Door node circuit applied to I-type concentrator door opening and closing state detection

Abstract

The invention discloses a door node circuit applied to I-type concentrator door opening and closing state detection, and relates to the technical field of switch detection, in particular to a door node circuit applied to I-type concentrator door opening and closing state detection, which comprises a thermistor and a TVS (Transient Voltage Suppressor) and is used for overvoltage protection; the active filter circuit is used for eliminating external instantaneous pulse interference and amplifying signals; and the isolation circuit is used for isolating the front-stage circuit and the rear-stage circuit through a photoelectric coupler. The problem of overvoltage damage caused by heavy current misconnection of a traditional gate node detection circuit is solved, and accurate detection of a switching signal and the overvoltage protection capability of the circuit can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of switch detection, and particularly to a door node circuit for detecting the switch door state of a type-I concentrator. Background Art

[0002] With the rapid development of power grid technology, power consumption information can already reflect the economic development, power consumption structure of a region. It is urgent to protect the security of power consumption information. However, the existing technologies for detecting the switch door state have a single structure, weak functionality, and are prone to damage, and cannot adapt to complex on-site environments.

[0003] A type-I concentrator is a power electronic terminal, which refers to a device applied in the power consumption field for summarizing, analyzing, and uploading the power consumption information collected by electric energy meters, such as concentrators, dedicated transformers, ECUs and other devices.

[0004] The switch door state detection is to confirm whether the meter cover of the terminal device is opened to prevent the theft of power consumption information or the theft of electricity by modifying the device. The circuit with this function is called a door node detection circuit.

[0005] The existing technology only realizes the functions of switch state detection and filtering out external instantaneous pulse interference. The devices applying this circuit need to be connected to high voltage, and there may be misconnection of high voltage during the installation process, damaging the front and rear stage circuits;

[0006] The existing technology uses a Π-type filter circuit, which has no amplification effect on the switch door signal and cannot accurately detect the switch state. Summary of the Invention

[0007] In view of the deficiencies and defects existing in the prior art, the present invention provides a door node circuit for detecting the switch door state of a type-I concentrator. To achieve the above invention purpose, the invention adopts the following technical solutions. This technology has an overvoltage protection function, which can prevent damage to the device caused by misconnection of high voltage during the installation process; uses an active filter circuit to amplify the switch door signal, filter out external instantaneous pulse interference, accurately detect the switch state, and improve the accuracy of the device for collecting switch door data.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A door node circuit for detecting the switch door state of a type-I concentrator, including an overvoltage protection circuit, an active filter circuit and an isolation circuit, for realizing accurate switch signal detection, wherein:

[0010] The overvoltage protection circuit includes: a thermistor RT1, a TVS tube VP1, a resistor R4, and a 5V power supply;

[0011] The active filter circuit includes: resistors R1, R2, R3, a capacitor C1, and an operational amplifier A1;

[0012] The isolation circuit includes: optocoupler O1, resistor R5, and 3.3V power supply;

[0013] The connection relationship is as follows: TVS diode VP1 and thermistor RT1 are located at the input terminal of the gate node detection circuit; one end of resistor R3 is connected to TVS diode VP1, and the other end is connected to capacitor C1 and the 1st pin of the operational amplifier; the other end of capacitor C1 is grounded; one end of resistor R1 is connected to the thermistor and one end of TVS diode, and the other end is connected to resistor R2 and the 2nd pin of the operational amplifier; one end of resistor R2 is connected to resistor R1 and the 2nd pin of the operational amplifier, and the other end is connected to the 3rd pin of the operational amplifier and the 1st pin of the optocoupler; the 2nd pin of optocoupler O1 is grounded, the 3rd pin is connected to the main control, and the 4th pin is connected to resistor R5 and the power supply.

[0014] Further, for the overvoltage protection circuit, the TVS diode should be connected between the positive and negative poles of the gate node circuit and is located at the very front end of the input terminal. The thermistor is connected to one end of the input to avoid damage to the circuit caused by incorrect connection of high voltage and to achieve the overvoltage protection function.

[0015] Further, for the active filter circuit, an operational amplifier, resistors, and capacitors are used to form a filter circuit, which can filter out instantaneous pulse interference, amplify the signal, and prevent the device from malfunctioning.

[0016] Further, the isolation circuit uses an optocoupler for isolation to achieve isolation between the front and rear stage circuits and protect the rear stage circuit.

[0017] Further, for a gate node detection circuit for a terminal with a switch detection function, the switch state detection uses single - ended input and occupies one IO port.

[0018] The beneficial technical effects of the present invention are as follows: The gate node port can avoid damage caused by incorrect connection of high voltage, reducing the losses caused by the work mistakes of installers; it can eliminate most external interferences, avoid device malfunctions, and improve the accuracy of data; the existence of the isolation circuit protects the safety of the rear stage circuit and improves the reliability of the device during on - site operation. Description of the Drawings

[0019] Figure 1 is the overall circuit schematic diagram of the present invention.

[0020] Figure 2 is the schematic diagram of the overvoltage protection circuit of the present invention.

[0021] Figure 3 is the schematic diagram of the active filter circuit of the present invention.

[0022] Figure 4 is the schematic diagram of the isolation circuit of the present invention. Detailed implementation manners

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the present invention.

