Combustible gas alarm and compensation method, compensation relationship and reference resistance calibration method thereof

Abstract

The application discloses a combustible gas alarm and a compensation method, a compensation relationship and a calibration method of a reference resistance value thereof. The combustible gas alarm comprises a combustible gas sensing module, which is used for adjusting a resistance value according to a concentration of combustible gas; an environmental parameter detection module, which is used for detecting at least two environmental parameters, the at least two environmental parameters comprising a temperature parameter and a humidity parameter; and a processing module, which is electrically connected with the combustible gas sensing module and the environmental parameter detection module, and is used for detecting a current resistance value of the combustible gas sensing module and compensating the current resistance value according to a compensation relationship corresponding to each environmental parameter. The application can improve the false alarm problem of the combustible gas alarm and reduce the false alarm rate.

Description

Technical Field

[0001] This invention relates to the field of combustible gas detection technology, and in particular to a combustible gas alarm and its compensation method, compensation relationship, and calibration method for reference resistance value. Background Technology

[0002] Combustible gas detectors can monitor the concentration of combustible gas for a long time. When the concentration of combustible gas exceeds the alarm set value, the combustible gas detector will sound an alarm.

[0003] Combustible gas detectors in related technologies mostly use semiconductor gas sensors, which detect concentration by utilizing the change in resistance of the sensitive element caused by the oxidation-reduction reaction of gas on the semiconductor surface. Semiconductor gas sensors have advantages such as long service life, low cost, and high sensitivity to natural gas gases such as methane. However, combustible gas detectors in related technologies are greatly affected by ambient temperature and are prone to false alarms, i.e., the false alarm rate is relatively high. Summary of the Invention

[0004] This invention provides a combustible gas alarm and its compensation method, compensation relationship, and calibration method for reference resistance value, in order to improve the problem of false alarms in combustible gas alarms and reduce the false alarm rate.

[0005] According to one aspect of the present invention, a combustible gas alarm is provided, the combustible gas alarm comprising: A combustible gas sensing module is used to adjust its resistance value according to the concentration of combustible gas. An environmental parameter detection module is used to detect at least two environmental parameters, including a temperature parameter and a humidity parameter. The processing module is electrically connected to the combustible gas sensing module and the environmental parameter detection module. The processing module is used to detect the current resistance value of the combustible gas sensing module and compensate the current resistance value according to the compensation relationship corresponding to each environmental parameter. The compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter when it is under the calibration condition.

[0006] Optionally, the compensation relationship is a polynomial function.

[0007] Optionally, the combustible gas alarm further includes at least two sampling resistors; the resistance values ​​of the different sampling resistors are different; One end of the sampling resistor is electrically connected to the first end of the combustible gas sensing module, the second end of the sampling resistor is electrically connected to the processing module, and the first end of the combustible gas sensing module is electrically connected to the processing module; the processing module is used to output a reference voltage to at least one of the at least two sampling resistors and to acquire the sampling voltage of the first end of the combustible gas sensing module.

[0008] Optionally, the processing module is configured to output the reference voltage to a target sampling resistor among the at least two sampling resistors; wherein, when the combustible gas alarm is in calibration condition, the sampling voltage corresponding to the target sampling resistor is less than the upper limit voltage of the processing module; and among all the sampling resistors whose corresponding sampling voltage is less than the upper limit voltage, the sampling voltage corresponding to the target sampling resistor is closest to the upper limit voltage.

[0009] According to another aspect of the present invention, a compensation method for a combustible gas alarm is provided, the combustible gas alarm comprising: A combustible gas sensing module is used to adjust its resistance value according to the concentration of combustible gas; an environmental parameter detection module is used to detect at least two environmental parameters, including temperature and humidity; a processing module is electrically connected to the combustible gas sensing module and the environmental parameter detection module, the processing module is used to detect the current resistance value of the combustible gas sensing module and compensate the current resistance value according to the compensation relationship corresponding to each of the environmental parameters; wherein, the compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under the calibration condition; The compensation method includes: Obtain the current resistance value of the combustible gas sensing module; Obtain the at least two environmental parameters; The current resistance value is compensated based on the environmental parameters and the corresponding compensation relationship.

[0010] Optionally, the compensation relationship is a polynomial function; the processing module is provided with a first compensation relationship corresponding to the temperature parameter and a second compensation relationship corresponding to the humidity parameter; The step of compensating the current resistance value according to the environmental parameters and the compensation relationship includes: The current resistance value is compensated according to the temperature parameter and the first compensation relationship to obtain a first current resistance value; The first current resistance value is compensated according to the humidity parameter and the second compensation relationship to obtain the second current resistance value.

[0011] Optionally, before compensating the first current resistance value according to the humidity parameter and the second compensation relationship to obtain the second current resistance value, the method further includes: If the humidity parameter is greater than 100%RH, the humidity parameter is assigned a value of 100%RH; and / or, If the temperature parameter is less than the preset temperature threshold, the step of obtaining the humidity compensation coefficient based on the humidity parameter and the second compensation relationship will not be performed.

[0012] According to another aspect of the present invention, a calibration method for the compensation relationship of a combustible gas alarm is provided. The combustible gas alarm includes a combustible gas sensing module for adjusting its resistance value according to the concentration of combustible gas; an environmental parameter detection module for detecting at least two environmental parameters, including a temperature parameter and a humidity parameter; and a processing module electrically connected to the combustible gas sensing module and the environmental parameter detection module, the processing module being used to detect the current resistance value of the combustible gas sensing module; wherein the compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under calibration conditions. The method for determining the compensation relationship includes: The sample of the combustible gas alarm obtains multiple current resistance values ​​corresponding to multiple preset environmental parameters; wherein, the other environmental parameters are under calibration conditions. Using the current resistance value corresponding to the preset environmental parameters under the calibration condition as the reference resistance value, other current resistance values ​​are preprocessed. The preset environmental parameters are fitted with the corresponding preprocessed current resistance value to obtain the compensation relationship corresponding to the preset environmental parameters.

