) is fixedly connected with the main shielding shell (1). 6. A digital multimeter with anti-electromagnetic interference performance according to claim 1, characterized in that a sealing gasket is provided on the contact surface of the main shielding shell (1) and the shielding cover (2), Both the main shielding shell (1) and the shielding cover (2) are provided with sound insulation layers.

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