Sensing system based on post rotation mode and use method thereof

Abstract

The invention relates to the field of sensing control systems, in particular to a sensing system based on an on-duty mode and a use method thereof, and the system comprises at least two sensing units, a multifunctional circuit board, an embedded control module, a parameter monitoring module and an automatic switching module; when the sensing unit reaches a preset switching condition, the automatic switching module automatically switches the current sensing unit to another sensing unit to work so as to realize on-duty operation; the switching condition comprises that the working time of the current sensing unit reaches an effective working time threshold value or the running parameter of the current sensing unit drifts and exceeds a preset range. Through cooperative work of the preheating and self-checking module, the pause switching mechanism and the on-duty relay function, the system can flexibly adapt to different environments and detection requirements. The preheating ensures that the sensing unit is started in the optimal state, the pause mechanism reduces switching interference, the on-duty function improves the detection reliability, and the stability and the multi-scene applicability of the system are enhanced.

Description

Technical Field

[0001] The present invention relates to the field of sensor control systems, and in particular to a sensor system based on a rotation mode and a use method thereof. Background Art

[0002] With the rapid development of new generation information technologies such as the Internet of Things, big data and artificial intelligence, smart sensors have become an important technical means to support the interconnection of all things and the intelligent connection of all things, and continue to influence and change the economic industrial structure and people's lifestyles. For example, in the field of smart gas sensors, semiconductor gas sensors, as an important branch of sensor technology, are widely used in air quality monitoring, industrial waste gas detection, food safety and home safety due to their high sensitivity, low economic cost, portability and easy integration. The response mechanism of semiconductor gas sensors is based on the change of resistance or conductivity caused by the adsorption behavior and catalytic reaction of target gas molecules on the surface of gas-sensitive materials. Therefore, semiconductor gas sensors usually need to work at a certain temperature or light to activate the gas-sensitive material to respond to the gas. However, continuous high-temperature operation or light excitation will aggravate the changes in the physicochemical properties of gas-sensitive materials and even destroy the stability of the gas-sensitive material-device electrode interface, resulting in baseline drift. At the same time, the repeated adsorption, conversion and desorption of various gas molecules by gas-sensitive materials during long-term operation can easily lead to irreversible deterioration of their surface structure, causing the performance of semiconductor gas sensors to gradually decay. In addition, environmental factors such as temperature, humidity and environmental pollutants can also cause poisoning effects on gas-sensitive materials and affect the migration behavior of their carriers, thereby reducing the accuracy and long-term stability of their gas identification and detection.

[0003] The existing technology mainly starts from the gas-sensitive materials, and improves the performance loss of semiconductor gas sensors caused by environmental factors by modifying the components of the gas-sensitive materials, such as by introducing heteroatoms, precious metal loads or constructing heterojunctions to improve the anti-interference ability of gas-sensitive materials, thereby improving the response stability and reliability of gas sensors. Although the above methods can improve the anti-interference ability of the sensor to a certain extent, in practical applications, it is difficult for a single sensing unit to completely avoid the problems of baseline drift and poor long-term stability under long-term working conditions. In particular, most traditional semiconductor gas sensors rely on the continuous operation of a single gas sensing unit. Under continuous and long-term working environments, sensors generally face problems such as continuous performance degradation, poor continuous working reliability, and short life. Summary of the invention

[0004] The purpose of the present invention is to provide a sensing system based on a rotation mode and a method of using the same to solve the technical problems raised in the above-mentioned background technology.

[0005] Based on the above ideas, the present invention provides the following technical solutions:

[0006] A sensor system based on a rotation mode includes: at least two sensor units, a multifunctional circuit board, an embedded control module, a parameter monitoring module and an automatic switching module;

[0007] Wherein, the sensing units respectively have sensitive elements for the type and concentration of the target to be detected;

[0008] The multifunctional circuit board is integrated with the sensor unit to form a relatively complete embedded control system;

[0009] The multifunctional circuit board integrates an embedded control module, a parameter monitoring module and an automatic switching module, which is the basic condition for the operation of the system;

[0010] The embedded control module is used to obtain the working parameters of the current sensor unit, and determine whether the sensor unit meets the preset switching conditions according to the working parameters, so as to control the start, shutdown and switching of the sensor unit according to the rotation working mode;

[0011] The parameter monitoring module is used to monitor the operating parameters of each sensor unit in real time, and the operating parameters include resistance drift, conductance drift and current drift;

[0012] When the sensor unit reaches a preset switching condition, the automatic switching module automatically switches the current sensor unit to another sensor unit to achieve rotation operation;

[0013] The switching condition includes that the working time of the current sensor unit reaches the effective working time threshold or the operating parameter of the current sensor unit drifts beyond a preset range.

[0014] The multifunctional circuit board of the security module also includes a preheating and self-test module, a security module and an output module, which are supplementary conditions for the operation of the system;

[0015] The embedded control module is also used for the operation control of the preheating and self-checking module, the security module and the output module to achieve the benign operation of the system;

[0016] The preheating and self-checking module is used to perform preheating and self-checking operations before the sensing unit is started;

[0017] The security module is used to trigger the standby sensor unit to work when an abnormal working state is detected, and put the abnormal sensor unit into a dormant state;

[0018] The output module is used to output the processed test results and status information through display or communication, so that users can obtain the information required for system operation.

[0019] The control program is the operating software of the embedded control module in the multifunctional circuit board, and is a program assembly in which the parameter monitoring module, the automatic switching module, the preheating and self-checking module, the security module and the output module work in coordination.

[0020] By integrating multiple sensing units on a multifunctional circuit board and controlling them with an embedded control module, the system can operate efficiently according to the set rotation working mode. This design significantly reduces the problems of baseline drift, sensitivity reduction and material aging caused by long-term operation of a single sensing unit. Through the parameter monitoring module, key parameters such as resistance drift, conductivity drift and current drift are monitored in real time. The system can dynamically adjust the operating status of the sensing unit during the detection process to ensure the accuracy of the detection results. The automatic switching module switches between different sensing units through a rotation mechanism, ensuring the stability of the system under long-term operation. In addition, the preheating and self-test module ensures that the sensing unit reaches the best state before working, effectively avoiding errors caused by cold start, while the security module provides a safety mechanism to deal with sudden abnormalities, further improving the reliability and service life of the system. The overall design has significant advantages in detection accuracy, reliability and stability.

