A dry node signal transmission circuit and method

Abstract

The present invention provides a dry node signal transmission circuit and method, which relates to the field of signal transmission technology. The circuit includes: a second pull-up protection circuit electrically connected to a micro control unit; a first pull-up protection circuit electrically connected to a second pin of the dry node; an isolation control circuit electrically connected between the first pin of the dry node and the micro control unit; when the dry node is opened, the isolation control circuit receives a first low-level signal of the dry node, and the isolation control circuit is disconnected to isolate the dry node from the micro control unit; the micro control unit receives a second high-level signal of the second pull-up protection circuit; when the dry node is closed, the isolation control circuit receives the first high-level signal of the dry node, the isolation control circuit is turned on, and the second high-level signal of the second pull-up protection circuit is converted into a second low-level signal, and the micro control unit receives the second low-level signal. The solution of the present invention can effectively protect the micro control unit while satisfying the signal transmission between the dry node and the micro control unit.

Description

Technical Field

[0001] The present invention relates to the technical field of signal transmission, and in particular to a dry node signal transmission circuit and method. Background Art

[0002] Dry nodes are a common signal type in industrial equipment signal transmission, such as the output of door magnets and smoke sensors. Their outputs are generally connected to data detection and transmission equipment, and then transmitted to the cloud platform for response processing.

[0003] However, the signal of the dry node is generally unstable or has a lot of interference. In the current dry node signal transmission circuit, the dry node is directly connected to the communication port of the micro control unit and has no protection function. When the signal of the dry node is unstable or has a lot of interference, it will affect the micro control unit and even cause damage to the micro control unit. The current dry node signal transmission circuit cannot protect the micro control unit. Summary of the invention

[0004] The present invention provides a dry node signal transmission circuit and method, which realizes the isolation or connection between the dry node and a micro control unit according to the open or closed state of the dry node through an isolation control circuit, and controls the micro control unit to receive a high level signal or a low level signal, so that the micro control unit can be effectively protected while satisfying the signal transmission between the dry node and the micro control unit.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A dry node signal transmission circuit, comprising:

[0007] A second pull-up protection circuit electrically connected to the micro control unit;

[0008] a first pull-up protection circuit electrically connected to the second pin of the stem node;

[0009] An isolation control circuit electrically connected between the first pin of the stem node and the micro control unit;

[0010] When the dry node is opened, the isolation control circuit receives a first low-level signal of the dry node, and the isolation control circuit is disconnected to isolate the dry node from the micro control unit; the micro control unit receives a second high-level signal of the second pull-up protection circuit;

[0011] When the dry node is closed, the isolation control circuit receives the first high level signal of the dry node, the isolation control circuit is turned on, the isolation control circuit converts the second high level signal of the second pull-up protection circuit into a second low level signal, and the micro control unit receives the second low level signal.

[0012] Optionally, the first pull-up protection circuit includes:

[0013] a fuse electrically connected to the second pin of the stem node;

[0014] A first diode, wherein a cathode of the first diode is electrically connected to the fuse, and an anode of the first diode is electrically connected to an external power supply.

[0015] Optionally, the second pull-up protection circuit includes:

[0016] A first resistor, the first resistor is electrically connected to an IO pin of the micro control unit;

[0017] A second diode, wherein a cathode of the second diode is electrically connected to the first resistor, and an anode of the second diode is electrically connected to an external power supply.

[0018] Optionally, the isolation control circuit includes:

[0019] A first MOS tube, wherein the gate of the first MOS tube is electrically connected to the first pin of the dry node through a third resistor, the gate of the first MOS tube is grounded through a fourth resistor, the drain of the first MOS tube is grounded, and the source of the first MOS tube is electrically connected to the IO pin of the micro control unit.

[0020] Optionally, the dry node signal transmission circuit further includes:

[0021] A current limiting protection circuit, one end of which is electrically connected to the micro control unit, and the other end of which is electrically connected to the second pull-up protection circuit and the isolation control circuit.

[0022] Optionally, the current limiting protection circuit includes:

[0023] A second resistor, wherein the first resistor and the source of the first MOS tube are electrically connected to the IO pin of the micro control unit through the second resistor;

[0024] The IO pin of the micro control unit is grounded through a first capacitor.