[0013] According to another aspect of the present invention, a method for calibrating the reference resistance value of a combustible gas alarm is provided. The combustible gas alarm includes a combustible gas sensing module for adjusting its resistance value according to the concentration of combustible gas; an environmental parameter detection module for detecting at least two environmental parameters, including a temperature parameter and a humidity parameter; and a processing module electrically connected to the combustible gas sensing module and the environmental parameter detection module. The processing module is used to detect the current resistance value of the combustible gas sensing module and compensate the current resistance value according to a compensation relationship corresponding to each of the environmental parameters. The compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under calibration conditions. The calibration method for the reference resistance value includes: Get the current resistance value; If the duration during which the current resistance value is less than the calibration threshold is greater than or equal to a preset time, the current resistance value is used as the reference resistance value.

[0014] Optionally, the combustible gas alarm further includes at least two sampling resistors; one end of the sampling resistor is connected to the first end of the combustible gas sensing module, the second end of the sampling resistor is connected to the processing module, and the first end of the combustible gas sensing module is electrically connected to the processing module; the processing module is used to output a reference voltage to at least one of the at least two sampling resistors and to acquire the sampling voltage of the first end of the combustible gas sensing module. Before using the current resistance value as the reference resistance value, the following steps are also included: The processing module is controlled to output the reference voltage to the target sampling resistor among the at least two sampling resistors; wherein, when the combustible gas alarm is in calibration condition, the sampling voltage corresponding to the target sampling resistor is less than the upper limit voltage of the processing module; and among all the sampling resistors whose corresponding sampling voltage is less than the upper limit voltage, the sampling voltage corresponding to the target sampling resistor is closest to the upper limit voltage. Using the current resistance value as the reference resistance value includes: The current resistance value corresponding to the target sampling resistor is used as the reference resistance value.

[0015] The technical solution of this invention employs a combustible gas alarm comprising: a combustible gas sensing module for adjusting its resistance value according to the concentration of combustible gas; an environmental parameter detection module for detecting at least two environmental parameters, including temperature and humidity; and a processing module electrically connected to the combustible gas sensing module and the environmental parameter detection module. The processing module detects the current resistance value of the combustible gas sensing module and compensates the current resistance value according to a compensation relationship corresponding to each environmental parameter. By compensating the current resistance value according to the compensation relationship to the resistance value corresponding to the environmental parameter under calibrated operating conditions, the final compensated current resistance value can more accurately reflect the concentration of combustible gas, thereby reducing the false alarm rate.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A circuit structure diagram of a combustible gas alarm provided in an embodiment of the present invention; Figure 2 A schematic diagram of the circuit structure of another combustible gas alarm provided in an embodiment of the present invention; Figure 3 A flowchart of a compensation method for a combustible gas alarm provided in an embodiment of the present invention; Figure 4A flowchart illustrating another compensation method for a combustible gas alarm provided in an embodiment of the present invention; Figure 5 A flowchart of temperature compensation provided for an embodiment of the present invention; Figure 6 A flowchart of humidity compensation provided in an embodiment of the present invention; Figure 7 A flowchart illustrating a calibration method for the compensation relationship of a combustible gas alarm, provided as an embodiment of the present invention; Figure 8 A graph illustrating a first compensation relationship provided in an embodiment of the present invention; Figure 9 A graph illustrating a second compensation relationship provided in an embodiment of the present invention; Figure 10 A flowchart illustrating a method for calibrating the reference resistance value of a combustible gas alarm, as provided in an embodiment of the present invention; Figure 11 A flowchart illustrating a method for calibrating the reference resistance value of a combustible gas alarm, as provided in an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Figure 1 This is a circuit structure diagram of a combustible gas alarm provided in an embodiment of the present invention, with reference to... Figure 1The combustible gas alarm includes a combustible gas sensing module 11, an environmental parameter detection module 12, and a processing module 13. The combustible gas sensing module 11 adjusts its resistance value according to the concentration of combustible gas. The environmental parameter detection module 12 detects at least two environmental parameters, including temperature and humidity. The processing module 13 is electrically connected to both the combustible gas sensing module 11 and the environmental parameter detection module 12. The processing module 13 detects the current resistance value of the combustible gas sensing module 11 and compensates for the current resistance value according to a compensation relationship corresponding to each environmental parameter. This compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under calibrated operating conditions.

[0022] Specifically, a combustible gas alarm can detect the concentration of combustible gas and issue an alarm accordingly. Combustible gases include, for example, natural gas such as methane, or carbon monoxide. The combustible gas sensing module 11 is, for example, a semiconductor sensor; its resistance changes with different combustible gas concentrations. The processing module 13 determines the combustible gas concentration by detecting the current resistance of the sensing module 11. The processing module 13 can be, for example, a MCU (Microcontroller Unit), a microcontroller, or a FPGA (Field Programmable Gate Array).

[0023] The resistance of the combustible gas sensing module 11 is significantly affected not only by the concentration of combustible gas but also by environmental parameters, particularly temperature and humidity. In other words, if the influence of environmental parameters on the resistance of the combustible gas sensing module 11 is not considered, the detected concentration of combustible gas will deviate considerably from the actual concentration when the combustible gas alarm sounds, leading to a high risk of false alarms. In this embodiment, the combustible gas alarm also includes an environmental parameter detection module 12, which includes, for example, a temperature sensor and a humidity sensor. The temperature sensor detects temperature parameters, and the humidity sensor detects humidity parameters. It is understood that the environmental parameters referred to herein are the relevant parameters of the environment in which the combustible gas alarm is currently located. The processing module 13 stores the compensation relationship corresponding to each environmental parameter; that is, each environmental parameter corresponds to a compensation relationship, which is the relationship between the environmental parameter and the resistance of the combustible gas sensing module 11. After the processing module 13 detects the current resistance value, it can compensate the current resistance value to the resistance value corresponding to the environmental parameter when it is in the calibration condition according to the compensation relationship. This makes the final compensated current resistance value more accurately reflect the concentration of combustible gas, thereby reducing the false alarm rate.

