Combustible gas detector control circuit capable of resisting electromagnetic interference

Abstract

The invention provides a combustible gas detector control circuit capable of resisting electromagnetic interference, which comprises a power supply voltage regulation circuit, a temperature signal acquisition circuit, a sensor voltage regulation circuit, a sensor acquisition control circuit and a gas detector main control circuit in power supply connection, the gas detector main control circuit is in control connection with the 485 communication circuit, the acousto-optic prompt circuit, the LED state display circuit and the digital display screen, the gas detector main control circuit is in communication connection with the sensor acquisition control circuit, and the sensor acquisition control circuit is in control connection with the gas signal acquisition circuit and the temperature signal acquisition circuit. A TVS (Transient Voltage Suppressor) tube, a common mode inductor and a diode are arranged in the power supply voltage adjusting circuit; and a TVS tube and a diode are also arranged in the gas detector main control circuit. The combustible gas detector has the beneficial effects that the anti-electromagnetic interference capability, the reliability and the stability of the combustible gas detector when the combustible gas detector is independently used are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and particularly relates to a control circuit for a combustible gas detector capable of resisting electromagnetic interference. Background Art

[0002] A gas detector is an instrument for detecting gas concentration. Gas detectors are applicable to dangerous places where combustible gases or toxic gases exist, and can continuously monitor the content of the measured gas in the air within the lower explosion limit for a long time. They can be widely used in various industries such as gas, petrochemical, metallurgy, steel, coking, and electric power where combustible gases or toxic gases exist, and are important detection instruments for ensuring property and personal safety. Gas detectors use catalytic combustion type and electrochemical gas sensors as detection elements, requiring high sensitivity and rapid response time. Generally, they have a housing formed by die-casting aluminum in one piece and have certain explosion-proof grade requirements. According to the type of detected gas, they can be divided into combustible gas detectors and toxic gas detectors, etc. Combustible gas detectors can generally detect gases such as methane, ethane, propane, and other flammable gases. Currently, the industry is developing rapidly overall and is moving towards wireless functionality and miniaturization. The improvement of communication functionality helps integrate the detector into different devices and machines without reducing the detection ability of toxic or combustible gases within the safe distance.

[0003] In the prior art, a combustible gas detector generally forms a combustible gas detection and alarm system together with an alarm controller and linkage devices (such as a fan, solenoid valve, etc.). Usually, the power supply of the combustible gas detector is direct current, and the power supply of the alarm controller is alternating current. The power supply of the combustible gas detector comes from the internal power supply conversion of the alarm controller. According to the standard requirements, during the inspection and certification or type evaluation process of the alarm controller, there are various electromagnetic compatibility detection items, and it needs to be detected together with the corresponding type of detector.

[0004] According to the standard requirements, during the inspection and certification or type evaluation process of a combustible gas detector alone, since it is a direct current power supply device, various electromagnetic compatibility-related items are reduced. This results in the weakening of the anti-interference protection ability of the combustible gas detector with direct current power supply from the design requirements. When it is used alone without being connected to the alarm controller, it cannot ensure a high anti-electromagnetic interference ability. When it is subjected to electromagnetic interference, there is a possibility that the displayed concentration value of the combustible gas detector will jump irregularly and cause false alarms, and even situations such as shutdown and freeze may occur, resulting in poor user experience. Summary of the Invention

[0005] To solve the problems in the prior art, the present invention provides a control circuit for a combustible gas detector capable of resisting electromagnetic interference. By arranging a power supply voltage adjustment circuit, a sensor voltage adjustment circuit, a main control circuit of the gas detector, a sensor acquisition control circuit, a gas signal acquisition circuit, a temperature signal acquisition circuit, a 485 communication circuit, an acoustic-optic prompt circuit, an LED status display circuit and a digital display screen that cooperate with each other in the control circuit for a combustible gas detector capable of resisting electromagnetic interference, a TVS tube, a common-mode inductor and a diode are provided in the power supply voltage adjustment circuit, a common-mode inductor and multiple TVS tubes are also provided in the 485 communication circuit, and a TVS tube and a diode are also provided in the main control circuit of the gas detector. The TVS tube, the common-mode inductor and the diode can improve the electromagnetic interference resistance ability of the main control circuit of the gas detector, the 485 communication circuit and the power supply voltage adjustment circuit. That is, through multiple electronic circuit protection measures, the electromagnetic interference resistance ability, reliability and stability of the combustible gas detector when used alone are greatly improved, and the problems of poor electromagnetic interference resistance ability and easy occurrence of failures of the combustible gas detector when used alone in the prior art are solved.

[0006] A control circuit for a combustible gas detector capable of resisting electromagnetic interference provided by the present invention includes a power supply voltage adjustment circuit, a sensor voltage adjustment circuit, a main control circuit of the gas detector, a sensor acquisition control circuit, a gas signal acquisition circuit, a temperature signal acquisition circuit, a 485 communication circuit, an acoustic-optic prompt circuit, an LED status display circuit and a digital display screen. The input end of the power supply voltage adjustment circuit is connected to a 24V power supply, and the output end of the power supply voltage adjustment circuit is connected to the temperature signal acquisition circuit, the sensor voltage adjustment circuit, the sensor acquisition control circuit and the main control circuit of the gas detector for power supply. The output end of the sensor voltage adjustment circuit is connected to the gas signal acquisition circuit for power supply. The output end of the main control circuit of the gas detector is connected to the input end of the 485 communication circuit, the input end of the acoustic-optic prompt circuit, the input end of the LED status display circuit and the input end of the digital display screen for control connection. The main control circuit of the gas detector is also communicatively connected to the sensor acquisition control circuit, and the sensor acquisition control circuit is connected to the gas signal acquisition circuit and the temperature signal acquisition circuit for control connection. A current loop module and a relay module are provided in the main control circuit of the gas detector. A TVS tube, a common-mode inductor and a diode are provided in the power supply voltage adjustment circuit, a common-mode inductor and multiple TVS tubes are also provided in the 485 communication circuit, and a TVS tube and a diode are also provided in the main control circuit of the gas detector. The TVS tube, the common-mode inductor and the diode can improve the electromagnetic interference resistance ability of the main control circuit of the gas detector, the 485 communication circuit and the power supply voltage adjustment circuit.

