Anti-surge ventilation type pressure type water level gauge

Abstract

The utility model relates to an anti-surge ventilation type pressure water level gauge which comprises a hydraulic cable, a lightning protection module, an RS485 communication module, an LDO module, a single-chip microcomputer module and a pressure sensor. The hydraulic cable comprises a cable core and a shielding layer, the shielding layer is arranged on the periphery of the cable core, one end of the cable core is coupled to the lightning protection module, the other end of the cable core is coupled to the pressure sensor, and the lightning protection module comprises a first lightning protection sub-module and a second lightning protection sub-module; the first lightning protection sub-module is coupled to the LDO module, and the LDO module is coupled to the single-chip microcomputer module. The second lightning protection sub-module is coupled to the RS485 communication module, the RS485 communication module is coupled to the single-chip microcomputer module, the RS485 communication module is coupled between the second lightning protection sub-module and the second single-chip microcomputer module, the pressure sensor is connected to the single-chip microcomputer module, and through the design of the lightning protection module and the shielding layer, lightning stroke can be prevented, the interference resistance of the water level gauge equipment is improved, and the working efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of water level gauges, and in particular to a surge-proof ventilated pressure water level gauge. Background Art

[0002] At present, ventilation pressure water level gauges are mainly used in reservoir dam safety monitoring sites to achieve accurate monitoring of water level depth and water temperature.

[0003] However, the existing common ventilation pressure water level gauge has low lightning protection performance. During use, there will be strong lightning intervention in many occasions, which is easy to be damaged by strong lightning strikes, so it is necessary to improve it.

[0004] Based on this, the present application provides a surge-proof ventilated pressure water level gauge to solve the above-mentioned problems. Utility Model Content

[0005] In order to overcome the deficiencies of the prior art, the present application provides a surge-proof ventilated pressure water level gauge to solve the problem in the prior art that the lightning protection performance is low and the equipment is easily damaged by strong lightning strikes.

[0006] One of the embodiments of the present application provides a surge-proof ventilated pressure water level gauge, including: a hydraulic cable, a lightning protection module, an RS485 communication module, an LDO module, a single-chip microcomputer module, and a pressure sensor;

[0007] The hydraulic cable comprises a cable core and a shielding layer, wherein the shielding layer is arranged on the periphery of the cable core, one end of the cable core is coupled to a lightning protection module, and the other end of the cable core is coupled to a pressure sensor, and the lightning protection module comprises a first lightning protection sub-module and a second lightning protection sub-module;

[0008] The first lightning protection submodule is coupled to the LDO module, and the LDO module is coupled to the single-chip microcomputer module;

[0009] The second lightning protection submodule is coupled to the RS485 communication module, the RS485 communication module is coupled to the single-chip computer module, and the RS485 communication module is coupled between the second lightning protection submodule and the second single-chip computer module; the pressure sensor is connected to the single-chip computer module.

[0010] By adopting the above technical solution, when an excessively high voltage signal is received, the lightning protection module is coupled to the cable core, so that the excessively high voltage signal passes through the lightning protection module. After processing the lightning strike signal, the lightning protection module guides the high voltage signal to the shielding layer. The shielding layer is arranged on the periphery of the cable core to further perform lightning protection and load discharge, and further guides the high voltage to the lightning protection ground, thereby resisting interference from lightning or other electromagnetic interference sources, and protecting the ventilation pressure water level gauge from damage. At the same time, the processed voltage is input to the LDO module, and the LDO module converts the received voltage into a low voltage signal, and provides power to the single-chip microcomputer module. At this time, the second lightning protection sub-module removes the high-voltage interference from the RS485 signal and transmits it to the RS485 communication module. The RS485 communication module outputs protocol data information to communicate with the single-chip microcomputer module, and finally obtains the protocol content, completes the interaction of instructions, and realizes accurate monitoring of the water level depth and water temperature of the ventilation pressure water level gauge.

[0011] Optionally, the hydraulic cable further comprises a heat-insulating lining, the cable core is arranged in the heat-insulating lining, and a filler is arranged between the cable cores;

[0012] The cable core comprises a conductor, an insulating layer, a thermal insulation lining and a protective layer; the conductor is installed in the insulating layer, the protective layer is wrapped on the outer wall of the insulating layer, and the conductor, the insulating layer and the protective layer are all arranged in the thermal insulation lining.

[0013] By adopting the above technical solution, fillers are provided between the cable cores to protect the cable cores and enhance the insulation performance of the cables; the conductor, the insulating layer and the protective layer are all installed in the thermal insulation lining to prevent the cable cores from short circuiting, leaking and other safety accidents when used in the event of lightning.

[0014] Optionally, the first lightning protection submodule includes a first level protection and a second level protection;

[0015] The first level protection is coupled to the second level protection, the first level protection is a discharge tube D1, the anode of the discharge tube D1 is coupled to the POWER+ end of the cable core, the cathode of the discharge tube D1 is coupled to the POWER- end of the cable core, and the grounding level of the discharge tube D1 is connected to the lightning protection ground;

[0016] The second level protection includes a resettable fuse F1 and a resettable fuse F2;

[0017] The input end of the resettable fuse F1 is coupled to the anode of the discharge tube D1 and then coupled to the POWER+ end of the cable core. The input end of the resettable fuse F1 is connected in series with the discharge tube D1 and then coupled to the POWER- end of the cable core. The input end of the resettable fuse F2 is coupled to the cathode of the discharge tube D1 and then coupled to the POWER- end of the cable core. The input end of the resettable fuse F2 is connected in series with the discharge tube D1 and then coupled to the POWER+ end of the cable core.

[0018] By adopting the above technical solution, when the cable receives an excessively high voltage signal, the anode of the discharge tube D1 is coupled to the POWER+ end of the cable core, and the discharge tube D1 (90V) is turned on to discharge, so that the discharge tube D1 (90V) absorbs most of the high-voltage signal to the lightning protection ground, and the input end of the resettable fuse F1 is coupled to the anode of the discharge tube D1 and then coupled to the POWER+ end of the cable core, and the input end of the resettable fuse F2 is coupled to the cathode of the discharge tube D1 and then coupled to the POWER- end of the cable core, so that the residual signal processed by the discharge tube D1 enters the resettable fuse F1 and the resettable fuse F2 and then performs the second-level disconnection processing, so that the discharge tube D1 can absorb the high-voltage signal as much as possible, thereby realizing the second-level protection of the water level meter.

[0019] Optionally, the first lightning protection submodule further includes third-level protection and fourth-level protection;

[0020] The third level protection is coupled to the second level protection, and the third level protection is coupled to the first level protection through the second level protection; the fourth level protection is coupled to the third level protection, and the fourth level protection is coupled to the second level protection and the first level protection in sequence through the third level protection.