[0024] It should be noted that the processing module 13 compensates for the detected current resistance value using each environmental parameter separately; that is, one compensation corresponds to one environmental parameter. In this embodiment, the current resistance value is compensated twice using the compensation relationships corresponding to the temperature parameter and the humidity parameter, thereby reducing the influence of humidity and temperature on concentration detection and lowering the false alarm rate.

[0025] The technical solution of this embodiment employs a combustible gas alarm comprising: a combustible gas sensing module for adjusting its resistance value according to the concentration of combustible gas; an environmental parameter detection module for detecting at least two environmental parameters, including temperature and humidity; and a processing module electrically connected to the combustible gas sensing module and the environmental parameter detection module. The processing module detects the current resistance value of the combustible gas sensing module and compensates for the current resistance value according to the compensation relationship corresponding to each environmental parameter. The current resistance value is compensated to the resistance value corresponding to the environmental parameter under calibrated operating conditions, thereby ensuring that the final compensated current resistance value more accurately reflects the concentration of combustible gas and reduces the false alarm rate.

[0026] Optionally, in the above embodiments, the calibration conditions can be calibration conditions under national standards, such as a concentration of 4000ppm, a temperature of 20℃, and a humidity of 65%RH.

[0027] Optionally, the aforementioned environmental parameters may also include parameters such as illumination, air pressure, and airflow, etc., which are not specifically limited in this embodiment. It should be noted that each environmental parameter corresponds to a compensation relationship.

[0028] Optionally, the compensation relationship is a polynomial function.

[0029] Specifically, the compensation relationship is a function relating the environmental parameter to a preset ratio, where the preset ratio is the ratio of the current resistance to a reference resistance. For example, for the compensation relationship corresponding to the temperature parameter, the independent variable is temperature, and the dependent variable is the temperature compensation coefficient. The temperature compensation coefficient can be the ratio of the current resistance to the reference resistance, i.e., Rs / R0, where Rs is the current resistance and R0 is the reference resistance. The reference resistance is the resistance of the combustible gas sensing module 11 when the combustible gas alarm is in the aforementioned calibration condition. The compensation relationship is a polynomial function, which can be expressed as Y=A×X. 2 +B×X+C. Where X is an environmental parameter, Y is the corresponding preset ratio, and A, B, and C are fixed coefficients that can be obtained through fitting or other methods. This embodiment uses a quadratic polynomial as an example of a polynomial function; in some implementations, it can also be a cubic or higher-order polynomial. Compensation relationships obtained through polynomial function fitting have higher compensation accuracy compared to linear fitting. For example, if the current temperature is T1, then the temperature compensation coefficient is A×T1.2 +B×T1+C. If the current resistance value detected by the processing module 13 is D1, then the compensated current resistance value is D1 / (A×T1). 2 +B×T1+C).

[0030] Optionally, the compensation relationship can be stored in the processing module as firmware. In some embodiments, the compensation relationship can also be implemented using methods such as analog circuits. This embodiment does not limit the specific implementation form of the compensation relationship in the combustible gas alarm. In some embodiments, the compensation relationship can also be stored in a storage structure independent of the processing module.

[0031] Optionally, the coefficients in the compensation relationship can be floating-point numbers, thereby reducing errors and improving compensation accuracy.

[0032] Furthermore, the calibration method for the compensation relationship will be explained later; this embodiment only introduces the specific form of the compensation relationship. The calibration method for the compensation relationship can be performed before the combustible gas alarm device leaves the factory and / or during maintenance. During daily use, the compensation relationship is stored inside the combustible gas alarm device.

[0033] Optionally, Figure 2 This is a circuit structure diagram of another combustible gas alarm provided in an embodiment of the present invention, with reference to... Figure 2 The combustible gas alarm also includes at least two sampling resistors. In this embodiment, the combustible gas alarm includes three sampling resistors: a first sampling resistor R1, a second sampling resistor R2, and a third sampling resistor R3. The resistance values ​​of the different sampling resistors are different.

[0034] The first end of the sampling resistor is electrically connected to the first end of the combustible gas sensing module 11, and the second end of the sampling resistor is electrically connected to the processing module 13. The first end of the combustible gas sensing module 11 is electrically connected to the processing module 13. The processing module 13 is used to output a reference voltage to at least one of the at least two sampling resistors and to acquire the sampling voltage of the first end of the combustible gas sensing module 11.

[0035] Specifically, such as Figure 2As shown, the combustible gas sensing module 11 includes, for example, a concentration sensor. The concentration sensor includes a heating wire and a semiconductor gas sensor. The first end of the semiconductor gas sensor serves as the first end of the concentration sensor, and the second end of the semiconductor gas sensor is connected to a power supply Vcc. The first end of the heating wire is connected to the power supply Vcc, and the second end of the heating wire is grounded through a voltage divider resistor R5. The second end of the heating wire is also electrically connected to the processing module 13 through a first output port To1. The heating wire provides energy for the concentration sensor's detection. When the heating wire is energized, the resistance of the semiconductor gas sensor changes with the gas concentration. The first output port To1 is used for voltage sampling, and the processing module 13 can use the first output port To1 to confirm whether the concentration sensor is working properly.

[0036] The first end of the concentration sensor is also electrically connected to the processing module 13 via the second output port To2. The processing module 13 can calculate the current resistance value of the semiconductor gas sensor in the concentration sensor, which is also the current resistance value of the combustible gas sensing module 11, based on the sampling voltage at the second output port To2. More specifically, the processing module 13 can select at least one sampling resistor and transmit a reference voltage to the second end of the selected sampling resistor. The reference voltage can be any voltage different from the power supply Vcc, such as ground voltage. Since the reference voltage is different from the power supply Vcc, there will be a sampling voltage at the second output port To2 that is different from both the reference voltage and the power supply Vcc. The current resistance value of the combustible gas sensing module 11 can be calculated using the value of the sampling voltage, the power supply Vcc, the reference voltage, and the value of the selected sampling resistor. The sampling resistor can be a high-precision resistor with an accuracy of at least one-thousandth.