[0007] For further improvement of the present invention, a detector main control chip U5, a crystal oscillator X1, a bead B1, a bead B2, a capacitor C14, a capacitor C16 and a capacitor C18 are provided in the main control circuit of the gas detector. The detector main control chip U5 has 48 pins. The first pin of the detector main control chip U5 is connected to the output end of the power supply voltage adjustment circuit. The 31st, 29th and 30th pins of the detector main control chip U5 are connected to the input end of the 485 communication circuit. The 11th and 46th pins of the detector main control chip U5 are connected to the input end of the acoustic-optic prompt circuit. The 16th, 15th, 14th and 28th pins of the detector main control chip U5 are connected to the input end of the LED status display circuit. The 20th, 19th and 18th pins of the detector main control chip U5 are connected to the input end of the digital display screen. The 5th and 6th pins of the detector main control chip U5 are connected to the sensor acquisition control circuit. The 5th pin of the detector main control chip U5 is connected to one end of the bead B1. The 6th pin of the detector main control chip U5 is connected to one end of the bead B2 and one end of the capacitor C18. The other end of the bead B1 is connected to one end of the capacitor C14 and one end of the crystal oscillator X1. The other end of the bead B2 is connected to one end of the capacitor C16 and the other end of the crystal oscillator X1. The other ends of the capacitor C14, the capacitor C16 and the capacitor C18 are grounded.

[0008] The present invention is further improved. An current loop chip U11, a triode Q1, a field effect transistor Q2, a capacitor C19, a resistor R17, a diode D12, a TVS diode D11, a relay K1 and a triode Q3 are further provided in the main control circuit of the gas detector. Among them, the current loop chip U11 has 10 pins. The 4th pin of the current loop chip U11 is connected to the 4th pin of the detector main control chip U5. The 6th pin of the current loop chip U11 can receive an external AD digital signal. The 2nd pin of the current loop chip U11 is connected to the emitter of the triode. The 3rd pin of the current loop chip U11 is connected to the collector of the triode and the gate of the field effect transistor Q2. The base of the triode is connected to the source of the field effect transistor Q2. The drain of the field effect transistor Q2 is connected to one end of the capacitor C19 and one end of the resistor R17. The other end of the resistor R17 is connected to the positive electrode of the diode D12. The negative electrode of the diode D12 is connected to one end of the TVS diode D11. The negative electrode of the diode D12 can output a current signal. The other end of the TVS diode D11 and the other end of the capacitor C19 are grounded. The relay K1 has 5 pins. The 2nd pin of the relay K1 is connected to the collector of the triode Q3. The base of the triode Q3 is connected to the 3rd pin of the detector main control chip U5. The emitter of the triode Q3 is grounded. The 3rd, 4th and 5th pins of the relay K1 can be connected to other external electronic devices.

[0009] The present invention is further improved. The power supply voltage adjustment circuit is provided with a voltage regulator chip U1, a voltage regulator chip U2, a voltage regulator chip U3, a fuse resistor F1, a diode D10, a TVS diode D1, a common mode inductor L1, a capacitor C4, an inductor L2, capacitors C7, C8 and C9. Among them, the voltage regulator chip U1 has 6 pins, the voltage regulator chip U2 has 3 pins, and the voltage regulator chip U3 has 5 pins. The 4th pin of the voltage regulator chip U1 is connected to the output end of the common mode inductor L1, one end of the capacitor C4 and one end of the capacitor C7. The input end of the common mode inductor L1 is connected to one end of the TVS diode D1 and one end of the fuse resistor F1. The other end of the fuse resistor F1 is connected to the negative electrode of the diode D10. The positive electrode of the diode D10 is connected to a 24V power supply. The 6th pin of the voltage regulator chip U1 is connected to one end of the inductor L2. The other end of the inductor L2 is connected to one end of the capacitor C8, one end of the capacitor C9, the 3rd pin of the voltage regulator chip U2 and the 1st pin of the voltage regulator chip U3. The 2nd pin of the voltage regulator chip U2 is connected to the 1st pin of the detector main control chip U5 for power supply. The 5th pin of the voltage regulator chip U3 is connected to the sensor voltage adjustment circuit, the sensor acquisition control circuit and the temperature signal acquisition circuit for power supply. The other end of the TVS diode D1, the other end of the capacitor C7, the other end of the capacitor C8 and the other end of the capacitor C9 are grounded. The sensor voltage adjustment circuit is provided with a voltage regulator chip U4. The voltage regulator chip U4 has 5 pins. The 3rd and 5th pins of the voltage regulator chip U4 are connected to the 5th pin of the voltage regulator chip U3. The 4th pin of the voltage regulator chip U4 is connected to the gas signal acquisition circuit for power supply.

[0010] The present invention is further improved. The sensor acquisition control circuit is provided with a sensor acquisition control chip U13. The sensor acquisition control chip U13 has 20 pins. The 2nd pin of the sensor acquisition control chip U13 is connected to the 5th pin of the voltage regulator chip U3. The 1st and 20th pins of the sensor acquisition control chip U13 are respectively connected to the 6th and 5th pins of the detector main control chip U5. The 6th and 8th pins of the sensor acquisition control chip U13 are connected to the gas signal acquisition circuit for control. The 5th pin of the sensor acquisition control chip U13 is connected to the temperature signal acquisition circuit for control.

[0011] The present invention is further improved. A combustible gas detection sensor U16, a resistor R8, a resistor R9 and a capacitor C4 are provided in the gas signal acquisition circuit. The combustible gas detection sensor U16 has 8 pins. The 3rd and 6th pins of the combustible gas detection sensor U16 are respectively connected to the 8th and 6th pins of the sensor acquisition control chip U13. The 7th pin of the combustible gas detection sensor U16 is connected to the 5th pin of the voltage regulator chip U3. The 2nd pin of the combustible gas detection sensor U16 is connected to one end of the resistor R8 and one end of the resistor R9. The other end of the resistor R8 is connected to one end of the capacitor C4 and the 4th pin of the voltage regulator chip U4. The other ends of the resistor R9 and the capacitor C4 are grounded.