[0021] Preferably, the sensing unit is a gas sensing unit, an electrochemical sensing unit or an optical sensing unit. Most preferably, the sensing unit is a gas sensing unit.

[0022] Preferably, the sensing unit is a gas sensing unit, an electrochemical sensing unit or an optical sensing unit. Most preferably, the sensing element is a gas sensing element.

[0023] Preferably, the automatic switching program includes a sensor unit switching algorithm, and the specific steps include:

[0024] S1. Acquire the operating parameters of the current sensor unit from the parameter monitoring module, wherein the operating parameters include resistance drift, conductance drift and current drift;

[0025] S2. Calculate the effective working time of the sensor unit according to the obtained working parameters, and compare it with the preset maximum effective working time;

[0026] S3, comparing the effective working time with the preset maximum effective working time to determine whether the current sensor unit reaches the preset switching condition;

[0027] S4. When the effective working time of the currently working sensor unit is reached, the embedded control module triggers the automatic program switching mechanism. The automatic switching module controls the start of the next sensor unit to take over the work and continues the detection according to the working mode of the previous sensor unit, while putting the current sensor unit into a sleep state.

[0028] Through the logical structure of steps S1 to S4, the system first obtains the real-time operating parameters of the sensor unit from the parameter monitoring module, including resistance drift, conductance drift and current drift. These parameters directly reflect the operating status of the sensor unit and its detection performance. Subsequently, the effective working time is calculated according to the operating parameters and compared with the preset maximum effective working time to determine whether the current sensor unit needs to be switched. This calculation process not only ensures that the unit works in the optimal performance range, but also avoids misjudgment caused by parameter drift. Finally, the automatic switching module controls the start-up of the next sensor unit through the embedded control module to achieve seamless connection of the detection task. This program design effectively reduces the risk of system failure and improves operating efficiency, while also providing technical support for long-term and stable detection.

[0029] Preferably, the effective working time of the sensor unit is determined according to the following formula:

[0030] < 3-5% or

[0031] < 3-5% or

[0032] < 3-5%

[0033]

[0034] In the above formula, is the resistance drift; is the resistance value of the sensing unit at T0; T x The resistance value of the sensing unit; T e is the effective working time of the sensor unit; is the effective coefficient, which is determined by the characteristics of the sensor unit and the external working environment; is the conductivity drift; is the conductivity value of the sensor unit at T0; T x The conductivity value of the sensing unit; is the current drift; is the current value of the sensor unit at T0; T x The current value of the sensing unit;

[0035] The sensing unit characteristics include the composition of the sensitive material, the microstructure of the sensitive material, and the substrate type of the sensing unit;

[0036] The external operating environment includes ambient temperature, humidity, and interference.

[0037] The parameters in the above formula reflect the core performance indicators of the sensing unit, which intuitively reflect the response stability of the gas-sensitive material. By setting the drift range to 3-5%, the sensing unit can be strictly controlled to work in the best state, thereby avoiding the accumulation of errors caused by excessive drift. The formula reflects the combined influence of the external environment (such as temperature, humidity, interference, etc.) and material properties (such as the composition and structure of sensitive materials), and quantifies complex environmental variables into operational control parameters. The introduction of this formula not only ensures the accuracy of switching, but also provides a theoretical basis for system optimization design, significantly improving the actual application performance of the system.

[0038] Preferably, before each sensor unit starts working, it performs preheating and self-testing before entering formal operation, and the time of preheating and self-testing is set according to the characteristics of the sensor unit and the external environment.

[0039] The preheating and self-test modules ensure that each sensor unit is in the best working state before starting. The preheating process controls the gas-sensitive material to reach the response temperature to avoid performance deviation caused by cold start; the self-test function can dynamically detect the key parameters of the unit, troubleshoot potential fault risks, and prevent abnormal units from entering the detection state. The preheating time is usually adjusted according to the composition, microstructure and external environment of the gas-sensitive material, taking into account the balance between performance optimization and energy consumption control. The design of this module significantly improves the startup accuracy of the sensor unit and the overall reliability of the system, providing an important guarantee for continuous and stable detection.

[0040] Preferably, when the automatic switching module encounters one of the following special situations, it forces the next sensor unit to work and outputs a warning message:

[0041] (1) When the preset limit working time is reached, the limit working time is set to 2 times the effective working time;

[0042] (2) The resistance of the currently working sensor unit is short-circuited, open-circuited, or has serious abnormalities in the electrical signal;

[0043] (3) Other systemic failures.

[0044] The automatic switching module can quickly trigger forced protective switching. By setting the limit working time to twice the effective working time, the system avoids the problem of too frequent switching while ensuring safety margin. When there are situations such as short circuit, open circuit or serious abnormality of electrical signal, the system immediately switches to the backup sensing unit and outputs a warning message to prompt the user to replace the faulty unit. The introduction of this protection mechanism effectively improves the system's ability to cope with sudden failures, ensures the continuity and safety of detection, and avoids detection interruption or error accumulation due to single point failure.

[0045] Preferably, when the automatic switching module encounters one of the following situations, the automatic program switching mechanism is not activated, and the currently working sensor unit suspends the execution of the switching function and continues to work:

[0046] (1) Excluding baseline drift and determining the trigger response state: within a fixed time interval, the resistance drift, conductance drift or current drift of the currently working sensor unit is greater than or equal to 10%, and the state is continuously triggered more than the set number of times;

[0047] (2) The currently operating sensor unit has detected a response and is in the measurement process;

[0048] When the above situation disappears, the automatic program switching mechanism is reactivated.