[0037] In related technologies, using only one sampling resistor results in poor compatibility. This is because the combustible gas sensing module 11 contains analog devices such as semiconductor gas sensors. Even semiconductor sensors fabricated on the same wafer can have different resistance values, and these differences can be significant. In other words, the consistency of combustible gas sensing modules in different combustible gas alarms is poor; however, the consistency of other modules in a combustible gas alarm is relatively high. Therefore, using a single sampling resistor to adapt to different combustible gas sensing modules may lead to problems such as low sampling accuracy or sampling exceeding the processing module's range. In this embodiment, by setting at least two sampling resistors, different voltage division ranges can be provided for different combustible gas sensing modules 11, thereby improving the compatibility of the combustible gas alarm. It should be noted that in the above embodiment, a reference voltage can be output to one sampling resistor, or to two or more sampling resistors. The specific sampling resistor to which the reference voltage is output can be determined before shipment and / or during maintenance.

[0038] Further optionally, the processing module 13 is used to output a reference voltage to the target sampling resistor among at least two sampling resistors; wherein, when the combustible gas alarm is in the calibration condition, the sampling voltage corresponding to the target sampling resistor is less than the upper limit voltage of the processing module 13; and among all sampling resistors whose corresponding sampling voltage is less than the upper limit voltage, the sampling voltage corresponding to the target sampling resistor is closest to the upper limit voltage.

[0039] Specifically, the processing module 13 includes, for example, an analog-to-digital converter (ADC) that converts the acquired sampled voltage into digital form for use by the processing module 13. The ADC has an upper limit for sampling, namely the upper sampling voltage. Under calibration conditions, the closer the sampled voltage is to the upper sampling voltage, the higher the sampling accuracy and the better the subsequent compensation effect. Of course, it is understood that the sampled voltage needs to be within the upper sampling voltage limit. In this embodiment, the selected sampling resistor ensures that the sampled voltage is within the upper sampling voltage limit while also making the sampled voltage closer to the upper sampling voltage limit, thereby greatly improving the sampling accuracy and enhancing the effect of subsequent compensation.

[0040] Optionally, continue to refer to Figure 2 The combustible gas alarm may also include a first filter capacitor C1. One end of the first filter capacitor C1 is electrically connected to the first output port To1, and the other end is grounded. The first filter capacitor C1 is used to filter the voltage at the first output port To1.

[0041] Optionally, continue to refer to Figure 2 The combustible gas alarm may also include a second filter capacitor C2. One end of the second filter capacitor C2 is electrically connected to the second output port To2, and the other end is grounded. The second filter capacitor C2 is used to filter the voltage at the second output port To2.

[0042] Optionally, continue to refer to Figure 2 The combustible gas alarm may also include a fourth resistor R4, one end of which is connected to the power supply Vcc, and the other end is connected to the second terminal of the combustible gas sensing module. The fourth resistor R4 can be a 0-ohm resistor.

[0043] Optionally, in the above embodiments, the environmental parameter detection module 12 can be an analog device or a digital device.

[0044] Optionally, in the above embodiments, since the heating wire continuously generates heat during operation, and the concentration sensor's housing is generally made of metal, the concentration sensor will dissipate heat. Therefore, the temperature sensor is positioned away from the heating wire within the combustible gas alarm to prevent the heating wire from affecting the temperature sensor's data acquisition. The humidity sensor can also be positioned away from the heating wire to avoid affecting the accuracy of the acquired humidity parameters.

[0045] Optionally, in some embodiments, the combustible gas alarm may further include a serial port, and the processing module 13 is electrically connected to the serial port. The processing module 13 communicates with a host computer such as a PC (Personal Computer) via the serial port. The communication protocol may be a proprietary communication protocol. For example, the digital sampled voltage collected by the processing module 13 can be sent to the PC for recording via the serial port.

[0046] Optionally, in some embodiments, the combustible gas alarm may also include other peripheral circuits. For example, it may include an audible alarm module or a visual alarm module, and may also include a wireless communication module to send alarm signals to the user's mobile phone.

[0047] Based on the same inventive concept, this invention also provides a compensation method for a combustible gas alarm, executed by the combustible gas alarm provided in any embodiment of this invention, such as... Figure 3 As shown, Figure 3 A flowchart illustrating a compensation method for a combustible gas alarm provided in an embodiment of the present invention. The compensation method for the combustible gas alarm includes: Step S110: Obtain the current resistance value of the combustible gas sensing module; Specifically, the processing module 13 can first obtain the sampling voltage, and then calculate the current resistance value of the combustible gas sensing module 11 based on the sampling voltage and the resistance value of the sampling resistor.

[0048] Step S120: Obtain at least two environmental parameters; Specifically, after the environmental parameter detection module 12 detects the environmental parameter, the processing module 13 collects the environmental parameter. It should be noted that the order of steps S120 and S110 is not limited.

[0049] Step S130: Compensate the current resistance value according to the environmental parameters and the corresponding compensation relationship.

[0050] Specifically, each environmental parameter corresponds to a compensation relationship. For example, temperature and humidity parameters have different compensation relationships. The current resistance value is compensated using the compensation relationship corresponding to each environmental parameter. Based on the compensation relationship, the current resistance value is compensated to the resistance value corresponding to the environmental parameter under the calibration condition. This allows the final compensated current resistance value to more accurately reflect the concentration of combustible gas, thereby reducing the false alarm rate.

[0051] The technical solution of this embodiment employs a compensation method for a combustible gas alarm, which includes: acquiring the current resistance value of the combustible gas sensing module; acquiring at least two environmental parameters; and compensating the current resistance value according to the environmental parameters and the corresponding compensation relationship. The current resistance value is compensated to the resistance value corresponding to the environmental parameter under calibrated operating conditions according to the compensation relationship, thereby enabling the finally obtained compensated current resistance value to more accurately reflect the concentration of combustible gas, thus reducing the false alarm rate.

