Combustible gas detector control circuit capable of resisting electromagnetic interference

Abstract

The utility model 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 which are 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] This utility model relates to the field of gas detection technology, specifically to a control circuit for a combustible gas detector that is resistant to electromagnetic interference. Background Technology

[0002] A gas detector is an instrument used to detect gas concentrations. Gas detectors are suitable for hazardous locations where flammable or toxic gases are present, and can continuously monitor the concentration of the gas in the air up to its lower explosive limit. They are widely used in various industries such as gas, petrochemicals, metallurgy, steel, coking, and power generation, where flammable or toxic gases are present, and are crucial instruments for ensuring the safety of property and personnel. Gas detectors use catalytic combustion or electrochemical gas sensors as detection elements, requiring high sensitivity and rapid response time. They are generally made with a die-cast aluminum housing and have certain explosion-proof requirements. Based on the type of gas detected, they can be divided into flammable gas detectors and toxic gas detectors. Flammable gas detectors can generally detect flammable gases such as methane, ethane, and propane. Currently, the industry is developing rapidly and is moving towards wireless functionality and miniaturization. Improvements in communication capabilities will help integrate detectors into different devices and machines without reducing the ability to detect toxic or flammable gases within a safe distance.

[0003] In existing technologies, combustible gas detectors are generally combined with alarm controllers and linkage devices (fans, solenoid valves, etc.) to form a combustible gas detection and alarm system. Typically, combustible gas detectors are powered by DC, while alarm controllers are powered by AC. The power supply for the combustible gas detectors comes from the power conversion within the alarm controller. According to standards, alarm controllers undergo various electromagnetic compatibility (EMC) tests during inspection and certification or type evaluation processes, and these tests must be performed together with the corresponding model of detector.

[0004] According to standard requirements, combustible gas detectors, when used independently in testing and certification or type evaluation processes at inspection institutes, have fewer electromagnetic compatibility-related items due to being DC-powered devices. This results in a weakening of the anti-interference protection capability of DC-powered combustible gas detectors in terms of design requirements. When used independently without being connected to an alarm controller, they cannot guarantee a high level of electromagnetic interference resistance. When subjected to electromagnetic interference, the concentration value displayed by the combustible gas detector may fluctuate irregularly, leading to false alarms, or even shutdown and system crashes, resulting in a poor user experience. Utility Model Content

[0005] To address the problems in existing technologies, this utility model provides a combustible gas detector control circuit capable of resisting electromagnetic interference. This circuit incorporates 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 audible and visual prompt circuit, an LED status display circuit, and a digital display screen. The power supply voltage adjustment circuit includes a TVS diode, a common-mode inductor, and a diode. Similarly, the 485 communication circuit includes a common-mode inductor and multiple TVS diodes, and the gas detector main control circuit also includes a TVS diode and a diode. These components enhance the electromagnetic interference resistance of the gas detector main control circuit, the 485 communication circuit, and the power supply voltage adjustment circuit. Through these multiple electronic circuit protection measures, the electromagnetic interference resistance, reliability, and stability of the combustible gas detector when used alone are significantly improved, solving the problems of poor electromagnetic interference resistance and susceptibility to malfunction in existing combustible gas detectors when used alone.

[0006] This utility model provides a combustible gas detector control circuit capable of resisting electromagnetic interference, including 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 audible and visual prompt circuit, an LED status display circuit, and a digital display screen. The output terminal 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 for power supply. The output terminal of the sensor voltage adjustment circuit is connected to the gas signal acquisition circuit for power supply. The output terminal of the gas detector main control circuit is connected to the input terminal of the 485 communication circuit. The input terminals of the sound and light prompt circuit, the LED status display circuit, and the digital display screen are controlled and connected. The main control circuit of the gas detector is also communicatively connected to the sensor acquisition and control circuit. The sensor acquisition and control circuit is controlled and connected to the gas signal acquisition circuit and the temperature signal acquisition circuit. The power supply voltage adjustment circuit is equipped with a TVS diode, a common-mode inductor, and a diode. The 485 communication circuit is also equipped with a common-mode inductor and multiple TVS diodes. The main control circuit of the gas detector is also equipped with a TVS diode and a diode. The TVS diode, common-mode inductor, and 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.