[0024] The present invention will be further described below with reference to the accompanying drawings. The following content is only used to more clearly illustrate the technical solution of the present invention and cannot be used to limit the protection scope of the present invention.

[0025] As Figure 1 shown, a door node circuit applied to the detection of the switch door state of a type-I concentrator includes an overvoltage protection circuit, an active filter circuit and an isolation circuit, which are used to accurately detect the terminal switch door signal.

[0026] The overvoltage protection circuit includes a thermistor RT1, a resistor R4, a TVS tube VP1 and a 5V power supply. The TVS tube VP1 is connected between the input terminals, the ground terminal of the input terminals is connected in series with the thermistor RT1, and one end of the TVS tube VP1 is connected to the 5V power supply after being connected in series with the resistor R4. As Figure 2 shown, the thermistor and the TVS tube are used for overvoltage protection. The thermistor can protect against the misconnection of high-voltage electricity at the 380V level. When the current is large, the temperature of the thermistor rises, the resistance value increases, and the current passing through the thermistor is inhibited. The TVS tube is not conducting under normal conditions. In the case of overvoltage, the voltage is clamped to the safe operating state of the circuit to prevent the circuit from being damaged by overvoltage.

[0027] The filter circuit is an active filter circuit, which includes an operational amplifier U1, resistors R1, R2, R3, and a capacitor C1. The non-inverting input terminal of the operational amplifier is connected to the resistor R3 and the capacitor C1, the inverting input terminal is connected to the resistor R1, and the feedback resistor R2 is connected to the output terminal and the inverting input terminal of the operational amplifier. As Figure 3 shown, while filtering out external instantaneous pulse interference, this circuit amplifies the switch state signal, and the output value of the switch signal

[0028]

[0029] The isolation circuit includes an optocoupler O1, a resistor R5 and a 3.3V power supply. The 1st pin of the optocoupler is connected to the output terminal of the operational amplifier, the 2nd pin is grounded, the 3rd pin is connected to the I / O port, and the 4th pin is connected to the 3.3V power supply after being connected in series with the resistor R5. As Figure 4 shown, the "electric-optical-electric" signal conversion is realized through the optocoupler to isolate the front-stage and rear-stage circuits and provide overvoltage protection for the rear-stage circuit.

[0030] Normally, IO_SW is at a high level and is the same as IO1. When IO_SW changes to a low level, the optocoupler is not conducting, and IO1 also becomes low. The main control CPU pin connected to IO1 will detect the low level and then perform corresponding operations. The filtering circuit filters out external instantaneous pulse interference to prevent the main control CPU from misjudging the level state of IO1 at the misjudgment terminal and then performing misoperations. At the same time, it amplifies the switch state signal to drive the optocoupler.

[0031] The present invention realizes the precise detection of the terminal door opening and closing states, ensures normal operation in an environment with strong electricity, can achieve isolation between the front and rear stage circuits, and meets the requirements for protecting electrical usage information.

[0032] The above embodiments are illustrative of the specific implementation manners of the present invention rather than limitations thereof. Those skilled in the relevant technical fields can make various transformations and changes without departing from the spirit and scope of the present invention to obtain corresponding equivalent technical solutions. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. A door node circuit applied to the detection of the open / close state of the type-I concentrator, characterized in that, It includes an overvoltage protection circuit, an active filter circuit, and an isolation circuit, where: The overvoltage protection circuit includes: a thermistor RT1, a TVS diode VP1, a resistor R4, and a 5V power supply; The active filter circuit includes: resistors R1, R2, R3, a capacitor C1, and an operational amplifier A1; The isolation circuit includes: an optocoupler O1, a resistor R5, and a 3.3V power supply; The TVS diode VP1 and the thermistor RT1 are located at the input terminal of the gate node detection circuit; one end of the resistor R3 is connected to the TVS diode VP1, and the other end is connected to the capacitor C1 and the pin 1 of the operational amplifier A1; the other end of the capacitor C1 is grounded; one end of the resistor R1 is connected to one end of the thermistor and the TVS diode, and the other end is connected to the resistor R2 and the pin 2 of the operational amplifier; one end of the resistor R2 is connected to the resistor R1 and the pin 2 of the operational amplifier, and the other end is connected to the pin 3 of the operational amplifier and the pin 1 of the optocoupler; the pin 2 of the optocoupler O1 is grounded, the pin 3 is connected to the main control, and the pin 4 is connected to the resistor R5 and the 3.3V power supply.

2. The door node circuit for detecting the open / close state of the switch of the type-I concentrator according to claim 1, wherein, The TVS diode should be connected between the positive and negative poles of the gate node circuit and is located at the forefront of the input terminal. One end of the thermistor connected to the input is used to avoid damage to the circuit caused by misconnection of strong electricity, thereby realizing the overvoltage protection function.

3. The door node circuit for detecting the open / closed state of the switch of the type-I concentrator according to claim 1, wherein The filtering circuit is an active filtering circuit, which can filter out instantaneous pulse interference, amplify the signal, and prevent the device from malfunctioning.

4. The door node circuit for detecting the open / close state of the switch of the type-I concentrator according to claim 1, wherein, The isolation method of the isolation circuit is to use an optocoupler for isolation. In addition to the isolation function, it enhances the overvoltage protection function of the circuit.

5. The door node circuit for detecting the open / close state of the I-type concentrator as described in claim 1, characterized in that, The switch state detection uses single-ended input and occupies one IO port.

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