[0012] The present invention is further improved. A temperature signal acquisition chip U15 and a capacitor C12 are provided in the temperature signal acquisition circuit. The temperature signal acquisition chip U15 has 3 pins. The 1st pin of the temperature signal acquisition chip U15 is connected to the 5th pin of the voltage regulator chip U3 and one end of the capacitor C12. The 2nd pin of the temperature signal acquisition chip U15 is connected to the 5th pin of the sensor acquisition control chip U13. The 3rd pin of the temperature signal acquisition chip U15 and the other end of the capacitor C12 are grounded.

[0013] The present invention is further improved. A 485 communication chip U6, a common mode inductor L6, a TVS diode D7 and a TVS diode D9 are provided in the 485 communication circuit. Among them, the 485 communication chip U6 has 8 pins. The 1st, 3rd and 4th pins of the 485 communication chip U6 are respectively connected to the 31st, 29th and 30th pins of the detector main control chip U5. The 8th pin of the 485 communication chip U6 is connected to the 2nd pin of the voltage regulator chip U2. The 6th and 7th pins of the 485 communication chip U6 are connected to one end of the common mode inductor L6. The other end of the common mode inductor L6 can be connected to an external 485 communication device. The other end of the common mode inductor L6 is also connected to the negative electrodes of the TVS diode D7 and the TVS diode D9. The positive electrodes of the TVS diode D7 and the TVS diode D9 are grounded.

[0014] The present invention is further improved. The acousto-optic prompt circuit is provided with a triode Q4, a speaker prompt interface J6, a triode Q5 and a light-emitting prompt interface J7. Among them, the base of the triode Q4 is connected to the 11th pin of the detector main control chip U5, the collector of the triode Q4 is connected to the input end of the speaker prompt interface J6, the output end of the speaker prompt interface J6 can be connected to an external speaker, the emitter of the triode Q4 is grounded, the base of the triode Q5 is connected to the 46th pin of the detector main control chip U5, the collector of the triode Q5 is connected to the input end of the light-emitting prompt interface J7, the output end of the light-emitting prompt interface J7 can be connected to an external light-emitting LED lamp, and the emitter of the triode Q5 is grounded; the LED status display circuit is provided with a light-emitting diode D1, a light-emitting diode D2, a light-emitting diode D3 and a light-emitting diode D4. Among them, the positive poles of the light-emitting diode D1, the light-emitting diode D2, the light-emitting diode D3 and the light-emitting diode D4 are connected to the 2nd pin of the voltage regulator chip U2, the negative pole of the light-emitting diode D1 is connected to the 16th pin of the detector main control chip U5, the negative pole of the light-emitting diode D2 is connected to the 15th pin of the detector main control chip U5, the negative pole of the light-emitting diode D3 is connected to the 14th pin of the detector main control chip U5, and the negative pole of the light-emitting diode D4 is connected to the 28th pin of the detector main control chip U5.

[0015] The present invention is further improved. The model of the detector main control chip U5 is STM32F103C8T6, the model of the current loop chip U11 is XTR111, the model of the voltage regulator chip U1 is LM2842, the model of the voltage regulator chip U2 is AMS1117-3V3, the model of the voltage regulator chip U3 is TPS76333DBV, the model of the voltage regulator chip U4 is TLV376IDBVR, the model of the sensor acquisition control chip U13 is STM32C011F4U6TR, the model of the combustible gas detection sensor U16 is INA333AIDGKR, the model of the temperature signal acquisition chip U15 is TMP235A2DBZR, and the model of the 485 communication chip U6 is SN65HVD72.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: A combustible gas detector control circuit capable of resisting electromagnetic interference is provided. By arranging a power supply voltage adjustment circuit, a sensor voltage adjustment circuit, a gas detector main control circuit, a sensor acquisition control circuit, a gas signal acquisition circuit, a temperature signal acquisition circuit, a 485 communication circuit, an acoustic-optic prompt circuit, an LED status display circuit, and a digital display screen that cooperate with each other in the combustible gas detector control circuit capable of resisting electromagnetic interference, a TVS tube, a common-mode inductor, and a diode are provided in the power supply voltage adjustment circuit, a common-mode inductor and multiple TVS tubes are also provided in the 485 communication circuit, and a TVS tube and a diode are also provided in the gas detector main control circuit. The TVS tube, the common-mode inductor, and the diode can improve the electromagnetic interference resistance ability of the gas detector main control circuit, the 485 communication circuit, and the power supply voltage adjustment circuit. That is, through multiple electronic circuit protection measures, the electromagnetic interference resistance ability of the combustible gas detector when used alone is greatly improved, the reliability and stability of the combustible gas detector are improved, so that in the scenario where the combustible gas detector is used alone without being powered by an alarm controller or external power supply, the concentration of combustible gas can be accurately detected in real time, and various complex interference environments can be adapted, improving the user experience, and solving the problems of poor electromagnetic interference resistance ability and easy failure when the combustible gas detector is used alone in the prior art. Brief Description of the Drawings

[0017] In order to more clearly illustrate the solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic block diagram of a combustible gas detector control circuit capable of resisting electromagnetic interference according to the present invention;

[0019] Figure 2 It is a circuit diagram of the gas detector main control circuit according to the present invention;

[0020] Figure 3 It is a circuit diagram of the gas detector main control circuit according to the present invention;

[0021] Figure 4 It is a circuit diagram of the gas detector main control circuit according to the present invention;

[0022] Figure 5 It is a circuit diagram of the gas detector main control circuit according to the present invention;

[0023] Figure 6 It is a circuit diagram of the power supply voltage adjustment circuit according to the present invention;

[0024] Figure 7 This is the circuit diagram of the power supply voltage adjustment circuit of the present invention;

[0025] Figure 8 This is the circuit diagram of the sensor acquisition control circuit of the present invention;

[0026] Figure 9 This is the circuit diagram of the gas signal acquisition circuit of the present invention;

[0027] Figure 10 This is the circuit diagram of the temperature signal acquisition circuit of the present invention;

[0028] Figure 11 This is the circuit diagram of the 485 communication circuit of the present invention;

[0029] Figure 12 This is the circuit diagram of the acoustic-optic prompt circuit of the present invention. Detailed implementation manners

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs; the terms used in the description of the present application in this specification are only for the purpose of describing specific embodiments, and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present invention or the above drawings are used to distinguish different objects, not to describe a specific order.