[0007] This utility model is further improved in that the main control circuit of the gas detector includes a main control chip U5, a crystal oscillator X1, a ferrite bead B1, a ferrite bead B2, capacitors C14, C16, and C18. The main control chip U5 has 48 pins. Pin 1 of the main control chip U5 is connected to the output terminal of the power supply voltage adjustment circuit. Pins 31, 29, and 30 of the main control chip U5 are connected to the input terminal of the 485 communication circuit. Pins 11 and 46 of the main control chip U5 are connected to the input terminal of the audio-visual prompt circuit. Pins 16, 15, 14, and 28 of the main control chip U5 are connected to the input terminal of the LED status display circuit. Pins 20, 19, and 18 of the detector main control chip U5 are connected to the input terminal of the digital display screen. Pins 5 and 6 of the detector main control chip U5 are connected to the sensor acquisition and control circuit. Pin 5 of the detector main control chip U5 is connected to one end of the magnetic bead B1. Pin 6 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. The other ends of the capacitors C14, C16, and C18 are grounded.

[0008] This utility model is further improved by including a current loop chip U11, a transistor Q1, a field-effect transistor Q2, a capacitor C19, a resistor R17, a diode D12, a TVS diode D11, a relay K1, and a transistor Q3 in the main control circuit of the gas detector. The current loop chip U11 has 10 pins. Pin 4 of the current loop chip U11 is connected to pin 4 of the main control chip U5. Pin 6 of the current loop chip U11 can receive external AD digital signals. Pin 2 of the current loop chip U11 is connected to the emitter of the transistor. Pin 3 of the current loop chip U11 is connected to the collector of the transistor and the gate of the field-effect transistor Q2. The base of the transistor is connected to the field-effect transistor Q3. The source of transistor Q2 is connected to the source of transistor Q3. The drain of transistor Q2 is connected to one end of capacitor C19 and one end of resistor R17. The other end of resistor R17 is connected to the anode of diode D12. The cathode of diode D12 is connected to one end of TVS diode D11. The cathode of diode D12 can output a current signal. The other end of TVS diode D11 and the other end of capacitor C19 are grounded. Relay K1 has 5 pins. The second pin of relay K1 is connected to the collector of transistor Q3. The base of transistor Q3 is connected to the third pin of detector main control chip U5. The emitter of transistor Q3 is grounded. The third, fourth, and fifth pins of relay K1 can be connected to other external electronic devices.

[0009] This utility model is further improved in that the power supply voltage adjustment circuit includes 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. 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 fourth pin of the voltage regulator chip U1 is connected to the output terminal of the common-mode inductor L1, one end of the capacitor C4, and one end of the capacitor C7. The input terminal 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 cathode of the diode D10. The anode of the diode D10 is connected to a 24V power supply. The sixth pin of the voltage regulator chip U1 is connected to the inductor L1... One end of the inductor L2 is connected to the capacitor C8, the capacitor C9, the third pin of the voltage regulator chip U2, and the first pin of the voltage regulator chip U3. The second pin of the voltage regulator chip U2 is connected to the first pin of the detector main control chip U5 for power supply. The fifth 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 ends of the TVS diode D1, the capacitor C7, the capacitor C8, and the capacitor C9 are grounded. The sensor voltage adjustment circuit contains a voltage regulator chip U4 with five pins. The third and fifth pins of the voltage regulator chip U4 are connected to the fifth pin of the voltage regulator chip U3. The fourth pin of the voltage regulator chip U4 is connected to the gas signal acquisition circuit for power supply.

[0010] This utility model is further improved by including a sensor acquisition and control chip U13 in the sensor acquisition and control circuit. The sensor acquisition and control chip U13 has 20 pins. The second pin of the sensor acquisition and control chip U13 is connected to the fifth pin of the voltage regulator chip U3. The first and second pins of the sensor acquisition and control chip U13 are connected to the sixth and fifth pins of the detector main control chip U5, respectively. The sixth and eighth pins of the sensor acquisition and control chip U13 are controlled and connected to the gas signal acquisition circuit. The fifth pin of the sensor acquisition and control chip U13 is controlled and connected to the temperature signal acquisition circuit.

[0011] This utility model is further improved by including a combustible gas detection sensor U16, resistors R8 and R9, and capacitor C4 in the gas signal acquisition circuit. The combustible gas detection sensor U16 has 8 pins. Pins 3 and 6 of the combustible gas detection sensor U16 are connected to pins 8 and 6 of the sensor acquisition control chip U13, respectively. Pin 7 of the combustible gas detection sensor U16 is connected to pin 5 of the voltage regulator chip U3. Pin 2 of the combustible gas detection sensor U16 is connected to one end of resistor R8 and one end of resistor R9. The other end of resistor R8 is connected to one end of capacitor C4 and pin 4 of voltage regulator chip U4. The other ends of resistor R9 and capacitor C4 are grounded.

[0012] This utility model is further improved by including a temperature signal acquisition chip U15 and a capacitor C12 in the temperature signal acquisition circuit. The temperature signal acquisition chip U15 has three 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 and control chip U13. The third pin of the temperature signal acquisition chip U15 and the other end of the capacitor C12 are grounded.

