A modular flame detection module based on pyroelectric principle

Abstract

The utility model provides a kind of modularization flame detection module based on pyroelectric principle, to solve the technical problems that existing flame detector cannot modularization design, structure is more complex, production and after-sales debugging are complicated.The utility model includes circuit board, and single-chip microcontroller, external output interface and at least two sensors are equipped on circuit board, and at least two sensors are connected with single-chip microcontroller respectively through a signal processing circuit, and external output interface is connected with single-chip microcontroller.The utility model modularization design and concentrate in a small size circuit board to the core circuit, separate component modularization, facilitate production test, save a lot of time for the production of complete machine, improve production efficiency;Modularization design makes production process more standardized and flow, reduces uncertainty and complexity in production;Shorten production cycle, improve efficiency, also save a lot of time for the research and development of complete machine;With specific function and interface, different specifications of product can be built.

Description

Technical Field

[0001] This utility model relates to the technical field of flame detection, and in particular to a modular flame detection module based on the principle of pyroelectricity. Background Technology

[0002] In recent years, with increasingly stringent safety requirements, the demand for flame detection products has increased significantly. Application scenarios mainly include aerospace, chemical, highway tunnels, paint factories, oil and petrochemical plants, pharmaceutical factories, power plants, warehouses, and other similar locations.

[0003] Existing industrial solutions often feature complex structural designs and high product costs. They typically include pyroelectric sensors, operational amplifiers, power supply circuits, MCUs, 4-20mA circuits, and relay circuits. Due to the complexity of the circuit design, actual production is challenging, requiring testing of each module, which is tedious and inefficient, resulting in high production and after-sales maintenance costs.

[0004] When a burning substance is burning, it radiates energy to the outside world, mainly concentrated in the ultraviolet and mid-infrared. Another important characteristic is the scintillation effect, the frequency of which is affected by the surrounding environment such as airflow, but is basically within a certain range. The infrared radiation spectrum emitted by the heated object is different from the radiation spectrum emitted by the flame. Through these two important characteristics, it is possible to distinguish between a real and effective flame and a source of interference.

[0005] The combustion of hydrocarbons exhibits specific spectral characteristics, releasing energy across ultraviolet, visible, and infrared light, but primarily concentrated in the mid-infrared band, with varying energies across different bands. (See...) Figure 1 As shown, the radiation spectra of the combustion flames of ethanol, wood, candles, and methane are fundamentally similar. CO2 produced during the combustion of hydrocarbons releases infrared radiation at high temperatures, with a central wavelength of 4.35 μm. Flame radiation includes radiation from ultraviolet to infrared light; the infrared band radiation energy is significantly stronger than the ultraviolet band, hence the burning sensation of the flame. Infrared flame detectors use two single-channel sensors. The signals received by the two sensors convert the infrared energy of different wavelengths into different electrical signals. Because the received signal from the sensitive element is very weak, the sensor internally uses a junction field-effect transistor (JFET) for impedance matching to output the signal. The signal is then amplified by the bandpass filter circuit of the operational amplifier. After the MCU acquires the signal from the infrared sensor, it combines the corresponding data characteristics to determine the occurrence of a fire and issue a fire alarm signal. Most existing infrared flame detectors are discrete components, lacking modularity, making production, debugging, and after-sales service cumbersome and inefficient.

[0006] Patent application number 202410029607.6 discloses a dual-infrared channel flame detector and flame identification method, relating to the field of flame detection technology. The detector includes a main body and a detection system controlling its operation. The detection system includes an infrared module composed of two sets of infrared photoelectric sensors. Each set of infrared photoelectric sensors includes an infrared transmitter and an infrared receiver, with two narrowband filter elements of different wavelengths (3.8 and 4.3) positioned below it. The two infrared transmitters emit infrared signals outwards through two different alternating narrowband filters below them. The two infrared receivers are used to detect changes in light intensity. This invention performs two calculations on the two sets of light signals and compares the results to determine whether a fire has occurred, thereby reducing the false alarms and reliability issues that single-channel infrared photoelectric sensors may cause during flame detection. However, the aforementioned patent has a complex structure and calculation method, cannot be modularly designed, and is cumbersome to produce and debug. Utility Model Content

