Intrinsically safe pilot circuit and fault diagnosis control method thereof

Abstract

This invention relates to the field of pilot circuit technology, and more particularly to an intrinsically safe pilot circuit, comprising: a constant current source module connected to an intrinsically safe power supply terminal to obtain intrinsically safe DC power and output a constant current; a polarity reversal module connected to the constant current source module to generate a pulse current from the constant current; a starting module connected to the polarity reversal module to obtain the pulse current and convert the pulse current into a current signal; a sampling module connected to the starting module to convert the obtained current signal into a voltage signal; and a processing module, in which both the polarity reversal module and the sampling module are connected; wherein, the processing module generates a controllable switching frequency, and controls the polarity reversal module to generate a pulse current from the constant current through the controllable switching frequency; the processing module also obtains and analyzes the voltage signal. This invention has circuit state diagnosis function, strong anti-interference performance, long signal transmission distance, improved safety and reliability, and low implementation cost.

Description

Technical Field

[0001] This invention relates to the field of pilot circuit technology, and in particular to an intrinsically safe pilot circuit and its fault diagnosis and control method. Background Technology

[0002] A pilot circuit is an electrical circuit that uses a small current to control a high-power device. It is a remote control circuit mainly used to remotely connect and disconnect the front-end power supply switch of the mining equipment at the working face, and then connect the main circuit of the equipment to realize remote power management and ensure the safe operation of personnel and equipment.

[0003] In the complex environment of underground coal mines, the pilot circuits leading from combination switches or other electrical equipment to the main control room need to consider safety factors. Electrical equipment should be able to distinguish between short circuits and open circuits in the pilot circuit caused by accidents and normal closing and closing operations of switches, and be able to analyze and identify the type of fault and take appropriate actions. However, existing pilot circuits lack fault diagnosis capabilities, and are susceptible to external interference during signal transmission. Furthermore, the complex existing circuit structure easily generates interference signals, making the equipment prone to malfunctions, leading to safety, reliability, and cost issues. Summary of the Invention

[0004] The technical problem to be solved by this invention is: in order to solve the technical problems that the pilot circuit in the prior art does not have fault diagnosis function and is easily affected by interference signals, which makes the equipment prone to malfunction, resulting in high safety, reliability and cost, this invention provides an intrinsically safe pilot circuit that has circuit status diagnosis function, strong anti-interference performance, long signal transmission distance, improves safety and reliability and has low cost.

[0005] The technical solution adopted by this invention to solve its technical problem is: an intrinsically safe pilot circuit, comprising: a constant current source module connected to an intrinsically safe power supply terminal to obtain an intrinsically safe DC power supply, and outputting a constant current through the constant current source module; a polarity reversal module connected to the constant current source module to generate a pulse current from the constant current; a starting module connected to the polarity reversal module to obtain the pulse current and convert the pulse current into a current signal; a sampling module connected to the starting module to obtain the current signal and convert the current signal into a voltage signal; and a processing module, wherein the polarity reversal module and the sampling module are both connected to the processing module; wherein the processing module generates a controllable switching frequency, and controls the polarity reversal module to generate a pulse current from the constant current through the controllable switching frequency; the processing module also obtains the voltage signal and analyzes the voltage signal.

[0006] Furthermore, specifically, the processing module parses the voltage signal, and based on the control timing of the processing module and the acquired voltage signal, the processing module performs fault state diagnosis and analysis on the pilot circuit.

[0007] Furthermore, specifically, it also includes a power module, and both the polarity reversal module and the processing module are connected to the power module.