[0049] A pause function is introduced in the switching mechanism. When the baseline drift is detected and judged as a response state or the sensor unit is in the measurement process, the automatic switching module will not activate the switching function temporarily. This design can effectively distinguish the drift caused by environmental factors from the response signal by setting a fixed time interval and a drift threshold, and prevent the occurrence of false switching. In addition, this function allows the sensor unit to maintain continuous operation at critical moments, thereby improving the detection integrity and response accuracy of the system. After the abnormal state disappears, the system automatically restores the switching mechanism, ensuring the organic combination of operational flexibility and stability.

[0050] Preferably,

[0051] The automatic program switching mechanism is activated and will automatically switch to the next sensor unit to work when one of the following situations occurs:

[0052] (1) When the preset effective working time is reached;

[0053] (2) When the resistance drift, conductance drift or current drift of the currently operating sensor unit is greater than or equal to 3-5%;

[0054] Among them, situation (1) is a regular switching condition, and situation (2) is an unconventional switching condition. When situation (2) is triggered, the automatic switching module performs cumulative counting. When the count value reaches a preset value, the automatic switching module will give a prompt to replace the sensor unit.

[0055] Automatic switching between sensing units can be achieved under both conventional switching conditions (such as reaching the effective working time) and unconventional switching conditions (such as drift exceeding the limit). When unconventional conditions are triggered, the system accumulates the number of abnormal events through the abnormality counter, and outputs replacement prompt information after reaching the preset threshold to guide users to perform maintenance in a timely manner. This multi-level switching management strategy not only improves the detection efficiency of the system, but also reduces the errors caused by abnormal operation of the unit, laying a solid foundation for long-term stable operation.

[0056] A method for using a sensor system based on a rotation mode includes using the sensor system based on the rotation mode, and the specific steps include:

[0057] S1. When starting, first select the first sensor unit to enter preheating and self-testing. After the preheating and self-testing, it enters the working state and performs type and concentration detection;

[0058] S2. During the operation of the first sensor unit A, real-time monitoring of operating parameters, including resistance drift, conductance drift, and current drift, etc., is performed to determine in real time whether the first sensor unit exceeds a predetermined limit. When the preset effective working time is reached or the resistance drift, conductance drift, or current drift of the first sensor unit is greater than or equal to 3-5%, the first sensor unit is automatically stopped from working and put into a dormant state;

[0059] S3, before the first sensor unit stops working, the second sensor unit is started in advance to perform a preheating self-test. When the first sensor unit stops working, the second sensor unit immediately takes over its work and continues to detect according to the detection mode of the first sensor unit, and then takes over in sequence;

[0060] S4. During the entire operation cycle, multiple sensor units are periodically rotated. If the second sensor unit is dormant, a new third sensor unit can be started or the first sensor unit can be started again to work.

[0061] The preheating and self-test modules in step S1 ensure the stability of unit startup; the real-time monitoring and judgment in step S2 improve the accuracy of operating parameters; the seamless relay mode in step S3 ensures the continuity of system operation; and step S4 realizes the periodic rotation operation between units, effectively extending the overall life of the system. Through this method of use, the system can adapt to complex working environments while operating uninterruptedly, providing stable and reliable technical support for multi-field detection.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] The present invention significantly reduces the baseline drift, sensitivity reduction and material aging problems caused by long-term continuous work of a single sensor unit by introducing a rotating work mode. The intelligent switching of multiple units is realized through an embedded control module, which not only disperses the workload of the units, but also effectively extends the overall service life of the sensor. Compared with the traditional design that relies on a single sensor unit, the system shows better stability and durability in long-term and high-frequency detection tasks. In addition, the automatic switching module can accurately determine the switching timing according to the drift parameters monitored in real time, avoid performance degradation and detection errors caused by excessive work, and ensure the high reliability and sustainability of the system in complex working environments.

[0064] Through the real-time parameter monitoring module, the present invention can efficiently obtain the key operating parameters of the sensor unit, including resistance drift, conductivity drift and current drift, and calculate the effective working time based on these parameters. The mathematical formula used defines the optimal working range of the sensor unit in a quantitative manner, and combines the characteristics of the sensing material and the external environmental conditions to achieve scientific decision-making on the switching timing. In particular, by controlling the drift within the range of 3-5%, the accuracy of the test results and the stability of the unit operation are ensured. In addition, the automatic switching module is also designed with an abnormality detection and forced switching mechanism, which can respond quickly to problems such as short circuits and open circuits, and switch to the backup unit to continue working, greatly improving the system's adaptability to emergencies.

[0065] The sensor control system design proposed in the present invention has flexible adaptability and supports various types of sensor units, such as semiconductor sensor units, electrochemical sensor units, catalytic combustion sensor units, and optical sensor units. The significance of this design is that through the selection of diversified sensor units, the system performance can be optimized according to different application requirements. For example, semiconductor gas sensor units are particularly suitable for air quality monitoring, industrial waste gas detection and other occasions, electrochemical sensor units perform outstandingly in low-concentration gas detection, and optical sensor units have high selectivity and stability in high-precision, specific gas detection. According to different application scenarios, users can choose the most suitable sensor units to combine or mix them to achieve the best detection effect, thereby greatly improving the versatility, flexibility and reliability of the system.

[0066] Among the various sensor unit options, the gas sensor unit is defined as the best choice based on its comprehensive advantages in cost, stability and performance. Gas sensor units, especially those based on semiconductor materials, usually have lower costs and longer service life, as well as better durability and stability. Compared with electrochemical and optical sensor units, the sensitivity and response speed of gas sensor units in gas concentration detection can already meet the needs of most conventional applications, so they are preferred in many applications. Through this design, the system can maintain low operating costs while ensuring high efficiency, thus providing a more economical and practical solution.