[0021] The third level protection includes a discharge tube D6, a common mode inductor L1, a first varistor RV1, a second varistor RV2 and a third varistor RV3;

[0022] The output end of the resettable fuse F2 is coupled to the third varistor RV3, the other end of the third varistor RV3 is coupled to the discharge tube D6, and one end of the discharge tube D6 away from the third varistor RV3 is coupled to the lightning protection ground;

[0023] One end of the second varistor RV2 is coupled to the output end of the resettable fuse F1, and the other end of the second varistor RV2 is coupled to one end of the third varistor RV3 close to the discharge tube D6;

[0024] One end of the first varistor RV1 is coupled to the output end of the resettable fuse F1 through the second varistor RV2; the other end of the first varistor RV1 is coupled to the output end of the resettable fuse F2 through the third varistor RV3;

[0025] The output end of the resettable fuse F1 is coupled to the first input end of the common mode inductor L1 through the second varistor RV2 and the first varistor RV1, and the output end of the resettable fuse F2 is coupled to the second input end of the common mode inductor L1 through the third varistor RV3 and the first varistor RV1; the first output end of the common mode inductor L1 is coupled to the fourth level protection, and the second output end of the common mode inductor L1 is coupled to the fourth level protection;

[0026] The fourth level protection includes a first TVS tube D2, a second TVS tube D3, a third TVS tube D5, a first high-voltage capacitor C5 and a second high-voltage capacitor C6;

[0027] The anode of the first TVS tube D2 is coupled to the first output end of the common mode inductor L1, and the cathode of the first TVS tube D2 is connected to the lightning protection ground; the anode of the third TVS tube D5 is coupled to the second output end of the common mode inductor L1, and the cathode of the third TVS tube D5 is connected to the lightning protection ground; the third TVS tube D5 is connected in series with the first TVS tube D2;

[0028] One end of the second TVS tube D3 is respectively coupled to the anode of the first TVS tube D2 and the first output end of the common mode inductor L1, and the other end of the second TVS tube D3 is respectively coupled to the anode of the third TVS tube D5 and the second output end of the common mode inductor L1;

[0029] The anode of the first high-voltage capacitor C5 is coupled to the anodes of the second TVS tube D3 and the first TVS tube D2 and the first output end of the common-mode inductor L1 in sequence, and the cathode of the first high-voltage capacitor C5 is connected to the lightning protection ground; the anode of the second high-voltage capacitor C6 is coupled to the anodes of the second TVS tube D3 and the third TVS tube D5 and the second output end of the common-mode inductor L1 in sequence, and the cathode of the second high-voltage capacitor C6 is connected to the lightning protection ground; the first high-voltage capacitor C5 and the second high-voltage capacitor C6 are connected in series.

[0030] By adopting the above technical solution, when the over-high voltage signal is processed by the discharge tube D1, the resettable fuse F1 and the resettable fuse F2, the discharge tube D6, the common mode inductor L1, the first varistor RV1, the second varistor RV2 and the third varistor RV3 are in the on state. After the first varistor RV1, the second varistor RV2 and the third varistor RV3 are turned on, their resistance values ​​are changed rapidly to absorb the overvoltage. At the same time, the discharge tube D6 discharges and absorbs most of the high-voltage signal to the lightning protection ground and the common mode inductor L1 to prevent the high-voltage interference signal from propagating through the circuit. After the absorption of the first three levels, the high-voltage signal becomes a low The high-voltage signal is fully absorbed by the first TVS tube D2, the second TVS tube D3, the third TVS tube D5, the first high-voltage capacitor C5 and the second high-voltage capacitor C6 of the fourth-level protection. The first TVS tube D2, the second TVS tube D3 and the third TVS tube D5 are turned on to absorb and consume excessive voltage energy to prevent overvoltage from damaging other components in the circuit. The absorbed low-voltage signal is filtered by the first high-voltage capacitor C5 and the second high-voltage capacitor C6 to remove high-frequency noise and interference signals at the input end, so that the low-voltage signal output is more stable, thereby realizing lightning protection for the water level meter circuit.

[0031] Optionally, a Zener diode D4 is connected in series between the anode of the first high-voltage capacitor C5 and the anode of the second high-voltage capacitor C6 , an anode V_IN terminal of the Zener diode D4 is coupled to the LDO module, and a cathode of the Zener diode D4 is grounded.

[0032] By adopting the above technical solution, when under extremely strong high-voltage interference, the first four levels of protection cannot absorb all of it, and the anode of the first high-voltage capacitor C5 and the anode of the second high-voltage capacitor C6 are connected in series with a Zener diode D4, so that the Zener diode D4 is turned on for voltage stabilization protection, and the anode V_IN end of the Zener diode D4 is coupled to the LDO module to output the voltage signal of the hydraulic cable after passing through the lightning protection circuit to the LDO module, so that the LDO module provides a processed voltage signal to power the entire water level meter.

[0033] Optionally, the LDO module further includes a power chip U2 of model ME6214A33PG, the input voltage of the power chip U2 is coupled to the anode V_IN terminal of the voltage stabilizing diode D4, and the output voltage of the power chip U2 is coupled to the single-chip microcomputer module.

[0034] By adopting the above technical solution, since the anode V_IN end of the voltage zener diode D4 is the voltage signal of the cable after passing through the lightning protection circuit, the input voltage of the power chip U2 is coupled to the anode V_IN end V_IN of the voltage zener diode D4, and the output voltage of the power chip U2 is coupled to the microcontroller module. The voltage signal is converted into 3.3V through the power chip U2, thereby providing power support for the entire system.

[0035] Optionally, the second lightning protection submodule includes fifth-level protection and sixth-level protection;

[0036] The fifth level protection is coupled to the sixth level protection, the fifth level protection is a discharge tube D7, the anode of the discharge tube D7 is coupled to the pin RS485_RX of the RS485 communication module, the cathode of the discharge tube D7 is coupled to the pin RS485_TX of the RS485 communication module, and the grounding level of the discharge tube D7 is connected to the lightning protection ground;

[0037] The sixth level protection includes a resettable fuse F3 and a resettable fuse F4;

[0038] The input end of the resettable fuse F3 is coupled to the anode of the discharge tube D7 and then coupled to the pin RS485_RX of the RS485 communication module. The input end of the resettable fuse F3 is connected in series with the discharge tube D7 and then coupled to the pin RS485_TX of the RS485 communication module. The pin RS485_TX of the RS485 communication module is connected in series with the discharge tube D7 and then coupled to the input end of the resettable fuse F4. The pin RS485_RX of the RS485 communication module is connected in series with the discharge tube D7 and then coupled to the input end of the resettable fuse F4.