[0031] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0032] In order to enable those skilled in the art of this technology to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0033] Such as Figures 1 - 12As shown in the figure, a control circuit for a combustible gas detector capable of resisting electromagnetic interference provided by the present invention includes a power supply voltage adjustment circuit, a sensor voltage adjustment circuit, a main control circuit of the gas detector, a sensor acquisition control circuit, a gas signal acquisition circuit, a temperature signal acquisition circuit, a 485 communication circuit, an audible and visual prompt circuit, an LED status display circuit, and a digital display screen. The input end of the power supply voltage adjustment circuit is connected to a 24V power supply, and the output end of the power supply voltage adjustment circuit is connected to the temperature signal acquisition circuit, the sensor voltage adjustment circuit, the sensor acquisition control circuit, and the main control circuit of the gas detector for power supply. The output end of the sensor voltage adjustment circuit is connected to the gas signal acquisition circuit for power supply. The output end of the main control circuit of the gas detector is connected to the input end of the 485 communication circuit, the input end of the audible and visual prompt circuit, the input end of the LED status display circuit, and the input end of the digital display screen for control connection. The main control circuit of the gas detector is also communicatively connected to the sensor acquisition control circuit, and the sensor acquisition control circuit is connected to the gas signal acquisition circuit and the temperature signal acquisition circuit for control connection. The main control circuit of the gas detector is provided with a current loop module and a relay module. In this embodiment, the power supply voltage adjustment circuit is provided with a TVS tube, a common mode inductor, and a diode. The 485 communication circuit is also provided with a common mode inductor and a plurality of TVS tubes. The main control circuit of the gas detector is also provided with a TVS tube and a diode. The TVS tube, the common mode inductor, and the diode can improve the electromagnetic interference resistance of the main control circuit of the gas detector, the 485 communication circuit, and the power supply voltage adjustment circuit. That is, through multiple electronic circuit protection measures, the electromagnetic interference resistance of the combustible gas detector when used alone is greatly improved, the reliability and stability of the combustible gas detector are improved, so that in the scenario where the combustible gas detector is used alone without being powered by an alarm controller or external power supply, it can accurately detect the concentration of combustible gas in real time, and can adapt to various complex interference environments, improving the user experience.

[0034] As Figures 2 - 3As shown in the figure, the main control circuit of the gas detector is provided with a detector main control chip U5, a crystal oscillator X1, a bead B1, a bead B2, a capacitor C14, a capacitor C16, and a capacitor C18. Among them, the model of the detector main control chip U5 is STM32F103C8T6. The detector main control chip U5 has 48 pins. The first pin of the detector main control chip U5 is connected to the output end of the power supply voltage adjustment circuit. The 31st, 29th, and 30th pins of the detector main control chip U5 are connected to the input end of the 485 communication circuit. The 11th and 46th pins of the detector main control chip U5 are connected to the input end of the sound and light prompt circuit. The 16th, 15th, 14th, and 28th pins of the detector main control chip U5 are connected to the input end of the LED status display circuit. The 20th, 19th, and 18th pins of the detector main control chip U5 are connected to the input end of the digital display screen. The 5th and 6th pins of the detector main control chip U5 are connected to the sensor acquisition control circuit. The 5th pin of the detector main control chip U5 is connected to one end of the bead B1. The 6th pin of the detector main control chip U5 is connected to one end of the bead B2 and one end of the capacitor C18. The other end of the bead B1 is connected to one end of the capacitor C14 and one end of the crystal oscillator X1. The other end of the bead B2 is connected to one end of the capacitor C16 and the other end of the crystal oscillator X1. The other ends of the capacitor C14, the capacitor C16, and the capacitor C18 are grounded. As Figures 4 - 5As shown, the main control circuit of the gas detector further includes a current loop chip U11, a triode Q1, a field effect transistor Q2, a capacitor C19, a resistor R17, a diode D12, a TVS diode D11, a relay K1, and a triode Q3. Among them, the model of the current loop chip U11 is XTR111. The current loop chip U11 has 10 pins. The 4th pin of the current loop chip U11 is connected to the 4th pin of the detector main control chip U5. The 6th pin of the current loop chip U11 can receive an external AD digital signal. The 2nd pin of the current loop chip U11 is connected to the emitter of the triode. The 3rd pin of the current loop chip U11 is connected to the collector of the triode and the gate of the field effect transistor Q2. The base of the triode is connected to the source of the field effect transistor Q2. The drain of the field effect transistor Q2 is connected to one end of the capacitor C19 and one end of the resistor R17. The other end of the resistor R17 is connected to the positive electrode of the diode D12. The negative electrode of the diode D12 is connected to one end of the TVS diode D11. The negative electrode of the diode D12 can output a current signal. The other end of the TVS diode D11 and the other end of the capacitor C19 are grounded. The relay K1 has 5 pins. The 2nd pin of the relay K1 is connected to the collector of the triode Q3. The base of the triode Q3 is connected to the 3rd pin of the detector main control chip U5. The emitter of the triode Q3 is grounded. The 3rd, 4th, and 5th pins of the relay K1 can be connected to other external electronic devices. In this embodiment, the main control circuit of the gas detector is used to control the sensor acquisition control circuit to control the gas signal acquisition circuit and the temperature signal acquisition circuit to collect the concentration and temperature of combustible gas. At the same time, it is also used to control the sound and light prompt circuit to issue an alarm prompt, the LED status display circuit to display various states, and the digital display screen to display various information. It is also used to communicate with external devices through the 485 communication circuit. Among them, the crystal oscillator X1 provides a clock frequency for the operation of the detector main control chip U5. The capacitors C14 and C16 are used as starting capacitors. The magnetic beads B1 and B2 can filter the noise signals in the clock frequency signal. The capacitor C18 can bypass the noise signals in the clock frequency signal. Compared with the ordinary crystal oscillator circuit, this circuit structure provides a higher clock frequency accuracy for the entire circuit. The current loop chip U11 controls the output of a 4mA - 20mA current signal at the output end through the AD digital signal at the input end. The TVS diode D11 plays a role in releasing high voltage protection. The diode D12 plays a role in preventing current backflow protection. The resistor R17 plays a role in current limiting protection. The capacitor C19 plays a role in filtering. As an important module of the combustible gas detector, this circuit structure enables the combustible gas detector to output a stable, reliable, and high-precision 4mA - 20mA current. The relay K1 can enable the combustible gas detector to provide an interface for external linkage devices (such as fans, solenoid valves, etc.).