[0052] Optionally, after obtaining the current resistance value after compensation according to the compensation relationships corresponding to each environmental parameter, it can be determined whether an alarm is needed based on the reference resistance value and the compensated current resistance value. For example, if the compensated current resistance value is less than a certain threshold, an alarm is triggered; if the compensated current resistance value is greater than or equal to the threshold, no alarm is triggered. This threshold value can be determined based on the reference resistance value, and its specific value is not limited.

[0053] Optionally, Figure 4 A flowchart of a compensation method for a combustible gas alarm provided in an embodiment of the present invention is shown below. Figure 4 In this embodiment, step S110, namely obtaining the current resistance value of the combustible gas sensing module, includes: Step S1101: Obtain the sampled voltage; Specifically, obtaining the sampling voltage means that the analog-to-digital converter in the processing module 13 samples the voltage at the first terminal of the combustible gas sensing module 11. The sampling voltage can be in digital form.

[0054] Step S1102: Determine whether the number of samples is greater than the preset number. If the number of samples is greater than the preset number, proceed to step S1103; if the number of samples is less than or equal to the preset number, return to step S1101.

[0055] Specifically, in this embodiment, multiple sampling voltages can be acquired, thereby improving the accuracy of the sampling voltages. There can be a certain time interval between two adjacent samples. The preset number of samplings can be 12, but it can also be any other number. That is to say, in this embodiment, a total of 12 sampling voltages are acquired.

[0056] Step S1103: Perform smoothing filtering on multiple sampled voltages.

[0057] Specifically, smoothing filtering processes include methods such as averaging, weighted averaging, low-pass filtering, and median filtering to eliminate noise interference. After smoothing filtering, a filtered sampled voltage is obtained.

[0058] Step S1104: Calculate the current resistance value.

[0059] Specifically, once the filtered sampling voltage is obtained, the current resistance value of the combustible gas sensing module 11 can be calculated based on the resistance value of the sampling resistor, the power supply Vcc, and the reference voltage. It can be understood that the resistance value calculated in this step is the actual resistance value of the combustible gas sensing module 11, which is determined by environmental parameters such as temperature and humidity of the environment where the combustible gas alarm is located, as well as the concentration of the combustible gas.

[0060] Optionally, the compensation relationship is a polynomial function; the processing module is equipped with a first compensation relationship for the corresponding temperature parameter and a second compensation relationship for the corresponding humidity parameter. Step S130, which involves compensating for the current resistance value based on environmental parameters and compensation relationships, includes: Step S1301: Compensate the current resistance value according to the temperature parameter and the first compensation relationship to obtain the first current resistance value; Specifically, if the current temperature is T1, the temperature compensation coefficient is A×T1. 2 +B×T1+C. If the current resistance value detected by the processing module 13 is D1, then the compensated current resistance value, i.e., the first current resistance value, is D1 / (A×T1). 2 +B×T1+C).

[0061] Step S1303: Compensate the first current resistance value according to the humidity parameter and the corresponding second compensation relationship to obtain the second current resistance value.

[0062] Specifically, similar to the temperature compensation steps, this embodiment performs humidity compensation on the current resistance value after temperature compensation, thereby eliminating the influence of humidity and reducing the false alarm rate. In this embodiment, both the first and second compensation relationships are polynomial functions. The compensation relationship is obtained by fitting a polynomial function, which has higher compensation accuracy compared to linear fitting.

[0063] It should be noted that this embodiment uses temperature compensation followed by humidity compensation as an example. In some implementations, humidity compensation may be performed first, followed by temperature compensation.

[0064] Optionally, Figure 5 A flowchart of temperature compensation provided for an embodiment of the present invention is shown below. Figure 5 Temperature compensation, or step S1301, includes: Step S13011: Determine if the temperature parameter is positive. If the temperature parameter is positive, proceed to step S13012; otherwise, proceed to step S13013. Step S13012 involves a positive temperature function calculation, which means substituting a positive temperature value into the first compensation relationship. Step S13013 involves a negative temperature function calculation, which means substituting a negative temperature value into the first compensation relationship. In this embodiment, adding the determination of whether the temperature parameter is positive or negative can prevent errors when the subsequent processing module 13 automatically calculates the temperature compensation coefficient.

[0065] After step S13012 or S13013, step S13014 is executed, which generates the temperature compensation coefficient. The temperature compensation coefficient is calculated by substituting the temperature parameter into the first compensation relationship. Then, step S13015 is executed to generate the first current resistance value. That is, the current resistance value is divided by the temperature compensation coefficient to obtain the first current resistance value.

[0066] Optionally, Figure 6 A flowchart of humidity compensation provided in an embodiment of the present invention is shown below. Figure 6 Before step S1303, which involves compensating the first current resistance value based on the humidity parameter and the second compensation relationship to obtain the second current resistance value, the following steps are also included: Step S13021: Determine if the humidity parameter is greater than 100%RH. If the humidity parameter is greater than 100%RH, proceed to step S13022, which means assigning the humidity parameter a value of 100%RH.

[0067] Specifically, the humidity parameter detected by the humidity sensor may fluctuate, meaning it may exceed 100%RH. In this case, the humidity parameter is assigned a value of 100%RH to avoid errors when the processing module calculates the humidity compensation coefficient.

[0068] When the humidity parameter is less than 100%RH, step S13023 is executed, which determines whether the temperature is greater than a preset temperature threshold. The preset temperature threshold is related to the detection accuracy of the humidity sensor. When the temperature is greater than the preset temperature threshold, the detection accuracy of the humidity sensor is higher, and step S13031 is executed; while when the temperature is less than the preset temperature threshold, the detection accuracy of the humidity sensor is lower, and step S13024 is executed. The preset temperature threshold is, for example, 20℃.