[0013] This utility model is further improved by including a 485 communication chip U6, a common-mode inductor L6, a TVS diode D7, and a TVS diode D9 in the 485 communication circuit. The 485 communication chip U6 has 8 pins. Pins 1, 3, and 4 of the 485 communication chip U6 are connected to pins 31, 29, and 30 of the detector main control chip U5, respectively. Pin 8 of the 485 communication chip U6 is connected to pin 2 of the voltage regulator chip U2. Pins 6 and 7 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 terminals of the TVS diodes D7 and D9. The positive terminals of the TVS diodes D7 and D9 are grounded.

[0014] This utility model is further improved by including a transistor Q4, a speaker prompt interface J6, a transistor Q5, and a light-emitting prompt interface J7 in the audio-visual prompt circuit. The base of transistor Q4 is connected to pin 11 of the detector's main control chip U5, and the collector of transistor Q4 is connected to the input of the speaker prompt interface J6. The output of the speaker prompt interface J6 can be connected to an external speaker. The emitter of transistor Q4 is grounded. The base of transistor Q5 is connected to pin 46 of the detector's main control chip U5, and the collector of transistor Q5 is connected to the input of the light-emitting prompt interface J7. The output of the light-emitting prompt interface J7 can be connected to an external LED. The emitter of transistor Q5 is grounded. The LED status display circuit includes LEDs D1, D2, D3, and D4. The positive terminals of LEDs D1, D2, D3, and D4 are connected to pin 2 of the voltage regulator chip U2. The negative terminal of LED D1 is connected to pin 16 of the detector main control chip U5. The negative terminal of LED D2 is connected to pin 15 of the detector main control chip U5. The negative terminal of LED D3 is connected to pin 14 of the detector main control chip U5. The negative terminal of LED D4 is connected to pin 28 of the detector main control chip U5.

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

[0016] Compared with the prior art, the beneficial effects of this utility model are: it provides a combustible gas detector control circuit capable of resisting electromagnetic interference. This is achieved by setting up 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 audible and visual prompt circuit, an LED status display circuit, and a digital display screen in a mutually cooperating manner. The power supply voltage adjustment circuit includes a TVS diode, a common-mode inductor, and a diode; the 485 communication circuit also includes a common-mode inductor and multiple TVS diodes; and the gas detector main control circuit also includes a TVS diode. In conjunction with diodes, TVS diodes, and common-mode inductors, the electromagnetic interference (EMI) immunity of the gas detector's main control circuit, 485 communication circuit, and power supply voltage adjustment circuit is enhanced. Through multiple electronic circuit protection measures, the EMI immunity of the combustible gas detector is significantly improved when used alone, enhancing its reliability and stability. This allows the combustible gas detector to accurately detect combustible gas concentration in real time when used independently without the alarm controller's power supply or an external power supply. It also adapts to various complex interference environments, improving the user experience and solving the problems of poor EMI immunity and susceptibility to failure in existing combustible gas detectors when used alone. Attached Figure Description

[0017] To more clearly illustrate the solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the control circuit for a combustible gas detector that is resistant to electromagnetic interference, according to the present invention.

[0019] Figure 2 This is a circuit diagram of the main control circuit of the gas detector of this utility model;

[0020] Figure 3 This is a circuit diagram of the main control circuit of the gas detector of this utility model;

[0021] Figure 4 This is a circuit diagram of the main control circuit of the gas detector of this utility model;

[0022] Figure 5 This is a circuit diagram of the main control circuit of the gas detector of this utility model;

[0023] Figure 6This is a circuit diagram of the power supply voltage adjustment circuit of this utility model;

[0024] Figure 7 This is a circuit diagram of the power supply voltage adjustment circuit of this utility model;

[0025] Figure 8 This is a circuit diagram of the sensor acquisition and control circuit of this utility model;

[0026] Figure 9 This is a circuit diagram of the gas signal acquisition circuit of this utility model;

[0027] Figure 10 This is a circuit diagram of the temperature signal acquisition circuit of this utility model;

[0028] Figure 11 This is a circuit diagram of the 485 communication circuit of this utility model;

[0029] Figure 12 This is a circuit diagram of the sound and light prompt circuit of this utility model. Detailed Implementation