[0025] Optionally, the dry node signal transmission circuit further includes:

[0026] a first signal filtering circuit electrically connected to the second pin of the stem node;

[0027] A second signal filtering circuit is electrically connected to the first pin of the stem node.

[0028] Optionally, the first signal filtering circuit includes:

[0029] a first transient voltage suppression diode, wherein the positive electrode of the first transient voltage suppression diode is connected to the power supply ground, and the negative electrode of the first transient voltage suppression diode is electrically connected to the second pin of the dry node;

[0030] A first lightning protection tube, one end of which is electrically connected to the second pin of the dry node, and the other end of which is connected to the power ground.

[0031] Optionally, the second signal filtering circuit includes:

[0032] a second transient voltage suppression diode, wherein the anode of the second transient voltage suppression diode is connected to the power supply ground, and the cathode of the second transient voltage suppression diode is electrically connected to the first pin of the dry node;

[0033] A second lightning protection tube, one end of which is electrically connected to the first pin of the dry node, and the other end of which is connected to the power ground.

[0034] The present invention also provides a dry node signal transmission method, which is applied to the dry node signal transmission circuit described above, and the method comprises:

[0035] Receiving a first low-level signal of the dry node through the isolation control circuit; the first low-level signal is used to control the isolation control circuit to be in a disconnected state according to the first low-level signal;

[0036] Receiving a second high level signal from the second pull-up protection circuit by a micro control unit;

[0037] Receiving a first high level signal of the dry node through the isolation control circuit;

[0038] The isolation control circuit is in an on state according to the first high level signal, the isolation control circuit converts the second high level signal of the second pull-up protection circuit into a second low level signal; and sends the second low level signal to the micro control unit.

[0039] The above solution of the present invention includes at least the following beneficial effects:

[0040] The above scheme of the present invention realizes the isolation or connection of the dry node and the micro control unit according to the open or closed state of the dry node through the isolation control circuit, and controls the micro control unit to receive high level signals or low level signals. While satisfying the signal transmission between the dry node and the micro control unit, the micro control unit can be effectively protected. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a module diagram of a dry node signal transmission circuit provided by an embodiment of the present invention;

[0042] Figure 2 4 is a circuit diagram of a dry node signal transmission circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0044] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a dry node signal transmission circuit, comprising:

[0045] A second pull-up protection circuit 30 electrically connected to the micro control unit U1;

[0046] A first pull-up protection circuit 20 electrically connected to a second pin of the stem node P1;

[0047] An isolation control circuit 10 electrically connected between the first pin of the dry node P1 and the micro control unit U1;

[0048] When the stem node P1 is opened, the isolation control circuit 10 receives the first low level signal of the stem node P1, and the isolation control circuit 10 is disconnected to isolate the stem node P1 from the micro control unit U1; the micro control unit U1 receives the second high level signal of the second pull-up protection circuit 30;

[0049] When the dry node P1 is closed, the isolation control circuit 10 receives the first high level signal of the dry node P1, the isolation control circuit 10 is turned on, the isolation control circuit 10 converts the second high level signal of the second pull-up protection circuit 30 into a second low level signal, and the micro control unit U1 receives the second low level signal.

[0050] In this embodiment, during the signal transmission process, when the stem node P1 is opened, the first pin and the second pin of the stem node P1 are not connected, and the second pin of the stem node P1 is pulled to a high level by the pull-up effect of the second pull-up protection circuit 30, and the first pin of the stem node P1 is in a low level state, and the isolation control circuit 10 receives the first low level signal of the first pin of the stem node P1, and the isolation control circuit 10 is disconnected to isolate the stem node P1 from the micro control unit U1, and the micro control unit U1 receives the second high level signal of the second pull-up protection circuit 30;

[0051] When the dry node P1 is closed, the first pin of the dry node P1 is connected to the second pin, the first pin of the dry node P1 is pulled to a high level, the isolation control circuit 10 receives the first high level signal of the first pin of the dry node P1, the isolation control circuit 10 is turned on, the isolation control circuit 10 converts the second high level signal of the second pull-up protection circuit 30 into a second low level signal, and the micro control unit U1 receives the second low level signal;

[0052] The isolation control circuit 10 is used to isolate or connect the dry node P1 and the micro control unit U1 according to the open or closed state of the dry node P1, and to control the micro control unit U1 to receive a high level signal or a low level signal. While satisfying the signal transmission between the dry node P1 and the micro control unit U1, the micro control unit U1 can be effectively protected.