[0007] To address the technical problems of existing flame detectors, such as their inability to be modularized, their complex structure, and the cumbersome production and after-sales debugging, this utility model proposes a modular flame detection module based on the pyroelectric principle. Following the modular design concept, the core circuitry of the flame detector is concentrated on a small circuit board, possessing specific functions and interfaces, allowing for the construction of products of different specifications.

[0008] To achieve the above objectives, the technical solution of this utility model is as follows: a modular flame detection module based on the pyroelectric principle, including a circuit board, on which a microcontroller, an external output interface and at least two sensors are provided. The at least two sensors are respectively connected to the microcontroller through a signal processing circuit, and the external output interface is connected to the microcontroller.

[0009] Preferably, the external output interface includes a power interface, a serial port output interface, and other signal interfaces. The power interface is connected to the microcontroller, the signal processing circuit, and at least two sensors respectively through an LDO power supply circuit. The serial port output interface and other signal interfaces are all connected to the microcontroller, and the serial port output interface and other signal interfaces are respectively connected to external interfaces.

[0010] Preferably, the power interface, serial port output interface and other signal interfaces are located on one side of the circuit board, while the microcontroller and sensor are located on the other side of the circuit board.

[0011] Preferably, the circuit board is further provided with an LED indicator circuit, which is connected to the microcontroller.

[0012] Preferably, the sensor includes a first sensor and a second sensor, wherein the first sensor is a 4.4μm channel sensor as a detection channel, and the second sensor is a 5.0μm channel sensor as a reference channel.

[0013] Preferably, the other signal interface outputs at least one of the following: IIC signal, high / low level signal, alarm signal, fault signal, or PWM signal output by the microcontroller.

[0014] Preferably, the LDO power supply circuit includes a power chip. The input terminal of the power chip is connected to one end of capacitor C37 and the negative terminal of diode D1, respectively. The other end of capacitor C37 is grounded. The positive terminal of diode D1 is connected to a 5V power supply through a power interface. The ground terminal of the power chip is grounded. The output terminal of the power chip outputs VCC voltage. The output terminal of the power chip is grounded through capacitors C33 and C34, respectively. The output VCC voltage is connected to the power input terminal of each sensor, the power input terminal of the microcontroller, the power input terminal of the signal processing circuit, and the power input terminal of the LED indicator circuit.

[0015] Preferably, the power input terminal of the sensor is grounded through capacitor I, and the output terminal of the sensor is grounded through capacitor II; the signal processing circuit includes a non-inverting amplifier circuit and a voltage follower, the input terminal of the non-inverting amplifier circuit is connected to the output terminal of the sensor, the output terminal of the non-inverting amplifier circuit is connected to the voltage follower through the first capacitor, and the output terminal of the voltage follower is connected to the microcontroller.

[0016] Preferably, the non-inverting amplifier circuit includes a first operational amplifier. The non-inverting input of the first operational amplifier is connected to the output of the sensor through a first resistor. The inverting input of the first operational amplifier is connected to one end of a second resistor and a third resistor, respectively. The other end of the second resistor is grounded. The other end of the third resistor is connected to the output of the first operational amplifier. The power input of the first operational amplifier is connected to the VCC voltage, which is grounded through capacitor III. The output of the first operational amplifier is connected to the input of a voltage follower through a second capacitor. The voltage follower includes a second operational amplifier. The non-inverting input of the second operational amplifier is connected to one end of a fourth resistor. The other end of the fourth resistor is connected to one end of a second capacitor and a fifth resistor, respectively. The other end of the fifth resistor is connected to the VCC / 2 voltage. The inverting input of the second operational amplifier is connected to its output. The output of the second operational amplifier is connected to one end of a sixth resistor and a seventh resistor, respectively. The other end of the sixth resistor is the output terminal and is connected to a pin of the microcontroller through a resistor. The other end of the seventh resistor is grounded.