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this invention are used to distinguish different objects, not to describe a particular order.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] To enable those skilled in the art to better understand 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] like Figures 1-12As shown, this utility model provides a combustible gas detector control circuit capable of resisting electromagnetic interference, including 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 audible and visual prompt circuit, an LED status display circuit, and a digital display screen. The output terminal 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 for power supply. The output terminal of the sensor voltage adjustment circuit is connected to the gas signal acquisition circuit for power supply. The output terminal of the gas detector main control circuit is connected to the input terminals of the 485 communication circuit, the audible and visual prompt circuit, the LED status display circuit, and the digital display screen for control. The gas detector main control circuit is also connected to the sensor acquisition control circuit for communication. The sensor acquisition control circuit is connected to the gas signal acquisition circuit and the temperature signal acquisition circuit for control. In this embodiment, the power supply voltage adjustment circuit includes a TVS diode, a common-mode inductor, and a diode. The 485 communication circuit also includes a common-mode inductor and multiple TVS diodes. The main control circuit of the gas detector also includes a TVS diode and a diode. The TVS diode, common-mode inductor, and diode enhance the electromagnetic interference resistance of the main control circuit, 485 communication circuit, and power supply voltage adjustment circuit of the gas detector. In other words, through multiple electronic circuit protection measures, the electromagnetic interference resistance of the combustible gas detector when used alone is significantly improved, enhancing the reliability and stability of the combustible gas detector. This allows the combustible gas detector to accurately detect the concentration of combustible gas in real time when used independently without the power supply of the alarm controller or an external power supply, and it can adapt to various complex interference environments, improving the user experience.

[0034] like Figures 2-3As shown, the main control circuit of the gas detector includes a detector main control chip U5, crystal oscillator X1, ferrite bead B1, ferrite bead B2, capacitors C14, C16, and C18. The detector main control chip U5 is an STM32F103C8T6 with 48 pins. Pin 1 of U5 is connected to the output of the power supply voltage adjustment circuit. Pins 31, 29, and 30 are connected to the input of the 485 communication circuit. Pins 11 and 46 are connected to the input of the audible and visual alert circuit. Pins 16, 15, 14, and 28 are connected to the input of the audible and visual alert circuit. The pins are connected to the input terminals of the LED status display circuit. Pins 20, 19, and 18 of the detector's main control chip U5 are connected to the input terminals of the digital display screen. Pins 5 and 6 of the detector's main control chip U5 are connected to the sensor acquisition and control circuit. Pin 5 of the detector's main control chip U5 is connected to one end of the ferrite bead B1. Pin 6 of the detector's main control chip U5 is connected to one end of the ferrite bead B2 and one end of the capacitor C18. The other end of the ferrite bead B1 is connected to one end of the capacitor C14 and one end of the crystal oscillator X1. The other end of the ferrite 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 capacitors C14, C16, and C18 are grounded. Figures 4-5As shown, the main control circuit of the gas detector also includes a current loop chip U11, a transistor Q1, a field-effect transistor Q2, a capacitor C19, a resistor R17, a diode D12, a TVS diode D11, a relay K1, and a transistor Q3. The current loop chip U11 is model XTR111 and has 10 pins. Pin 4 of the current loop chip U11 is connected to pin 4 of the detector's main control chip U5. Pin 6 of the current loop chip U11 can receive external AD digital signals. Pin 2 of the current loop chip U11 is connected to the emitter of the transistor, and pin 3 of the current loop chip U11 is connected to the collector of the transistor and the gate of the field-effect transistor Q2. The base of transistor Q2 is connected to the source of transistor Q2. The drain of transistor Q2 is connected to one end of capacitor C19 and one end of resistor R17. The other end of resistor R17 is connected to the anode of diode D12. The cathode of diode D12 is connected to one end of TVS diode D11. The cathode of diode D12 can output a current signal. The other end of TVS diode D11 and the other end of capacitor C19 are grounded. Relay K1 has 5 pins. The second pin of relay K1 is connected to the collector of transistor Q3. The base of transistor Q3 is connected to the third pin of detector main control chip U5. The emitter of transistor Q3 is grounded. The third, fourth and fifth pins of 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 acquire the concentration and temperature of combustible gas. It is also used to control the audible and visual alert circuit to issue alarm prompts, the LED status display circuit to display various statuses, and the digital display screen to display various information. Furthermore, it is used to communicate with external devices via the 485 communication circuit. Crystal oscillator X1 provides the clock frequency for the detector's main control chip U5. Capacitors C14 and C16 serve as starting capacitors, ferrite beads B1 and B2 can filter noise signals in the clock frequency signal, and capacitor C18 can bypass noise signals in the clock frequency signal. Compared to ordinary crystal oscillator circuits, this circuit structure provides higher clock frequency accuracy for the entire circuit. The current loop chip U11 controls the output of a 4mA-20mA current signal via the input AD digital signal. TVS diode D11 provides high-voltage protection, diode D12 prevents reverse current flow, resistor R17 limits current, and capacitor C19 filters the signal. This circuit structure, as a crucial module of the combustible gas detector, enables the detector to output a stable, reliable, and high-precision 4mA-20mA current. Relay K1 provides an interface for the combustible gas detector to connect to external linkage devices (fans, solenoid valves, etc.).

