Power distribution cabinet temperature monitoring system

Abstract

The utility model relates to the technical field of power distribution equipment, and provides a power distribution cabinet temperature monitoring system which comprises a temperature detector installed on a power distribution cabinet site, a monitoring terminal installed in a central control room and a data transmission network used for establishing communication connection between the temperature detector and the monitoring terminal. The temperature detector comprises a detection circuit board and a plurality of non-contact temperature sensors arranged on the detection circuit board, the non-contact temperature sensors of the power distribution cabinet temperature monitoring system are not in contact with components in the power distribution cabinet, the structure of the power distribution cabinet is not changed, the installation is simple, and the cost is low. And the power distribution cabinet temperature monitoring system and the power distribution cabinet system are two independent systems and do not influence each other, so that unmanned monitoring of the temperature of the power distribution cabinet is realized.

Description

Technical Field

[0001] This utility model belongs to the field of power distribution equipment technology, and in particular relates to a power distribution cabinet temperature monitoring system. Background Technology

[0002] A distribution cabinet is a general term for a motor control center, including power distribution cabinets, lighting distribution cabinets, and metering cabinets. It is the final stage equipment in a power distribution system. Distribution cabinets are used in situations where loads are relatively dispersed and there are few circuits. A distribution cabinet distributes electrical energy from a circuit of the upstream power distribution equipment to the nearest load.

[0003] To enhance power distribution safety, it is necessary to monitor the temperature inside the distribution cabinet. The conventional method for monitoring the internal temperature of the distribution cabinet is manual inspection, which involves manually opening the distribution cabinet at regular intervals and using an infrared temperature detector to measure and record the temperature of the main terminals. The main problems with this approach are: manual temperature measurement requires opening the distribution cabinet door, which may cause personal injury, making it unsafe, and the operation is also relatively complicated.

[0004] With the advancement of technology, some temperature monitoring systems for power distribution cabinets have emerged in existing technologies. Most of them use temperature sensors to automatically monitor the temperature inside the power distribution cabinet. However, existing temperature monitoring systems for power distribution cabinets are usually inconvenient to install and replace temperature sensors, making them relatively inconvenient to use. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a distribution cabinet temperature monitoring system. The system aims to solve the problem that most existing distribution cabinet temperature monitoring systems use temperature sensors to automatically monitor the temperature inside the distribution cabinet. This monitoring method is usually inconvenient for the installation and replacement of temperature sensors, making it relatively inconvenient to use.

[0006] The technical solution provided by this utility model is: a power distribution cabinet temperature monitoring system, including a temperature detector installed at the power distribution cabinet site, a monitoring terminal installed in the central control room, and a data transmission network for establishing communication between the temperature detector and the monitoring terminal;

[0007] The temperature detector includes a detection circuit board and several non-contact temperature sensors disposed on the detection circuit board.

[0008] As an improved solution, several of the aforementioned non-contact temperature sensors include point monitoring infrared sensors, surface monitoring infrared sensors, and ambient temperature sensors.

[0009] The point monitoring infrared sensor is installed at the temperature monitoring point corresponding to each component in the power distribution cabinet, and the area monitoring infrared sensor is installed in the densely populated area of ​​the power distribution cabinet.

[0010] As an improved solution, the detection circuit board includes a main control circuit, a 485 communication circuit, a sensor mounting circuit, a relay control circuit, an audible and visual alarm circuit, and an indicator light circuit.

[0011] The 485 communication circuit, sensor mounting circuit, relay control circuit, audible and visual alarm circuit, and indicator light circuit are all connected to the main control circuit.

[0012] As an improved solution, the main control circuit includes a microcontroller U4, with pin 38 of the microcontroller U4 leading out a voltage terminal VCC, and the lines leading out from pins 14 and 15 of the microcontroller U4 being connected in series with capacitors C2 and C3 respectively and then grounded.

[0013] As an improved solution, the 485 communication circuit includes an RS-485 interface chip U3;

[0014] The line leading out from pin 1 of the RS-485 interface chip U3 is connected to pin 7 of the microcontroller U4, the lines leading out from pins 2 and 3 of the RS-485 interface chip U3 are connected to pin 1 of the microcontroller U4, and the line leading out from pin 4 of the RS-485 interface chip U3 is connected to pin 5 of the microcontroller U4.