[0008] Further, specifically, the constant current source module includes: resistors R1, R3, R5, and R8; diodes D1 and D3; Zener diodes V1 and V2; and transistor Q1. The base of transistor Q1 is connected to the positive terminal of the intrinsically safe power supply. One end of resistor R1 and one end of resistor R3 are both connected to the collector of transistor Q1. The other end of resistor R1 and the anode of diode D1 are both connected to the emitter of transistor Q1. The other end of resistor R3 and the cathode of diode D1 are both connected to the anode of diode D3. The cathode of diode D3 is connected to one end of resistor R5. One end of resistor R5 is connected to one end of Zener diode V2. The other end of Zener diode V2 is connected to the negative terminal of intrinsically safe power supply. Zener diode V2 and Zener diode V1 are connected in parallel. The two ends after connection are the output terminals, which are the positive input1-1 terminal and the negative input1-2 terminal, respectively.

[0009] Specifically, the polarity reversal module includes four relays, transistors Q3 and Q4, resistors R9 and R11; the four relays are relay U1, relay U2, relay U3, and relay U4. Pin 4 of relay U1 and pin 3 of relay U4 are both connected to the positive polarity input1-1 terminal; pin 3 of relay U2 and pin 4 of relay U3 are both connected to the negative polarity input1-2 terminal; pin 2 of relay U1 and pin 1 of relay U2 are connected; one end of resistor R9 and pin 1 of relay U1 are both connected to the emitter of transistor Q3; pin 2 of relay U2 and the transistor... The collectors of Q3 are all connected to the common ground terminal. Pin 2 of relay U3 and pin 1 of relay U4 are connected. Pin 1 of relay U3 is connected to one end of resistor R11. Pin 2 of relay U4 is connected to the emitter of transistor Q4. The collector of transistor Q4 is connected to the common ground terminal. The other ends of resistor R11 and resistor R9 are both connected to the power supply module. The bases of transistors Q3 and Q4 are both connected to the processing module. Pin 3 of relay U1 and pin 3 of relay U3 are connected, and pin 4 of relay U2 and pin 4 of relay U4 are connected, and these connections are then connected to the startup module.

[0010] Preferably, the processing module includes a microcontroller.

[0011] A fault diagnosis and control method for an intrinsically safe pilot circuit, wherein the fault diagnosis and control method employs the intrinsically safe pilot circuit as described above, and the fault diagnosis and control method includes:

[0012] S1: Obtain intrinsically safe DC power supply and output a constant current through the constant current source module;

[0013] S2: The processing module generates a controllable switching frequency;

[0014] S3: The polarity reversal module obtains the controllable switching frequency and converts the constant current into a pulse current according to the controllable switching frequency;

[0015] S4: The polarity reversal module transmits the pulse current to the start-up module, and the start-up module converts the pulse current into a current signal;

[0016] S5: The sampling module acquires the current signal, converts the current signal into a voltage signal, and transmits the voltage signal to the processing module;

[0017] S6: The processing module acquires the voltage signal and parses the voltage signal.

[0018] Furthermore, specifically, S6 includes: the processing module parsing the voltage signal, and based on the control timing of the processing module and the acquired voltage signal, the processing module performing fault state diagnosis and analysis on the pilot circuit.

[0019] Furthermore, specifically, the fault states of the pilot circuit include open circuit and short circuit.

[0020] The beneficial effects of this invention are that the intrinsically safe pilot circuit of this invention has a simple structure, possesses circuit state diagnosis function, and improves anti-interference capability through the set constant current source module. It has strong anti-interference performance, long signal transmission distance, and improved safety and reliability, while maintaining low implementation cost. Furthermore, the controllable switching frequency control polarity reversal module generated by the processing module improves the speed of fault diagnosis, and can promptly and effectively avoid the hazards of equipment erroneous start-up and shutdown caused by line short circuits or open circuits. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0023] Figure 2 This is a partial circuit diagram of the constant current source module in Embodiment 1 of the present invention.

[0024] Figure 3 This is a partial circuit diagram of the polarity reversal module in Embodiment 1 of the present invention.

[0025] Figure 4 This is a partial circuit diagram of the startup module in Embodiment 1 of the present invention.

[0026] Figure 5 This is a flowchart illustrating Embodiment 2 of the present invention.