[0039] By adopting the above technical solution, when it is necessary to receive the RS485 signal, the anode of the discharge tube D7 is coupled to the pin RS485_RX of the RS485 communication module, and the cathode of the discharge tube D7 is coupled to the pin RS485_TX of the RS485 communication module. The RS485 signal a enters the RS485_RX receiving end and the RS485_TX transmitting end of the RS485 communication module through the hydraulic cable, and is discharged through the discharge tube D7 (90V), so that the discharge tube D7 (90V) absorbs most of the high-voltage signal to the lightning protection ground for the first level of protection, and then the residual signal processed by the discharge tube D7 enters the self-resetting fuse F3, and the self-resetting fuse F3 is disconnected for the second level, so that the discharge tube D7 can absorb the high-voltage signal as much as possible, thereby realizing the second level of protection for the water level meter.

[0040] Optionally, the second lightning protection submodule further includes seventh-level protection and eighth-level protection;

[0041] The seventh level protection is coupled to the sixth level protection, and the seventh level protection is coupled to the fifth level protection through the sixth level protection; the eighth level protection is coupled to the seventh level protection, and the eighth level protection is coupled to the sixth level protection and the fifth level protection in sequence through the seventh level protection.

[0042] The seventh level protection includes a discharge tube D11, a common mode inductor L2, a fourth varistor RV4, a fifth varistor RV5 and a sixth varistor RV6;

[0043] The output end of the resettable fuse F3 is coupled to the sixth varistor RV6, the other end of the sixth varistor RV6 is coupled to the discharge tube D11, and one end of the discharge tube D11 away from the sixth varistor RV6 is coupled to the lightning protection ground;

[0044] One end of the fifth varistor RV5 is coupled to the output end of the resettable fuse F3, and the other end of the fifth varistor RV5 is coupled to one end of the sixth varistor RV6 close to the discharge tube D11;

[0045] One end of the fourth varistor RV4 is coupled to the output end of the resettable fuse F3 through the fifth varistor RV5; the other end of the fourth varistor RV4 is coupled to the output end of the resettable fuse F4 through the sixth varistor RV6;

[0046] The output end of the resettable fuse F3 is coupled to the first input end of the common mode inductor L2 through the fifth varistor RV5 and the fourth varistor RV4, and the output end of the resettable fuse F4 is coupled to the second input end of the common mode inductor L2 through the sixth varistor RV6 and the fourth varistor RV4; the first output end of the common mode inductor L2 is coupled to the eighth level protection, and the second output end of the common mode inductor L2 is coupled to the eighth level protection;

[0047] The eighth level protection includes a fourth TVS tube D8, a fifth TVS tube D9 and a sixth TVS tube D10;

[0048] The anode of the fourth TVS tube D8 is coupled to the first output end of the common mode inductor L2, and the cathode of the fourth TVS tube D8 is connected to the lightning protection ground; the anode of the sixth TVS tube D10 is coupled to the second output end of the common mode inductor L2, and the cathode of the sixth TVS tube D10 is connected to the lightning protection ground; the sixth TVS tube D10 is connected in series with the fourth TVS tube D8;

[0049] One end of the fifth TVS tube D9 is respectively coupled to the anode of the fourth TVS tube D8 and the first output end of the common mode inductor L2, and the other end of the fifth TVS tube D9 is respectively coupled to the anode of the sixth TVS tube D10 and the second output end of the common mode inductor L2;

[0050] The fifth TVS tube D9 is coupled to the RS485 communication module.

[0051] By adopting the above technical solution, when the excessive voltage signal is processed by the discharge tube D7, the resettable fuse F3 and the resettable fuse F4, the discharge tube D11, the common mode inductor L2, the fourth varistor RV4, the fifth varistor RV5 and the sixth varistor RV6 are in the on state. After the fourth varistor RV4, the fifth varistor RV5 and the sixth varistor RV6 are turned on, their resistance values ​​are rapidly changed to absorb the overvoltage. At the same time, the discharge tube D11 discharges and absorbs most of the high-voltage signal to the lightning protection ground and the common mode inductor L2 to prevent the high-voltage interference signal from propagating through the circuit. After the first three levels of absorption, the high-voltage signal becomes a low-voltage signal, and then the fourth TVS tube D8, the fifth TVS tube D9 and the sixth TVS tube D10 of the fourth level of protection are turned on for absorption, so that all interference signals are absorbed and filtered. After the four-level protection processing, the RS485 signal a becomes the RS485 signal b and the high-voltage interference signal has been removed, thereby becoming a normal RS485 signal.

[0052] Optionally, the RS485 communication module further includes a communication chip U3 of model SP3485EN-L / TR; the seventh pin of the communication chip U3 is connected in series with a fifth resistor R5 and then coupled to the first output end of the common mode capacitor L2;

[0053] The 6th pin of the communication chip U3 is connected in series with the seventh resistor R7 and then coupled to the second output end of the common mode capacitor L2; the end of the fifth resistor R5 away from the communication chip U3 is coupled to the fourth resistor R4 and then grounded; the end of the seventh resistor R7 away from the communication chip U3 is coupled to the eighth resistor R8;

[0054] The 8th pin of the communication chip U3 is connected in series with the capacitor C7 and then grounded, and a power supply is connected in parallel between the 8th pin of the communication chip U3 and the capacitor C7; the 5th pin of the communication chip U3 is grounded;

[0055] The 4th pin of the communication chip U3 is connected in series with the sixth resistor R6 and then coupled to the base of the transistor Q1. The collector of the transistor Q1 is respectively coupled to the 2nd pin of the communication chip U3 and the third resistor R3. The emitter of the transistor Q1 is grounded, and the 1st pin of the communication chip U3 is coupled to the microcontroller module.

[0056] By adopting the above technical solution, the RS485 module also includes a communication chip U3 of model SP3485EN-L / TR, one end of the common-mode capacitor L2 is connected in parallel with the fourth resistor R4 and then in series with the fifth resistor, the other end of the common-mode capacitor L2 is connected in parallel with the eighth resistor R8 and then in series with the seventh resistor R7, the 7th pin of the communication chip U3 is connected in series with the fifth resistor R5, and the 6th pin of the communication chip U3 is connected in series with the seventh resistor R7. When a normal RS485 signal passes through the R5 and R7 current limiting protection resistors and reaches the communication chip U3 through the 6th and 7th pins of the communication chip U3, the communication chip U3 converts the RS485 signal into a TTL signal, and the TTL signal is transmitted to the STM32 microcontroller serial port through the 2nd and 3rd pins of the communication chip U3, thereby realizing data interactive communication between the RS485 signal and the STM32 microcontroller.