[0015] A line leading from pin 8 of the RS-485 interface chip U3 is connected in series with capacitor C2 and then to pin 1 of interface P3. A first circuit node is provided on the line between capacitor C2 and pin 1 of interface P3. A line leading from the first circuit node is connected in series with resistor R15 and then to pin 2 of interface P3. A second circuit node is provided on the line between resistor R15 and pin 2 of interface P3. A line leading from the second circuit node is connected to pin 7 of the RS-485 interface chip U3. The connection between the second circuit node and pin 7 of the RS-485 interface chip U3 is... A third circuit node is provided on the line between the two points. The line leading out of the third circuit node is connected to pin 6 of the RS-485 interface chip U3 after being connected in series with resistor R16. A fourth circuit node is provided on the line between pin 6 of the RS-485 interface chip U3 and resistor R16. The line leading out of the fourth circuit node is connected to pin 3 of the interface P3. A fifth circuit node is provided on the line between the fourth circuit node and pin 3 of the interface P3. The line leading out of the fifth circuit node is connected to pin 8 of the RS-485 interface chip U3 after being connected in series with resistor R17.

[0016] As an improved solution, the sensor mounting circuit includes a first infrared sensor interface circuit J1, a first infrared sensor interface circuit J3, a first infrared sensor interface circuit J4, a second infrared sensor interface circuit J2, and a third infrared sensor interface circuit U3, wherein:

[0017] In the first infrared sensor interface circuit J1, the line leading out of pin 1 of the first infrared sensor interface circuit J1 is connected to the voltage terminal VCC, the line leading out of pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R2, the line leading out between pin 3 and the resistor R2 is connected to pin 40 of the microcontroller U4, the line leading out of pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R1, and the line leading out between pin 4 and the resistor R1 is connected to pin 41 of the microcontroller U4.

[0018] In the first infrared sensor interface circuit J3, the line leading out of pin 1 of the first infrared sensor interface circuit J3 is connected to the voltage terminal VCC, the line leading out of pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R10, the line leading out between pin 3 and resistor R10 is connected to pin 31 of the microcontroller U4, the line leading out of pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R6, and the line leading out between pin 4 and resistor R6 is connected to pin 30 of the microcontroller U4.

[0019] In the first infrared sensor interface circuit J4, the line leading out from pin 1 of the first infrared sensor interface circuit J4 is connected to the voltage terminal VCC, the line leading out from pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R13, the line leading out from pin 3 and the resistor R13 is connected to pin 33 of the microcontroller U4, the line leading out from pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R12, and the line leading out from pin 4 and the resistor R12 is connected to pin 32 of the microcontroller U4.

[0020] In the second infrared sensor interface circuit J2, the line leading out of pin 1 of the second infrared sensor interface circuit J2 is connected to the voltage terminal VCC, the line leading out of pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R8, the line leading out between pin 3 and resistor R8 is connected to pin 3 of the microcontroller U4, the line leading out of pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R5, and the line leading out between pin 4 and resistor R5 is connected to pin 2 of the microcontroller U4.

[0021] In the third infrared sensor interface circuit U3, the line led out from pin 2 of the third infrared sensor interface circuit U3 is connected to the voltage terminal VCC after being connected in series with resistor R14. The line led out from pin 3 between the resistor R14 is connected to pin 42 of the microcontroller U4. The line led out from pin 1 is connected to the voltage terminal VCC.

[0022] As an improved solution, the relay control circuit includes a relay U2. The line leading out from pin 5 of the relay U2 is connected to pin 1 of interface P1, the line leading out from pin 4 of the relay U2 is connected to pin 3 of interface P1, the line leading out from pin 3 of the relay U2 is connected to pin 2 of interface P1, the line leading out from pin 1 of the relay U2 is connected to the positive terminal of diode D2, and the line leading out from the negative terminal of diode D2 is connected to pin 2 of the relay U2.

[0023] A sixth circuit node is provided on the line between pin 1 of the relay U2 and the positive terminal of the diode D2, and a seventh circuit node is provided on the line between pin 2 of the relay U2 and the negative terminal of the diode D2. A resistor R9 and a diode D1 are connected in series on the connection line between the sixth circuit node and the seventh circuit node.