[0069] Step S13031 can be understood as a detailed step within step S1303. First, the humidity parameter is substituted into the second compensation relationship to obtain the humidity compensation coefficient. Then, step S13032 is executed to generate the second current resistance value. The second current resistance value is, for example, the first current resistance value divided by the humidity compensation coefficient. In this embodiment, if the temperature is not greater than a preset temperature threshold, step S13024 is executed, meaning no humidity compensation is performed, and the humidity compensation coefficient is assigned a value of 1. By assigning a humidity compensation coefficient of 1, the current resistance value finally obtained by the processing module 13 is the result after only temperature compensation, avoiding the inaccuracy of the humidity parameter from affecting the compensation accuracy.

[0070] Based on the same inventive concept, this invention also provides a method for calibrating the compensation relationship of a combustible gas alarm, used to calibrate the compensation relationship of the combustible gas alarm provided in any embodiment of this invention. For example... Figure 7 As shown, Figure 7 A flowchart illustrating a calibration method for the compensation relationship of a combustible gas alarm, provided as an embodiment of the present invention, is included. The calibration method for the compensation relationship comprises: Step S210: Obtain multiple current resistance values ​​corresponding to the combustible gas alarm sample under multiple preset environmental parameter values; wherein, other environmental parameters are under calibration conditions; Specifically, the number of combustible gas alarm samples may be one or more, preferably multiple. When calibrating the compensation relationship for a certain environmental parameter, i.e., a preset environmental parameter, other environmental parameters are fixed at the calibration conditions. For example, when calibrating the compensation relationship corresponding to the temperature parameter, the humidity parameter is fixed at 65%RH; when calibrating the compensation relationship corresponding to the humidity parameter, the temperature parameter is fixed at 20℃. It can be understood that the concentration is fixed at 4000ppm. For each environmental parameter value, multiple sets of current resistance values ​​can be tested, and accuracy can be improved by averaging or other methods.

[0071] Step S220: Using the current resistance value corresponding to the preset environmental parameters under the calibration condition as the reference resistance value, preprocess other current resistance values; Specifically, when calibrating the compensation relationship, it is necessary to use samples of combustible gas alarms for calibration, meaning that it is not necessary to calibrate all combustible gas alarms, thereby improving calibration efficiency. Different combustible gas alarms have different reference resistance values, but the influence of environmental parameters on the current resistance value follows a consistent trend. Therefore, this embodiment can eliminate dimensions through preprocessing. For example, if the reference resistance is R0 and the current resistance is Rs, then the preprocessing method is Rs / R0. Of course, the preprocessing method can also be R0 / Rs, etc. This embodiment does not limit this, as long as the dimensions can be eliminated.

[0072] Step S230: Fit the preset environmental parameters with the corresponding preprocessed current resistance value to obtain the compensation relationship corresponding to the preset environmental parameters.

[0073] Specifically, once multiple sets of data are obtained, the compensation relationship can be calculated through fitting. Subsequently, it is only necessary to input the compensation relationship into all combustible gas alarm devices.

[0074] The calibration method for the compensation relationship in this embodiment can quickly calibrate the compensation relationship, thereby reducing the false alarm rate of combustible gas alarm devices. Furthermore, during calibration, different environmental parameters are calibrated independently to avoid mutual interference.

[0075] Optionally, a polynomial fitting method can be used to fit the compensation relationship to further improve the compensation accuracy.

[0076] Optionally, the temperature parameter can take multiple values ​​between 0℃ and 60℃, meaning the temperature parameter takes values ​​within this range, with a step size of 10℃. A current resistance value is calculated for each temperature parameter value, and each temperature parameter value can be maintained for at least one hour to further improve accuracy.

[0077] Optionally, the humidity parameter can take multiple values ​​ranging from 0%RH to 100%RH, meaning the humidity parameter can be taken within this range, with a step size of 20%RH. A current resistance value is calculated for each humidity parameter value, and each humidity parameter value can be maintained for at least one hour to further improve accuracy.

[0078] For example, Figure 8 The curve diagram of the first compensation relationship provided in the embodiment of the present invention plots the pre-processed current resistance value as a temperature curve; the corresponding polynomial function, i.e. the first compensation relationship, can be automatically generated according to the temperature curve, and finally the polynomial function is written into the firmware of each combustible gas alarm.

[0079] For example, Figure 9 The curve diagram of the second compensation relationship provided in the embodiment of the present invention plots the preprocessed current resistance value as a humidity curve; the corresponding polynomial function, i.e. the second compensation relationship, can be automatically generated according to the humidity curve, and finally the polynomial function is written into the firmware of each combustible gas alarm.

[0080] It should be noted that, in some implementations, the compensation relationship can also be stored in the processing module in the form of a lookup table.

[0081] Optionally, if the combustible gas alarm includes multiple sampling resistors, a reference voltage can be output to any one of the sampling resistors when calibrating the compensation relationship, without affecting the calibration result.

[0082] Based on the same inventive concept, this invention also provides a calibration system for the compensation relationship of a combustible gas alarm, used to perform any of the above-mentioned calibration methods for the compensation relationship. The calibration system for the compensation relationship includes: The system comprises a ring mixing chamber, an infrared gas analyzer, and a controller. The ring mixing chamber is used to configure environmental parameters, controlling the sample from the combustible gas alarm to be in a corresponding calibration environment. The infrared gas analyzer is used to detect the concentration of combustible gas. The controller, such as a PC, executes steps S210, S220, and S230. It should be noted that step S210 can also be executed by the processing module within the combustible gas alarm.

[0083] Based on the same inventive concept, this invention also provides a method for calibrating the reference resistance value of a combustible gas alarm, used to calibrate the reference resistance value of the combustible gas alarm provided in any embodiment of this invention. It is understood that the reference resistance value of the combustible gas alarm is the resistance value of the combustible gas sensing module under calibration conditions, and the reference resistance value may differ for different combustible gas alarms. After the compensation relationship is determined, the reference resistance value is still needed to determine whether an alarm should be triggered based on the compensated current resistance value.