[0027] In the diagram: 1. Constant current source module; 2. Polarity reversal module; 3. Startup module; 4. Sampling module; 5. Processing module; 6. Power supply module. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Example 1

[0032] like Figure 1 The diagram illustrates an embodiment of the present invention, an intrinsically safe pilot circuit comprising: a constant current source module 1, connected to an intrinsically safe power supply terminal, for acquiring intrinsically safe DC power and outputting a constant current through the constant current source module 1; a polarity reversal module 2, connected to the constant current source module 1, for generating a pulse current from the constant current; a starting module 3, connected to the polarity reversal module 2, for acquiring the pulse current and converting the pulse current into a current signal; a sampling module 4, connected to the starting module 3, for acquiring the current signal and converting the current signal into a voltage signal; and a processing module 5, to which both the polarity reversal module 2 and the sampling module 4 are connected; wherein the processing module 5 generates a controllable switching frequency, and controls the polarity reversal module 2 to generate a pulse current from the constant current through the controllable switching frequency; the processing module 5 also acquires and analyzes the voltage signal.

[0033] It should be noted that existing technologies obtain pulse voltages from AC power during pilot circuit diagnosis, typically at a frequency of 50Hz. The frequency during diagnosis is uncontrollable, and pilot diagnosis can only be performed during a waiting period, resulting in slow identification speed. In one embodiment of this invention, pilot circuit diagnosis obtains pulse currents from DC power. The controllable switching frequency generated by the processing module 5 is controllable, enabling rapid identification of normal start-up, normal shutdown, short circuit, or open circuit during pilot circuit diagnosis. It allows for quick polarity switching and detection of the next state; it can effectively and promptly prevent the hazards of equipment erroneous start-up or shutdown caused by line short circuits or open circuits; furthermore, it increases the normal operating transmission distance of the pilot circuit, resulting in a longer transmission distance.

[0034] In this embodiment, the processing module 5 parses the voltage signal and, based on the control timing of the processing module 5 and the acquired voltage signal, performs fault state diagnosis and analysis on the pilot circuit. The processing module 5 includes a microcontroller, preferably an STM32L431 series integrated circuit, but is not limited to this; the processing module 5 can also be other microprocessors with logic processing and signal acquisition capabilities.

[0035] In this embodiment, the intrinsically safe pilot circuit also includes a power module 6, and the polarity reversal module 2 and the processing module 5 are both connected to the power module 6. The power module 6 is used to supply power to the polarity reversal module 2 and the processing module 5.

[0036] In an embodiment, such as Figure 2As shown, the constant current source module 1 includes: resistors R1, R3, R5, and R8; diodes D1 and D3; Zener diodes V1 and V2; and transistor Q1. The base of transistor Q1 is connected to the positive terminal of the intrinsically safe power supply. One end of resistor R1 and one end of resistor R3 are both connected to the collector of transistor Q1. The other end of resistor R1 and the anode of diode D1 are both connected to the emitter of transistor Q1. The other end of resistor R3 and the cathode of diode D1 are both connected to the anode of diode D3. The cathode of diode D3 is connected to one end of resistor R5. One end of resistor R5 is connected to one end of Zener diode V2. The other end of Zener diode V2 is connected to the negative terminal of the intrinsically safe power supply. Zener diode V2 and Zener diode V1 are connected in parallel. The two ends after the connection are the output terminals, which are the positive input1-1 terminal and the negative input1-2 terminal, respectively. By using resistor R5, Zener diode V1, and Zener diode V2 to limit the maximum allowable output current and voltage, the intrinsically safe DC power input to the intrinsically safe power supply terminal outputs a constant current after passing through constant current source module 1. When powering field equipment, the distance between the power supply and the main circuit of the equipment is long. Connecting via cables increases line impedance, leading to circuit instability and interference signals coupling onto the field line circuit, resulting in poor anti-interference capability and power instability. By using constant current source module 1 as a signal source to generate a constant current, anti-interference capability is improved, signal transmission distance is extended, safety and reliability are enhanced, and the implementation cost is low, making it suitable for underground use.