[0035] As Figures 6 - 7As shown in the figure, the power supply voltage adjustment circuit is provided with a voltage regulator chip U1, a voltage regulator chip U2, a voltage regulator chip U3, a fuse resistor F1, a diode D10, a TVS diode D1, a common mode inductor L1, a capacitor C4, an inductor L2, a capacitor C7, a capacitor C8, and a capacitor C9. Among them, the model of the voltage regulator chip U1 is LM2842, the model of the voltage regulator chip U2 is AMS1117-3V3, the model of the voltage regulator chip U3 is TPS76333DBV. The voltage regulator chip U1 has 6 pins, the voltage regulator chip U2 has 3 pins, and the voltage regulator chip U3 has 5 pins. The 4th pin of the voltage regulator chip U1 is connected to the output end of the common mode inductor L1, one end of the capacitor C4, and one end of the capacitor C7. The input end of the common mode inductor L1 is connected to one end of the TVS diode D1 and one end of the fuse resistor F1. The other end of the fuse resistor F1 is connected to the negative electrode of the diode D10. The positive electrode of the diode D10 is connected to a 24V power supply. The 6th pin of the voltage regulator chip U1 is connected to one end of the inductor L2. The other end of the inductor L2 is connected to one end of the capacitor C8, one end of the capacitor C9, the 3rd pin of the voltage regulator chip U2, and the 1st pin of the voltage regulator chip U3. The 2nd pin of the voltage regulator chip U2 is connected to the 1st pin of the detector main control chip U5 for power supply. The 5th pin of the voltage regulator chip U3 is connected to the sensor voltage adjustment circuit, the sensor acquisition control circuit, and the temperature signal acquisition circuit for power supply. The other end of the TVS diode D1, the other end of the capacitor C7, the other end of the capacitor C8, and the other end of the capacitor C9 are grounded; the sensor voltage adjustment circuit is provided with a voltage regulator chip U4, the model of the voltage regulator chip U4 is TLV376IDBVR, the voltage regulator chip U4 has 5 pins, the 3rd and 5th pins of the voltage regulator chip U4 are connected to the 5th pin of the voltage regulator chip U3, and the 4th pin of the voltage regulator chip U4 is connected to the gas signal acquisition circuit for power supply. In this embodiment, the power supply voltage adjustment circuit is used to supply power to the temperature signal acquisition circuit, the sensor voltage adjustment circuit, the sensor acquisition control circuit, and the gas detector main control circuit. The power supply voltage adjustment circuit consists of 3 sub-modules. The first sub-circuit module consists of the voltage regulator chip U1 and its peripheral circuit, which steps down the 24V DC power supply to 6V DC power supply, namely V6.0 in the figure. The second sub-circuit module consists of the voltage regulator chip U2 and its peripheral circuit, which steps down the 6V DC power supply to a 3.3V DC power supply, namely V3.3 in the figure. The third sub-circuit module consists of the voltage regulator chip U3 and its peripheral circuit, which steps down the 6V DC power supply to another 3.3V DC power supply, namely SV3.3 in the figure.Among them, the diode D10 serves to prevent reverse connection of the power supply. The fuse resistor F1 plays a role in fusing to protect the circuit when the current is too large. The TVS tube D1 can release transient high voltages, such as surge voltages, etc. The common-mode inductor L1 can suppress common-mode / differential-mode interference signals in the current and enhance the anti-electromagnetic interference ability. The capacitors C4 and C10 and the ground form a Y-shaped circuit, which can also effectively filter out differential-mode interference signals in the current signal. The voltage regulator chip U1 selects a high-precision and high-stability model LM2842. The capacitors C7, C8, and C9 are filter capacitors. Through the multiple protections formed by the above-mentioned electronic components, the entire power supply voltage adjustment circuit has a high anti-electromagnetic interference ability and provides a stable and reliable power supply for the subsequent circuit.

[0036] As Figure 8 shown, a sensor acquisition control chip U13 is provided in the sensor acquisition control circuit. The model of the sensor acquisition control chip U13 is STM32C011F4U6TR. The sensor acquisition control chip U13 has 20 pins. The second pin of the sensor acquisition control chip U13 is connected to the fifth pin of the voltage regulator chip U3. The first and 20th pins of the sensor acquisition control chip U13 are respectively connected to the sixth and fifth pins of the detector main control chip U5. The sixth and eighth pins of the sensor acquisition control chip U13 are connected to the gas signal acquisition circuit for control. The fifth pin of the sensor acquisition control chip U13 is connected to the temperature signal acquisition circuit for control. In this embodiment, the sensor acquisition control circuit is used to control the gas signal acquisition circuit to acquire the concentration signal of combustible gas and the temperature signal acquisition circuit to acquire the temperature signal.