[0084] like Figure 10 As shown, Figure 10 A flowchart illustrating a method for calibrating the reference resistance value of a combustible gas alarm according to an embodiment of the present invention. The method for calibrating the reference resistance value includes: Step S310: Obtain the current resistance value; Specifically, in this embodiment, the current resistance value can be determined based on the sampling voltage. When there are multiple sampling resistors, a reference voltage can be output to any one of the sampling resistors first. In other words, there is no requirement for the calculation accuracy of the current resistance value.

[0085] Step S320: If the duration during which the current resistance value is less than the calibration threshold is greater than or equal to a preset time, the current resistance value is used as the reference resistance value.

[0086] Specifically, the calibration threshold is, for example, an empirical value of the resistance of the combustible gas sensing module under calibration conditions. Since the resistance of the combustible gas sensing module decreases as the concentration of combustible gas increases, when the current resistance is less than the calibration threshold and exceeds a preset time, it is determined that the combustible gas alarm is in an environment for calibrating a reference resistance, and at this time, the current resistance value can be used as the reference resistance value.

[0087] In this embodiment, steps S310 and S320 can both be automatically executed by the processing module 13. As mentioned above, although the compensation relationship for different combustible gas alarms can be universal, the reference resistance values ​​for different combustible gas alarms are different, requiring calibration of the reference resistance value for each combustible gas alarm. Related technologies require manual calibration, while this application allows for automatic calibration, thus greatly improving calibration efficiency.

[0088] It should be noted that after the reference resistance value of the combustible gas alarm is calibrated, a calibration mark can be stored inside the combustible gas alarm. Before step S310, it can be first determined whether a calibration mark is stored. If a calibration mark is stored, it is not necessary to calibrate the reference resistance value again.

[0089] Optionally, such as Figure 11 As shown, Figure 11 A flowchart illustrating a method for calibrating the reference resistance value of a combustible gas alarm according to an embodiment of the present invention. The method for calibrating the reference resistance value includes: Step S309: Determine if a calibration flag is stored. If yes, end the calibration. Otherwise, determine if the device is in a calibration environment. This involves determining if the current resistance is less than a calibration threshold and if the duration of this value being less than the threshold is greater than or equal to a preset time. Specifically, the determination of whether the device is in a calibration environment may include step S3101, which determines if the current resistance is below the calibration threshold and the device is not in a calibration state. The processing module can internally set a flag indicating that the device is in a calibration state. If this flag is set, it indicates that the device is in a calibration state. When the current resistance is below the calibration threshold and the device is not in a calibration state, step S3102 is executed, which sets the device to be in a calibration state and synchronizes the time. The synchronized time is used to subsequently determine if the calibration state time is greater than or equal to a preset time. After step S3102 and when the result of step S3101 is negative, step S3103 is executed, which determines if the current resistance is above the calibration threshold and the device is in a calibration state. If the judgment result of step S3103 is yes, then step S3103 is executed, which clears the calibration state and synchronizes the time. In other words, it is determined at this point that the calibration state has been exited. If the judgment result of step S1303 is no, and after step S3103, step S3104 is executed, which determines whether the calibration state is greater than or equal to a preset time. If the judgment result is yes, then the calibration ends; otherwise, if the judgment result is yes, then subsequent steps such as step S320 are executed.

[0090] Optionally, in some embodiments, the combustible gas sensor includes a sampling resistor, in which case step S320 can be executed directly.

[0091] Optionally, in some embodiments, the combustible gas detector includes at least two sampling resistors. Further reference may be made at this point. Figure 11Before using the current resistance value as the reference resistance value, the following steps are also included: The control processing module outputs a reference voltage to the target sampling resistor among at least two sampling resistors; wherein, when the combustible gas alarm is in the calibration condition, the sampling voltage corresponding to the target sampling resistor is less than the upper limit voltage of the processing module; and among all sampling resistors whose corresponding sampling voltage is less than the upper limit voltage, the sampling voltage corresponding to the target sampling resistor is closest to the upper limit voltage. Specifically, the above steps may include step S311, which determines whether the current resistance value is less than the first threshold value; if so, step S312 is executed, otherwise step S313 is executed. Step S313 determines whether the current resistance value is less than the second threshold value; if so, step S314 is executed, otherwise step S315 is executed. Step S312 controls the selection of the first sampling resistor, step S314 controls the selection of the second sampling resistor, and step S315 controls the selection of the third sampling resistor.

[0092] More specifically, when there are three sampling resistors, two boundary values, namely the first boundary value and the second boundary value, can be used to determine which sampling resistor needs to be selected. Before determining which sampling resistor to select, since one sampling resistor has already been selected and its current resistance value is obtained, in some implementations, the sampling resistor to be selected (i.e., the target sampling resistor) can be determined by the sampling voltage under calibration conditions. This is done by sequentially turning on the three sampling resistors to determine the target sampling resistor. After accumulating a large number of sampling voltages and selected target sampling resistors, it is no longer necessary to sequentially turn on the three sampling resistors. Instead, the two boundary values ​​can be found through clustering or other methods, and the target sampling resistor can be determined directly based on the relationship between the current resistance value and the boundary value, thereby improving efficiency. It is understood that there is a definite correspondence between the current resistance value and the sampling voltage. Determining the relationship between the current resistance value and the boundary value can specifically mean determining the relationship between the sampling voltage and the corresponding voltage boundary value. This embodiment uses the example of the first sampling resistor having a resistance value less than the second sampling resistor, and the second sampling resistor having a resistance value less than the third sampling resistor, but it is not limited to this.

[0093] After selecting the sampling resistor, step S316, which stores the calibrated flag, can be executed. In this embodiment, using the current resistance value as the reference resistance value includes: Step S3201: The current resistance value corresponding to the target sampling resistor is used as the reference resistance value. That is, after selecting the target sampling resistor, the current resistance value is calculated again, and this current resistance value is stored in the processing module 13 as the reference resistance value. This completes the calibration of the reference resistance value.

