CN221746262U - A real-time ground detection circuit - Google Patents

Abstract

The utility model discloses a real-time grounding detection circuit, which is a circuit capable of real-time sampling of electronic signals, including: a relay, a pull-up circuit, and an IO module. It is mainly used in electronic equipment to perform real-time inspections on the grounding conditions of each unit in the preparation stage of the electronic equipment and during the entire operation process, so that users can understand the real-time working status of each unit of the electronic equipment based on the detection results. The circuit has strong resistance to electromagnetic environments and will not cause fluctuations in the detection results due to excessive environmental electromagnetic interference. The circuit can be integrated into the entire electronic circuit system as a part of the electronic equipment, with strong adaptability and high reliability.

Description

A real-time ground detection circuit

Technical Field

The utility model belongs to the technical field of grounding test, and in particular relates to a real-time grounding detection circuit.

Background Art

With the development of electronic technology, electronic products are becoming smaller and smaller, the integration of electronic equipment is getting higher and higher, the working speed of computers is getting higher and higher, and the electromagnetic environment is becoming more and more complex. During the operation of each unit of electronic equipment, the metal shell of the equipment must be effectively grounded. This is a necessary condition to protect the safety of electronic equipment and operators. If it is found that the electronic equipment is not grounded during operation, the work is stopped and the grounding of the equipment needs to be checked. The original test plan either conducts a visual inspection of the grounding condition or conducts a ground resistance test before the test begins.

Use visual inspection to check whether the grounding connection of each unit of the electronic equipment is firm and reliable. This method relies on subjective judgment, has the risk of human error, and lacks technical guarantee for the status of the electronic equipment.

There is also static resistance measurement, that is, the computer controls the multimeter module to measure the static resistance between each unit ground of the electronic equipment and the earth. There are two problems with this technology: 1. The multimeter module is a scarce resource on the computer, and is generally only configured with 1 to 2 channels. When measuring the grounding, the channel needs to be switched to the multimeter test. After the measurement, the channel is disconnected, and real-time inspection cannot be achieved. If the unit grounding wire of the electronic equipment is disconnected during operation, this method cannot detect the problem; 2. The static resistance test results are greatly affected by the electromagnetic and temperature and humidity environment. It is more stable when used in a temperature and humidity controlled factory, but electronic equipment in a temporary factory or even outdoors directly connected to the power supply will have false alarms due to interference.

Utility Model Content

The purpose of the utility model is to provide a real-time grounding detection circuit, which displays the detection situation in real time for users to understand the grounding status of the equipment. The circuit is simple and reliable, can work stably in complex electromagnetic environments and extreme temperature and humidity environments, and meet the use requirements of harsh environments.

To solve the above problems, the technical solution of the utility model is:

A real-time ground detection circuit, comprising: a relay, a pull-up circuit, and an IO module;

The positive input terminal of the IO module is electrically connected to the positive output terminal of the relay, the positive input terminal of the relay is electrically connected to the positive output terminal of the pull-up circuit, and the positive input terminal of the pull-up circuit is electrically connected to the positive electrode of the unit structure ground of the device under test;

The negative pole of the unit structure ground of the device under test is connected to the negative input end of the pull-up circuit through the grounding wire of the device under test by a grounding pile, the negative output end of the pull-up circuit is electrically connected to the negative input end of the relay, and the negative output end of the relay is electrically connected to the negative input end of the IO module;

The output end of the IO module is connected to a display, and the display is used to display the measured voltage value in real time during grounding detection.

According to an embodiment of the utility model, the pull-up circuit includes a voltage comparator, an inverter and an OC gate with a pull-up;

The positive input terminal of the voltage comparator is connected to the output terminal of a voltage divider circuit, and receives a comparison voltage output by the voltage divider circuit during ground detection;

The negative input terminal of the voltage comparator is electrically connected to the unit structure ground of the device under test;

The output end of the voltage comparator is electrically connected to the input end of the inverter, the output end of the inverter is electrically connected to the input end of the OC gate with pull-up, and the output end of the OC gate with pull-up is connected to the input end of the relay.

According to an embodiment of the utility model, the voltage divider circuit includes a first resistor and a second resistor;

One end of the first resistor is connected to the power supply of the device under test, and the other end is connected to the positive input terminal of the voltage comparator;

The second resistor is connected in parallel between the positive input terminal of the voltage comparator and the negative power supply terminal of the voltage comparator.