[0053] like Figure 2 As shown, in an optional embodiment of the present invention, the first pull-up protection circuit 20 includes:

[0054] Fuse F1, fuse F1 is electrically connected to the second pin of the dry node P1;

[0055] A first diode D1 , wherein a cathode of the first diode D1 is electrically connected to the fuse F1 , and an anode of the first diode D1 is electrically connected to an external power source.

[0056] In this embodiment, the second pin of the stem node P1 is pulled to a high level through the pull-up action of the external power supply, the first diode D1 and the fuse F1;

[0057] At the same time, the first diode D1 and the fuse F1 can play a protective role to prevent the unstable signal of the dry node P1 from impacting the external power supply.

[0058] like Figure 2 As shown, in an optional embodiment of the present invention, the second pull-up protection circuit 30 includes:

[0059] A first resistor R1, the first resistor R1 is electrically connected to an IO pin of the micro control unit U1;

[0060] The second diode D2 has a cathode electrically connected to the first resistor R1 , and an anode electrically connected to the external power supply.

[0061] In this embodiment, the second high level signal can be provided by the pull-up effect of the external power supply, the second diode D2 and the first resistor R1, so that the IO pin of the micro control unit U1 is in a high level state when the dry node P1 is opened;

[0062] At the same time, the second diode D2 and the first resistor R1 can play a protective role to prevent external signals from impacting the external power supply.

[0063] like Figure 2 As shown, in an optional embodiment of the present invention, the isolation control circuit 10 includes:

[0064] The first MOS transistor Q1, the gate of the first MOS transistor Q1 is electrically connected to the first pin of the dry node P1 through the third resistor R3, the gate of the first MOS transistor Q1 is grounded through the fourth resistor R4, the drain of the first MOS transistor Q1 is grounded, and the source of the first MOS transistor Q1 is electrically connected to the IO pin of the micro control unit U1.

[0065] In this embodiment, when the stem node P1 is opened, the first pin and the second pin of the stem node P1 are not connected, and the second pin of the stem node P1 is pulled to a high level by the pull-up action of the second pull-up protection circuit 30; due to the action of the third resistor R3 and the fourth resistor R4, the first pin of the stem node P1 is in a low level state, and the gate of the first MOS transistor Q1 is in a low level state, so that the drain and the source of the first MOS transistor Q1 are in a disconnected state, thereby isolating the stem node P1 from the micro control unit U1, and the micro control unit U1 receives the second high level signal of the second pull-up protection circuit 30, and the IO pin of the micro control unit U1 is in a high level state;

[0066] When the dry node P1 is closed, the first pin of the dry node P1 is connected to the second pin, and the first pin of the dry node P1 is pulled to a high level. After voltage division by the third resistor R3 and the fourth resistor R4, the gate of the first MOS tube Q1 is in a high level state, and the drain and source of the first MOS tube Q1 are in an open state, so that the second pull-up protection circuit 30 is grounded, thereby converting the second high level signal of the second pull-up protection circuit 30 into a second low level signal, and the IO pin of the micro control unit U1 is in a low level state.

[0067] like Figure 1 As shown, in an optional embodiment of the present invention, the dry node signal transmission circuit further includes:

[0068] The current limiting protection circuit 40 has one end electrically connected to the micro control unit U1 , and the other end electrically connected to the second pull-up protection circuit 30 and the isolation control circuit 10 .

[0069] In this embodiment, the micro control unit U1 is protected by the current limiting protection circuit 40 to prevent the micro control unit U1 from being damaged by a large current.

[0070] like Figure 2 As shown, in an optional embodiment of the present invention, the current limiting protection circuit 40 includes:

[0071] The second resistor R2, the first resistor R1 and the source of the first MOS tube Q1 are electrically connected to the IO pin of the micro control unit U1 through the second resistor R2;

[0072] The IO pin of the micro control unit U1 is grounded via the first capacitor C1.