[0017] Preferably, both the output terminal of the first operational amplifier and the microcontroller are provided with reserved test points; the PB7 pin of the microcontroller is connected to the RX input terminal of the serial port output interface through an eighth resistor, and the PB6 pin of the microcontroller is connected to the TX input terminal of the serial port output interface through a ninth resistor; the PB0, PB1, and PB2 pins of the microcontroller are respectively connected to the input terminals of other signal interfaces through a tenth resistor. The VCC / 2 voltage is connected to the VCC voltage through a voltage divider circuit; The LED indicator circuit includes a red LED and a green LED connected in parallel. One end of each LED is connected to the output of the LDO power supply circuit. The other end of the red LED is connected to the PA8 pin of the microcontroller through the eleventh resistor, and the other end of the green LED is connected to the PA9 pin of the microcontroller.

[0018] Compared with existing technologies, the beneficial effects of this utility model are as follows: Modularizing the core circuit and concentrating it on a single circuit board, and modularizing separate components, facilitates production testing, saves significant time in the production of the entire machine, and improves production efficiency. Simultaneously, the modular design also saves considerable time in the research and development of the entire machine, requiring only simple peripheral circuitry. It can also solve the problem for users with insufficient R&D capabilities, enabling rapid transition from sensor to product, saving significant time and effort. Modular products can leverage their low-cost advantage to enter other industries. This utility model offers controllability throughout the entire process from R&D to production and after-sales service. The utility model provides a comprehensive range of output signals, giving downstream customers more choices, including serial ports, high / low levels, and IIC, offering better compatibility and wider adaptability. The design includes a reserved upgrade function, allowing firmware upgrades via serial port commands, making after-sales maintenance more convenient and efficient. It has the following advantages: Cost: Modular design enables large-scale production and standardized manufacturing, reducing production costs; the reusability of modules reduces redundant investment in design and development, while also increasing the scale of raw material procurement and reducing procurement costs.

[0019] Production efficiency: Modular design makes the production process more standardized and streamlined, reducing uncertainty and complexity in production; shortening the production cycle and improving efficiency.

[0020] Product quality: Individual testing and intelligent control ensure compliance with standards. Quality issues are easier to locate and resolve, reducing the overall product defect rate and improving product quality, stability, and reliability.

[0021] Market: Quickly cooperate with customers to launch new products, meet different market demands and customer-customized products, and rapidly launch new products to improve product adaptability and competitiveness. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of 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 only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The image shows a comparison of flame spectra, where (a) represents ethanol, (b) represents wood, (c) represents a candle, and (d) represents methane.

[0024] Figure 2 This is a schematic diagram of the structure of this utility model.

[0025] Figure 3 This is a schematic diagram of the principle of this utility model.

[0026] Figure 4 This is the circuit diagram of the LDO power supply circuit of this utility model.

[0027] Figure 5 This is a circuit diagram of the signal processing circuit of this utility model.

[0028] Figure 6 This is the circuit diagram of the microcontroller of this utility model.

[0029] Figure 7 This is a circuit diagram of the LED indicator circuit of this utility model.

[0030] Figure 8 The circuit diagram shows the external output interface of this utility model, where (a) is the power interface, (b) is the serial port output interface, and (c) is other signal interfaces.

[0031] Figure 9 for Figure 5 The circuit diagram of voltage in the signal processing circuit.