According to an embodiment of the utility model, the device under test has multiple unit structural grounds, and the positive input end of the pull-up circuit is electrically connected to the positive electrodes of the multiple unit structural grounds.

Due to the adoption of the above technical solution, the utility model has the following advantages and positive effects compared with the prior art:

1) The real-time grounding detection circuit in one embodiment of the utility model, in view of the problem that the visual inspection method relies on subjective judgment, there is a risk of human error, and lacks technical support for the status of electronic equipment, the measured structure is displayed in real time on the computer screen through the IO module, eliminating the risk of human error.

2) The real-time grounding detection circuit in one embodiment of the utility model addresses the problem that the multimeter and AD sampling module are not sensitive enough to effectively reflect the actual grounding conditions of each unit of the equipment in places with complex electromagnetic environments. By adopting electronic equipment to test IO modules and relays with high sensitivity, grounding detection is achieved. It can work stably in complex electromagnetic environments and extreme temperature and humidity environments, meeting the use requirements of harsh environments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram of a real-time ground detection circuit in an embodiment of the present utility model;

FIG. 2 is a diagram of a pull-up circuit in an embodiment of the present invention.

Description of reference numerals:

1: Relay; 2: Pull-up circuit; 3: IO module; 4: Unit structure ground of the device under test; 5: Computer; 6: Voltage comparator; 7: Inverter; 8: OC gate with pull-up.

DETAILED DESCRIPTION

The following is a further detailed description of a real-time ground detection circuit proposed by the utility model in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the utility model will become more apparent according to the following description and claims.

This embodiment provides a real-time grounding detection circuit, please refer to FIG1, the real-time grounding detection circuit includes: a relay 1, a pull-up circuit 2, and an IO module 3. The positive input terminal of the IO module 3 is electrically connected to the positive output terminal of the relay 1, the positive input terminal of the relay 1 is electrically connected to the positive output terminal of the pull-up circuit 2, and the positive input terminal of the pull-up circuit 2 is electrically connected to the positive electrode of the unit structure ground 4 of the device under test.

The negative pole of the unit structure ground 4 of the device under test is connected to the negative input terminal of the pull-up circuit 2 through the grounding pile and the grounding wire of the device under test, the negative output terminal of the pull-up circuit 2 is electrically connected to the negative input terminal of the relay 1, and the negative output terminal of the relay 1 is electrically connected to the negative input terminal of the IO module 3.

The output end of the IO module 3 is connected to the computer 5, and the computer 5 is used to display the measured voltage value in real time during the grounding detection.

The real-time grounding detection circuit has the characteristics of real-time monitoring, strong anti-interference and low resource occupation. Among them, real-time monitoring is reflected in the computer that converts the on-resistance into an electrical signal and transmits it to the electronic device. The computer can monitor the grounding situation in real time and display it on the display, which is convenient for operators to identify.

Strong anti-interference is reflected in the conversion of on-resistance into electrical signals for testing. The electrical signal test has much stronger anti-interference ability than direct on-resistance testing, and can suppress test false alarms caused by factory environment or power supply interference.

Less resource usage means that it can be realized by only one pull-up circuit, one relay channel and one IO channel. To ensure the test sensitivity, the circuit does not use a computer multimeter or AD channel, but uses the IO channel. The circuit runs independently and does not use other circuit resources, which minimizes the impact on the overall electronic circuit system and maximizes safety.

The following is the ground detection principle of the real-time ground detection circuit:

When the device under test is not working, the pull-up circuit is not powered. When the test device is grounded, the pull-up circuit is connected to the device power supply. If the IO module samples and measures a low voltage, it means that the structure of the unit is connected to the earth, indicating that the grounding is good; if the IO module samples and measures the voltage of the pull-up circuit, it means that the structure of the unit is not grounded, and an alarm prompt can be given on the display.

Please refer to FIG2 for the pull-up circuit mentioned above. The pull-up circuit includes a voltage comparator 6, an inverter 7 and an OC gate 8 with pull-up. The positive input terminal of the voltage comparator 6 is connected to the output terminal of a voltage divider circuit. During ground detection, a comparison voltage output by the voltage divider circuit is received. The negative input terminal of the voltage comparator 6 is electrically connected to the unit structure ground 4 of the device under test. The output terminal of the voltage comparator 6 is electrically connected to the input terminal of the inverter 7, the output terminal of the inverter 7 is electrically connected to the input terminal of the OC gate 8 with pull-up, and the output terminal of the OC gate 8 with pull-up is connected to the input terminal of the relay 1.