[0024] An eighth circuit node is provided on the line between diode D2 and the seventh circuit node. The line leading out of the eighth circuit node is connected to the emitter of transistor Q1. The line leading out of the base of transistor Q1 is connected to pin 4 of optocoupler chip U1 after being connected in series with resistor R7. A ninth circuit node is provided on the line between resistor R7 and pin 4 of optocoupler chip U1. The line leading out of the ninth circuit node is connected to the collector of transistor Q1 after being connected in series with resistor R3.

[0025] The line leading out from pin 1 of the optocoupler chip U1 is connected to pin 35 of the microcontroller U4, and the line leading out from pin 2 of the optocoupler chip U1 is connected to ground after being connected in series with resistor R11.

[0026] As an improved solution, the audible and visual alarm circuit includes an alarm interface P2. The line leading out of pin 2 of the alarm interface P2 is connected to pin 34 of the microcontroller U4 after being connected in series with a resistor R15. A tenth circuit node is provided on the line between the resistor R15 and pin 34 of the microcontroller U4. The line leading out of the tenth circuit node is connected to the base of the transistor Q2 after being connected in series with a resistor 18. The emitter of the transistor Q2 is grounded. The line leading out of the collector of the transistor Q2 is connected to pin 1 of the alarm interface P2.

[0027] In this invention, the distribution cabinet temperature monitoring system includes a temperature detector installed at the distribution cabinet site, a monitoring terminal installed in the central control room, and a data transmission network for establishing communication between the temperature detector and the monitoring terminal. The temperature detector includes a detection circuit board and several non-contact temperature sensors mounted on the detection circuit board. The non-contact temperature sensors of this distribution cabinet temperature monitoring system do not contact the components inside the distribution cabinet, do not change the structure of the distribution cabinet, are easy to install, and the distribution cabinet temperature monitoring system and the distribution cabinet system are two independent systems that do not affect each other, thus achieving unmanned monitoring of the distribution cabinet temperature. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0029] Figure 1 This is a structural block diagram of the power distribution cabinet temperature monitoring system provided by this utility model;

[0030] Figure 2 This is a structural block diagram of the detection circuit board provided by this utility model;

[0031] Figure 3 This is a circuit diagram of the main control circuit and the 485 communication circuit provided by this utility model;

[0032] Figure 4 This is a circuit diagram of the sensor mounting circuit provided by this utility model;

[0033] Figure 5 This is a circuit diagram of the relay control circuit provided by this utility model;

[0034] Figure 6 This is a circuit diagram of the audible and visual alarm circuit provided by this utility model. Detailed Implementation

[0035] The embodiments of the present utility model will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present utility model and should not be construed as limiting its scope of protection.

[0036] Figure 1 The diagram shows a structural block diagram of the power distribution cabinet temperature monitoring system provided by the present invention. For ease of explanation, only the parts related to the embodiments of the present invention are shown in the diagram.

[0037] The distribution cabinet temperature monitoring system includes a temperature detector 1 installed at the distribution cabinet site, a monitoring terminal installed in the central control room, and a data transmission network 3 for establishing communication between the temperature detector 1 and the monitoring terminal 2.

[0038] The temperature detector 1 includes a detection circuit board 4 and a plurality of non-contact temperature sensors 5 disposed on the detection circuit board 4.

[0039] Furthermore, the temperature detector 1 is installed in the distribution cabinet without contacting the components inside, thus not altering the cabinet's structure. It is compact and easy to install. The detector is small in size, offers high measurement accuracy, and is simple to assemble. It is a separate system independent of the distribution cabinet system and will not adversely affect its operation. The detector also features a display screen for on-site monitoring, facilitating personnel inspections.

[0040] Among them, several non-contact temperature sensors 5 include point monitoring infrared sensors, surface monitoring infrared sensors and ambient temperature sensors;

[0041] The infrared sensors used for point monitoring are installed at the temperature monitoring points corresponding to various components within the power distribution cabinet. The MLX90614 series sensor manufactured by Melexos (see diagram below) can be selected. This chip is small in size, low in cost, integrates an ADC and DSP, reduces external circuitry, and allows for a smaller and more integrated detector. Its detection range is -40℃ to 125℃, with a measurement accuracy of ±0.5℃ and a temperature resolution of 0.02℃. It supports the SMBus communication protocol and is easy to operate. Several MLX90614 sensors are used for point monitoring of critical components, such as the power distribution cabinet inlet lines and inverter inlet lines, to prevent safety hazards such as overcurrent in the lines and overheating at loose connections.