[0057] Optionally, the pressure sensor also includes a pressure sensor probe with model MPM258, which is coupled to a terminal P1, and the first and second pins of the terminal P1 are grounded; the third pin of the terminal P1 is coupled to an SDA line, and the SDA line is connected in series with a tenth resistor R10; the fourth pin of the terminal P1 is coupled to an SCL line, and the SCL line is connected in series with a ninth resistor R9; and the fifth pin of the terminal P1 is coupled to the pressure sensor probe.

[0058] By adopting the above technical solution, the terminal P1 is coupled to the pressure sensor probe, the first and second pins of the terminal P1 are grounded, the third pin of the terminal P1 is connected in series with the tenth resistor R10, the fourth pin of the terminal P1 is connected in series with the ninth resistor R9 and then connected in parallel to the fifth pin of the terminal P1, the voltage output unit is connected in series with the TVS tube D12 and the capacitor C10 and then grounded; the clock line SDA is connected in series with the TVS tube D13 and the capacitor C11 and then grounded; the data line SCL is connected in series with the TVS tube D14 and the capacitor C12 and then grounded, completing the STM32 The single-chip microcomputer is connected for communication to realize data interaction and obtain the water level and water temperature values; among them, the pressure sensor probe adopts the imported ventilation pressure type, the ninth resistor R9 and the tenth resistor R10 are both pull-up resistors, which improve the reliability of IIC communication. The TVS tube (D12, D13, D14) and the capacitor (C10, C11, C12) form an electrostatic protection circuit to realize electrostatic reception, and the TVS tube (D12, D13, D14) is turned on to absorb static electricity and protect the pressure sensor probe, thereby connecting and communicating with the single-chip microcomputer module to realize data interaction and obtain the water level and water temperature values.

[0059] The surge-proof ventilated pressure water level gauge provided in the above embodiments has the following beneficial effects:

[0060] 1. The lightning protection module is coupled to the cable core to stabilize the voltage after lightning signal processing. At the same time, the shielding layer is designed to further prevent lightning load. When the lightning protection module guides the voltage to the shielding layer, it guides the voltage to the lightning protection ground along the shielding layer, effectively resisting interference from lightning or other electromagnetic interference sources, protecting the ventilation pressure water level gauge from damage, and ensuring the safe and stable operation of subsequent circuits.

[0061] 2. In one of the embodiments, the overvoltage is released by turning on the first protection level discharge tube D1, absorbing most of the high-voltage signal to the lightning protection ground, and then the input end of the self-resetting fuse F1 is coupled to the anode of the discharge tube D1 and the input end of the self-resetting fuse F2 is coupled to the cathode of the discharge tube D1, so that the residual high-voltage signal enters the self-resetting fuse F1, and the self-resetting fuse F2 is used as the second-level protection to perform the second-level disconnection processing, so that the discharge tube D1 can absorb as much as possible, thereby solving the problems of lightning protection and lightning induction, protecting the ventilation pressure water level gauge from external interference such as lightning strikes, and improving the reliability and stability of the ventilation pressure water level gauge.

[0062] 3. In one of the embodiments, the first varistor RV1, the second varistor RV2, the third varistor RV3 and the discharge tube D6 are discharged, and the common mode inductor L1 is used for the third stage absorption. After the first three stages, the high-voltage signal becomes a low-voltage signal, and then passes through the fourth stage T first TVS tube D2, the second TVS tube D3 and the third TVS tube D5 for conduction absorption and the first high-voltage capacitor C5 and the second high-voltage capacitor C6 for filtering, so as to filter out all interference signals; if under extremely strong high-voltage interference, the first four stages cannot absorb all of it, and finally the D4 voltage regulator diode performs voltage stabilization protection, so as to effectively protect the subsequent circuit, thereby solving the problems of lightning protection and lightning induction, protecting the ventilation pressure water level gauge from external interference such as lightning strikes, and improving the reliability and stability of the ventilation pressure water level gauge.

[0063] 4. In one of the embodiments, the input voltage of the power chip U2 is coupled to the anode V_IN terminal V_IN of the voltage-stabilizing diode D4, and the high-voltage voltage signal of the first lightning protection sub-module is converted into a low-voltage voltage signal, thereby realizing voltage conversion. At the same time, the output voltage of the power chip U2 is coupled to the single-chip microcomputer module to provide a stable power supply voltage for the single-chip microcomputer module, thereby ensuring the normal operation of the single-chip microcomputer module. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0065] Figure 1 A schematic diagram of the internal structure of a surge-proof ventilated pressure water level gauge provided in an embodiment of the present application;

[0066] Figure 2 for Figure 1 Schematic diagram of the hydraulic cable structure of the anti-surge ventilated pressure water level gauge;

[0067] Figure 3 A circuit diagram of a first lightning protection submodule of a surge-proof ventilated pressure water level gauge provided in an embodiment of the present application;

[0068] Figure 4 A circuit diagram of an LDO module of a surge-proof ventilated pressure water level gauge provided in an embodiment of the present application;

[0069] Figure 5 A circuit diagram of an RS485 communication module of a surge-proof ventilated pressure water level gauge provided in an embodiment of the present application;

[0070] Figure 6 A circuit diagram of a single-chip microcomputer module of a surge-proof ventilated pressure water level gauge provided in an embodiment of the present application;

[0071] Figure 7 A circuit diagram of a sensor of a surge-proof ventilated pressure water level gauge provided in an embodiment of the present application.

[0072] Figure Number:

[0073] 1. Hydraulic cable; 2. First lightning protection sub-module; 3. LDO module; 4. RS485 communication module; 5. Second lightning protection sub-module; 6. Single chip microcomputer module; 7. Sensor; 100. Conductor; 200. Insulation layer; 300. Protective layer; 400. Thermal insulation lining; 500. Shielding layer; 600. Filler. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solutions and advantages of this application more clear, the following Figure 1-4 It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0075] The present application embodiment discloses a surge-proof ventilated pressure water level gauge. Figure 1The surge-proof ventilated pressure water level gauge includes a hydraulic cable, a lightning protection module, an RS485 communication module, an LDO module, a single-chip computer module and a pressure sensor; the RS485 communication module is coupled to the first lightning protection module for data exchange communication, and the LDO module is coupled to the output end of the second lightning protection module for receiving the voltage after processing and stabilization; one end of the cable core is coupled to the lightning protection module, and the other end of the cable core is coupled to the pressure sensor, and the lightning protection module includes a first lightning protection sub-module and a second lightning protection sub-module; the first lightning protection sub-module is coupled to the LDO module, and the LDO module is coupled to the single-chip computer module; the second lightning protection sub-module is coupled to the RS485 communication module, the RS485 communication module is coupled to the single-chip computer module, the RS485 communication module is coupled between the second lightning protection sub-module and the second single-chip computer module, and the pressure sensor is connected to the single-chip computer module.