The voltage divider circuit includes a first resistor R7 and a second resistor R9; one end of the first resistor R7 is connected to the power supply of the device under test, and the other end is connected to the positive input terminal of the voltage comparator 6. The second resistor R9 is connected in parallel between the positive input terminal of the voltage comparator 6 and the negative terminal of the power supply of the voltage comparator 6.

The working principle of the pull-up circuit is as follows:

During ground detection, the positive end of the voltage comparator 6 receives a comparison voltage output by the voltage divider circuit formed by the power supply of the device under test through R7 and R9. The resistance ratio of R7 and R9 can be adjusted according to the sensitivity of different units of the electronic device to the ground voltage. Once the voltage of the unit ground to the earth exceeds the comparison voltage, the voltage comparator 6 will output a low level, which is reversed to a high level by the inverter 7, driven by the OC gate circuit with a pull-up power supply, and output to the IO module through the relay.

The real-time grounding detection circuit in this embodiment is mainly used in electronic equipment to perform real-time inspection on the grounding conditions of each unit in the preparation stage and the entire operation process of the electronic equipment, so that users can understand the real-time working status of each unit of the electronic equipment according to the detection results. The real-time grounding detection circuit can not only realize the monitoring of a single unit structure ground, but also realize the simultaneous monitoring of multiple unit structures. That is, when there are multiple unit structures of the device under test, the positive input end of the pull-up circuit can be divided into multiple lines to electrically connect the positive poles of the multiple unit structures. Correspondingly, the negative poles of the multiple unit structures are also connected to the negative input end of the pull-up circuit. By simultaneously monitoring the grounding conditions of multiple unit structures, users can understand the real-time working status of each unit of the electronic equipment in real time, which is very convenient.

In summary, the real-time grounding detection circuit in this embodiment has strong resistance to electromagnetic environment, and will not cause fluctuations in the detection results due to excessive environmental electromagnetic interference. Moreover, it can be integrated into the entire electronic circuit system as a part of the circuit of the electronic device, with strong adaptability and high reliability. For example, the real-time grounding detection circuit is not made on a printed circuit board, but can be made directly in the chassis. It can be made on the inside of the front panel of the chassis and fixed with the wiring harness. This design does not affect the reliability of the product, does not require additional space, and the sampling point is as close as possible to the structure of each unit, thereby enhancing the anti-interference ability of the detection circuit.

The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims (4)

1. A real-time ground detection circuit, characterized in that it comprises: a relay, a pull-up circuit, and an IO module; The positive input terminal of the IO module is electrically connected to the positive output terminal of the relay, the positive input terminal of the relay is electrically connected to the positive output terminal of the pull-up circuit, and the positive input terminal of the pull-up circuit is electrically connected to the positive electrode of the unit structure ground of the device under test; The negative pole of the unit structure ground of the device under test is connected to the negative input end of the pull-up circuit through the grounding wire of the device under test by a grounding pile, the negative output end of the pull-up circuit is electrically connected to the negative input end of the relay, and the negative output end of the relay is electrically connected to the negative input end of the IO module; The output end of the IO module is connected to a display, and the display is used to display the measured voltage value in real time during grounding detection. 2. The real-time ground detection circuit according to claim 1, characterized in that the pull-up circuit comprises a voltage comparator, an inverter and an OC gate with a pull-up; The positive input terminal of the voltage comparator is connected to the output terminal of a voltage divider circuit, and receives a comparison voltage output by the voltage divider circuit during ground detection; The negative input terminal of the voltage comparator is electrically connected to the unit structure ground of the device under test; The output end of the voltage comparator is electrically connected to the input end of the inverter, the output end of the inverter is electrically connected to the input end of the OC gate with pull-up, and the output end of the OC gate with pull-up is connected to the input end of the relay. 3. The real-time ground detection circuit according to claim 2, characterized in that the voltage divider circuit comprises a first resistor and a second resistor; One end of the first resistor is connected to the power supply of the device under test, and the other end is connected to the positive input terminal of the voltage comparator; The second resistor is connected in parallel between the positive input terminal of the voltage comparator and the negative power supply terminal of the voltage comparator. 4. The real-time ground detection circuit according to claim 1, characterized in that there are multiple unit structures of the device under test, and the positive input end of the pull-up circuit is electrically connected to the positive electrodes of the multiple unit structures.