Sensor unit sampling circuit for gas detector and gas detector

Abstract

The utility model discloses a sensor unit sampling circuit for a gas detector, which comprises a CPU (central processing unit) control unit, a sensor unit, a storage unit, a serial port communication unit, a power supply and a key display control unit, the input end of the CPU control unit is connected with the power supply, the input end of the CPU control unit is connected with the output end of the sensor unit, and the input end of the storage unit is connected with the input end of the serial port communication unit. The CPU control unit is respectively and interactively connected with the key display control unit, the serial port communication unit and the storage unit, so that efficient, accurate and stable signal acquisition, processing, storage, transmission and control functions of the gas detector are realized, and the actual requirements of gas detection are met.

Description

Technical Field

[0001] This utility model relates to the field of sampling circuit technology, and in particular to a sensor unit sampling circuit and a gas detector for a gas detector. Background Technology

[0002] A gas detector is an instrument for detecting gas concentrations. It is 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. It is widely used in various industries such as gas, petrochemicals, metallurgy, steel, coking, and power generation, where flammable or toxic gases are present, making it an ideal monitoring instrument for ensuring property and personal safety.

[0003] When gas detectors are used in the field, changes in ambient temperature and the aging of sensors and other electronic components can affect the accuracy and reliability of the detectors. Therefore, a sensor unit sampling circuit for gas detectors is needed to realize the efficient, accurate, and stable signal acquisition, processing, storage, transmission, and control functions of gas detectors to meet the actual needs of gas detection. Utility Model Content

[0004] The purpose of this invention is to provide a sampling circuit for a sensor unit of a gas detector, enabling efficient, accurate, and stable signal acquisition, processing, storage, transmission, and control functions to meet the actual needs of gas detection.

[0005] This utility model provides a sampling circuit for a sensor unit of a gas detector, including a CPU control unit, a sensor unit, a storage unit, a serial communication unit, a power supply and a key display control unit. The input terminal of the CPU control unit is connected to the power supply, and the input terminal of the CPU control unit is connected to the output terminal of the sensor unit. The CPU control unit is interactively connected to the key display control unit, the serial communication unit and the storage unit respectively.

[0006] Preferably, the CPU control unit includes an MCU microcontroller unit U1. One side of the first port of the MCU microcontroller unit U1 is connected to a power supply via resistor R3. The other side of the first port of the MCU microcontroller unit U1 is connected to a capacitor C3 and grounded. The fourth port of the MCU microcontroller unit U1 is grounded. The fifth port of the MCU microcontroller unit U1 is connected to capacitors C4 and C5 connected in parallel and grounded. The sixth port of the MCU microcontroller unit U1 is connected to capacitor C6 and grounded. The twelfth port of the MCU microcontroller unit U1 is connected to a resistor R18 and grounded. The thirteenth port of the MCU microcontroller unit U1 is connected to the SI sensor unit signal. The sixteenth port of the MCU microcontroller unit U1 is connected to the TX1 serial port signal. The seventeenth port of the MCU microcontroller unit U1 is connected to the RX1 serial port signal. The nineteenth port of the MCU microcontroller unit U1 is connected to a resistor R8 for the SDA signal. The twentieth port of the MCU microcontroller unit U1 is connected to a resistor R6 for the SCL signal.

[0007] Preferably, the nineteenth and twentieth ports of the MCU microcontroller U1 are connected to resistors R2 and R1 respectively and connected to the power supply. Resistor R8 and the SDA signal, and resistor R6 and the SCL signal are connected to capacitors C2 and C1 respectively and grounded.

[0008] Preferably, the sensor unit includes several operational amplifiers, several resistors, and several capacitors. One side of the non-inverting input terminal of operational amplifier A2B is connected to a power supply via resistor R2, and the other side of the non-inverting input terminal of operational amplifier A2B is connected to a resistor R3 and grounded. The inverting input terminal and the output terminal of operational amplifier A2B are connected to the non-inverting input terminal of operational amplifier A1B via resistor R4. The inverting input terminal of operational amplifier A1B is connected to the output terminal of operational amplifier A2A. One output terminal of operational amplifier A1B is connected to the output terminal of operational amplifier A2A via resistors R8, R10, and R11 connected in series. The other output terminal of operational amplifier A1B is connected to the inverting input terminal of operational amplifier A1A via resistor R5. The non-inverting input terminal of operational amplifier A1A is connected to the output terminal of operational amplifier A2A and grounded. The output terminal of operational amplifier A1A is connected to the output terminal of operational amplifier A1B via resistor R1.