[0076] Reference Figure 2 The hydraulic cable includes a cable core and a shielding layer. The shielding layer is located on the periphery of the cable core. A thermal insulation lining is fixed on the inner wall of the shielding layer. There are 4 cable cores, and the 4 cable cores are evenly installed in the thermal insulation lining. There are fillers between the cable cores. 2 cable cores are connected to the positive and negative poles of the power supply, and the other 2 cable cores are connected to the lightning protection module. The hydraulic cable also includes an air duct for exhaust. The cable core includes a conductor, an insulating layer and a protective layer. The conductor is installed in the insulating layer, and the protective layer is wrapped on the outer wall of the insulating layer. The conductor, the insulating layer and the protective layer are all installed in the thermal insulation lining.

[0077] Reference Figure 3The first lightning protection submodule includes a first-level protection and a second-level protection; the first-level protection is coupled to the second-level protection, the first-level protection is a discharge tube D1, the anode of the discharge tube D1 is coupled to the POWER+ end of the cable core, the cathode of the discharge tube D1 is coupled to the POWER- end of the cable core, and the grounding level of the discharge tube D1 is connected to the lightning protection ground; the second-level protection includes a resettable fuse F1 and a resettable fuse F2; the input end of the resettable fuse F1 is coupled to the anode of the discharge tube D1 and then coupled to the POWER+ end of the cable core, the input end of the resettable fuse F1 is connected in series with the discharge tube D1 and then coupled to the POWER- end of the cable core; the input end of the resettable fuse F2 is coupled to the cathode of the discharge tube D1 and then coupled to the POWER- end of the cable core, the input end of the resettable fuse F2 is connected in series with the discharge tube D1 and then coupled to the POWER+ end of the cable core. The first lightning protection sub-module also includes a third-level protection and a fourth-level protection; the third-level protection is coupled to the second protection, and the third-level protection is coupled to the first-level protection through the second-level protection; the fourth-level protection is coupled to the third-level protection, and the fourth-level protection is coupled to the second-level protection and the first-level protection in sequence through the third-level protection.The third level protection includes a discharge tube D6, a common mode inductor L1, a first varistor RV1, a second varistor RV2 and a third varistor RV3; the output end of the resettable fuse F2 is coupled to the third varistor RV3, the other end of the third varistor RV3 is coupled to the discharge tube D6, and the end of the discharge tube D6 away from the third varistor RV3 is coupled to the lightning protection ground; one end of the second varistor RV2 is coupled to the output end of the resettable fuse F1, and the other end of the second varistor RV2 is coupled to the end of the third varistor RV3 close to the discharge tube D6; one end of the first varistor RV1 is connected to the resettable fuse F1 through the resettable fuse F1. The second varistor RV2 is coupled to the output end of the resettable fuse F1; the other end of the first varistor RV1 is coupled to the output end of the resettable fuse F2 through the third varistor RV3; the output end of the resettable fuse F1 is coupled to the first input end of the common-mode inductor L1 through the second varistor RV2 and the first varistor RV1, and the output end of the resettable fuse F2 is coupled to the second input end of the common-mode inductor L1 through the third varistor RV3 and the first varistor RV1; the first output end of the common-mode inductor L1 is coupled to the fourth level protection, and the second output end of the common-mode inductor L1 is coupled to Fourth level protection; The fourth level protection includes a first TVS tube D2, a second TVS tube D3, a third TVS tube D5, a first high-voltage capacitor C5 and a second high-voltage capacitor C6; the anode of the first TVS tube D2 is coupled to the first output end of the common-mode inductor L1, and the cathode of the first TVS tube D2 is connected to the lightning protection ground; the anode of the third TVS tube D5 is coupled to the second output end of the common-mode inductor L1, and the cathode of the third TVS tube D5 is connected to the lightning protection ground; the third TVS tube D5 is connected in series with the first TVS tube D2; one end of the second TVS tube D3 is respectively coupled to the anode of the first TVS tube D2 and the first output end of the common-mode inductor L1 An output end, the other end of the second TVS tube D3 is respectively coupled to the anode of the third TVS tube D5 and the second output end of the common mode inductor L1; the anode of the first high-voltage capacitor C5 is sequentially coupled to the anode of the second TVS tube D3 and the first TVS tube D2 and the first output end of the common mode inductor L1, and the cathode of the first high-voltage capacitor C5 is connected to the lightning protection ground; the anode of the second high-voltage capacitor C6 is sequentially coupled to the anode of the second TVS tube D3 and the third TVS tube D5 and the second output end of the common mode inductor L1, and the cathode of the second high-voltage capacitor C6 is connected to the lightning protection ground; the first high-voltage capacitor C5 and the second high-voltage capacitor C6 are connected in series. The anode of the first high-voltage capacitor C5 and the anode of the second high-voltage capacitor C6 are connected in series with a voltage regulator diode D4, the anode V_IN end of the voltage regulator diode D4 is coupled to the LDO module, and the cathode of the voltage regulator diode D4 is grounded.

[0078] Reference Figure 4The LDO module also includes a power chip U2 of model ME6214A33PG. The input voltage of the power chip U2 is coupled to the anode V_IN terminal of the voltage-stabilizing diode D4. The output voltage of the power chip U2 is coupled to the single-chip microcomputer module. The input voltage of the power chip U2 is connected in series with the first filter capacitor C1. The output voltage of the power chip U2 is connected in series with the second filter capacitor C2. The first filter capacitor C1 and the second filter capacitor C2 filter out interference signals.