[0032] In the diagram, 1 is the circuit board, 2 is the first sensor, 3 is the second sensor, 4 is the power interface, 5 is the serial output interface, 6 is other signal interfaces, and 7 is the microcontroller. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] like Figure 2 and Figure 3 As shown, a modular flame detection module based on the pyroelectric principle includes a circuit board 1. The circuit board 1 has a microcontroller 7, an external output interface, and at least two sensors. Each of the at least two sensors is connected to the microcontroller 7 via a signal processing circuit. The external output interface is also connected to the microcontroller 7. At least one of the at least two sensors serves as a detection channel for detecting flame signals; at least one sensor serves as a reference channel. The external output interface is used to connect to external circuits, including power supply and control circuits.

[0035] like Figure 2 As shown, the external output interfaces include a power interface 4, a serial port output interface 5, and other signal interfaces 6. The power interface 4 is connected to the microcontroller 7, the signal processing circuit, and at least two sensors via an LDO power supply circuit to power the components on the circuit board 1. The serial port output interface 5 and other signal interfaces 6 are all connected to the microcontroller 7. The serial port output interface 5 is used for communication and internal data viewing. The other signal interfaces 6 can output IIC signals, high and low level signals, alarm signals, fault signals, PWM signals, etc., from the microcontroller. These signals can be selected by the user, such as driving buzzers, relays, etc. The power interface 4, serial port output interface 5, and other signal interfaces 6 are located on one side of the circuit board 1, while the microcontroller 7 and sensors are located on the other side. The sensors and indicator lights are through-hole devices on one side of the PCB board of the circuit board 1, while the surface mount devices are on the other side of the PCB board of the circuit board 1. Surface mount devices are convenient to install and only require one reflow soldering.

[0036] like Figure 3 As shown, the circuit board 1 is also equipped with an LED indicator circuit, which is connected to the microcontroller 7. The LED indicator circuit is used to display whether the circuit board 1 is working properly and whether a flame signal has been detected.

[0037] This application proposes a flame detection module based on an infrared pyroelectric sensor and utilizing infrared detection technology. The main focus is on centralizing the core circuitry of industrial flame detectors, designing a small-sized and widely applicable flame detection module. Circuit board 1 contains the core circuitry of the flame detection product: an LDO power supply circuit, a signal processing circuit, a microcontroller 7, etc., and provides various interface circuits. This design effectively solves the problem of complex peripheral circuitry in the entire device. Using this module solution, the entire circuitry only requires simple power supply and relay circuits, eliminating the need for an additional MCU, thus effectively controlling costs and simplifying the manufacturing process. It also reduces production and after-sales costs, and the module's various output signals can be matched to applications in other scenarios.

[0038] In a preferred embodiment of this application, the application includes a two-channel sensor, namely a first sensor 2 and a second sensor 3, with wavelengths of 4.4μm and 5.0μm respectively. The first sensor 2 is a 4.4μm channel sensor, serving as the detection channel. The peak energy of the flame radiation spectrum is located in this band, representing the peak of radiation energy; therefore, this wavelength data is used as the primary condition for the presence of a flame. The second sensor 3 is a 5.0μm channel sensor, used as a reference channel. This wavelength represents the low peak of flame radiation energy, with a significant drop compared to the peak. Another purpose is to use this wavelength to filter out the influence of low-temperature objects, such as humans and small animals, ensuring that the software on the microcontroller 7 can filter out interference from low-temperature objects when the detection module is affected. Through this combination of detection and reference channels, the flame detection module can adapt to scenarios with different temperatures, improving the stability and reliability of the product. By changing the number of sensors and the wavelength, this application can also select multi-channel infrared flame detection products, ultraviolet flame detection products, and infrared / ultraviolet composite flame detection products with similar principles. Both the first sensor 2 and the second sensor 3 are pyroelectric sensors, ensuring accurate flame detection; they feature multi-channel detection technology and strong anti-interference capabilities; external signal interface 6 allows for multiple signal outputs, providing wider adaptability; and firmware can be upgraded online and remotely via microcontroller 7. Microcontroller 7 communicates with the user's MCU through the P2 interface, enabling software-based upgrades.