[0009] Preferably, the inverting input of operational amplifier A2A is connected to the output of operational amplifier A1B, the non-inverting input of operational amplifier A2A is connected to the corresponding socket via resistor R14, the first port of socket SJD1 is connected to resistor R15 and capacitor C13 and grounded, the second port of socket SJD1 is connected to capacitor C11 and connected to the non-inverting input of operational amplifier A2A via the first port of socket SJC1, and the second port of socket SJC1 is connected to the power supply and connected to capacitor C14 and grounded.

[0010] Preferably, a test point VR1 is provided between the non-inverting input terminal of the operational amplifier A2B and the resistor.

[0011] Preferably, the operational amplifier A1A has a test point SI1 on its output terminal.

[0012] Preferably, the MCU microcontroller unit U1 is an STM32G030.

[0013] This invention also provides a gas detector, including the aforementioned sensor unit sampling circuit for a gas detector.

[0014] Because of the adoption of the above technical solution, this utility model has the following advantages and positive effects compared with the prior art:

[0015] The sampling circuit of the sensor unit for a gas detector provided by this utility model collects environmental parameters such as gas concentration through the sensor unit. After processing by circuits such as operational amplifiers, the data is converted into signals that can be recognized by the CPU control unit. The collected data is processed by the CPU control unit, stored in the storage unit, and transmitted to other devices or control systems via a serial communication unit. The CPU control unit is responsible for the operation control of the entire sampling circuit. Simultaneously, user interaction is achieved through the button display control unit, such as setting parameters and viewing data. By optimizing the circuit design, the detection accuracy and stability of the gas detector are improved, ensuring accurate detection of gas concentration under various environmental conditions. Attached Figure Description

[0016] Figure 1 This is a block diagram of the sampling circuit principle of the sensor unit for a gas detector in an embodiment of this utility model;

[0017] Figure 2 This is an internal circuit diagram of the CPU control unit in an embodiment of the present invention;

[0018] Figure 3This is an internal circuit diagram of the sensor unit in an embodiment of the present invention. Detailed Implementation

[0019] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the vehicle logo switching device and control method proposed in this utility model. The advantages and features of this utility model will become clearer from the following description and claims.

[0020] like Figure 1 As shown, this utility model provides a sampling circuit for a sensor unit of a gas detector, including a CPU control unit, a sensor unit, a storage unit, a serial communication unit, a power supply, and a keypad display control unit. The input terminal of the CPU control unit is connected to the power supply, and the input terminal of the CPU control unit is connected to the output terminal of the sensor unit. The CPU control unit is interactively connected to the keypad display control unit, the serial communication unit, and the storage unit. This solution improves system integration, reduces size and weight, and facilitates installation and use by integrating the CPU control unit, sensor unit, storage unit, serial communication unit, power supply, and keypad display control unit into a single circuit. The circuit design considers power supply stability and signal processing, such as using capacitor filtering and resistor voltage division, ensuring stable operation even in complex environments.

[0021] like Figure 2As shown, the CPU control unit includes an MCU microcontroller unit U1. One side of the first port of the MCU microcontroller unit U1 is connected to a power supply via resistor R3. The other side of the first port of the MCU microcontroller unit U1 is connected to a capacitor C3 and grounded. The fourth port of the MCU microcontroller unit U1 is grounded. The fifth port of the MCU microcontroller unit U1 is connected to capacitors C4 and C5 connected in parallel and grounded. The sixth port of the MCU microcontroller unit U1 is connected to capacitor C6 and grounded. The twelfth port of the MCU microcontroller unit U1 is connected to a resistor R18 and grounded. The thirteenth port of the MCU microcontroller unit U1 is connected to the SI sensor unit signal. The sixteenth port of the MCU microcontroller unit U1 is connected to the TX1 serial port signal. The seventeenth port of the MCU microcontroller unit U1 is connected to the RX1 serial port signal. The nineteenth port of the MCU microcontroller unit U1 is connected to a resistor R8 for the SDA signal. The twentieth port of the MCU microcontroller unit U1 is connected to a resistor R6 for the SCL signal. The MCU microcontroller unit U1 is an STM32G030. By connecting the first port of the MCU to the power supply via resistor R3 and grounding it via capacitor C3, power supply decoupling and filtering are achieved, reducing power supply noise and ensuring stable power supply to the MCU. Grounding the fourth port and grounding the fifth port via parallel capacitors C4 and C5 further helps to reduce noise interference and improve the circuit's anti-interference capability. The sixth port is connected to capacitor C6 and grounded, typically used for clock circuit stability, ensuring the stability of the MCU's internal clock, which is crucial for accurate data sampling and signal processing. The twelfth port is grounded via resistor R18, possibly for filtering analog signals or protecting the MCU from electrostatic discharge (ESD) damage. The thirteenth port is connected to the SI sensor unit signal, enabling the MCU to directly receive and process sensor signals, improving the efficiency and accuracy of signal processing. The sixteenth port is connected to the TX1 serial port signal, and the seventeenth port is connected to the RX1 serial port signal, providing the ability to communicate with external devices, facilitating data transmission and remote control. The nineteenth port is connected to the SDA signal, and the twentieth port is connected to the SCL signal. Through resistors R8 and R6, an I2C communication interface is provided for the MCU, which can connect to other I2C devices, such as EEPROM memory or sensors, expanding the detector's functionality. Through the above circuit connection, not only is the overall performance of the gas detector improved, but its stability and reliability in complex environments are also ensured.