[0035] like Figures 6-7As shown, the power supply voltage adjustment circuit includes voltage regulator chips U1, U2, and U3, a fuse resistor F1, a diode D10, a TVS diode D1, a common-mode inductor L1, capacitors C4, L2, C7, C8, and C9. Voltage regulator chip U1 is an LM2842, U2 is an AMS1117-3V3, and U3 is a TPS76333DBV. Voltage regulator chip U1 has 6 pins, U2 has 3 pins, and U3 has 5 pins. Pin 4 of voltage regulator chip U1 is connected to the output of common-mode inductor L1, one end of capacitor C4, and one end of capacitor C7. The input of common-mode inductor L1 is connected to one end of TVS diode D1 and one end of fuse resistor F1. The other end of fuse resistor F1 is connected to the cathode of diode D10, and the anode of diode D10 is connected to 24V. The power supply consists of a voltage regulator chip U1, pin 6 of which is connected to one end of inductor L2. The other end of inductor L2 is connected to one end of capacitor C8, one end of capacitor C9, pin 3 of voltage regulator chip U2, and pin 1 of voltage regulator chip U3. Pin 2 of voltage regulator chip U2 is connected to pin 1 of the detector main control chip U5. Pin 5 of voltage regulator chip U3 is connected to the sensor voltage adjustment circuit, sensor acquisition control circuit, and temperature signal acquisition circuit. The other ends of TVS diode D1, capacitor C7, capacitor C8, and capacitor C9 are grounded. The sensor voltage adjustment circuit contains a voltage regulator chip U4, model TLV376IDBVR, with 5 pins. Pins 3 and 5 of voltage regulator chip U4 are connected to pin 5 of voltage regulator chip U3. Pin 4 of voltage regulator chip U4 is connected to the gas signal acquisition circuit. In this embodiment, the power supply voltage adjustment circuit supplies power to the temperature signal acquisition circuit, sensor voltage adjustment circuit, sensor acquisition control circuit, and gas detector main control circuit. The power supply voltage adjustment circuit consists of three sub-modules. The first sub-module, composed of voltage regulator chip U1 and peripheral circuitry, steps down the 24V DC power supply to a 6V DC power supply (V6.0 in the diagram). The second sub-module, composed of voltage regulator chip U2 and peripheral circuitry, steps down the 6V DC power supply to a 3.3V DC power supply (V3.3 in the diagram). The third sub-module, composed of voltage regulator chip U3 and peripheral circuitry, steps down the 6V DC power supply to another 3.3V DC power supply (SV3.3 in the diagram).In this circuit, diode D10 prevents reverse connection of the power supply, fuse resistor F1 provides protection against excessive current, TVS diode D1 releases transient high voltages such as surge voltages, common-mode inductor L1 suppresses common-mode / differential-mode interference signals in the current, enhancing electromagnetic interference immunity, capacitors C4 and C10 form a Y-type circuit with ground, effectively filtering out differential-mode interference signals in the current signal, voltage regulator chip U1 is a high-precision, high-stability LM2842, and capacitors C7, C8, and C9 are filter capacitors. Through these multiple layers of protection provided by these electronic components, the entire power supply voltage regulation circuit has high electromagnetic interference immunity, providing a stable and reliable power supply for subsequent circuits.

[0036] like Figure 8 As shown, the sensor acquisition and control circuit includes a sensor acquisition and control chip U13, model STM32C011F4U6TR. The sensor acquisition and control chip U13 has 20 pins. Pin 2 of the sensor acquisition and control chip U13 is connected to pin 5 of the voltage regulator chip U3. Pins 1 and 20 of the sensor acquisition and control chip U13 are connected to pins 6 and 5 of the detector main control chip U5, respectively. Pins 6 and 8 of the sensor acquisition and control chip U13 are connected to the gas signal acquisition circuit, and pin 5 of the sensor acquisition and control chip U13 is connected to the temperature signal acquisition circuit. In this embodiment, the sensor acquisition and control circuit is used to control the gas signal acquisition circuit to acquire the combustible gas concentration signal and the temperature signal acquisition circuit to acquire the temperature signal.