[0073] In this embodiment, the second resistor R2 plays a current limiting role to prevent the micro control unit U1 from being damaged by a large current.

[0074] like Figure 1 As shown, in an optional embodiment of the present invention, the dry node signal transmission circuit further includes:

[0075] A first signal filtering circuit 50 electrically connected to the second pin of the dry node P1;

[0076] The second signal filtering circuit 60 is electrically connected to the first pin of the dry node P1.

[0077] In this embodiment, the signal of the second pin of the trunk node P1 is filtered by the first signal filtering circuit 50, and the signal of the first pin of the trunk node P1 is filtered by the second signal filtering circuit 60. When the signal of the trunk node P1 has a large interference signal, the interference signal is filtered by the first signal filtering circuit 50 and the second signal filtering circuit 60, so as to avoid the subsequent circuits such as the isolation control circuit 10 being affected.

[0078] like Figure 2 As shown, in an optional embodiment of the present invention, the first signal filtering circuit 50 includes:

[0079] A first transient voltage suppression diode D3, wherein the positive electrode of the first transient voltage suppression diode D3 is connected to the power supply ground, and the negative electrode of the first transient voltage suppression diode D3 is electrically connected to the second pin of the dry node P1;

[0080] A first lightning protection tube D4, one end of which is electrically connected to the second pin of the dry node P1, and the other end of which is connected to the power ground;

[0081] The second signal filtering circuit 60 comprises:

[0082] a second transient voltage suppression diode D5, wherein the anode of the second transient voltage suppression diode D5 is connected to the power ground, and the cathode of the second transient voltage suppression diode D5 is electrically connected to the first pin of the dry node P1;

[0083] A second lightning arrester D6, one end of the second lightning arrester D6 is electrically connected to the first pin of the dry node P1, and the other end of the second lightning arrester D6 is connected to the power ground.

[0084] In this embodiment, the signal of the second pin of the dry node P1 is filtered by the first transient voltage suppression diode D3 and the first lightning arrester D4; the signal of the first pin of the dry node P1 is filtered by the second transient voltage suppression diode D5 and the second lightning arrester D6;

[0085] When the signal of the dry node P1 has a large interference signal, the interference signal is filtered through the first transient voltage suppression diode D3, the first lightning arrester D4, the second transient voltage suppression diode D5 and the second lightning arrester D6, so as to avoid the subsequent circuits such as the isolation control circuit 10 being affected.

[0086] Dry node signal transmission process:

[0087] In a normal state, the stem node P1 is in an open state, that is, the first pin and the second pin of the stem node P1 are not connected. The second pin of the stem node P1 is pulled to a high level by the pull-up action of the external power supply, the first diode D1 and the fuse F1. Due to the action of the third resistor R3 and the fourth resistor R4, the first pin of the stem node P1 is in a low level state, and the gate of the first MOS tube Q1 is in a low level state, so that the drain and the source of the first MOS tube Q1 are in a disconnected state, thereby isolating the stem node P1 from the micro control unit U1. Due to the pull-up action of the second diode D2 and the first resistor R1, Figure 2 The level of the Q point in the circuit is in a high level state, so that the IO pin of the micro control unit U1 is in a high level state. At this time, the micro control unit U1 reads the state of its IO pin as "1";

[0088] When working, the first pin of the dry node P1 is connected to the second pin, the first pin of the dry node P1 is pulled to a high level, and the gate of the first MOS tube Q1 is in a high level state after voltage division by the third resistor R3 and the fourth resistor R4, and the drain and source of the first MOS tube Q1 are in an open state, so that the second pull-up protection circuit 30 is grounded, that is, Figure 2 The Q point in the circuit is pulled to the ground and is in a low level state, so that the IO pin of the micro control unit U1 is in a low level state. At this time, the micro control unit U1 reads the state of its IO pin as "0";

[0089] From the above process, it can be known that the isolation control circuit 10 realizes the isolation or connection between the dry node P1 and the micro control unit U1 according to the open or closed state of the dry node P1, and controls the micro control unit U1 to receive a high level signal or a low level signal, while satisfying the signal transmission between the dry node P1 and the micro control unit U1, the micro control unit U1 can be effectively protected;