[0022] Specifically, the nineteenth and twentieth ports of the MCU microcontroller U1 are connected to resistors R2 and R1 respectively and connected to the power supply. Resistor R8 and the SDA signal, and resistor R6 and the SCL signal are connected to capacitors C2 and C1 respectively and grounded. Resistors R2 and R1 act as pull-up resistors to ensure that the I2C bus (SDA and SCL lines) remains at a high level when idle. Pull-up resistors help improve signal integrity, reduce signal attenuation during transmission, and ensure stable signal transmission.

[0023] like Figure 3As shown, the sensor unit includes several operational amplifiers, several resistors, and several capacitors. One side of the non-inverting input of operational amplifier A2B is connected to a power supply via resistor R2. The other side of the non-inverting input of operational amplifier A2B is connected to a ground via resistor R3. The inverting input and output of operational amplifier A2B are connected to the non-inverting input of operational amplifier A1B via resistor R4. The inverting input of operational amplifier A1B is connected to the output of operational amplifier A2A. One output of operational amplifier A1B is connected to the output of operational amplifier A2A via resistors R8, R10, and R11 (connected in series). The other output of operational amplifier A1B is connected to the inverting input of operational amplifier A1A via resistor R5. The non-inverting input of operational amplifier A1A is connected to the output of operational amplifier A2A and grounded. The output of operational amplifier A1A is connected to the output of operational amplifier A1B via resistor R1. This circuit uses a cascaded configuration of multiple operational amplifiers (such as operational amplifiers A1B, A2B, etc.). This multi-stage amplification structure can progressively amplify the weak signals output by the sensor. For example, the weak electrical signal caused by a change in gas concentration detected by the sensor is initially amplified by the first-stage operational amplifier (such as A2B) and then transmitted to a subsequent operational amplifier (such as A1B) for further amplification. In this way, even very weak gas concentration change signals can be effectively captured and amplified, thereby improving the detection sensitivity of gas concentration changes. A feedback resistor (such as R4) is cleverly incorporated into the operational amplifier circuit design. Taking operational amplifier A2B as an example, its inverting input and output are connected through resistor R4. This feedback method allows for precise control of the amplification factor. By appropriately adjusting the value of the feedback resistor, the amplification factor can be adjusted to the optimal state according to the specific sensor characteristics and detection requirements, ensuring that the sensor output signal is amplified with the most suitable amplitude, further improving the sensitivity of gas concentration detection. The non-inverting input of operational amplifier A2B is connected to the power supply through resistor R2 and grounded through resistor R3. This design provides a stable bias voltage for the operational amplifier. A stable bias voltage helps maintain the operational amplifier within its normal linear range, reducing signal distortion caused by bias instability. For example, under conditions of changing ambient temperature or component aging, a stable bias ensures that the operational amplifier can still accurately amplify the sensor signal, thereby enhancing signal stability. As seen at the output of operational amplifier A1B, one path is connected to the output of operational amplifier A2A via resistors R8, R10, and R11 (connected in series), while the other path is connected to the inverting input of operational amplifier A1A via resistor R5. This multi-channel signal transmission method allows signals from different paths to complement and integrate each other.When the gas concentration changes, the signals from different paths can be quickly adjusted and combined according to the actual situation, enabling the circuit to better adapt to the dynamic changes in gas concentration, thereby improving the overall dynamic response characteristics.