[0079] Reference Figure 5The second lightning protection submodule includes a fifth level protection and a sixth level protection; the fifth level protection is coupled to the sixth level protection, the fifth level protection is a discharge tube D7, the anode of the discharge tube D7 is coupled to the pin RS485_RX of the RS485 communication module, the cathode of the discharge tube D7 is coupled to the pin RS485_TX of the RS485 communication module, and the grounding level of the discharge tube D7 is connected to the lightning protection ground; the sixth level protection includes a resettable fuse F3 and a resettable fuse F4; the input end of the resettable fuse F3 is coupled to the anode of the discharge tube D7 and then coupled to the pin RS485_RX of the RS485 communication module, and the input end of the resettable fuse F3 is connected in series with the discharge tube D7. Tube D7 is then coupled to the pin RS485_TX of the RS485 communication module; the pin RS485_TX of the RS485 communication module is connected in series to the discharge tube D7 and then coupled to the input end of the resettable fuse F4; the pin RS485_RX of the RS485 communication module is connected in series to the discharge tube D7 and then coupled to the input end of the resettable fuse F4; the second lightning protection sub-module also includes a seventh level of protection and an eighth level of protection; the seventh level of protection is coupled to the sixth level of protection, and the seventh level of protection is coupled to the fifth level of protection through the sixth level of protection; the eighth level of protection is coupled to the seventh level of protection, and the eighth level of protection is sequentially coupled to the sixth level of protection and the fifth level of protection through the seventh level of protection.The seventh level protection includes a discharge tube D11, a common mode inductor L2, a fourth varistor RV4, a fifth varistor RV5 and a sixth varistor RV6; the output end of the resettable fuse F3 is coupled to the sixth varistor RV6, the other end of the sixth varistor RV6 is coupled to the discharge tube D11, and the end of the discharge tube D11 away from the sixth varistor RV6 is coupled to the lightning protection ground; one end of the fifth varistor RV5 is coupled to the output end of the resettable fuse F3, the other end of the fifth varistor RV5 is coupled to the end of the sixth varistor RV6 close to the discharge tube D11, and one end of the fourth varistor RV4 is coupled to the output end of the resettable fuse F3 through the fifth varistor RV5; the other end of the fourth varistor RV4 is coupled to the output end of the resettable fuse F4 through the sixth varistor RV6; the output end of the resettable fuse F3 is coupled to the first input end of the common mode inductor L2 after passing through the fifth varistor RV5 and the fourth varistor RV4, and the output end of the resettable fuse F4 is coupled to the first input end of the common mode inductor L2 through the fifth varistor RV5 and the fourth varistor RV4. The sixth varistor RV6 and the fourth varistor RV4 are coupled to the second input terminal of the common mode inductor L2; the first output terminal of the common mode inductor L2 is coupled to the eighth level protection, and the second output terminal of the common mode inductor L2 is coupled to the eighth level protection; the eighth level protection includes a fourth TVS tube D8, a fifth TVS tube D9 and a sixth TVS tube D10; the anode of the fourth TVS tube D8 is coupled to the first output terminal of the common mode inductor L2, and the cathode of the fourth TVS tube D8 is connected to the lightning protection ground; the sixth TVS tube The anode of D10 is coupled to the second output end of the common-mode inductor L2, and the cathode of the sixth TVS tube D10 is connected to the lightning protection ground; the sixth TVS tube D10 is connected in series with the fourth TVS tube D8; one end of the fifth TVS tube D9 is respectively coupled to the anode of the fourth TVS tube D8 and the first output end of the common-mode inductor L2, and the other end of the fifth TVS tube D9 is respectively coupled to the anode of the sixth TVS tube D10 and the second output end of the common-mode inductor L2; the fifth TVS tube D9 is coupled to the RS485 communication module.

[0080] The RS485 communication module also includes a communication chip U3 of model SP3485EN-L / TR; the 7th pin of the communication chip U3 is connected in series with the fifth resistor R5 and then coupled to the first output end of the common-mode capacitor L2; the 6th pin of the communication chip U3 is connected in series with the seventh resistor R7 and then coupled to the second output end of the common-mode capacitor L2, and the end of the fifth resistor R5 away from the communication chip U3 is coupled to the fourth resistor R4 and then grounded; the end of the seventh resistor R7 away from the communication chip U3 is coupled to the eighth resistor R8; the 8th pin of the communication chip U3 is connected in series with the capacitor C7 and then grounded, and a power supply is connected in parallel between the 8th pin of the communication chip U3 and the capacitor C7; the 5th pin of the communication chip U3 is grounded; the 4th pin of the communication chip U3 is connected in series with the sixth resistor R6 and then coupled to the base of the transistor Q1, and the collector of the transistor Q1 is respectively coupled to the 2nd pin of the communication chip U3 and the third resistor R3; the emitter of the transistor Q1 is grounded, and the 1st pin of the communication chip U3 is coupled to the said single-chip microcomputer module.

[0081] Reference Figure 6 The single-chip computer module also includes a chip U1 of model STM32G030F6P6 and a debugging interface H1. The 4th pin of the chip U1 is coupled to the voltage output unit, the 5th pin of the chip U1 is grounded, one end of the second resistor R2 is coupled to the voltage output unit, the other end of the second resistor R2 is connected in series with the third capacitor C3 and then grounded to form a reset circuit, and the 6th pin of the chip U1 is connected in series between the second resistor R2 and the third capacitor C3; the 18th pin and the 19th pin of the chip U1 are both coupled to the debugging interface H1, the 11th pin and the 12th pin of the chip U1 are respectively coupled to the clock line SCL and the data line SDA, the 2nd pin and the 3rd pin of the debugging interface H1 are respectively coupled to the 18th pin and the 19th pin of the chip U1, the 1st pin of the debugging interface H1 is connected to the voltage output unit, and the 4th pin of the debugging interface H1 is grounded.

[0082] Reference Figure 7 The pressure sensor also includes a pressure sensor probe with model number MPM258, which is coupled to a terminal P1, and the first and second pins of the terminal P1 are grounded; the third pin of the terminal P1 is coupled to an SDA line, and the SDA line is connected in series with a tenth resistor R10; the fourth pin of the terminal P1 is coupled to an SCL line, and the SCL line is connected in series with a ninth resistor R9; and the fifth pin of the terminal P1 is coupled to the pressure sensor probe.