[0067] Through the collaborative work of a series of modules (such as preheating and self-testing modules, pause switching mechanism, and rotation relay function), flexible adaptation to different environments and detection requirements is achieved. When the system starts, the preheating and self-testing modules enable the sensor unit to start working in the best state, avoiding performance deviations caused by cold start; the pause switching mechanism allows the unit to maintain continuous operation during detection response, effectively reducing switching interference; the rotation relay function further improves the system's detection efficiency and multi-scenario applicability through periodic rotation operation. In addition, the system can also automatically count and prompt under unconventional conditions, helping users to maintain the sensor unit in a timely manner and optimizing the long-term operation and maintenance costs of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic structural diagram of a semiconductor sensing system based on a rotation mode provided by the present invention;

[0069] Figure 2 It is a structural schematic diagram of a multifunctional circuit board of a semiconductor gas sensor system based on a rotation mode provided by the present invention;

[0070] Figure 3 It is an optical photograph of the multifunctional circuit board of the semiconductor gas sensing system based on the rotation mode provided by the present invention;

[0071] Figure 4a to Figure 4g The resistance change recorded by the semiconductor gas sensor system based on the rotation mode of Pt loaded SnO2 in Example 1 of the present invention when it runs continuously for 24 hours for 7 days;

[0072] Figure 5 The resistance change recorded by the semiconductor gas sensor system based on the rotation mode of Pt loaded SnO2 in Example 1 of the present invention after continuous operation for 4 days;

[0073] Figure 6 The resistance change recorded by the semiconductor gas sensor system based on the rotation mode of Pt loaded SnO2 in Example 1 of the present invention after continuous operation for 5 days;

[0074] Figure 7 The resistance change recorded by the semiconductor gas sensor system based on the rotation mode of Pt loaded SnO2 in Example 1 of the present invention when it is exposed to air environment and operates continuously for 232 days;

[0075] Figure 8 This is the resistance drift of the MEMS sensing unit based on Pt loaded SnO2 in Example 1 of the present invention when it runs alone for 112 hours;

[0076] Fig. 9 The resistance drift of a commercially available semiconductor gas sensor based on a single sensitive element after continuous operation for 84 days is compared with the present invention;

[0077] Fig.10 The resistance change recorded by the semiconductor gas sensor system based on the rotation mode of Pt-loaded WO3 in Example 2 of the present invention after long-term continuous operation for 77 days;

[0078] Fig.11 This is the resistance change recorded by the semiconductor gas sensor system based on the rotation mode of Pd-loaded ZnO and Au-loaded ZnO in Example 3 of the present invention after long-term continuous operation for 184 days.

[0079] In the figure: 1. Sensitive unit A; 2. Sensitive unit B; 3. Spare sensitive unit; 4. Sensor electrical signal interface; 5. Multi-function circuit board; 6. Heating control circuit of sensitive unit A; 7. Heating control circuit of sensitive unit B; 8. Display function chip; 9. Embedded single-chip microcomputer and auxiliary circuit; 10. Sensor test resistance sampling circuit; 11. Power supply, sensor access and control output interface; 12. PCB board; 13. Program burning interface. DETAILED DESCRIPTION

[0080] Embodiment 1:

[0081] This embodiment provides a semiconductor gas sensing system based on a rotation mode, comprising two gas sensing units (named as gas sensing unit A1 and gas sensing unit B1 respectively). Both gas sensing units use a MEMS substrate and Pt-loaded SnO2 as a gas-sensitive material for detecting methane concentration. The system operates at 350°C and detects methane by real-time monitoring of resistance changes. The semiconductor gas sensing system sets the effective working time of each gas sensing unit to 2 hours, and the resistance drift of gas sensing unit A1 and gas sensing unit B1 is less than 5% during this effective working time. The system first starts gas sensing unit A1 for preheating self-test, and the preheating self-test time is 5 minutes. After gas sensing unit A1 has been working continuously for 1 hour and 55 minutes, it automatically starts gas sensing unit B1 for preheating self-test. At this time, gas detection is still performed by gas sensing unit A1. The preheating self-test time of gas sensor unit B1 is set to 5 minutes. After the preheating self-test is completed, the gas sensor unit B1 takes over the work, and the gas sensor unit A1 enters the sleep mode. Similarly, after the gas sensor unit B1 has been working continuously for 1 hour and 55 minutes, the gas sensor unit A1 is automatically started again for preheating self-test. After 5 minutes, the gas sensor unit B1 enters sleep mode, and the gas sensor unit A1 takes over the work. A rotation cycle mode is formed in sequence. This mode effectively reduces the workload of a single gas sensor and is suitable for long-term methane detection applications that require high stability.

[0082] like Figure 4a to Figure 4g As shown in the figure, the resistance change of the system during 24 hours of continuous operation was monitored in real time (the resistance change during the warm-up self-test was not recorded), and the resistance change was recorded for 7 days. The test results showed that within 24 hours, the baseline resistance of the two gas sensing units remained stable with little fluctuation. Figure 5 and Figure 6 The resistance changes of the system after 4 and 5 days of continuous operation are shown respectively, and the baseline resistance of the two gas sensing units remains stable. In addition, in order to simulate the real air quality detection environment, the semiconductor gas sensing system of the present invention is exposed to the air environment, continuously operated for 232 days and its resistance changes are monitored. Figure 7 The resistance change curve of the system after 232 days of continuous rotation in the air environment is shown. The results show that the baseline resistance trend of the two gas sensor units is relatively stable. Although the baseline fluctuates due to environmental factors, it is always within a stable range. This result proves that the rotation mode of the present invention can effectively resist the sensor stability degradation and baseline drift caused by environmental factors, thereby ensuring the reliability of the system in air quality monitoring.