[0024] Specifically, the inverting input of operational amplifier A2A is connected to the output of operational amplifier A1B. The non-inverting input of operational amplifier A2A is connected to the corresponding socket via resistor R14. The first port of socket SJD1 is connected to resistor R15 and capacitor C13 and grounded. The second port of socket SJD1 is connected to capacitor C11 and connected to the non-inverting input of operational amplifier A2A via the first port of socket SJC1. The second port of socket SJC1 is connected to the power supply and to capacitor C14 and grounded. The non-inverting input of operational amplifier A2A is connected to the corresponding socket via resistor R14. This design allows for flexible adjustment of the input signal of operational amplifier A2A by changing the connection method of the socket or adjusting the value of resistor R14. The first port of socket SJD1 is connected to resistor R15 and capacitor C13 and grounded. The second port of socket SJD1 is connected to capacitor C11 and connected to the non-inverting input of operational amplifier A2A via the first port of socket SJC1. The second port of socket SJC1 is connected to the power supply and to capacitor C14 and grounded. This design, where multiple components (resistors, capacitors, and power supply) are connected to the operational amplifier input via sockets, allows for precise control of the DC bias and AC coupling characteristics of the input signal. By appropriately selecting the values ​​of capacitors and resistors, the input signal can be properly filtered and biased before entering the operational amplifier, thus better adapting to different signal processing needs. The application of multiple capacitors (such as C11, C13, C14, etc.) in the circuit constitutes a complex capacitor filtering network. These capacitors work in conjunction with resistors and the operational amplifier to selectively pass or attenuate signals of different frequencies. The connection of socket SJC1 to the power supply and capacitor C14 may be used for frequency compensation. By appropriately selecting the value of capacitor C14, the frequency response of operational amplifier A2A can be corrected, ensuring good gain flatness and phase linearity within its operating frequency range. This is crucial for accurately detecting changes in electrical signals caused by variations in gas concentration, as poor frequency response characteristics can lead to signal distortion and affect the accuracy of the detection results.

[0025] Specifically, a test point VR1 is provided between the non-inverting input terminal of the operational amplifier A2B and the resistor. During circuit debugging, test point VR1 allows users to conveniently monitor the signal at the non-inverting input terminal of operational amplifier A2B in real time using tools such as oscilloscopes and multimeters. This is very helpful for checking whether the signal is transmitted normally, whether it reaches the expected level, and whether there is noise or interference. For example, if an abnormal signal level is found, the preceding circuit (such as the sensor interface circuit or the signal preprocessing circuit) can be adjusted in time to correct the problem. When a circuit fault occurs, test point VR1 can be used to quickly determine whether the problem is in the circuit section before the non-inverting input terminal of operational amplifier A2B. If the signal at test point VR1 is normal, but the operational amplifier output is abnormal, it can be preliminarily determined that the problem may be in the operational amplifier itself or its subsequent circuits; conversely, if the signal at test point VR1 is abnormal, the focus can be on checking the preceding signal path, thereby speeding up fault location and improving repair efficiency. By comparing the actual measured value and the theoretical calculated value at test point VR1, the performance indicators of the circuit can be evaluated to determine whether they meet the design requirements. For example, according to the circuit design, when the non-inverting input of operational amplifier A2B receives a sensor signal corresponding to a certain gas concentration, there should be a specific voltage range. If the voltage measured at test point VR1 is within this range and is stable, it indicates that the circuit performs well in the signal transmission and amplification process and can meet the requirements for gas concentration detection accuracy.

[0026] Specifically, the operational amplifier A1A has a test point SI1 at its output terminal. Test point SI1 directly acquires the output signal of operational amplifier A1A, enabling real-time monitoring of parameters such as waveform, amplitude, and frequency. For example, in a gas concentration detection circuit, observing the signal at test point SI1 allows analysis of whether the electrical signal processed by operational amplifier A1A meets expectations. If the output signal exhibits waveform distortion, abnormal amplitude, or frequency deviation, circuit parameters can be adjusted promptly, or circuit faults can be checked. Test point SI1 also serves as a crucial reference point for system calibration. During system initialization or periodic calibration, the output signal at test point SI1 is measured and compared with a known standard input signal to calculate parameters such as circuit gain and offset. For gas detection equipment, accurate system calibration is crucial for ensuring accurate detection results. Data acquired through test point SI1 provides a benchmark for subsequent data processing and analysis, guaranteeing detection accuracy. When a circuit malfunctions, test point SI1 helps to quickly determine whether the problem lies in the operational amplifier A1A itself or in the circuit preceding it. If the output signal of test point SI1 is normal, but the subsequent circuit (such as the circuit connected to other operational amplifiers or data acquisition modules) has a problem, then it can be preliminarily judged that the fault may be in the later part. Conversely, if the signal of test point SI1 is abnormal, you can focus on checking the circuit components related to operational amplifier A1A (such as input signal source, feedback network, etc.), thereby narrowing down the scope of fault investigation and speeding up the fault location.