[0037] like Figure 9 As shown, the gas signal acquisition circuit includes a combustible gas detection sensor U16, resistors R8 and R9, and capacitor C4. The combustible gas detection sensor U16 is model INA333AIDGKR and has eight pins. Pins 3 and 6 of the combustible gas detection sensor U16 are connected to pins 8 and 6 of the sensor acquisition control chip U13, respectively. Pin 7 of the combustible gas detection sensor U16 is connected to pin 5 of the voltage regulator chip U3. Pin 2 of the combustible gas detection sensor U16 is connected to one end of resistor R8 and one end of resistor R9. The other end of resistor R8 is connected to one end of capacitor C4 and pin 4 of the voltage regulator chip U4. The other ends of resistor R9 and capacitor C4 are grounded. In this embodiment, the gas signal acquisition circuit is used to convert the concentration value signal of the detected gas into an electrical signal in real time according to the control commands of the sensor acquisition control circuit and output it to the sensor acquisition control circuit.

[0038] like Figure 10As shown, the temperature signal acquisition circuit includes a temperature signal acquisition chip U15 and a capacitor C12. The temperature signal acquisition chip U15 is a TMP235A2DBZR and has three pins. Pin 1 of the temperature signal acquisition chip U15 is connected to pin 5 of the voltage regulator chip U3 and one end of capacitor C12. Pin 2 of the temperature signal acquisition chip U15 is connected to pin 5 of the sensor acquisition and control chip U13. Pin 3 of the temperature signal acquisition chip U15 and the other end of capacitor C12 are grounded. In this embodiment, the temperature signal acquisition circuit is used to acquire the ambient temperature in real time according to the control commands of the sensor acquisition and control circuit, convert it into a digital signal, and output it to the sensor acquisition and control circuit.

[0039] like Figure 11 As shown, the 485 communication circuit includes a 485 communication chip U6, a common-mode inductor L6, a TVS diode D7, and a TVS diode D9. The 485 communication chip U6 has 8 pins and its model number is SN65HVD72. Pins 1, 3, and 4 of the 485 communication chip U6 are connected to pins 31, 29, and 30 of the detector main control chip U5, respectively. Pin 8 of the 485 communication chip U6 is connected to pin 2 of the voltage regulator chip U2. Pins 6 and 7 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 terminals of TVS diodes D7 and D9. The positive terminals of TVS diodes D7 and D9 are grounded. In this embodiment, the 485 communication chip U6 is selected as the SN65HVD72 model with strong anti-interference capability; resistors R20, R22, and R24 serve as current limiters; common-mode inductor L6 filters out interference signals; resistor R21 pulls down the communication signal; resistor R25 pulls up the communication signal; capacitors C26 and C27 serve as filters; TVS diodes D7, D8, and D9 can release 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] like Figure 12As shown, the audio-visual prompt circuit includes transistor Q4, speaker prompt interface J6, transistor Q5, and light prompt interface J7. The base of transistor Q4 is connected to pin 11 of the detector's main control chip U5, and the collector of transistor Q4 is connected to the input of speaker prompt interface J6. The output of speaker prompt interface J6 can be connected to an external speaker. The emitter of transistor Q4 is grounded. The base of transistor Q5 is connected to pin 46 of the detector's main control chip U5, and the collector of transistor Q5 is connected to the input of light prompt interface J7. The output of light prompt interface J7 can be connected to an external LED. The emitter of transistor Q5 is grounded. The ED status display circuit includes LEDs D1, D2, D3, and D4. The positive terminals of LEDs D1, D2, D3, and D4 are connected to pin 2 of the voltage regulator chip U2. The negative terminal of LED D1 is connected to pin 16 of the detector main control chip U5. The negative terminal of LED D2 is connected to pin 15 of the detector main control chip U5. The negative terminal of LED D3 is connected to pin 14 of the detector main control chip U5. The negative terminal of LED D4 is connected to pin 28 of the detector main control chip U5. In this embodiment, the audible and visual alarm circuit consists of an audible alarm submodule and a visual alarm submodule. The audible alarm submodule, composed of transistor Q4 and peripheral circuitry, provides an audible alarm for the combustible gas detector. The visual alarm submodule, composed of transistor Q5 and peripheral circuitry, provides a light source alarm for the combustible gas detector. The audible and visual alarm modules serve as warnings when the detector detects different gas concentrations. The LED status display circuit indicates the operating status of the combustible gas detector; for example, a lit red LED D1 indicates normal power supply, while a lit yellow LED D3 indicates a malfunction.