[0083] In contrast, if the MEMS gas sensing unit based on Pt-loaded SnO2 is operated alone, such as Figure 8As shown in the figure, its baseline resistance gradually increases with the increase of running time. After 112 hours of continuous operation, the baseline resistance drift rate reaches 212.34%, and it does not show a trend of gradual stabilization. The results show that when a single gas sensing unit is operated continuously alone, its baseline resistance shows a large drift and extremely poor stability, which is not conducive to real-time and accurate gas monitoring. In addition, the resistance of four commercially available semiconductor gas sensors using a single sensitive element during continuous operation was monitored, such as Fig. 9 As shown in the figure, after 60 days of continuous operation, the baseline resistance of the four semiconductor gas sensors all began to drift, and their resistance increased sharply after 68 days of operation. The results show that the commercially available semiconductor gas sensor can work normally and perform accurate gas monitoring within 60 days. After 60 days, the commercially available semiconductor gas sensor gradually fails. Therefore, compared with the commercially available semiconductor gas sensor that uses a single sensitive element to operate, the semiconductor gas sensing system based on the rotation mode provided in this embodiment greatly improves its long-term continuous operation stability and increases the service life of the gas sensor.

[0084] Embodiment 2:

[0085] This embodiment provides a semiconductor gas sensor system based on a rotation mode for air quality detection, including two sensitive units (named as sensitive unit A2 and sensitive unit B2). Both of these sensitive units use MEMS substrates and Pt-loaded WO3 to detect the concentration of ammonia in the environment. The system operates at 260°C and detects ammonia by real-time monitoring of resistance changes. The semiconductor gas sensor system sets the effective working time of each sensitive unit to 2 hours, and the resistance drift of sensitive unit A2 and sensitive unit B2 during this effective working time is less than 4%. The system first starts sensitive unit A2 for preheating self-test, and the preheating self-test time is 5 minutes. When sensitive unit A2 works continuously for 1 hour and 55 minutes, it automatically starts sensitive unit B2 for preheating self-test. At this time, gas detection is still performed by sensitive unit A2. The preheating self-test time of sensitive unit B2 is set to 5 minutes. After the preheating self-test is completed, it switches to sensitive unit B2 to take over, and sensitive unit A2 enters sleep mode. Similarly, when the sensitive unit B2 works continuously for 1 hour and 55 minutes, the sensitive unit A2 is automatically started again for preheating self-test. After 5 minutes, the sensitive unit B2 goes into sleep mode and the sensitive unit A2 takes over. The A2-B2-A2 cyclic relay mechanism works cyclically between the two sensitive units to achieve continuous and stable detection of ammonia in the air.

[0086] Fig.10The results of the resistance change of the system during 77 days of continuous operation are shown. The resistance change of the two sensitive units remains stable, which verifies that the rotating relay working mode proposed in the present invention can effectively improve the long-term stability of the semiconductor gas sensor system.

[0087] Embodiment three:

[0088] This embodiment relates to a semiconductor gas sensing system based on a rotation mode, and the system includes three minimum sensitive units (named as sensitive unit A3 and sensitive unit B3 respectively). The sensitive material of sensitive unit A3 is Pd-modified ZnO, and the sensitive material of sensitive unit B3 is Au-modified ZnO. The substrates of the two sensitive units are flexible polyimide materials, which are used to detect the formaldehyde concentration in the air. Ammonia is detected by real-time monitoring of the changes in the system current. The semiconductor gas sensing system sets the effective working time of each sensitive unit to 4 hours, and the current drift of the three sensitive units during this effective working time is less than 3%. The system first starts sensitive unit A3 for preheating self-test, and the preheating self-test time is 8 minutes. When sensitive unit A3 works continuously for 3 hours and 52 minutes, it automatically starts sensitive unit B3 for preheating self-test. At this time, gas detection is still performed by sensitive unit A3. The preheating self-test time of sensitive unit B3 is set to 8 minutes. After the preheating self-test is completed, it switches to sensitive unit B3 to relay work, and sensitive unit A3 enters sleep mode. When the sensitive unit B3 goes into sleep after working continuously for 4 hours, the sensitive unit A3 takes over again, and the two sensitive units work in a cyclic relay mechanism of A3-B3-A3, realizing continuous and stable detection of formaldehyde in the air.

[0089] Fig.11 The resistance change results of the semiconductor gas sensor system in this embodiment during 184 days of continuous operation with an A3-B3-A3 cyclic relay mechanism are shown. From the results, it can be seen that the resistance changes of the two sensitive units remain stable, which once again verifies that the rotating relay working mode proposed in the present invention can effectively improve the long-term stability of the semiconductor gas sensor system.

[0090] Embodiment 4:

[0091] This embodiment provides a semiconductor gas sensor system for hydrogen sulfide detection at room temperature, including four sensitive units (named as sensitive unit A4, sensitive unit B4, sensitive unit C4 and sensitive unit D4 respectively), all of which use a composite material of CuO and redox graphene as a sensitive material, and the substrate is a flexible PET material. Hydrogen sulfide is detected by real-time monitoring of changes in the conductivity of the system. The semiconductor gas sensor system sets the effective working time of each sensitive unit to 3 hours, and the current drift of the four sensitive units during this effective working time is less than 4%. The system first starts sensitive unit A4 for preheating self-test, and the preheating self-test time is 6 minutes. When sensitive unit A4 works continuously for 2 hours and 54 minutes, it automatically starts sensitive unit B4 for preheating self-test. At this time, gas detection is still performed by sensitive unit A4. The preheating self-test time of sensitive unit B4 is set to 6 minutes. After the preheating self-test is completed, it switches to sensitive unit B4 to take over, and sensitive unit A4 enters sleep mode. Similarly, after sensitive unit B4 has worked continuously for 2 hours and 54 minutes, sensitive unit C4 is automatically started for preheating self-test, and at this time, sensitive unit B4 is still performing gas detection. The preheating self-test time of sensitive unit C4 is also set to 6 minutes. After the preheating self-test is completed, it switches to sensitive unit C4 to take over the work, and sensitive unit B4 enters sleep mode. After sensitive unit C4 has worked continuously for 2 hours and 54 minutes, sensitive unit D4 is automatically started for preheating self-test, and at this time, sensitive unit C4 is still performing gas detection. The preheating self-test time of sensitive unit D4 is also set to 6 minutes. After the preheating self-test is completed, it switches to sensitive unit D4 to take over the work, and sensitive unit C4 enters sleep mode. After sensitive unit D4 has worked continuously for 3 hours and enters sleep mode, sensitive unit A4 takes over the work again, and works between the four sensitive units in a cyclic relay mechanism of A4-B4-C4-D4-A4, realizing continuous and stable detection of hydrogen sulfide at room temperature.