[0037] As Figure 9 shown, a combustible gas detection sensor U16, resistors R8, R9, and a capacitor C4 are provided in the gas signal acquisition circuit. The model of the combustible gas detection sensor U16 is INA333AIDGKR. The combustible gas detection sensor U16 has 8 pins. The third and sixth pins of the combustible gas detection sensor U16 are respectively connected to the eighth and sixth pins of the sensor acquisition control chip U13. The seventh pin of the combustible gas detection sensor U16 is connected to the fifth pin of the voltage regulator chip U3. The second pin of the combustible gas detection sensor U16 is connected to one end of the resistor R8 and one end of the resistor R9. The other end of the resistor R8 is connected to one end of the capacitor C4 and the fourth pin of the voltage regulator chip U4. The other ends of the resistor R9 and the capacitor C4 are grounded. In this embodiment, the gas signal acquisition circuit is used to convert the concentration value signal of the gas to be detected into an electrical signal in real time according to the control instruction of the sensor acquisition control circuit and output it to the sensor acquisition control circuit.

[0038] As Figure 10As shown, the temperature signal acquisition circuit is provided with a temperature signal acquisition chip U15 and a capacitor C12. The model of the temperature signal acquisition chip U15 is TMP235A2DBZR. The temperature signal acquisition chip U15 has 3 pins. The first pin of the temperature signal acquisition chip U15 is connected to the fifth pin of the voltage regulator chip U3 and one end of the capacitor C12. The second pin of the temperature signal acquisition chip U15 is connected to the fifth pin of the sensor acquisition control chip U13. The third pin of the temperature signal acquisition chip U15 and the other end of the capacitor C12 are grounded. In this embodiment, the temperature signal acquisition circuit is used to collect the ambient temperature in real time according to the control instruction of the sensor acquisition control circuit, convert it into a digital signal, and output it to the sensor acquisition control circuit.

[0039] As Figure 11 shown, the 485 communication circuit is provided with a 485 communication chip U6, a common mode inductor L6, TVS diodes D7 and D9. Among them, the 485 communication chip U6 has 8 pins. The model of the 485 communication chip U6 is SN65HVD72. The first, third, and fourth pins of the 485 communication chip U6 are respectively connected to the 31st, 29th, and 30th pins of the detector main control chip U5. The eighth pin of the 485 communication chip U6 is connected to the second pin of the voltage regulator chip U2. The sixth and seventh pins of the 485 communication chip U6 are connected to one end of the common mode inductor L6. The other end of the common mode inductor L6 can be connected to an external 485 communication device. The other end of the common mode inductor L6 is also connected to the negative electrodes of the TVS diode D7 and the TVS diode D9. The positive electrodes of the TVS diode D7 and the TVS diode D9 are grounded. In this embodiment, the 485 communication chip U6 selects the model SN65HVD72 with strong anti-interference ability; the resistors R20, R22, and R24 play a current limiting role; the common mode inductor L6 plays a role in filtering out interference signals; the resistor R21 pulls down the communication signal; the resistor R25 pulls up the communication signal; the capacitors C26 and C27 play a filtering role; the TVS diodes D7, D8, and D9 can release the transient high voltage noise / interference signals in the communication signal. The advantage of this circuit structure is that it can improve the reliability and stability of the communication signal.

[0040] As Figure 12As shown, the acoustic-optic prompt circuit is provided with a triode Q4, a speaker prompt interface J6, a triode Q5, and a light-emitting prompt interface J7. Among them, the base of the triode Q4 is connected to the 11th pin of the detector main control chip U5. The collector of the triode Q4 is connected to the input end of the speaker prompt interface J6. The output end of the speaker prompt interface J6 can be connected to an external speaker. The emitter of the triode Q4 is grounded. The base of the triode Q5 is connected to the 46th pin of the detector main control chip U5. The collector of the triode Q5 is connected to the input end of the light-emitting prompt interface J7. The output end of the light-emitting prompt interface J7 can be connected to an external light-emitting LED lamp. The emitter of the triode Q5 is grounded. The LED status display circuit is provided with a light-emitting diode D1, a light-emitting diode D2, a light-emitting diode D3, and a light-emitting diode D4. Among them, the positive electrodes of the light-emitting diode D1, the light-emitting diode D2, the light-emitting diode D3, and the light-emitting diode D4 are connected to the 2nd pin of the voltage regulator chip U2. The negative electrode of the light-emitting diode D1 is connected to the 16th pin of the detector main control chip U5. The negative electrode of the light-emitting diode D2 is connected to the 15th pin of the detector main control chip U5. The negative electrode of the light-emitting diode D3 is connected to the 14th pin of the detector main control chip U5. The negative electrode of the light-emitting diode D4 is connected to the 28th pin of the detector main control chip U5. In this embodiment, the acoustic-optic prompt circuit is composed of an acoustic reporting sub-module and a light reporting sub-module. Among them, the acoustic reporting sub-module is composed of the triode Q4 and its peripheral circuit, providing a sound alarm function for the combustible gas detector. The light reporting sub-module is composed of the triode Q5 and its peripheral circuit, providing a light source alarm function for the combustible gas detector. The acoustic-optic module serves as a warning function when the detector detects different gas concentrations. The LED status display circuit is used to indicate the operating status of the combustible gas detector. For example, when the red light-emitting diode D1 is on, it indicates that the power supply is normal. When the yellow light-emitting diode D3 is on, it indicates an operating fault.

[0041] As can be seen from the above, the present invention provides a control circuit for a combustible gas detector capable of resisting electromagnetic interference. By arranging a power supply voltage adjustment circuit, a sensor voltage adjustment circuit, a main control circuit of the gas detector, a sensor acquisition control circuit, a gas signal acquisition circuit, a temperature signal acquisition circuit, a 485 communication circuit, an acoustic-optic prompt circuit, an LED status display circuit and a digital display screen that cooperate with each other in the control circuit of the combustible gas detector capable of resisting electromagnetic interference, a TVS tube, a common-mode inductor and a diode are provided in the power supply voltage adjustment circuit, a common-mode inductor and a plurality of TVS tubes are also provided in the 485 communication circuit, and a TVS tube and a diode are also provided in the main control circuit of the gas detector. The TVS tube, the common-mode inductor and the diode can improve the electromagnetic interference resistance of the main control circuit of the gas detector, the 485 communication circuit and the power supply voltage adjustment circuit. That is, through multiple electronic circuit protection measures, the electromagnetic interference resistance of the combustible gas detector when used alone is greatly improved, the reliability and stability of the combustible gas detector are improved, so that in the scenario where the combustible gas detector is used alone without being powered by an alarm controller or external power supply, the concentration of combustible gas can be detected in real time and accurately, and it can adapt to various complex interference environments, improving the user experience and solving the problems of poor electromagnetic interference resistance and easy failure when the combustible gas detector is used alone in the prior art.