[0083] The implementation principle of a surge-proof ventilated pressure water level gauge in the embodiment of the present application is as follows: when the hydraulic cable receives a lightning strike or other electromagnetic overvoltage signal, the lightning protection module performs first-level protection, second-level protection, third-level protection, and fourth-level protection and absorption. The first-level discharge tube D1 (90V) is first turned on for discharge to absorb most of the high-voltage signal to the lightning protection ground. The remaining signal enters the self-resetting fuse F1 and the self-resetting fuse F2 as the second-level protection for the second-level disconnection processing, so that the discharge tube absorbs as much as possible, and then passes through the discharge tube D6, the common-mode inductor L1, the first varistor RV1, and the second varistor RV 2 and the third varistor RV3; perform the third stage absorption, after the first three stages, the high voltage signal becomes a low voltage signal, and then passes through the first TVS tube D2, the second TVS tube D3 and the third TVS tube D5 of the fourth stage for absorption and the first high voltage capacitor C5 and the second high voltage capacitor C6 for filtering, so as to filter out all interference signals; if under extremely strong high voltage interference, the first four stages cannot absorb all of them, and finally the voltage stabilizing diode D4 performs voltage stabilizing protection and outputs a voltage signal to the U2 chip at the anode V_IN end of the output voltage stabilizing diode D4, which is converted into 3.3V to provide power for the entire system. At the same time, when the high voltage interference signal is The command RS485 signal a comes in through the hydraulic cable, and is discharged through the fifth-level discharge tube D7 (90V) of the lightning protection module, absorbing most of the high-voltage signal to the lightning protection ground. The remaining signal enters the self-recovery fuse F3 and the self-recovery fuse F4 as the sixth-level protection for the second-level disconnection process, allowing the discharge tube to absorb as much as possible. The discharge tube D11, the common-mode inductor L2, the fourth varistor RV4, the fifth varistor RV5 and the sixth varistor RV6 perform the seventh-level absorption. After the first three levels, the high-voltage signal becomes a low-voltage signal, and then passes through the fourth TVS tube D8, the fifth TVS tube D9 and the sixth TVS tube D11 of the eighth level. TVS tube D10 is turned on for absorption, so as to absorb and filter out all interference signals, and transmit the normal RS485 signal through the current limiting protection resistors R5 and R7 to reach the U3 chip SP3485EN-L / TR. The chip converts the RS485 signal into a TTL signal, and transmits the TTL signal to the serial port of the STM32 microcontroller, so as to realize the data interaction and communication between the RS485 signal and the STM32 microcontroller. The sensor signal of the pressure sensor probe is an analog signal, which is connected and communicated with the microcontroller module through the SCL clock line and SDA data line of the IIC interface to realize data interaction and obtain the transmission of water level and water temperature values.

[0084] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. A surge-proof ventilated pressure water level gauge. It is characterized in that include: Hydraulic cables, lightning protection modules, RS485 communication modules, LDO modules, single-chip microcomputer modules and pressure sensors; The hydraulic cable comprises a cable core and a shielding layer, wherein the shielding layer is arranged on the periphery of the cable core, one end of the cable core is coupled to a lightning protection module, and the other end of the cable core is coupled to a pressure sensor, and the lightning protection module comprises a first lightning protection sub-module and a second lightning protection sub-module; The first lightning protection submodule is coupled to the LDO module, and the LDO module is coupled to the single-chip microcomputer module; The second lightning protection submodule is coupled to the RS485 communication module, the RS485 communication module is coupled to the single-chip computer module, and the RS485 communication module is coupled between the second lightning protection submodule and the second single-chip computer module; the pressure sensor is connected to the single-chip computer module.

2. The surge-proof ventilated pressure water level gauge according to claim 1, Features: The hydraulic cable further comprises a heat-insulating lining, the cable core is arranged in the heat-insulating lining, and a filler is arranged between the cable cores; The cable core comprises a conductor, an insulating layer, a thermal insulation lining and a protective layer; the conductor is installed in the insulating layer, the protective layer is wrapped on the outer wall of the insulating layer, and the conductor, the insulating layer and the protective layer are all arranged in the thermal insulation lining.

3. The surge-proof ventilated pressure water level gauge according to claim 1, It is characterized in that The first lightning protection submodule includes first-level protection and second-level protection; The first level protection is coupled to the second level protection, the first level protection is a discharge tube D1, the anode of the discharge tube D1 is coupled to the POWER+ end of the cable core, the cathode of the discharge tube D1 is coupled to the POWER- end of the cable core, and the grounding level of the discharge tube D1 is connected to the lightning protection ground; The second level protection includes a resettable fuse F1 and a resettable fuse F2; The input end of the resettable fuse F1 is coupled to the anode of the discharge tube D1 and then coupled to the POWER+ end of the cable core. The input end of the resettable fuse F1 is connected in series with the discharge tube D1 and then coupled to the POWER- end of the cable core. The input end of the resettable fuse F2 is coupled to the cathode of the discharge tube D1 and then coupled to the POWER- end of the cable core. The input end of the resettable fuse F2 is connected in series with the discharge tube D1 and then coupled to the POWER+ end of the cable core.

4. The surge-proof ventilated pressure water level gauge according to claim 3, It is characterized in that The first lightning protection submodule also includes third-level protection and fourth-level protection; The third level protection is coupled to the second level protection, and the third level protection is coupled to the first level protection through the second level protection; the fourth level protection is coupled to the third level protection, and the fourth level protection is sequentially coupled to the second level protection and the first level protection through the third level protection; The third level protection includes a discharge tube D6, a common mode inductor L1, a first varistor RV1, a second varistor RV2 and a third varistor RV3; The output end of the resettable fuse F2 is coupled to the third varistor RV3, the other end of the third varistor RV3 is coupled to the discharge tube D6, and one end of the discharge tube D6 away from the third varistor RV3 is coupled to the lightning protection ground; One end of the second varistor RV2 is coupled to the output end of the resettable fuse F1, and the other end of the second varistor RV2 is coupled to one end of the third varistor RV3 close to the discharge tube D6; One end of the first varistor RV1 is coupled to the output end of the resettable fuse F1 through the second varistor RV2; the other end of the first varistor RV1 is coupled to the output end of the resettable fuse F2 through the third varistor RV3; The output end of the resettable fuse F1 is coupled to the first input end of the common mode inductor L1 through the second varistor RV2 and the first varistor RV1, and the output end of the resettable fuse F2 is coupled to the second input end of the common mode inductor L1 through the third varistor RV3 and the first varistor RV1; the first output end of the common mode inductor L1 is coupled to the fourth level protection, and the second output end of the common mode inductor L1 is coupled to the fourth level protection; The fourth level protection includes a first TVS tube D2, a second TVS tube D3, a third TVS tube D5, a first high-voltage capacitor C5 and a second high-voltage capacitor C6; The anode of the first TVS tube D2 is coupled to the first output end of the common mode inductor L1, and the cathode of the first TVS tube D2 is connected to the lightning protection ground; the anode of the third TVS tube D5 is coupled to the second output end of the common mode inductor L1, and the cathode of the third TVS tube D5 is connected to the lightning protection ground; the third TVS tube D5 is connected in series with the first TVS tube D2; One end of the second TVS tube D3 is respectively coupled to the anode of the first TVS tube D2 and the first output end of the common mode inductor L1, and the other end of the second TVS tube D3 is respectively coupled to the anode of the third TVS tube D5 and the second output end of the common mode inductor L1; The anode of the first high-voltage capacitor C5 is coupled to the anodes of the second TVS tube D3 and the first TVS tube D2 and the first output end of the common-mode inductor L1 in sequence, and the cathode of the first high-voltage capacitor C5 is connected to the lightning protection ground; the anode of the second high-voltage capacitor C6 is coupled to the anodes of the second TVS tube D3 and the third TVS tube D5 and the second output end of the common-mode inductor L1 in sequence, and the cathode of the second high-voltage capacitor C6 is connected to the lightning protection ground; the first high-voltage capacitor C5 and the second high-voltage capacitor C6 are connected in series.