[0092] Embodiment five:

[0093] The present embodiment relates to a semiconductor gas sensor system in a rotating mode for automobile exhaust monitoring, which includes five gas sensors (named as sensitive unit A5, sensitive unit B5, sensitive unit C5, sensitive unit D5 and sensitive unit E5 respectively). The five sensitive units all use a heterojunction composite material of SnO2 / NiO as a sensitive material and a ceramic tube as a substrate, and detect carbon monoxide by real-time monitoring of changes in system resistance. The semiconductor gas sensor system sets the effective working time of each sensitive unit to 2 hours, and the resistance drift of the five sensitive units during this effective working time is less than 5%. The system first starts sensitive unit A5 for preheating self-test, and the preheating self-test time is 5 minutes. When sensitive unit A5 works continuously for 1 hour and 55 minutes, it automatically starts sensitive unit B5 for preheating self-test. At this time, gas detection is still performed by sensitive unit A5. The preheating self-test time of sensitive unit B5 is set to 5 minutes. After the preheating self-test is completed, it switches to sensitive unit B5 to take over, and sensitive unit A5 enters sleep mode. Similarly, after sensitive unit B5 has been working continuously for 1 hour and 55 minutes, sensitive unit C5 is automatically started for preheating self-test, and at this time, sensitive unit B5 is still performing gas detection. The preheating self-test time of sensitive unit C5 is also set to 5 minutes. After the preheating self-test is completed, it switches to sensitive unit C5 to take over the work, and sensitive unit B5 enters sleep mode. After sensitive unit C5 has been working continuously for 1 hour and 55 minutes, sensitive unit D5 is automatically started for preheating self-test, and at this time, sensitive unit C5 is still performing gas detection. The preheating self-test time of sensitive unit D5 is also set to 5 minutes. After the preheating self-test is completed, it switches to sensitive unit D5 to take over the work, and sensitive unit C5 enters sleep mode. After sensitive unit D5 has been working continuously for 1 hour and 55 minutes, sensitive unit E5 is automatically started for preheating self-test, and at this time, sensitive unit D5 is still performing gas detection. The preheating self-test time of sensitive unit E5 is also set to 5 minutes. After the preheating self-test is completed, it switches to sensitive unit E5 to take over the work, and sensitive unit D5 enters sleep mode. When the sensitive unit E5 goes into sleep after working continuously for 2 hours, the sensitive unit A5 takes over again, working among the five sensitive units in a cyclic relay mechanism of A5-B5-C5-D5-E5-A5, thus achieving continuous and stable detection of carbon monoxide in automobile exhaust.

[0094] Embodiment six:

[0095] This embodiment is applied to the rotating mode semiconductor gas sensor system for gas monitoring in agricultural greenhouses, which includes six sensitive units (named as sensitive unit A6, sensitive unit B6, sensitive unit C6, sensitive unit D6, sensitive unit E6 and sensitive unit F6 respectively). The six sensitive units all use MoS2-MXene heterojunction composite materials as sensitive materials, and the substrate is MEMS. The concentration of nitrogen dioxide in the greenhouse is detected by real-time monitoring of the change in system resistance. The semiconductor gas sensor system sets the effective working time of each sensitive unit to 3 hours. During this effective working time, the resistance drift of the six sensitive units is less than 3%. The system first starts sensitive unit A6 for preheating self-test, and the preheating self-test time is 7 minutes. When sensitive unit A6 works continuously for 2 hours and 53 minutes, it automatically starts sensitive unit B6 for preheating self-test. At this time, gas detection is still performed by sensitive unit A6. The preheating self-test time of sensitive unit B6 is set to 7 minutes. After the preheating self-test is completed, it switches to sensitive unit B6 to take over, and sensitive unit A6 enters sleep mode. Similarly, after sensitive unit B6 has worked continuously for 2 hours and 53 minutes, sensitive unit C6 is automatically started for preheating self-test, and at this time, sensitive unit B6 is still performing gas detection. The preheating self-test time of sensitive unit C6 is also set to 7 minutes. After the preheating self-test is completed, it switches to sensitive unit C6 to take over, and sensitive unit B6 enters sleep mode. After sensitive unit C6 has worked continuously for 2 hours and 53 minutes, sensitive unit D6 is automatically started for preheating self-test, and at this time, sensitive unit C6 is still performing gas detection. The preheating self-test time of sensitive unit D6 is also set to 7 minutes. After the preheating self-test is completed, it switches to sensitive unit D6 to take over, and sensitive unit C6 enters sleep mode. After sensitive unit D6 has worked continuously for 2 hours and 53 minutes, sensitive unit E6 is automatically started for preheating self-test, and at this time, sensitive unit D6 is still performing gas detection. The preheating self-test time of sensitive unit E6 is also set to 7 minutes. After the preheating self-test is completed, it switches to sensitive unit E6 to take over, and sensitive unit D6 enters sleep mode. After the sensitive unit E6 has worked continuously for 2 hours and 53 minutes, the sensitive unit F6 is automatically started for preheating self-test. At this time, the sensitive unit E6 is still used for gas detection. The preheating self-test time of the sensitive unit F6 is also set to 7 minutes. After the preheating self-test is completed, the sensitive unit F6 takes over the work and the sensitive unit E6 enters the sleep mode. After the sensitive unit F6 has worked continuously for 3 hours and enters the sleep mode, the sensitive unit A6 takes over the work again. The six sensitive units work in a cyclic relay mechanism of A6-B6-C6-D6-E6-F6-A6, realizing continuous and stable detection of nitrogen dioxide concentration in the greenhouse.