[0042] The above-mentioned specific implementation manners are the preferred implementation manners of the present invention, and do not limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to this specific implementation manner. All equivalent changes made in accordance with the present invention are within the protection scope of the present invention.

Claims

1. A combustible gas detector control circuit capable of resisting electromagnetic interference, characterized in that: It includes a power supply voltage adjustment circuit, a sensor voltage adjustment circuit, a gas detector main control circuit, a sensor acquisition control circuit, a gas signal acquisition circuit, a temperature signal acquisition circuit, a 485 communication circuit, an audio-visual prompt circuit, an LED status display circuit and a digital display screen. The input end of the power supply voltage adjustment circuit is connected to a 24V power supply. The output end of the power supply voltage adjustment circuit is connected to the temperature signal acquisition circuit, the sensor voltage adjustment circuit, the sensor acquisition control circuit and the gas detector main control circuit. The output end of the sensor voltage adjustment circuit is connected to the gas signal acquisition circuit. The output end of the gas detector main control circuit is connected to the input end of the 485 communication circuit, the input end of the audio-visual prompt circuit and the L The input end of the ED status display circuit and the input end of the digital display screen are controlled and connected. The gas detector main control circuit is also communicated with the sensor acquisition control circuit. The sensor acquisition control circuit is controlled and connected with the gas signal acquisition circuit and the temperature signal acquisition circuit. The gas detector main control circuit is provided with a current loop module and a relay module. The power supply voltage adjustment circuit is provided with a TVS tube, a common-mode inductor and a diode. The 485 communication circuit is also provided with a common-mode inductor and multiple TVS tubes. The gas detector main control circuit is also provided with a TVS tube and a diode. The TVS tube, common-mode inductor and diode can enhance the anti-electromagnetic interference capability of the gas detector main control circuit, the 485 communication circuit and the power supply voltage adjustment circuit.

2. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 1 is characterized in that: The gas detector main control circuit is provided with a detector main control chip U5, a crystal oscillator X1, a magnetic bead B1, a magnetic bead B2, a capacitor C14, a capacitor C16 and a capacitor C18. The detector main control chip U5 is provided with 48 pins. The first pin of the detector main control chip U5 is connected to the output end of the power supply voltage adjustment circuit, the 31st, 29th and 30th pins of the detector main control chip U5 are connected to the input end of the 485 communication circuit, the 11th and 46th pins of the detector main control chip U5 are connected to the input end of the sound and light prompt circuit, the 16th, 15th, 14th and 28th pins of the detector main control chip U5 are connected to the input end of the LED status display circuit, and the detector main The 20th, 19th and 18th pins of the control chip U5 are connected to the input end of the digital display screen, the 5th and 6th pins of the detector main control chip U5 are connected to the sensor acquisition control circuit, the 5th pin of the detector main control chip U5 is connected to one end of the magnetic bead B1, the 6th pin of the detector main control chip U5 is connected to one end of the magnetic bead B2 and one end of the capacitor C18, the other end of the magnetic bead B1 is connected to one end of the capacitor C14 and one end of the crystal oscillator X1, the other end of the magnetic bead B2 is connected to one end of the capacitor C16 and the other end of the crystal oscillator X1, and the other end of the capacitor C14, the other end of the capacitor C16 and the other end of the capacitor C18 are grounded.

3. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 2 is characterized in that: The main control circuit of the gas detector is also provided with a current loop chip U11, a transistor Q1, a field effect transistor Q2, a capacitor C19, a resistor R17, a diode D12, a TVS tube D11, a relay K1 and a transistor Q3, wherein the current loop chip U11 is provided with 10 pins, the 4th pin of the current loop chip U11 is connected to the 4th pin of the detector main control chip U5, the 6th pin of the current loop chip U11 can receive external AD digital signals, the 2nd pin of the current loop chip U11 is connected to the emitter of the transistor, the 3rd pin of the current loop chip U11 is connected to the collector of the transistor and the gate of the field effect transistor Q2, and the base of the transistor is connected to the source of the field effect transistor Q2 , the drain of the field effect tube Q2 is connected to one end of the capacitor C19 and one end of the resistor R17, the other end of the resistor R17 is connected to the positive electrode of the diode D12, the cathode of the diode D12 is connected to one end of the TVS tube D11, the cathode of the diode D12 can output a current signal, the other end of the TVS tube D11 and the other end of the capacitor C19 are grounded; the relay K1 is provided with 5 pins, the second pin of the relay K1 is connected to the collector of the transistor Q3, the base of the transistor Q3 is connected to the third pin of the detector main control chip U5, the emitter of the transistor Q3 is grounded, and the 3rd, 4th and 5th pins of the relay K1 can be connected to other external electronic devices.

4. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 3 is characterized in that: The power supply voltage adjustment circuit is provided with a voltage stabilizing chip U1, a voltage stabilizing chip U2, a voltage stabilizing chip U3, a fuse resistor F1, a diode D10, a TVS tube D1, a common mode inductor L1, a capacitor C4, an inductor L2, a capacitor C7, a capacitor C8 and a capacitor C9, wherein the voltage stabilizing chip U1 is provided with 6 pins, the voltage stabilizing chip U2 is provided with 3 pins, and the voltage stabilizing chip U3 is provided with 5 pins. The 4th pin of the voltage stabilizing chip U1 is connected to the output end of the common mode inductor L1, one end of the capacitor C4, and one end of the capacitor C7. The input end of the common mode inductor L1 is connected to one end of the TVS tube D1 and one end of the fuse resistor F1. The other end of the fuse resistor F1 is connected to the negative electrode of the diode D10. The positive electrode of the diode D10 is connected to a 24V power supply. The 6th pin of the voltage stabilizing chip U1 is connected to one end of the inductor L2. The other end of the inductor L2 is connected to one end of the capacitor C8, one end of the capacitor C9, the third pin of the voltage stabilizing chip U2, and the first pin of the voltage stabilizing chip U3. The second pin of the voltage stabilizing chip U2 is connected to the first pin of the detector main control chip U5 for power supply. The fifth pin of the voltage stabilizing chip U3 is connected to the sensor voltage adjustment circuit, the sensor acquisition control circuit, and the temperature signal acquisition circuit for power supply. The other end of the TVS tube D1, the other end of the capacitor C7, the other end of the capacitor C8, and the other end of the capacitor C9 are grounded. A voltage stabilizing chip U4 is provided in the sensor voltage adjustment circuit. The voltage stabilizing chip U4 is provided with 5 pins. The third and fifth pins of the voltage stabilizing chip U4 are connected to the fifth pin of the voltage stabilizing chip U3. The fourth pin of the voltage stabilizing chip U4 is connected to the gas signal acquisition circuit for power supply.

5. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 4 is characterized in that: A sensor acquisition control chip U13 is provided in the sensor acquisition control circuit. The sensor acquisition control chip U13 is provided with 20 pins. The 2nd pin of the sensor acquisition control chip U13 is connected to the 5th pin of the voltage stabilizing chip U3. The 1st and 20th pins of the sensor acquisition control chip U13 are respectively connected to the 6th and 5th pins of the detector main control chip U5. The 6th and 8th pins of the sensor acquisition control chip U13 are controlled and connected to the gas signal acquisition circuit. The 5th pin of the sensor acquisition control chip U13 is controlled and connected to the temperature signal acquisition circuit.

6. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 5, characterized in that: The gas signal acquisition circuit is provided with a combustible gas detection sensor U16, a resistor R8, a resistor R9 and a capacitor C4. The combustible gas detection sensor U16 is provided with 8 pins. The 3rd and 6th pins of the combustible gas detection sensor U16 are respectively connected to the 8th and 6th pins of the sensor acquisition control chip U13, the 7th pin of the combustible gas detection sensor U16 is connected to the 5th pin of the voltage stabilizing chip U3, the 2nd pin of the combustible gas detection sensor U16 is connected to one end of the resistor R8 and one end of the resistor R9, the other end of the resistor R8 is connected to one end of the capacitor C4 and the 4th pin of the voltage stabilizing chip U4, the other end of the resistor R9 and the other end of the capacitor C4 are grounded.

7. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 6, characterized in that: The temperature signal acquisition circuit is provided with a temperature signal acquisition chip U15 and a capacitor C12. The temperature signal acquisition chip U15 is provided with 3 pins. The first pin of the temperature signal acquisition chip U15 is connected to the fifth pin of the voltage stabilizing chip U3 and one end of the capacitor C12. The second pin of the temperature signal acquisition chip U15 is connected to the fifth pin of the sensor acquisition control chip U13. The third pin of the temperature signal acquisition chip U15 and the other end of the capacitor C12 are grounded.

8. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 7, characterized in that: The 485 communication circuit is provided with a 485 communication chip U6, a common-mode inductor L6, a TVS tube D7 and a TVS tube D9, wherein the 485 communication chip U6 is provided with 8 pins, the 1st, 3rd and 4th pins of the 485 communication chip U6 are respectively connected to the 31st, 29th and 30th pins of the detector main control chip U5, the 8th pin of the 485 communication chip U6 is connected to the 2nd pin of the voltage stabilizing chip U2, the 6th and 7th pins of the 485 communication chip U6 are connected to one end of the common-mode inductor L6, the other end of the common-mode inductor L6 can be connected to an external 485 communication device, the other end of the common-mode inductor L6 is also connected to the negative pole of the TVS tube D7 and the negative pole of the TVS tube D9, and the positive pole of the TVS tube D7 and the positive pole of the TVS tube D9 are grounded.

9. The electromagnetic interference resistant combustible gas detector control circuit according to claim 8, characterized in that: The sound and light prompt circuit is provided with a transistor Q4, a loudspeaker prompt interface J6, a transistor Q5 and a light prompt interface J7, wherein the base of the transistor Q4 is connected to the 11th pin of the detector main control chip U5, the collector of the transistor Q4 is connected to the input end of the loudspeaker prompt interface J6, the output end of the loudspeaker prompt interface J6 can be connected to an external loudspeaker, the emitter of the transistor Q4 is grounded, the base of the transistor Q5 is connected to the 46th pin of the detector main control chip U5, the collector of the transistor Q5 is connected to the input end of the light prompt interface J7, the output end of the light prompt interface J7 can be connected to an external light-emitting LED lamp, and the emitter of the transistor Q5 is grounded; the LE The D state display circuit is provided with a light-emitting diode D1, a light-emitting diode D2, a light-emitting diode D3 and a light-emitting diode D4, wherein the positive pole of the light-emitting diode D1, the positive pole of the light-emitting diode D2, the positive pole of the light-emitting diode D3 and the positive pole of the light-emitting diode D4 are connected to the second pin of the voltage regulator chip U2, the negative pole of the light-emitting diode D1 is connected to the 16th pin of the detector main control chip U5, the negative pole of the light-emitting diode D2 is connected to the 15th pin of the detector main control chip U5, the negative pole of the light-emitting diode D3 is connected to the 14th pin of the detector main control chip U5, and the negative pole of the light-emitting diode D4 is connected to the 28th pin of the detector main control chip U5.

10. The combustible gas detector control circuit capable of resisting electromagnetic interference according to claim 9, characterized in that: The model of the detector main control chip U5 is STM32F103C8T6, the model of the current loop chip U11 is XTR111, the model of the voltage regulator chip U1 is LM2842, the model of the voltage regulator chip U2 is AMS1117-3V3, the model of the voltage regulator chip U3 is TPS76333DBV, the model of the voltage regulator chip U4 is TLV376IDBVR, the model of the sensor acquisition control chip U13 is STM32C011F4U6TR, the model of the combustible gas detection sensor U16 is INA333AIDGKR, the model of the temperature signal acquisition chip U15 is TMP235A2DBZR, and the model of the 485 communication chip U6 is SN65HVD72.

Images