[0090] At the same time, the second resistor R2 plays a current limiting role to prevent large current from damaging the micro control unit U1; the signal of the second pin of the dry node P1 is filtered and processed by the first signal filtering circuit 50, and the signal of the first pin of the dry node P1 is filtered and processed by the second signal filtering circuit 60. When the signal of the dry node P1 has a large interference signal, the interference signal is filtered and processed by the first signal filtering circuit 50 and the second signal filtering circuit 60, so as to prevent the subsequent circuits such as the isolation control circuit 10 from being affected; the first diode D1 and the fuse F1 can play a protective role to prevent the unstable signal of the dry node P1 from impacting the external power supply; the second diode D2 and the first resistor R1 can play a protective role to prevent the external signal from impacting the external power supply; the micro control unit U1 can be provided with multiple protections.

[0091] An embodiment of the present invention further provides a dry node signal transmission method, which is applied to the dry node signal transmission circuit of any of the above embodiments, and the method includes:

[0092] The isolation control circuit 10 receives a first low level signal of the dry node P1; the first low level signal is used to control the isolation control circuit 10 to be in a disconnected state according to the first low level signal;

[0093] Receiving a second high level signal from the second pull-up protection circuit 30 through the micro control unit U1;

[0094] The isolation control circuit 10 receives the first high level signal of the dry node P1; the isolation control circuit 10 is in an on state according to the first high level signal, the isolation control circuit 10 converts the second high level signal of the second pull-up protection circuit 30 into a second low level signal; and sends the second low level signal to the micro control unit U1.

[0095] In this embodiment, the first low-level signal of the dry node P1 is received by the isolation control circuit 10; the isolation control circuit 10 is in a disconnected state according to the first low-level signal; the microcontroller unit U1 receives the second high-level signal of the second pull-up protection circuit 30; the isolation control circuit 10 receives the first high-level signal of the dry node P1; the isolation control circuit 10 is in an on state according to the first high-level signal, and the isolation control circuit 10 converts the second high-level signal of the second pull-up protection circuit 30 into a second low-level signal; the microcontroller unit U1 receives the second low-level signal; the dry node P1 and the microcontroller unit U1 can be disconnected or connected according to the open or closed state of the dry node P1, and the microcontroller unit U1 can be controlled to receive a high-level signal or a low-level signal, so that the microcontroller unit U1 can be effectively protected while satisfying the signal transmission between the dry node P1 and the microcontroller unit U1.

[0096] Wherein, the first pull-up protection circuit 20 includes:

[0097] Fuse F1, fuse F1 is electrically connected to the second pin of the dry node P1;

[0098] a first diode D1, wherein a cathode of the first diode D1 is electrically connected to the fuse F1, and an anode of the first diode D1 is electrically connected to an external power supply;

[0099] The second pull-up protection circuit 30 comprises:

[0100] A first resistor R1, the first resistor R1 is electrically connected to an IO pin of the micro control unit U1;

[0101] a second diode D2, wherein a cathode of the second diode D2 is electrically connected to the first resistor R1, and an anode of the second diode D2 is electrically connected to an external power supply;

[0102] The isolation control circuit 10 comprises:

[0103] The first MOS transistor Q1, the gate of the first MOS transistor Q1 is electrically connected to the first pin of the dry node P1 through the third resistor R3, the gate of the first MOS transistor Q1 is grounded through the fourth resistor R4, the drain of the first MOS transistor Q1 is grounded, and the source of the first MOS transistor Q1 is electrically connected to the IO pin of the micro control unit U1.

[0104] Optionally, the method further includes:

[0105] The current limiting protection circuit 40 performs current limiting processing on the second high level signal or the second low level signal.

[0106] In this embodiment, the current limiting protection circuit 40 performs current limiting processing on the second high level signal or the second low level signal to prevent the micro control unit U1 from being damaged by a large current.

[0107] Wherein, the current limiting protection circuit 40 includes:

[0108] The second resistor R2, the first resistor R1 and the source of the first MOS tube Q1 are electrically connected to the IO pin of the micro control unit U1 through the second resistor R2;

[0109] The IO pin of the micro control unit U1 is grounded via the first capacitor C1.