[0037] In an embodiment, such as Figure 3As shown, the polarity reversal module 2 includes four relays, transistors Q3 and Q4, resistors R9 and R11. The four relays are relay U1, relay U2, relay U3, and relay U4. Pin 4 of relay U1 and pin 3 of relay U4 are both connected to the positive polarity input1-1 terminal. Pin 3 of relay U2 and pin 4 of relay U3 are both connected to the negative polarity input1-2 terminal. Pin 2 of relay U1 and pin 1 of relay U2 are connected. One end of resistor R9 and pin 1 of relay U1 are both connected to the emitter of transistor Q3. Pin 2 of relay U2 and the collector of transistor Q3 are both connected to the common ground terminal. Pin 2 of relay U3 and pin 1 of relay U4 are connected... Connect the following: pin 1 of relay U3 is connected to one end of resistor R11; pin 2 of relay U4 is connected to the emitter of transistor Q4; the collector of transistor Q4 is connected to the common ground terminal; the other ends of resistor R11 and resistor R9 are both connected to power module 6; the bases of transistors Q3 and Q4 are both connected to processing module 5; pin 3 of relay U1 is connected to pin 3 of relay U3; and pin 4 of relay U2 is connected to pin 4 of relay U4. After these connections, they are respectively connected to start-up module 3. Specifically, pin 3 of relay U1 and pin 3 of relay U3 are connected to the X1A terminal of start-up module 3, and pin 4 of relay U2 and pin 4 of relay U4 are connected to the X1B terminal of start-up module 3.

[0038] In one specific embodiment, the relay is an optocoupler relay, and the on or off state of the optocoupler relay is determined by the controllable switching frequency generated by the processing module 5. When the controllable switching frequency input to the processing module 5 is high, both transistors Q3 and Q4 are off. At this time, relays U1 and U2 are on, and relays U3 and U4 are off. The positive input1-1 terminal of the constant current source module 1 is connected to the X1A terminal of the start-up module 3, and the negative input1-2 terminal of the constant current source module 1 is connected to the X1B terminal of the start-up module 3. The current signal flows through the positive input1-1 terminal, as well as the X1A and X1B terminals of the start-up module 3, and returns to the negative input1-2 terminal of the constant current source module 1. When the controllable switching frequency input to processing module 5 is low, transistors Q3 and Q4 are both turned on. At this time, relays U1 and U2 are turned off, and relays U3 and U4 are turned on. The positive input1-1 terminal of constant current source module 1 is connected to the X1B terminal of startup module 3, and the negative input1-2 terminal of constant current source module 1 is connected to the X1A terminal of startup module 3. The current signal flows through the positive input1-1 terminal, as well as the X1A and X1B terminals of startup module 3, and returns to the negative input1-2 terminal of constant current source module 1.

[0039] Processing module 5 controls the polarity reversal of polarity reversal module 2 by generating a controllable switching frequency, so that it converts constant current into pulse current and changes the flow direction in startup module 3. During the forward and reverse flow of current, sampling module 4 samples the current signal of startup module 3 and converts the current signal into a voltage signal, which is then transmitted to processing module 5 for analysis and processing. Processing module 5 determines the conduction, cut-off, short circuit, and open circuit status of the pilot circuit based on the different characteristics of the signal during the forward and reverse flow of current.

[0040] In an embodiment, such as Figure 4 As shown, the starting module 3 includes a diode D5, a normally closed switch S1, a normally open switch S2, a resistor R22, and a resistor R23. In one specific embodiment, the anode of diode D5 is the current signal input terminal X1A, and the cathode is connected to one end of the normally closed switch S1. The normally open switch S1 is connected in parallel with the resistor R22, and the end of the parallel connection is connected to the other end of the normally closed switch S2, which is the current signal output terminal X1B. The normally closed switch S1 is a stop button, the normally open switch S2 is a start button, and the resistor R22 is a resistor with a holding function used to monitor whether the start button is pressed. When the start button is pressed, the voltage signal of the starting module 3 changes accordingly, and the processing module 5 determines the state of the pilot circuit based on the changing voltage signal. In addition, the branch when the start button is not pressed is in an open state. If the resistor R22 is not set, it is impossible to identify the pilot circuit being open due to a fault. The resistor R22 makes the starting module form a loop, which facilitates the identification of the fault state of the pilot circuit being open due to a fault.