[0042] The surface monitoring infrared sensor is installed in the densely populated area of ​​the power distribution cabinet. The surface monitoring infrared sensor can be the AMG8833 series infrared sensor manufactured by Panasonic. It performs surface detection on the components in the power distribution cabinet. The infrared sensor has an 8×8 grid array (64 pixels) IR sensor, which can measure the temperature of objects within a certain area. It can be used to monitor the temperature of densely populated parts of components such as control circuits. Its temperature measurement range is -20℃ to 80℃, the measurement accuracy is ±2.5℃, and it uses the IIC communication protocol for transmission.

[0043] The DS18B20 ambient temperature sensor is selected to monitor the ambient temperature in the power distribution cabinet. When the power distribution cabinet is overheated due to a fault, the ambient temperature inside the cabinet will rise. When combined with an infrared temperature sensor, the temperature in the power distribution cabinet can be monitored more reliably. The ambient temperature sensor has a temperature detection range of -55℃ to +125℃, and also has an accuracy of ±0.5℃ when the temperature range exceeds -10℃ to 85℃.

[0044] Combination Figure 2 As shown, the detection circuit board 4 includes a main control circuit, a 485 communication circuit, a sensor mounting circuit, a relay control circuit, an audible and visual alarm circuit, and an indicator light circuit.

[0045] The 485 communication circuit, sensor mounting circuit, relay control circuit, audible and visual alarm circuit, and indicator light circuit are respectively connected to the main control circuit.

[0046] like Figure 3 As shown, the main control circuit includes a microcontroller U4. Pin 38 of the microcontroller U4 leads out the voltage terminal VCC. Pins 14 and 15 of the microcontroller U4 are connected in series with capacitors C2 and C3 respectively and then grounded. The microcontroller U4 can be an STC series chip. The characteristics of this series of chips are 16-bit processors, fast processing speed, ultra-low power consumption, and also integrate ADC, hardware IIC, etc., reducing the number of peripheral circuits, making development simpler and the instrument smaller.

[0047] The 485 communication circuit includes an RS-485 interface chip U3, which can be a MAX485.

[0048] The line leading out from pin 1 of the RS-485 interface chip U3 is connected to pin 7 of the microcontroller U4, the lines leading out from pins 2 and 3 of the RS-485 interface chip U3 are connected to pin 1 of the microcontroller U4, and the line leading out from pin 4 of the RS-485 interface chip U3 is connected to pin 5 of the microcontroller U4.

[0049] A line leading from pin 8 of the RS-485 interface chip U3 is connected in series with capacitor C2 and then to pin 1 of interface P3. A first circuit node is provided on the line between capacitor C2 and pin 1 of interface P3. A line leading from the first circuit node is connected in series with resistor R15 and then to pin 2 of interface P3. A second circuit node is provided on the line between resistor R15 and pin 2 of interface P3. A line leading from the second circuit node is connected to pin 7 of the RS-485 interface chip U3. The connection between the second circuit node and pin 7 of the RS-485 interface chip U3 is... A third circuit node is provided on the line between the two points. The line leading out of the third circuit node is connected to pin 6 of the RS-485 interface chip U3 after being connected in series with resistor R16. A fourth circuit node is provided on the line between pin 6 of the RS-485 interface chip U3 and resistor R16. The line leading out of the fourth circuit node is connected to pin 3 of the interface P3. A fifth circuit node is provided on the line between the fourth circuit node and pin 3 of the interface P3. The line leading out of the fifth circuit node is connected to pin 8 of the RS-485 interface chip U3 after being connected in series with resistor R17.

[0050] like Figure 4 As shown, the sensor mounting circuit includes a first infrared sensor interface circuit J1, a first infrared sensor interface circuit J3, a first infrared sensor interface circuit J4, a second infrared sensor interface circuit J2, and a third infrared sensor interface circuit U3, wherein:

[0051] In the first infrared sensor interface circuit J1, the line led out from pin 1 of the first infrared sensor interface circuit J1 is connected to the voltage terminal VCC, the line led out from pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R2, the line led out from pin 3 and the resistor R2 is connected to pin 40 of the microcontroller U4, the line led out from pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R1, and the line led out from pin 4 and the resistor R1 is connected to pin 41 of the microcontroller U4.