[0110] Optionally, the method further includes:

[0111] The first low-level signal or the first high-level signal is filtered by the first signal filtering circuit 50 and the second signal filtering circuit 60 .

[0112] In this embodiment, the first low-level signal or the first high-level signal is filtered by the first signal filtering circuit 50 and the second signal filtering circuit 60, so that interference signals in the first low-level signal or the first high-level signal can be filtered and processed, thereby preventing subsequent circuits such as the isolation control circuit 10 from being affected.

[0113] Wherein, the first signal filtering circuit 50 includes:

[0114] A first transient voltage suppression diode D3, wherein the positive electrode of the first transient voltage suppression diode D3 is connected to the power supply ground, and the negative electrode of the first transient voltage suppression diode D3 is electrically connected to the second pin of the dry node P1;

[0115] A first lightning protection tube D4, one end of which is electrically connected to the second pin of the dry node P1, and the other end of which is connected to the power ground;

[0116] The second signal filtering circuit 60 comprises:

[0117] a second transient voltage suppression diode D5, wherein the anode of the second transient voltage suppression diode D5 is connected to the power ground, and the cathode of the second transient voltage suppression diode D5 is electrically connected to the first pin of the dry node P1;

[0118] A second lightning arrester D6, one end of the second lightning arrester D6 is electrically connected to the first pin of the dry node P1, and the other end of the second lightning arrester D6 is connected to the power ground.

[0119] In the above embodiment of the present invention, the first diode D1 and the fuse F1 play a role in preventing external signals from impacting the external power supply of the micro control unit U1; the first transient voltage suppression diode D3 and the first lightning arrester D4, the second transient voltage suppression diode D5 and the second lightning arrester D6, respectively, play a role in signal filtering for the two pins of the dry node P1. When there is a large interference signal, these four components process the interference signal to avoid the subsequent circuit from being affected; the first MOS tube Q1, the third resistor R3 and the fourth resistor R4 constitute an isolation control circuit 10, which plays a role in isolating the dry node P1 and the micro control unit U1; the closing and opening of the dry node P1 will control the opening and closing of the first MOS tube Q1, which will make Figure 2 The level of the Q point in the circuit is in a low or high state, so the state of the IO pin of the micro control unit U1 will also be high or low; the second diode D2 prevents the external signal from impacting the external power supply of the micro control unit U1, and the second resistor R2 limits the current, which can protect the IO pin of the micro control unit U1.

[0120] In normal state, the stem node P1 is in an open state, that is, the first pin and the second pin of the stem node P1 are not connected; due to the pull-up effect of the first diode D1 and the fuse F1, the second pin of the stem node P1 is pulled to a high level; due to the effect of the third resistor R3 and the fourth resistor R4, the first pin of the stem node P1 is in a low level state, and the gate of the first MOS tube Q1 is in a low level, so that the drain and the source of the first MOS tube Q1 are in a disconnected state, and due to the pull-up effect of the second diode D2 and the first resistor R1, Figure 2 The Q point in is in a high level state, so that the IO pin of the micro control unit U1 is also in a high level. At this time, the micro control unit U1 reads the state of its IO pin as "1".

[0121] When working, the stem node P1 is in a closed state, that is, the first pin and the second pin of the stem node P1 are connected; at this time, the first pin of the stem node P1 is pulled to a high level, and after the voltage division of the third resistor R3 and the fourth resistor R4, the gate of the first MOS tube Q1 is at a high level, then the first MOS tube Q1 starts to work, and the drain and source are in an open state, then Figure 2 The Q point in the circuit is pulled to the ground and is in a low level state, so that the IO pin of the micro control unit U1 is also in a low level. At this time, the micro control unit U1 reads the state of its IO pin as "0". The electronic components in the circuit of the present application can protect the micro control unit U1, which is more practical.