[0041] Example 2

[0042] like Figure 5 The diagram illustrates Embodiment 2 of the present invention, a fault diagnosis and control method for an intrinsically safe pilot circuit. The fault diagnosis and control method employs the aforementioned intrinsically safe pilot circuit and includes:

[0043] S1: Obtain intrinsically safe DC power supply and output constant current through constant current source module 1;

[0044] S2: Processing module 5 generates a controllable switching frequency;

[0045] S3: The polarity reversal module 2 obtains the controllable switching frequency and converts the constant current into a pulse current according to the controllable switching frequency;

[0046] S4: The polarity reversal module 2 transmits the pulse current to the start-up module 3, and the start-up module 3 converts the pulse current into a current signal;

[0047] S5: Sampling module 4 acquires the current signal, converts the current signal into a voltage signal, and transmits the voltage signal to processing module 5;

[0048] S6: Processing module 5 acquires and parses the voltage signal.

[0049] In this embodiment, step S6 includes: processing module 5 parses the voltage signal, and based on the control timing of processing module 5 and the acquired voltage signal, processing module 5 performs fault state diagnosis and analysis on the pilot circuit.

[0050] In the embodiment, the fault states of the pilot circuit include open circuit and short circuit. Specifically, when the normally open button in the start module 3 is pressed, when the pilot circuit is normal, the positive sampling voltage obtained by the sampling circuit is U = R22 + R23 * I, and the negative sampling voltage is U = 0.

[0051] When the pilot circuit is open, a loop cannot be formed, and the positive and negative sampling voltages obtained by the sampling circuit are both U = 0.

[0052] When the pilot circuit is short-circuited, the positive polarity sampling voltage and the negative polarity sampling voltage obtained by the sampling circuit are both U = R22*I.

[0053] Table 1: Pilot Circuit Diagnostic Status Table

[0054]

[0055] Note: I is the current of the constant current source module.

[0056] The intrinsically safe pilot circuit of the present invention has a simple structure and a circuit status diagnosis function. The constant current source module 1 improves the anti-interference capability, with strong anti-interference performance and long signal transmission distance, thereby improving safety and reliability and achieving low cost. In addition, the controllable switching frequency control polarity reversal module 2 generated by the processing module 5 improves the speed of fault diagnosis and can timely and effectively avoid the harm of equipment erroneous start-up and erroneous stop-up caused by short circuits or wire breaks.