[0041] As can be seen from the above, this utility model provides a combustible gas detector control circuit capable of resisting electromagnetic interference. This is achieved by incorporating 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 audible and visual prompt circuit, an LED status display circuit, and a digital display screen. The power supply voltage adjustment circuit includes a TVS diode, a common-mode inductor, and a diode; the 485 communication circuit also includes a common-mode inductor and multiple TVS diodes; and the gas detector main control circuit also includes a TVS diode and a diode. TVS diodes, common-mode inductors, and diodes enhance the electromagnetic interference (EMI) immunity of the gas detector's main control circuit, 485 communication circuit, and power supply voltage adjustment circuit. Through multiple electronic circuit protection measures, the EMI immunity of the combustible gas detector is significantly improved when used alone, enhancing its reliability and stability. This allows the combustible gas detector to accurately detect combustible gas concentration in real time when used independently without an alarm controller or external power supply, and it can adapt to various complex interference environments, improving the user experience and solving the problems of poor EMI immunity and susceptibility to failure in existing combustible gas detectors when used alone.

[0042] The specific embodiments described above are preferred embodiments of this utility model, and are not intended to limit the specific scope of this utility model. The scope of this utility model includes but is not limited to the specific embodiments described above. All equivalent changes made in accordance with this utility model are within the protection scope of this utility model.

Claims

1. A combustible gas detector control circuit capable of resisting electromagnetic interference, characterized by: The gas detector main control circuit is internally provided with a detector main control chip U5, a crystal oscillator X1, magnetic beads B1, magnetic beads 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 with the output end of the power voltage adjusting circuit, the 31st, 29th and 30th pins of the detector main control chip U5 are connected with the input end of the 485 communication circuit, the 11th and 46th pins of the detector main control chip U5 are connected with the input end of the sound and light prompting circuit, the 16th, 15th, 14th and 28th pins of the detector main control chip U5 are connected with the input end of the LED state display circuit, the 20th, 19th and 18th pins of the detector main control chip U5 are connected with the input end of the digital display screen, the 5th and 6th pins of the detector main control chip U5 are connected with the sensor acquisition control circuit, the 5th pin of the detector main control chip U5 is connected with one end of the magnetic beads B1, the 6th pin of the detector main control chip U5 is connected with one end of the magnetic beads B2 and one end of the capacitor C18, the other end of the magnetic beads B1 is connected with one end of the capacitor C14 and one end of the crystal oscillator X1, the other end of the magnetic beads B2 is connected with one end of the capacitor C16 and the other end of the crystal oscillator X1, the other end of the capacitor C14, the other end of the capacitor C16 and the other end of the capacitor C18 are grounded.

2. The combustible gas detector control circuit capable of anti-electromagnetic interference according to claim 1, characterized in that: The gas detector main control circuit is internally provided with a detector main control chip U5, a crystal oscillator X1, magnetic beads B1, magnetic beads 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 with the output end of the power voltage adjusting circuit, the 31st, 29th and 30th pins of the detector main control chip U5 are connected with the input end of the 485 communication circuit, the 11th and 46th pins of the detector main control chip U5 are connected with the input end of the sound and light prompting circuit, the 16th, 15th, 14th and 28th pins of the detector main control chip U5 are connected with the input end of the LED state display circuit, the 20th, 19th and 18th pins of the detector main control chip U5 are connected with the input end of the digital display screen, the 5th and 6th pins of the detector main control chip U5 are connected with the sensor acquisition control circuit, the 5th pin of the detector main control chip U5 is connected with one end of the magnetic beads B1, the 6th pin of the detector main control chip U5 is connected with one end of the magnetic beads B2 and one end of the capacitor C18, the other end of the magnetic beads B1 is connected with one end of the capacitor C14 and one end of the crystal oscillator X1, the other end of the magnetic beads B2 is connected with one end of the capacitor C16 and the other end of the crystal oscillator X1, 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 anti-electromagnetic interference according to claim 2, characterized in that: The gas detector main control circuit is further 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 ten pins, the fourth pin of the current loop chip U11 is connected with the fourth pin of the detector main control chip U5, the sixth pin of the current loop chip U11 can receive external AD digital signals, the second pin of the current loop chip U11 is connected with the emitter of the transistor, the third pin of the current loop chip U11 is connected with the collector of the transistor and the gate of the field effect transistor Q2, the base of the transistor is connected with the source of the field effect transistor Q2, the drain of the field effect transistor Q2 is connected with one end of the capacitor C19 and one end of the resistor R17, the other end of the resistor R17 is connected with the anode of the diode D12, the cathode of the diode D12 is connected with one end of the TVS tube D11, the cathode of the diode D12 can output current signals, the other end of the TVS tube D11 and the other end of the capacitor C19 are grounded; the relay K1 is provided with five pins, the second pin of the relay K1 is connected with the collector of the transistor Q3, the base of the transistor Q3 is connected with the third pin of the detector main control chip U5, the emitter of the transistor Q3 is grounded, and the third, fourth and fifth pins of the relay K1 can be connected with other external electronic devices.