[0122] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dry node signal transmission circuit, characterized in that: include: A second pull-up protection circuit (30) electrically connected to the micro control unit (U1); A first pull-up protection circuit (20) electrically connected to a second pin of the stem node (P1); An isolation control circuit (10) electrically connected between the first pin of the dry node (P1) and the micro control unit (U1); When the dry node (P1) is opened, the isolation control circuit (10) receives a first low-level signal from the dry node (P1), and the isolation control circuit (10) is disconnected to isolate the dry node (P1) from the micro control unit (U1); the micro control unit (U1) receives a second high-level signal from the second pull-up protection circuit (30); When the dry node (P1) is closed, the isolation control circuit (10) receives a first high-level signal from the dry node (P1), the isolation control circuit (10) is turned on, the isolation control circuit (10) converts a second high-level signal from the second pull-up protection circuit (30) into a second low-level signal, and the micro control unit (U1) receives the second low-level signal; Wherein, the first pull-up protection circuit (20) comprises: A fuse (F1), the fuse (F1) being electrically connected to the second pin of the stem node (P1); a first diode (D1), wherein a cathode of the first diode (D1) is electrically connected to the fuse (F1), and an anode of the first diode (D1) is electrically connected to an external power supply; Wherein, the second pull-up protection circuit (30) comprises: A first resistor (R1), the first resistor (R1) being electrically connected to an IO pin of the micro control unit (U1); a second diode (D2), wherein a cathode of the second diode (D2) is electrically connected to the first resistor (R1), and an anode of the second diode (D2) is electrically connected to an external power supply; Wherein, the isolation control circuit (10) comprises: a first MOS tube (Q1), wherein the gate of the first MOS tube (Q1) is electrically connected to the first pin of the dry node (P1) through a third resistor (R3), the gate of the first MOS tube (Q1) is grounded through a fourth resistor (R4), the drain of the first MOS tube (Q1) is grounded, and the source of the first MOS tube (Q1) is electrically connected to the IO pin of the micro control unit (U1); a current limiting protection circuit (40), wherein one end of the current limiting protection circuit (40) is electrically connected to the micro control unit (U1), and the other end of the current limiting protection circuit (40) is electrically connected to the second pull-up protection circuit (30) and the isolation control circuit (10); The current limiting protection circuit (40) comprises: a second resistor (R2), wherein the source of the first resistor (R1) and the first MOS tube (Q1) are both electrically connected to the IO pin of the micro control unit (U1) through the second resistor (R2); The IO pin of the micro control unit (U1) is grounded via a first capacitor (C1).

2. The dry node signal transmission circuit according to claim 1, characterized in that: Also includes: A first signal filtering circuit (50) electrically connected to a second pin of the dry node (P1); A second signal filtering circuit (60) is electrically connected to the first pin of the dry node (P1).

3. The dry node signal transmission circuit according to claim 2, characterized in that: The first signal filtering circuit (50) comprises: a first transient voltage suppression diode (D3), wherein the positive electrode of the first transient voltage suppression diode (D3) is connected to the power supply ground, and the negative electrode of the first transient voltage suppression diode (D3) is electrically connected to the second pin of the dry node (P1); A first lightning protection tube (D4), one end of the first lightning protection tube (D4) is electrically connected to the second pin of the dry node (P1), and the other end of the first lightning protection tube (D4) is connected to the power ground.

4. The dry node signal transmission circuit according to claim 2, characterized in that: The second signal filtering circuit (60) comprises: a second transient voltage suppression diode (D5), wherein the anode of the second transient voltage suppression diode (D5) is connected to the power supply ground, and the cathode of the second transient voltage suppression diode (D5) is electrically connected to the first pin of the dry node (P1); A second lightning protection tube (D6), one end of the second lightning protection tube (D6) is electrically connected to the first pin of the dry node (P1), and the other end of the second lightning protection tube (D6) is connected to the power ground.

5. A dry node signal transmission method, characterized in that: Applied to the dry node signal transmission circuit according to any one of claims 1 to 4, the method comprises: Receiving a first low-level signal of the dry node (P1) through an isolation control circuit (10); the first low-level signal is used to control the isolation control circuit (10) to be in a disconnected state according to the first low-level signal; Receiving a second high level signal from the second pull-up protection circuit (30) via a micro control unit (U1); Receiving a first high level signal from the dry node (P1) through the isolation control circuit (10); The isolation control circuit (10) is in an on state according to the first high level signal, the isolation control circuit (10) converts the second high level signal of the second pull-up protection circuit (30) into a second low level signal, and sends the second low level signal to the micro control unit (U1).

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