[0094] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0095] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A combustible gas alarm, characterized in that, The combustible gas alarm includes: A combustible gas sensing module is used to adjust its resistance value according to the concentration of combustible gas. An environmental parameter detection module is used to detect at least two environmental parameters, including a temperature parameter and a humidity parameter. The processing module is electrically connected to the combustible gas sensing module and the environmental parameter detection module. The processing module is used to detect the current resistance value of the combustible gas sensing module and compensate the current resistance value according to the compensation relationship corresponding to each environmental parameter. The compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter when it is under the calibration condition.

2. The combustible gas alarm according to claim 1, characterized in that, The compensation relationship is a polynomial function.

3. The combustible gas alarm according to claim 1, characterized in that, The combustible gas alarm also includes at least two sampling resistors; the resistance values ​​of the different sampling resistors are different. One end of the sampling resistor is electrically connected to the first end of the combustible gas sensing module, the second end of the sampling resistor is electrically connected to the processing module, and the first end of the combustible gas sensing module is electrically connected to the processing module; the processing module is used to output a reference voltage to at least one of the at least two sampling resistors and to acquire the sampling voltage of the first end of the combustible gas sensing module.

4. The combustible gas alarm according to claim 3, characterized in that, The processing module is used to output the reference voltage to the target sampling resistor among the at least two sampling resistors; wherein, when the combustible gas alarm is in the calibration condition, the sampling voltage corresponding to the target sampling resistor is less than the upper limit voltage of the processing module; and among all the sampling resistors whose corresponding sampling voltage is less than the upper limit voltage, the sampling voltage corresponding to the target sampling resistor is closest to the upper limit voltage.

5. A compensation method for a combustible gas alarm, characterized in that, The combustible gas alarm includes: A combustible gas sensing module is used to adjust its resistance value according to the concentration of combustible gas; an environmental parameter detection module is used to detect at least two environmental parameters, including temperature and humidity; a processing module is electrically connected to the combustible gas sensing module and the environmental parameter detection module, the processing module is used to detect the current resistance value of the combustible gas sensing module and compensate the current resistance value according to the compensation relationship corresponding to each of the environmental parameters; wherein, the compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under the calibration condition; The compensation method includes: Obtain the current resistance value of the combustible gas sensing module; Obtain the at least two environmental parameters; The current resistance value is compensated based on the environmental parameters and the corresponding compensation relationship.

6. The compensation method for a combustible gas alarm according to claim 5, characterized in that, The compensation relationship is a polynomial function; the processing module is equipped with a first compensation relationship corresponding to the temperature parameter and a second compensation relationship corresponding to the humidity parameter; The step of compensating the current resistance value according to the environmental parameters and the compensation relationship includes: The current resistance value is compensated according to the temperature parameter and the first compensation relationship to obtain a first current resistance value; The first current resistance value is compensated according to the humidity parameter and the second compensation relationship to obtain the second current resistance value.

7. The compensation method for a combustible gas alarm according to claim 6, characterized in that, Before compensating the first current resistance value according to the humidity parameter and the second compensation relationship to obtain the second current resistance value, the method further includes: If the humidity parameter is greater than 100%RH, the humidity parameter is assigned a value of 100%RH; and / or, If the temperature parameter is less than the preset temperature threshold, the step of obtaining the humidity compensation coefficient based on the humidity parameter and the second compensation relationship will not be performed.

8. A method for calibrating the compensation relationship of a combustible gas alarm, characterized in that, The combustible gas alarm includes a combustible gas sensing module, which is used to adjust its resistance value according to the concentration of combustible gas. An environmental parameter detection module is used to detect at least two environmental parameters, including a temperature parameter and a humidity parameter; a processing module is electrically connected to the combustible gas sensing module and the environmental parameter detection module, and the processing module is used to detect the current resistance value of the combustible gas sensing module; wherein, the compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under the calibration condition; The method for determining the compensation relationship includes: The sample of the combustible gas alarm obtains multiple current resistance values ​​corresponding to multiple preset environmental parameters; wherein, the other environmental parameters are under calibration conditions. Using the current resistance value corresponding to the preset environmental parameters under the calibration condition as the reference resistance value, other current resistance values ​​are preprocessed. The preset environmental parameters are fitted with the corresponding preprocessed current resistance value to obtain the compensation relationship corresponding to the preset environmental parameters.

9. A method for calibrating the reference resistance value of a combustible gas alarm, characterized in that, The combustible gas alarm includes a combustible gas sensing module, which is used to adjust its resistance value according to the concentration of combustible gas. An environmental parameter detection module is used to detect at least two environmental parameters, including a temperature parameter and a humidity parameter; a processing module is electrically connected to the combustible gas sensing module and the environmental parameter detection module, the processing module is used to detect the current resistance value of the combustible gas sensing module, and compensate the current resistance value according to the compensation relationship corresponding to each of the environmental parameters; wherein, the compensation relationship is used to compensate the current resistance value to the resistance value corresponding to the environmental parameter under the calibration condition; The calibration method for the reference resistance value includes: Get the current resistance value; If the duration during which the current resistance value is less than the calibration threshold is greater than or equal to a preset time, the current resistance value is used as the reference resistance value.

10. The method for calibrating the reference resistance value of a combustible gas alarm according to claim 9, characterized in that, The combustible gas alarm further includes at least two sampling resistors; one end of each sampling resistor is connected to the first end of the combustible gas sensing module, the second end of each sampling resistor is connected to the processing module, and the first end of the combustible gas sensing module is electrically connected to the processing module; the processing module is used to output a reference voltage to at least one of the at least two sampling resistors and to acquire the sampling voltage of the first end of the combustible gas sensing module. Before using the current resistance value as the reference resistance value, the following steps are also included: The processing module is controlled to output the reference voltage to the target sampling resistor among the at least two sampling resistors; wherein, when the combustible gas alarm is in calibration condition, the sampling voltage corresponding to the target sampling resistor is less than the upper limit voltage of the processing module; and among all the sampling resistors whose corresponding sampling voltage is less than the upper limit voltage, the sampling voltage corresponding to the target sampling resistor is closest to the upper limit voltage. Using the current resistance value as the reference resistance value includes: The current resistance value corresponding to the target sampling resistor is used as the reference resistance value.

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