[0039] The dimensions of the product in this application are: 60mm in length, 25mm in width, and 14.5mm in height. It can be matched with a variety of industrial housings, has a small size, wide range of applications, and a rich variety of application scenarios.

[0040] The working process of this utility model is as follows: When a fire occurs, after the two sensors receive the signal, they amplify the signal using the signal processing circuit. The microcontroller 7 judges the collected data. When the detected value is higher than the alarm threshold, it sends an alarm signal in combination with the delay time. The high-level signal output through other signal interface 6 controls the external relay to activate, and the fire alarm controller performs corresponding actions in linkage. At the same time, the alarm signal output through other signal interface 6 is uploaded to the fire control room to remind relevant personnel.

[0041] This invention simplifies the design of the entire detection module by integrating the main circuits, shortens the research and development cycle, improves production efficiency, reduces hidden costs, and indirectly increases profits.

[0042] Figure 4 The LDO power supply circuit provides power to the various sensors and circuits on circuit board 1. The power processing circuit uses a low-dropout, low-noise LDO power supply circuit with a 5V input, supplying power to the microcontroller 7, sensors, etc. The LDO power supply circuit includes an AMS1117-3.3V power chip. The input terminal of the power chip is connected to one end of capacitor C37 and the negative terminal of diode D1, respectively. The other end of capacitor C37 is grounded. The positive terminal of diode D1 is connected to the 5V power supply through power interface 4. Diode D1 is used to prevent user error from reversing the power supply, which could damage the module. Capacitor C37 stabilizes the system power supply when there are fluctuations in the external power supply. The ground terminal of the power chip is grounded, and the output terminal of the power chip outputs VCC voltage, i.e., 3.3V. The output terminal of the power chip is grounded through capacitors C33 and C34, respectively. Capacitors C33 and C34 are used to stabilize the output voltage. If there is ripple in the 3.3V output, capacitors C33 and C34 will stabilize the 3.3V output. The output VCC voltage is connected to the power input terminal of each sensor, the power input terminal of the microcontroller, the power input terminal of the signal processing circuit, and the power input terminal of the LED indicator circuit.