[0027] This utility model also provides a gas detector, including a sensor unit sampling circuit for a gas detector as described in the above embodiments, which will not be repeated here.

[0028] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A sampling circuit for a sensor unit of a gas detector, characterized in that, It includes a CPU control unit, a sensor unit, a storage unit, a serial communication unit, a power supply and a key display control unit. The input terminal of the CPU control unit is connected to the power supply, and the input terminal of the CPU control unit is connected to the output terminal of the sensor unit. The CPU control unit is interactively connected to the key display control unit, the serial communication unit and the storage unit respectively. The CPU control unit includes an MCU microcontroller unit U1. One side of the first port of the MCU microcontroller unit U1 is connected to a power supply via resistor R3. The other side of the first port of the MCU microcontroller unit U1 is connected to a capacitor C3 and grounded. The fourth port of the MCU microcontroller unit U1 is grounded. The fifth port of the MCU microcontroller unit U1 is connected to capacitors C4 and C5 connected in parallel and grounded. The sixth port of the MCU microcontroller unit U1 is connected to a capacitor C6 and grounded. The twelfth port of the MCU microcontroller unit U1 is connected to a resistor R18 and grounded. The thirteenth port of the MCU microcontroller unit U1 is connected to the SI sensor unit signal. The sixteenth port of the MCU microcontroller unit U1 is connected to the TX1 serial port signal. The seventeenth port of the MCU microcontroller unit U1 is connected to the RX1 serial port signal. The nineteenth port of the MCU microcontroller unit U1 is connected to a resistor R8 for the SDA signal. The twentieth port of the MCU microcontroller unit U1 is connected to a resistor R6 for the SCL signal. The sensor unit includes several operational amplifiers, several resistors, and several capacitors. One side of the non-inverting input of operational amplifier A2B is connected to a power supply via resistor R2. The other side of the non-inverting input of operational amplifier A2B is connected to a resistor R3 and grounded. The inverting input and output of operational amplifier A2B are connected to the non-inverting input of operational amplifier A1B via resistor R4. The inverting input of operational amplifier A1B is connected to the output of operational amplifier A2A. One output of operational amplifier A1B is connected to the output of operational amplifier A2A via resistors R8, R10, and R11 connected in series. The other output of operational amplifier A1B is connected to the inverting input of operational amplifier A1A via resistor R5. The non-inverting input of operational amplifier A1A is connected to the output of operational amplifier A2A and grounded. The output of operational amplifier A1A is connected to the output of operational amplifier A1B via resistor R1.

2. The sensor unit sampling circuit for a gas detector as described in claim 1, characterized in that, The nineteenth and twentieth ports of the MCU microcontroller U1 are connected to resistors R2 and R1 respectively and connected to the power supply. Resistor R8 and the SDA signal, and resistor R6 and the SCL signal are connected to capacitors C2 and C1 respectively and grounded.

3. The sensor unit sampling circuit for a gas detector as described in claim 1, characterized in that, The inverting input of operational amplifier A2A is connected to the output of operational amplifier A1B. The non-inverting input of operational amplifier A2A is connected to the corresponding socket via resistor R14. The first port of socket SJD1 is connected to resistor R15 and capacitor C13 and grounded. The second port of socket SJD1 is connected to capacitor C11 and connected to the non-inverting input of operational amplifier A2A via the first port of socket SJC1. The second port of socket SJC1 is connected to the power supply and connected to capacitor C14 and grounded.

4. The sensor unit sampling circuit for a gas detector as described in claim 1, characterized in that, A test point VR1 is provided between the non-inverting input terminal of the operational amplifier A2B and the resistor.

5. The sensor unit sampling circuit for a gas detector as described in claim 1, characterized in that, The operational amplifier A1A has a test point SI1 at its output terminal.

6. The sensor unit sampling circuit for a gas detector as described in claim 1, characterized in that, The MCU microcontroller unit U1 is model STM32G030.

7. A gas detector, characterized in that, Includes a sensor unit sampling circuit for a gas detector as described in any one of claims 1 to 6.

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