5. The surge-proof ventilated pressure water level gauge according to claim 4, It is characterized in that A voltage stabilizing diode D4 is connected in series between the anode of the first high-voltage capacitor C5 and the anode of the second high-voltage capacitor C6 . The anode V_IN of the voltage stabilizing diode D4 is coupled to the LDO module, and the cathode of the voltage stabilizing diode D4 is grounded.

6. The surge-proof ventilated pressure water level gauge according to claim 5, It is characterized in that The LDO module further includes a power chip U2 of model ME6214A33PG. The input voltage of the power chip U2 is coupled to the anode V_IN terminal of the voltage stabilizing diode D4. The output voltage of the power chip U2 is coupled to the single-chip microcomputer module.

7. The surge-proof ventilated pressure water level gauge according to claim 5, It is characterized in that The second lightning protection submodule includes fifth-level protection and sixth-level protection; The fifth level protection is coupled to the sixth level protection, the fifth level protection is a discharge tube D7, the anode of the discharge tube D7 is coupled to the pin RS485_RX of the RS485 communication module, the cathode of the discharge tube D7 is coupled to the pin RS485_TX of the RS485 communication module, and the grounding level of the discharge tube D7 is connected to the lightning protection ground; The sixth level protection includes a resettable fuse F3 and a resettable fuse F4; The input end of the resettable fuse F3 is coupled to the anode of the discharge tube D7 and then coupled to the pin RS485_RX of the RS485 communication module. The input end of the resettable fuse F3 is connected in series with the discharge tube D7 and then coupled to the pin RS485_TX of the RS485 communication module. The pin RS485_TX of the RS485 communication module is connected in series with the discharge tube D7 and then coupled to the input end of the resettable fuse F4. The pin RS485_RX of the RS485 communication module is connected in series with the discharge tube D7 and then coupled to the input end of the resettable fuse F4.

8. The surge-proof ventilated pressure water level gauge according to claim 7, It is characterized in that The second lightning protection submodule also includes seventh-level protection and eighth-level protection; The seventh level of protection is coupled to the sixth level of protection, and the seventh level of protection is coupled to the fifth level of protection through the sixth level of protection; the eighth level of protection is coupled to the seventh level of protection, and the eighth level of protection is sequentially coupled to the sixth level of protection and the fifth level of protection through the seventh level of protection; The seventh level protection includes a discharge tube D11, a common mode inductor L2, a fourth varistor RV4, a fifth varistor RV5 and a sixth varistor RV6; The output end of the resettable fuse F3 is coupled to the sixth varistor RV6, the other end of the sixth varistor RV6 is coupled to the discharge tube D11, and one end of the discharge tube D11 away from the sixth varistor RV6 is coupled to the lightning protection ground; One end of the fifth varistor RV5 is coupled to the output end of the resettable fuse F3, and the other end of the fifth varistor RV5 is coupled to one end of the sixth varistor RV6 close to the discharge tube D11; One end of the fourth varistor RV4 is coupled to the output end of the resettable fuse F3 through the fifth varistor RV5; the other end of the fourth varistor RV4 is coupled to the output end of the resettable fuse F4 through the sixth varistor RV6; The output end of the resettable fuse F3 is coupled to the first input end of the common mode inductor L2 through the fifth varistor RV5 and the fourth varistor RV4, and the output end of the resettable fuse F4 is coupled to the second input end of the common mode inductor L2 through the sixth varistor RV6 and the fourth varistor RV4; the first output end of the common mode inductor L2 is coupled to the eighth level protection, and the second output end of the common mode inductor L2 is coupled to the eighth level protection; The eighth level protection includes a fourth TVS tube D8, a fifth TVS tube D9 and a sixth TVS tube D10; The anode of the fourth TVS tube D8 is coupled to the first output end of the common mode inductor L2, and the cathode of the fourth TVS tube D8 is connected to the lightning protection ground; the anode of the sixth TVS tube D10 is coupled to the second output end of the common mode inductor L2, and the cathode of the sixth TVS tube D10 is connected to the lightning protection ground; the sixth TVS tube D10 is connected in series with the fourth TVS tube D8; One end of the fifth TVS tube D9 is respectively coupled to the anode of the fourth TVS tube D8 and the first output end of the common mode inductor L2, and the other end of the fifth TVS tube D9 is respectively coupled to the anode of the sixth TVS tube D10 and the second output end of the common mode inductor L2; The fifth TVS tube D9 is coupled to the RS485 communication module.

9. The surge-proof ventilated pressure water level gauge according to claim 7, It is characterized in that The RS485 communication module further includes a communication chip U3 of model number SP3485EN-L / TR; the seventh pin of the communication chip U3 is connected in series with a fifth resistor R5 and then coupled to the first output end of the common mode capacitor L2; The 6th pin of the communication chip U3 is connected in series with the seventh resistor R7 and then coupled to the second output end of the common mode capacitor L2; the end of the fifth resistor R5 away from the communication chip U3 is coupled to the fourth resistor R4 and then grounded; the end of the seventh resistor R7 away from the communication chip U3 is coupled to the eighth resistor R8; The 8th pin of the communication chip U3 is connected in series with the capacitor C7 and then grounded, and a power supply is connected in parallel between the 8th pin of the communication chip U3 and the capacitor C7; the 5th pin of the communication chip U3 is grounded; The 4th pin of the communication chip U3 is connected in series with the sixth resistor R6 and then coupled to the base of the transistor Q1. The collector of the transistor Q1 is respectively coupled to the 2nd pin of the communication chip U3 and the third resistor R3. The emitter of the transistor Q1 is grounded, and the 1st pin of the communication chip U3 is coupled to the microcontroller module.

10. The surge-proof ventilated pressure water level gauge according to claim 7, It is characterized in that The pressure sensor also includes a pressure sensor probe with model MPM258, which is coupled to a terminal P1, and the first and second pins of the terminal P1 are grounded; the third pin of the terminal P1 is coupled to an SDA line, and the SDA line is connected in series with a tenth resistor R10; the fourth pin of the terminal P1 is coupled to an SCL line, and the SCL line is connected in series with a ninth resistor R9; and the fifth pin of the terminal P1 is coupled to the pressure sensor probe.

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