[0043] Each sensor is connected to a signal processing circuit, and the signal processing circuits for two sensors are as follows: Figure 5As shown, this circuit includes signal processing circuits for both 4.4μm and 5.0μm sensors. Since the sensor output signals are very weak, they need to be amplified. After amplification, the signal is raised to a suitable voltage for the microcontroller 7, facilitating data acquisition and calculation by the microcontroller 7. Different output labels represent the outputs of each channel, making it easier for the microcontroller to distinguish and acquire signals. The sensor's power input terminal is connected to VCC, the sensor's ground terminal is grounded, and the sensor's output terminal is connected to the signal processing circuit. The power input terminal of the 4.4μm channel sensor is grounded through capacitor C1, and the power input terminal of the 5.0μm channel sensor is grounded through capacitor C9. Capacitors C1 and C9 are added to the sensor power supply terminals to suppress high-frequency interference, ensuring stable power supply and thus stable output signals. The output terminal of the 4.4μm channel sensor is grounded through capacitor C6, and the output terminal of the 5.0μm channel sensor is grounded through capacitor C5. Capacitors C6 and C15 ensure stable sensor output signals. The signal processing circuit includes a non-inverting amplifier circuit and a voltage follower. The input of the non-inverting amplifier circuit for the 4.4μm channel sensor is connected to the output of the 4.4μm channel sensor. The output of the non-inverting amplifier circuit is connected to the voltage follower through a first capacitor. The output of the voltage follower is connected to the microcontroller 7. The non-inverting amplifier circuit includes a first operational amplifier. The non-inverting input of the first operational amplifier is connected to the output of the 4.4μm channel sensor through a resistor R2. The inverting input of the first operational amplifier U1A is connected to one end of resistors R5 and R8 respectively. The other end of resistor R5 is grounded, and the other end of resistor R8 is connected to the output of the first operational amplifier. The power input of the first operational amplifier U1A is connected to the VCC voltage, which is grounded through a capacitor C2. The output of the first operational amplifier is connected to the EAD4.4 pin, which is a reserved test point for debugging. The voltage follower includes a second operational amplifier U1B. The non-inverting input of U1B is connected to one end of resistor R4. The other end of R4 is connected to one end of capacitor C5 and one end of resistor R1. The other end of capacitor C5 is connected to the output of the first operational amplifier U1A. Capacitor C5 filters out DC signals and allows AC signals to pass. The other end of resistor R1 is connected to VCC / 2. Resistor R1 is a pull-up resistor, setting the voltage to VCC / 2. Resistor R4 is used for impedance matching of the second operational amplifier U1B.The inverting input and output of the second operational amplifier U1B are connected. The output of the second operational amplifier U1B is connected to one end of resistors R3 and R7 respectively. The other end of resistor R3 is the output terminal and is connected to the PA1 pin of microcontroller 7 through resistor R20 to limit the current of the output signal and prevent MCU pin current overload. The other end of resistor R7 is grounded, and resistor R7 discharges the parasitic capacitance of the second operational amplifier U1B. The output of the signal processing circuit of the 5.0μm channel sensor is connected to the PA4 pin of microcontroller 7 through resistor R24. The output of the 5.0μm channel sensor is connected to the non-inverting input of the first operational amplifier U3A in the non-inverting amplifier circuit via resistor R12. The inverting input of the first operational amplifier U3A is connected to one end of resistors R16 and R19 respectively. The other end of resistor R16 is grounded. The other end of resistor R19 is connected to the output of the first operational amplifier U3A. The output of the first operational amplifier U3A is connected to one end of resistors R11 and R15 via capacitor C14. The other end of resistor R11 is connected to the VCC / 2 voltage. The other end of resistor R15 is connected to the non-inverting input of the second operational amplifier U3B of the voltage follower. The inverting input of the second operational amplifier U3B is connected to its output. The output of the second operational amplifier U3B is connected to one end of resistors R18 and R13 respectively. The other end of resistor R18 is grounded. The other end of resistor R13 is connected to resistor R24. Pin 8 of the first operational amplifier U1A and the first operational amplifier U3A is connected to the voltage VCC and grounded through capacitor C2 or C10.

[0044] The VCC / 2 voltage is obtained by dividing the VCC voltage from the LDO power supply circuit. The voltage divider circuit includes a third operational amplifier. The VCC voltage is connected to the non-inverting input of the third operational amplifier through resistor R32, which is used for voltage division. The non-inverting input of the third operational amplifier is grounded through a parallel connection of resistor R38 and capacitor C27. R38 is used for voltage division, and capacitor C27 is used to filter out noise and eliminate input interference. The inverting input of the third operational amplifier is connected to its output. The output of the third operational amplifier is connected to one end of resistor R34, and the other end of resistor R34 is grounded through capacitor C30. Resistor R34 and capacitor C30 are used to filter out output interference and stabilize the output voltage. The other end of capacitor R24 ​​provides the VCC / 2 voltage.