4. The combustible gas detector control circuit capable of anti-electromagnetic interference of claim 3, wherein: The power voltage adjusting circuit is internally provided with voltage stabilizing chip U1, voltage stabilizing chip U2, voltage stabilizing chip U3, fuse resistor F1, diode D10, TVS tube D1, common mode inductor L1, capacitor C4, inductor L2, capacitor C7, capacitor C8 and capacitor C9, wherein the voltage stabilizing chip U1 is provided with 6 pins, the voltage stabilizing chip U2 is provided with 3 pins, the voltage stabilizing chip U3 is provided with 5 pins, the fourth pin of the voltage stabilizing chip U1 is connected with 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 with 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 with the negative electrode of the diode D10, the positive electrode of the diode D10 is connected with a 24V power supply, the sixth pin of the voltage stabilizing chip U1 is connected with one end of the inductor L2, the other end of the inductor L2 is connected with 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 with the first pin of the detector main control chip U5 for power supply, the fifth pin of the voltage stabilizing chip U3 is connected with the sensor voltage adjusting 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; the sensor voltage adjusting circuit is internally provided with voltage stabilizing chip U4, the voltage stabilizing chip U4 is provided with 5 pins, the third and fifth pins of the voltage stabilizing chip U4 are connected with the fifth pin of the voltage stabilizing chip U3, the fourth pin of the voltage stabilizing chip U4 is connected with the gas signal acquisition circuit for power supply.

5. The combustible gas detector control circuit capable of anti-electromagnetic interference of claim 4, wherein: The sensor acquisition control circuit is internally provided with sensor acquisition control chip U13, the sensor acquisition control chip U13 is provided with 20 pins, the second pin of the sensor acquisition control chip U13 is connected with the fifth pin of the voltage stabilizing chip U3, the first and twentieth pins of the sensor acquisition control chip U13 are respectively connected with 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 with the gas signal acquisition circuit for control, the fifth pin of the sensor acquisition control chip U13 is connected with the temperature signal acquisition circuit for control.

6. The combustible gas detector control circuit capable of anti-electromagnetic interference of claim 5, wherein: The gas signal acquisition circuit is internally 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 connected with the 8th and 6th pins of the sensor acquisition control chip U13 respectively, the 7th pin of the combustible gas detection sensor U16 is connected with the 5th pin of the voltage stabilizing chip U3, the 2nd pin of the combustible gas detection sensor U16 is connected with one end of the resistor R8 and one end of the resistor R9, the other end of the resistor R8 is connected with 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 anti-electromagnetic interference according to claim 6, characterized in that: The temperature signal acquisition circuit is internally provided with a temperature signal acquisition chip U15 and a capacitor C12, the temperature signal acquisition chip U15 is provided with 3 pins, the 1st pin of the temperature signal acquisition chip U15 is connected with the 5th pin of the voltage stabilizing chip U3 and one end of the capacitor C12, the 2nd pin of the temperature signal acquisition chip U15 is connected with 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.

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

9. The combustible gas detector control circuit capable of anti-electromagnetic interference of claim 8, wherein: The sound light prompt circuit is internally provided with a triode Q4, a loudspeaker prompt interface J6, a triode Q5 and a light emitting prompt interface J7, wherein the base of the triode Q4 is connected with the 11th pin of the detector main control chip U5, the collector of the triode Q4 is connected with the input end of the loudspeaker prompt interface J6, the output end of the loudspeaker prompt interface J6 can be connected with an external loudspeaker, the emitter of the triode Q4 is grounded, the base of the triode Q5 is connected with the 46th pin of the detector main control chip U5, the collector of the triode Q5 is connected with the input end of the light emitting prompt interface J7, the output end of the light emitting prompt interface J7 can be connected with an external light emitting LED lamp, and the emitter of the triode Q5 is grounded; the LED state display circuit is internally provided with light emitting diodes D1, D2, D3 and D4, wherein the anode of the light emitting diode D1, the anode of the light emitting diode D2, the anode of the light emitting diode D3 and the anode of the light emitting diode D4 are connected with the 2nd pin of the voltage stabilizing chip U2, the cathode of the light emitting diode D1 is connected with the 16th pin of the detector main control chip U5, the cathode of the light emitting diode D2 is connected with the 15th pin of the detector main control chip U5, the cathode of the light emitting diode D3 is connected with the 14th pin of the detector main control chip U5, and the cathode of the light emitting diode D4 is connected with the 28th pin of the detector main control chip U5.

10. The combustible gas detector control circuit capable of anti-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 stabilizing chip U1 is LM2842, the model of the voltage stabilizing chip U2 is AMS1117-3V3, the model of the voltage stabilizing chip U3 is TPS76333DBV, the model of the voltage stabilizing 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.

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