[0052] In the first infrared sensor interface circuit J3, the line led out from pin 1 of the first infrared sensor interface circuit J3 is connected to the voltage terminal VCC, the line led out from pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R10, the line led out from pin 3 and the resistor R10 is connected to pin 31 of the microcontroller U4, the line led out from pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R6, and the line led out from pin 4 and the resistor R6 is connected to pin 30 of the microcontroller U4.

[0053] In the first infrared sensor interface circuit J4, the line led out from pin 1 of the first infrared sensor interface circuit J4 is connected to the voltage terminal VCC, the line led out from pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R13, the line led out from pin 3 and the resistor R13 is connected to pin 33 of the microcontroller U4, the line led out from pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R12, and the line led out from pin 4 and the resistor R12 is connected to pin 32 of the microcontroller U4.

[0054] In the second infrared sensor interface circuit J2, the line led out from pin 1 of the second infrared sensor interface circuit J2 is connected to the voltage terminal VCC, the line led out from pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R8, the line led out from pin 3 and resistor R8 is connected to pin 3 of the microcontroller U4, the line led out from pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R5, and the line led out from pin 4 and resistor R5 is connected to pin 2 of the microcontroller U4.

[0055] In the third infrared sensor interface circuit U3, the line led out from pin 2 of the third infrared sensor interface circuit U3 is connected to the voltage terminal VCC after being connected in series with resistor R14. The line led out from pin 3 between the resistor R14 is connected to pin 42 of the microcontroller U4. The line led out from pin 1 is connected to the voltage terminal VCC.

[0056] like Figure 5 As shown, the relay control circuit includes a relay U2. The line leading out from pin 5 of the relay U2 is connected to pin 1 of interface P1. The line leading out from pin 4 of the relay U2 is connected to pin 3 of interface P1. The line leading out from pin 3 of the relay U2 is connected to pin 2 of interface P1. The line leading out from pin 1 of the relay U2 is connected to the positive terminal of diode D2. The line leading out from the negative terminal of diode D2 is connected to pin 2 of the relay U2.

[0057] A sixth circuit node is provided on the line between pin 1 of relay U2 and the positive terminal of diode D2, and a seventh circuit node is provided on the line between pin 2 of relay U2 and the negative terminal of diode D2. A resistor R9 and a diode D1 are connected in series on the connection line between the sixth circuit node and the seventh circuit node.

[0058] An eighth circuit node is provided on the line between diode D2 and the seventh circuit node. The line leading out of the eighth circuit node is connected to the emitter of transistor Q1. The line leading out of the base of transistor Q1 is connected to pin 4 of optocoupler chip U1 after being connected in series with resistor R7. A ninth circuit node is provided on the line between resistor R7 and pin 4 of optocoupler chip U1. The line leading out of the ninth circuit node is connected to the collector of transistor Q1 after being connected in series with resistor R3.

[0059] The line leading out from pin 1 of the optocoupler chip U1 is connected to pin 35 of the microcontroller U4, and the line leading out from pin 2 of the optocoupler chip U1 is connected to ground after being connected in series with resistor R11.

[0060] like Figure 6 As shown, the audible and visual alarm circuit includes an alarm interface P2. The line leading out of pin 2 of the alarm interface P2 is connected to pin 34 of the microcontroller U4 after being connected in series with a resistor R15. A tenth circuit node is provided on the line between the resistor R15 and pin 34 of the microcontroller U4. The line leading out of the tenth circuit node is connected to the base of the transistor Q2 after being connected in series with a resistor 18. The emitter of the transistor Q2 is grounded. The line leading out of the collector of the transistor Q2 is connected to pin 1 of the alarm interface P2.

[0061] In this embodiment, the indicator light circuit can be implemented with a conventional circuit, and will not be described in detail here, but it is not intended to limit the present invention.

[0062] In this utility model, the power supply unit has both a built-in battery and can be connected to an external power source. Even when the external power supply fails due to a power distribution cabinet malfunction, the temperature detector 1 can still monitor the temperature of the distribution cabinet and upload data. If the temperature control circuit of the distribution cabinet malfunctions (the cabinet reaches a certain temperature, but the fan does not rotate), the temperature detector 1 has a fan control circuit connected in parallel with the fan circuit used for temperature control in the distribution cabinet, which can monitor the temperature inside the cabinet. Even in the event of a circuit failure, the normal operation of the fan can still be guaranteed.