[0045] Figure 6This circuit uses a microcontroller (MCU) 7, which is a data processing circuit. It collects data from two sensors at wavelengths of 4.4μm and 5.0μm, analyzes the data, and uses a real-world flame combustion model as a basis to determine the true and reliable fire situation. The 5.0μm data is used in conjunction with the 4.4μm data to help eliminate interference from other heat-generating objects. The MCU 7 is a Lianshengde W806 control chip. The PB11 pin of the control chip is connected to KEY, a reserved test point for debugging. The VCC voltage is connected to the VDD33 pin of the control chip to power its internal components. The GNN pin of the control chip is grounded. The PB7 pin of the control chip is connected to the RX input of serial port output interface 5 through resistor R7, and the PB6 pin is connected to the TX input of serial port output interface 5 through resistor R11. The TX and RX inputs are standard serial communication interfaces for R&D debugging and user use. The PB0, PB1, and PB2 pins of the control chip are connected to the input terminals of other signal interface 6 via resistors R17, R15, and R14, respectively. PA_CON is a reserved test point for debugging. The PB19 and PB20 pins of the control chip are reserved MCU serial ports for testing, and the RST pin is the MCU reset pin. XTAL_OUT and XTAL_IN are external crystal oscillator circuits for the MCU, providing the system clock for MCU operation. The PB10 pin of the control chip is connected to the PWM pin of other signal interface 6 via resistor R22, which is grounded through capacitor C48. Capacitors C21, C48, C49, C47, and C32 are MCU power supply termination capacitors to suppress high-frequency interference.

[0046] The LED indicator circuit indicates the status of the module. The specific structure is as follows: Figure 7 As shown, the LED indicator circuit includes a red LED and a green LED connected in parallel. One end of each LED is connected to the output of the LDO power supply circuit to provide power. The other end of the red LED is connected to pin PA8 of the microcontroller 7 via resistor R8, and the other end of the green LED is connected to pin PA9 of the microcontroller 7 to receive control signals from the microcontroller 7. The LED indicator circuit is a dual-color red-green LED. A lit green LED indicates that the module is working normally, while a lit red LED indicates that the module has detected a flame signal, indicating a fire that needs to be dealt with.

[0047] Figure 8 This is the circuit diagram for the external output interface, where Figure 8The power interface 4 in (a) includes two pins. One pin is a 5V power input to power the input of the module's LDO power circuit and ensure stable system operation. The other pin is grounded. Figure 8 The serial output interface 5 in (b) includes two input terminals, which are connected to the PB7 and PB6 pins of the microcontroller 7 respectively. It can send out internally calculated data, allowing the operation of the flame detection module to be determined. The internally calculated data is sent out through the TX input terminal, and the PC receives the data for debugging personnel to observe. The serial output interface 5 has two grounding terminals. Figure 8 The PWM pin of other signal interface 6 in (c) receives the PWM signal from the microcontroller 7. The PWM signal is low-pass filtered and output as an analog signal, which can control an external 4-20mA circuit. The ACON and ECON signals can control two external relays. IO1 and SDA of other signal interface 6 are reserved signals that can be modified according to other customer requirements. The power input pin of other signal interface 6 is connected to a +5V power supply. P1 is a 2.0mm pitch socket, and J1 is a 1.25mm pitch socket. Users can choose the appropriate power supply according to their needs. The two ground terminals of other signal interface 6 are grounded.

[0048] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A modular flame detection module based on the pyroelectric principle, characterized in that, The circuit board (1) is provided with a microcontroller (7), an external output interface and at least two sensors. The at least two sensors are connected to the microcontroller (7) through a signal processing circuit, and the external output interface is connected to the microcontroller (7). The external output interface includes a power interface (4), a serial port output interface (5), and other signal interfaces (6). The power interface (4) is connected to the microcontroller (7), the signal processing circuit, and at least two sensors respectively through the LDO power circuit. The serial port output interface (5) and other signal interfaces (6) are all connected to the microcontroller (7). The serial port output interface (5) and other signal interfaces (6) are respectively connected to external interfaces. The power interface (4), serial output interface (5) and other signal interfaces (6) are located on one side of the circuit board (1), and the microcontroller (7) and sensor are located on the other side of the circuit board (1).

2. The modular flame detection module based on the pyroelectric principle according to claim 1, characterized in that, The circuit board (1) is also provided with an LED indicator circuit, which is connected to the microcontroller (7).