[0057] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An intrinsically safe pilot circuit, characterized by comprising: The application relates to a constant current source module (1) connected with an intrinsically safe power supply end, an polarity reversal module (2), a starting module (3), a sampling module (4) and a processing module (5). The constant current source module (1) obtains an intrinsically safe direct current power supply and outputs constant current through the constant current source module (1); The polarity reversal module (2) is connected with the constant current source module (1) and generates pulse current from the constant current; The starting module (3) is connected with the polarity reversal module (2), obtains the pulse current and converts the pulse current into a current signal; The sampling module (4) is connected with the starting module (3), obtains the current signal and converts the current signal into a voltage signal; The processing module (5) is connected with the polarity reversal module (2) and the sampling module (4); The processing module (5) generates a controllable switching frequency to control the polarity reversal module (2) to generate pulse current from the constant current; The processing module (5) also obtains the voltage signal and analyzes the voltage signal; The constant current source module (1) comprises resistors R1, R3, R5, R8, diodes D1, D3, voltage stabilizing diodes V1, V2 and a triode Q1; The base of the triode Q1 is connected with the positive terminal of the intrinsically safe power supply end, one end of the resistor R1 and one end of the resistor R3 are both connected with the collector of the triode Q1, the other end of the resistor R1 and the anode of the diode D1 are both connected with the emitter of the triode Q1, the other end of the resistor R3 and the cathode of the diode D1 are both connected with the anode of the diode D3, one end of the resistor R5 is connected with the cathode of the diode D3, one end of the resistor R5 is connected with one end of the voltage stabilizing diode V2, the other end of the voltage stabilizing diode V2 is connected with the negative terminal of the intrinsically safe power supply end, the voltage stabilizing diode V2 is connected with the voltage stabilizing diode V1 in parallel, and the two ends of the connection are output ends, and the two ends are respectively the positive polarity input1-1 terminal and the negative polarity input1-2 terminal; The polarity reversal module (2) comprises four relays, triodes Q3, Q4, a resistor R9 and a resistor R11. Four relays are relay U1, relay U2, relay U3 and relay U4, the pin 4 of the relay U1 and the pin 3 of the relay U4 are connected with the positive polarity input1-1 end, the pin 3 of the relay U2 and the pin 4 of the relay U3 are connected with the negative polarity input1-2 end, the pin 2 of the relay U1 and the pin 1 of the relay U2 are connected, one end of the resistance R9 and the pin 1 of the relay U1 are connected with the emitter of the triode Q3, the pin 2 of the relay U2 and the collector of the triode Q3 are connected with the common ground end, the pin 2 of the relay U3 and the pin 1 of the relay U4 are connected, the pin 1 of the relay U3 is connected with one end of the resistance R11, the pin 2 of the relay U4 is connected with the emitter of the triode Q4, the collector of the triode Q4 is connected with the common ground end, the other end of the resistance R11 and the other end of the resistance R9 are connected with the power module (6), the base of the triode Q3 and the base of the triode Q4 are connected with the processing module (5), the pin 3 of the relay U1 and the pin 3 of the relay U3 are connected, and the pin 4 of the relay U2 and the pin 4 of the relay U4 are connected, and after being connected, they are connected with the starting module (3) respectively.

2. The intrinsically safe pilot circuit of claim 1, wherein The processing module (5) analyzes the voltage signal, and according to the control time sequence of the processing module (5) and the obtained voltage signal, the processing module (5) diagnoses and analyzes the fault state of the pilot circuit.

3. The intrinsically safe pilot circuit of claim 1, wherein The power module (6) is further included, and the polarity reversing module (2) and the processing module (5) are connected with the power module (6).

4. The intrinsically safe pilot circuit of claim 2, wherein The processing module (5) includes a single-chip microcomputer.

5. A fault diagnosis control method of an intrinsically safe pilot circuit, characterized by, The fault diagnosis control method adopts the intrinsic safety pilot circuit according to any one of claims 1 to 4, and the fault diagnosis control method comprises: S1: obtaining an intrinsically safe DC power supply, and outputting a constant current through the constant current source module (1); S2: the processing module (5) generates a controllable switching frequency; S3: the polarity reversing module (2) obtains the controllable switching frequency, and converts the constant current into a pulse current according to the controllable switching frequency; S4: the polarity reversing module (2) transmits the pulse current to the starting module (3), and the starting module (3) converts the pulse current into a current signal; S5: the sampling module (4) obtains the current signal, converts the current signal into a voltage signal, and transmits the voltage signal to the processing module (5); S6: the processing module (5) obtains the voltage signal and analyzes the voltage signal.

6. The intrinsic pilot circuit fault diagnosis control method according to claim 5, characterized by, In the S6, the processing module (5) analyzes the voltage signal, and according to the control time sequence of the processing module (5) and the obtained voltage signal, the processing module (5) diagnoses and analyzes the fault state of the pilot circuit.

7. The intrinsic pilot circuit fault diagnosis control method according to claim 6, characterized by, The fault state of the pilot circuit includes open circuit and short circuit.

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