[0063] In this invention, the data transmission network is configured as follows:

[0064] Temperature data transmission can be achieved without building a new communication network; existing DDC system communication networks and PLC system networks can be used, which can greatly reduce costs. However, the infrared temperature detector 1 needs to be converted before it can be transmitted to the central control room for real-time monitoring.

[0065] In this utility model, the distribution cabinet temperature monitoring system includes a temperature detector 1 installed at the distribution cabinet site, a monitoring terminal installed in the central control room, and a data transmission network for establishing communication between the temperature detector 1 and the monitoring terminal. The temperature detector 1 includes a detection circuit board 4 and several non-contact temperature sensors disposed on the detection circuit board 4. The non-contact temperature sensors of this distribution cabinet temperature monitoring system do not contact the components inside the distribution cabinet, do not change the structure of the distribution cabinet, are easy to install, and the distribution cabinet temperature monitoring system and the distribution cabinet system are two independent systems that do not affect each other, thus realizing unmanned monitoring of the distribution cabinet temperature.

[0066] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A temperature monitoring system for a power distribution cabinet, characterized in that, This includes a temperature detector installed at the distribution cabinet site, a monitoring terminal installed in the central control room, and a data transmission network for establishing communication between the temperature detector and the monitoring terminal; The temperature detector includes a detection circuit board and several non-contact temperature sensors disposed on the detection circuit board.

2. The distribution cabinet temperature monitoring system according to claim 1, characterized in that, The aforementioned non-contact temperature sensors include point-monitoring infrared sensors, area-monitoring infrared sensors, and ambient temperature sensors; The point monitoring infrared sensor is installed at the temperature monitoring point corresponding to each component in the power distribution cabinet, and the area monitoring infrared sensor is installed in the densely populated area of ​​the power distribution cabinet.

3. The distribution cabinet temperature monitoring system according to claim 2, characterized in that, The detection circuit board includes a main control circuit, a 485 communication circuit, a sensor mounting circuit, a relay control circuit, an audible and visual alarm circuit, and an indicator light circuit. The 485 communication circuit, sensor mounting circuit, relay control circuit, audible and visual alarm circuit, and indicator light circuit are all connected to the main control circuit.

4. The distribution cabinet temperature monitoring system according to claim 3, characterized in that, The main control circuit includes a microcontroller U4. Pin 38 of the microcontroller U4 leads out a voltage terminal VCC. Pins 14 and 15 of the microcontroller U4 are connected in series with capacitors C2 and C3 respectively and then grounded.

5. The distribution cabinet temperature monitoring system according to claim 4, characterized in that, The 485 communication circuit includes an RS-485 interface chip U3; The line leading out from pin 1 of the RS-485 interface chip U3 is connected to pin 7 of the microcontroller U4, the lines leading out from pins 2 and 3 of the RS-485 interface chip U3 are connected to pin 1 of the microcontroller U4, and the line leading out from pin 4 of the RS-485 interface chip U3 is connected to pin 5 of the microcontroller U4. A line leading from pin 8 of the RS-485 interface chip U3 is connected in series with capacitor C2 and then to pin 1 of interface P3. A first circuit node is provided on the line between capacitor C2 and pin 1 of interface P3. A line leading from the first circuit node is connected in series with resistor R15 and then to pin 2 of interface P3. A second circuit node is provided on the line between resistor R15 and pin 2 of interface P3. A line leading from the second circuit node is connected to pin 7 of the RS-485 interface chip U3. The connection between the second circuit node and pin 7 of the RS-485 interface chip U3 is... A third circuit node is provided on the line between the two points. The line leading out of the third circuit node is connected to pin 6 of the RS-485 interface chip U3 after being connected in series with resistor R16. A fourth circuit node is provided on the line between pin 6 of the RS-485 interface chip U3 and resistor R16. The line leading out of the fourth circuit node is connected to pin 3 of the interface P3. A fifth circuit node is provided on the line between the fourth circuit node and pin 3 of the interface P3. The line leading out of the fifth circuit node is connected to pin 8 of the RS-485 interface chip U3 after being connected in series with resistor R17.