3. The modular flame detection module based on the pyroelectric principle according to claim 2, characterized in that, The sensor includes a first sensor (2) and a second sensor (3). The first sensor (2) is a 4.4μm channel sensor as a detection channel, and the second sensor (3) is a 5.0μm channel sensor as a reference channel.

4. The modular flame detection module based on the pyroelectric principle according to claim 3, characterized in that, The other signal interface (6) outputs at least one of the following signals: IIC signal, high / low level signal, alarm signal, fault signal, or PWM signal output by the microcontroller (7).

5. The modular flame detection module based on the pyroelectric principle according to claim 3 or 4, characterized in that, The LDO power supply circuit includes a power chip. The input terminal of the power chip is connected to one end of capacitor C37 and the negative terminal of diode D1, respectively. The other end of capacitor C37 is grounded. The positive terminal of diode D1 is connected to a 5V power supply through the power interface (4). The ground terminal of the power chip is grounded. The output terminal of the power chip outputs VCC voltage. The output terminal of the power chip is grounded through capacitor C33 and capacitor C34, respectively. The output VCC voltage is connected to the power input terminal of each sensor, the power input terminal of the microcontroller, the power input terminal of the signal processing circuit, and the power input terminal of the LED indicator circuit, respectively.

6. The modular flame detection module based on the pyroelectric principle according to claim 5, characterized in that, The power input terminal of the sensor is grounded through capacitor I, and the output terminal of the sensor is grounded through capacitor II. The signal processing circuit includes a non-inverting amplifier circuit and a voltage follower. The input terminal of the non-inverting amplifier circuit is connected to the output terminal of the sensor, and the output terminal of the non-inverting amplifier circuit is connected to the voltage follower through the first capacitor. The output terminal of the voltage follower is connected to the microcontroller (7).

7. The modular flame detection module based on the pyroelectric principle according to claim 6, characterized in that, The non-inverting amplifier circuit includes a first operational amplifier. The non-inverting input terminal of the first operational amplifier is connected to the output terminal of the sensor through a first resistor. The inverting input terminal of the first operational amplifier is connected to one end of a second resistor and a third resistor, respectively. The other end of the second resistor is grounded. The other end of the third resistor is connected to the output terminal of the first operational amplifier. The power input terminal of the first operational amplifier is connected to the VCC voltage, which is grounded through capacitor III. The output terminal of the first operational amplifier is connected to the input terminal of a voltage follower through a second capacitor. The voltage follower includes a second operational amplifier. The non-inverting input terminal of the second operational amplifier is connected to one end of a fourth resistor. The other end of the fourth resistor is connected to one end of a second capacitor and a fifth resistor, respectively. The other end of the fifth resistor is connected to the VCC / 2 voltage. The inverting input terminal of the second operational amplifier is connected to the output terminal. The output terminal of the second operational amplifier is connected to one end of a sixth resistor and a seventh resistor, respectively. The other end of the sixth resistor is the output terminal and is connected to the pin of the microcontroller (7) through a resistor. The other end of the seventh resistor is grounded.

8. The modular flame detection module based on the pyroelectric principle according to claim 7, characterized in that, Both the output terminal of the first operational amplifier and the microcontroller (7) are provided with reserved test points; the PB7 pin of the microcontroller (7) is connected to the RX input terminal of the serial output interface (5) through the eighth resistor, and the PB6 pin of the microcontroller (7) is connected to the TX input terminal of the serial output interface (5) through the ninth resistor; the PB0 pin, PB1 pin, and PB2 pin of the microcontroller (7) are respectively connected to the input terminals of other signal interfaces (6) through the tenth resistor; The VCC / 2 voltage is connected to the VCC voltage through a voltage divider circuit; The LED indicator circuit includes a red LED and a green LED connected in parallel. One end of each of the red and green LEDs is connected to the output of the LDO power supply circuit. The other end of the red LED is connected to the PA8 pin of the microcontroller (7) through the eleventh resistor. The other end of the green LED is connected to the PA9 pin of the microcontroller (7).

Images