[0096] Embodiment seven:

[0097] Gas sensing unit characteristics, including: Sensitive material composition: including the chemical composition of the material (such as semiconductor gas-sensitive materials such as SnO2 and ZnO);

[0098] The microstructure of sensitive materials, such as particle size, specific surface area, etc., these parameters affect the reaction rate and stability of the material;

[0099] Substrate type: The thermal conductivity and mechanical stability of different substrates (such as ceramic substrates, polyimide, etc.) affect the response time and drift rate of the sensor;

[0100] Working temperature: When the sensor works in a high temperature environment, the material aging is accelerated and a lower value to limit the working time of the unit;

[0101] Relative humidity: Increased humidity may cause a decrease in the gas adsorption capacity of the material surface. It should be adjusted down to ensure stability;

[0102] Interference gas: When there is a high concentration of interference gas in the environment, the performance of the sensor may deteriorate. The value controls the unit working time.

[0103] Effective coefficient It is a key parameter for evaluating the service life and stability of the gas sensor unit in actual work. This coefficient determines the maximum effective working time of the gas sensor unit and the degree of matching between its material properties and environmental conditions. In order to ensure that the sensor unit operates at the best performance, the present invention quantifies it through the following formula Calculation:

[0104] = 0×f1(M)×f2(S)×f3(B)×f4(T)×f5(H)×f6(G)

[0105] in:

[0106] 0 is the basic coefficient, take 0.4;

[0107] f1(M) is the correction factor of the sensitive material composition (e.g., SnO2: 1.0, ZnO: 0.9, WO3: 1.1);

[0108] f2(S) is the correction coefficient of the microstructure. In the present invention, the microstructure variable specifically refers to the pore structure (wherein, ordered open pores: 1.1, disordered but loose pores: 1.0, dense pores: 0.9);

[0109] f3(B) is the substrate type correction factor (ceramic: 1.0, metal: 0.95, polyimide: 1.05);

[0110] f4(T) operating temperature correction factor (>300°C: 0.9, 200-300°C: 1.0, <200°C: 1.1);

[0111] f5(H) is the humidity correction factor (RH <30%: 1.0, 30%-70%: 1.05, >70%: 0.95);

[0112] f6(G) is the interference gas correction factor (low interference: 1.0, medium interference: 0.95, high interference: 0.9).

[0113] The method of use is: according to the material characteristics of the sensing unit and the actual working environment, the values ​​of each correction factor are determined respectively;

[0114] Substitute all correction factors into the formula to calculate The value of

[0115] If the calculated result is not within the range of 0.3 to 0.5, the basic parameters need to be adjusted. 0 to ensure the stability of the system.

[0116] Examples:

[0117] SnO2-based gas sensing unit

[0118] Material properties: SnO2, microstructure: disordered but loose pores, ceramic substrate;

[0119] Working environment: temperature 250°C, humidity 40%, low interfering gas concentration;

[0120] Correction Factor:

[0121] f1(M)=1.0,f2(S)=1.0,f3(B)=1.0,f4(T)=1.0,f5(H)=1.05,f6(G)=1.0

[0122] Calculation results: =0.4×1.0×1.0×1.0×1.0×1.05×1.0=0.42.

[0123] Effective coefficient It is a key indicator for evaluating the performance stability and maximum effective working time of the gas sensing unit during operation. The present invention converts complex physical phenomena into controllable engineering parameters by quantifying the characteristics of the gas sensing unit and external environmental conditions. The formula is as follows:

[0124] Principle analysis:

[0125] 0 is the basic coefficient, reflecting the standard performance under ideal conditions;

[0126] Each correction factor (f1 to f6) introduces considerations for actual working conditions. For example, the composition f1 (M) of the sensitive material has different sensitivities to gas detection, the microstructure f2 determines the specific surface area and activity of the material, the substrate type f3 (B) affects thermal conductivity and mechanical stability, while temperature f4 (T), humidity f5 (H) and interfering gas f6 (G) comprehensively reflect the impact of the external environment on the working of the sensor unit.

[0127] Effect description:

[0128] By designing the formula, The range of is strictly controlled between 0.3-0.5 to ensure that the sensing unit always works in the best condition. For example, the sensitive material of the gas sensing unit usually has certain microstructural characteristics, and the pore structure is an important factor affecting the adsorption, diffusion and reaction of gas molecules. The arrangement and density of the pore structure directly determine the specific surface area of ​​the gas-sensitive material, the degree of exposure of the active sites, and the efficiency of gas transmission. By reasonably setting the microstructure correction coefficient f2(S), the performance matching of the gas sensing unit under different pore structure conditions is optimized to ensure that the material achieves the best balance between efficient response and stable operation.

[0129] According to the adsorption and diffusion characteristics of gas molecules in different pore structures, the present invention divides the pore structures into the following three categories and sets corresponding correction coefficients f2(S) for them:

[0130] Ordered open pores: Ordered open pores have regular arrangement and connectivity (such as molecular sieves or mesoporous materials), and gas molecules can be efficiently transported along a predetermined path. The regular pore structure not only increases the specific surface area, but also enhances the diffusion rate of gas molecules, promotes full contact between gas molecules and active sites, and significantly improves the sensing sensitivity.

[0131] Since the ordered pores contribute more to the sensitivity, it is necessary to enhance their effectiveness by f2(S)=1.1. to support the sensor unit to operate for a longer time and with higher accuracy.

[0132] Disordered but loose pores are common characteristics of porous materials. There is no obvious regularity in the distribution of pores, but there are many pores and good connectivity (such as typical porous oxide materials). This structure ensures the free diffusion of gas molecules in the pores while providing sufficient specific surface area. The sensitivity and stability of gas detection are relatively balanced. Because its performance is close to the standard state, f2(S)=1.0 is set to keep the performance output of the gas sensor unit under this microstructure unaffected by additional weights.