6. The distribution cabinet temperature monitoring system according to claim 4, characterized in that, The sensor mounting circuit includes a first infrared sensor interface circuit J1, a first infrared sensor interface circuit J3, a first infrared sensor interface circuit J4, a second infrared sensor interface circuit J2, and a third infrared sensor interface circuit U3, wherein: In the first infrared sensor interface circuit J1, the line leading out of pin 1 of the first infrared sensor interface circuit J1 is connected to the voltage terminal VCC, the line leading out of pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R2, the line leading out between pin 3 and the resistor R2 is connected to pin 40 of the microcontroller U4, the line leading out of pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R1, and the line leading out between pin 4 and the resistor R1 is connected to pin 41 of the microcontroller U4. In the first infrared sensor interface circuit J3, the line leading out of pin 1 of the first infrared sensor interface circuit J3 is connected to the voltage terminal VCC, the line leading out of pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R10, the line leading out between pin 3 and resistor R10 is connected to pin 31 of the microcontroller U4, the line leading out of pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R6, and the line leading out between pin 4 and resistor R6 is connected to pin 30 of the microcontroller U4. In the first infrared sensor interface circuit J4, the line leading out from pin 1 of the first infrared sensor interface circuit J4 is connected to the voltage terminal VCC, the line leading out from pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R13, the line leading out from pin 3 and the resistor R13 is connected to pin 33 of the microcontroller U4, the line leading out from pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R12, and the line leading out from pin 4 and the resistor R12 is connected to pin 32 of the microcontroller U4. In the second infrared sensor interface circuit J2, the line leading out of pin 1 of the second infrared sensor interface circuit J2 is connected to the voltage terminal VCC, the line leading out of pin 3 is connected to the voltage terminal VCC after being connected in series with resistor R8, the line leading out between pin 3 and resistor R8 is connected to pin 3 of the microcontroller U4, the line leading out of pin 4 is connected to the voltage terminal VCC after being connected in series with resistor R5, and the line leading out between pin 4 and resistor R5 is connected to pin 2 of the microcontroller U4. In the third infrared sensor interface circuit U3, the line led out from pin 2 of the third infrared sensor interface circuit U3 is connected to the voltage terminal VCC after being connected in series with resistor R14. The line led out from pin 3 between the resistor R14 is connected to pin 42 of the microcontroller U4. The line led out from pin 1 is connected to the voltage terminal VCC.

7. The distribution cabinet temperature monitoring system according to claim 4, characterized in that, The relay control circuit includes a relay U2. The line leading out from pin 5 of the relay U2 is connected to pin 1 of interface P1. The line leading out from pin 4 of the relay U2 is connected to pin 3 of interface P1. The line leading out from pin 3 of the relay U2 is connected to pin 2 of interface P1. The line leading out from pin 1 of the relay U2 is connected to the positive terminal of diode D2. The line leading out from the negative terminal of diode D2 is connected to pin 2 of the relay U2. A sixth circuit node is provided on the line between pin 1 of the relay U2 and the positive terminal of the diode D2, and a seventh circuit node is provided on the line between pin 2 of the relay U2 and the negative terminal of the diode D2. A resistor R9 and a diode D1 are connected in series on the connection line between the sixth circuit node and the seventh circuit node. An eighth circuit node is provided on the line between diode D2 and the seventh circuit node. The line leading out of the eighth circuit node is connected to the emitter of transistor Q1. The line leading out of the base of transistor Q1 is connected to pin 4 of optocoupler chip U1 after being connected in series with resistor R7. A ninth circuit node is provided on the line between resistor R7 and pin 4 of optocoupler chip U1. The line leading out of the ninth circuit node is connected to the collector of transistor Q1 after being connected in series with resistor R3. The line leading out from pin 1 of the optocoupler chip U1 is connected to pin 35 of the microcontroller U4, and the line leading out from pin 2 of the optocoupler chip U1 is connected to ground after being connected in series with resistor R11.

8. The distribution cabinet temperature monitoring system according to claim 4, characterized in that, The audible and visual alarm circuit includes an alarm interface P2. A line from pin 2 of the alarm interface P2 is connected in series with a resistor R15 and then connected to pin 34 of the microcontroller U4. A tenth circuit node is provided on the line between the resistor R15 and pin 34 of the microcontroller U4. A line from the tenth circuit node is connected in series with a resistor 18 and then connected to the base of a transistor Q2. The emitter of the transistor Q2 is grounded. A line from the collector of the transistor Q2 is connected to pin 1 of the alarm interface P2.

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