[0133] Dense pores: Dense pores have low porosity and limited internal diffusion (such as low-porosity samples in nanomaterials or sintered densified materials). Gas molecules have difficulty diffusing in dense pores and cannot quickly reach the active sites of the material, resulting in reduced sensing sensitivity and longer response time, affecting detection efficiency. In order to reflect the negative impact of dense pores on performance, f2(S)=0.9 is appropriately reduced in the effective coefficient. The weight in limits the long-term operation of this type of sensing unit to avoid over-reliance on low-performance units.

[0134] The role of pore structure can explain the scientific basis for setting the correction factor from the following two main aspects:

[0135] The pore structure directly affects the specific surface area of ​​the gas-sensitive material. Ordered open channels have a larger specific surface area, which can adsorb more gas molecules and provide more active sites to participate in the reaction. Due to the small specific surface area of ​​dense channels, the adsorption capacity is insufficient, and the contact opportunities between gas molecules and active sites are reduced, thus limiting the sensing performance. Ordered channels have good connectivity, and gas molecules can diffuse quickly and reach active sites efficiently, thereby improving the response speed and detection efficiency. The diffusion performance of disordered loose channels is moderate, showing stable and balanced response characteristics. Dense channels may have a diffusion limitation effect, which delays the response time and reduces the dynamic characteristics of the sensing performance.

[0136] By introducing f2(S) and classifying and assigning values ​​based on the characteristics of the pore structure, the present invention achieves the following effects:

[0137] By adjusting the correction factor of different pore structures, the effective coefficient The calculation is more consistent with the actual physical properties. For example, in an ideal environment, the ordered open pores can be The weight of the system is increased to extend the working time and improve the overall efficiency of the system.

[0138] The effect of the pore structure correction coefficient on the preheating time is reflected in the activation characteristics of gas molecule adsorption and diffusion in different pores. The preheating time of ordered open pores can be appropriately shortened due to their faster adsorption rate and smaller diffusion resistance, while the preheating time of dense pores needs to be appropriately extended because it takes longer to activate the adsorption process. Through the scientific setting of the above correction coefficients, the performance of the gas sensing unit can be optimized, the adaptability of the system under different environmental conditions is enhanced, and strong support is provided for the long-term stable operation of the sensing system.

[0139] When the operating temperature is high, the material may experience thermal aging. In this case, by reducing the value of f4(T), the , reducing the continuous working time of the unit and avoiding excessive performance degradation. In addition, the noise caused by environmental factors such as humidity and interfering gases can also be corrected by adjusting the values ​​of f5(H) and f6(G), thereby improving the adaptability and detection accuracy of the system.

Claims

1. A sensor system based on a rotation mode, characterized in that: include: At least two sensing units, a multifunctional circuit board, an embedded control module, a parameter monitoring module and an automatic switching module; Wherein, the sensing units respectively have sensitive elements for detecting the type and concentration of the target to be detected; The sensing unit is integrated with the multifunctional circuit board; The multifunctional circuit board is integrated with an embedded control module, a parameter monitoring module and an automatic switching module; The embedded control module is used to obtain the working parameters of the current sensor unit, and determine whether the sensor unit meets the preset switching conditions according to the working parameters, so as to control the start, shutdown and switching of the sensor unit according to the rotation working mode; The parameter monitoring module is used to monitor the operating parameters of each sensor unit in real time, and the operating parameters include resistance drift, conductance drift and current drift; When the sensor unit reaches a preset switching condition, the automatic switching module automatically switches the current sensor unit to another sensor unit to achieve rotation operation; The switching condition includes that the working time of the current sensor unit reaches the effective working time threshold or the operating parameter of the current sensor unit drifts beyond a preset range.

2. A sensor system based on a rotation mode according to claim 1, characterized in that: Also includes: Preheating and self-test module, security module and output module; The multifunctional circuit board further comprises a preheating and self-test module, a security module and an output module; The embedded control module is also used for the operation control of the preheating and self-checking module, the security module and the output module; The preheating and self-checking module is used to perform preheating and self-checking operations before the sensing unit is started; The security module is used to trigger the standby sensor unit to work when an abnormal working state is detected, and put the abnormal sensor unit into a dormant state; The output module is used to output the test results and status information after the control program is run through display or communication, so that the user can obtain the information required for system operation; The control program is the operating software of the embedded control module in the multifunctional circuit board, and is a program assembly in which the parameter monitoring module, the automatic switching module, the preheating and self-checking module, the security module and the output module work in coordination.

3. A sensor system based on a rotation mode according to claim 2, characterized in that: The automatic switching module includes a sensor unit switching algorithm, and the specific steps include: S1. Acquire the operating parameters of the current sensor unit from the parameter monitoring module, wherein the operating parameters include resistance drift, conductance drift and current drift; S2. Calculate the effective working time of the sensor unit according to the obtained working parameters, and compare it with the preset maximum effective working time; S3, comparing the effective working time with the preset maximum effective working time to determine whether the current sensor unit reaches the preset switching condition; S4. When the effective working time of the currently working sensor unit is reached, the embedded control module triggers the automatic program switching mechanism. The automatic switching module controls the start of the next sensor unit to take over the work and continues the detection according to the working mode of the previous sensor unit, while putting the current sensor unit into a sleep state.

4. A sensor system based on a rotation mode according to claim 3, characterized in that: The effective working time of the sensing unit is determined according to the following formula: < 3-5% or < 3-5% or < 3-5% In the above formula, is the resistance drift; is the resistance value of the sensing unit at T0; T x The resistance value of the sensing unit; T e is the effective working time of the sensor unit; is the effective coefficient, which is determined by the characteristics of the sensor unit and the external working environment; is the conductivity drift; is the conductivity value of the sensor unit at T0; T x The conductivity value of the sensing unit; is the current drift; is the current value of the sensor unit at T0; T x The current value of the sensing unit when The sensing unit characteristics include the composition of the sensitive material, the microstructure of the sensitive material, and the substrate type of the sensing unit; The external working environment includes ambient temperature, humidity, light and interference.

5. A sensor system based on a rotation mode according to claim 4, characterized in that: Before each sensor unit starts working, it will perform preheating and self-test before entering formal operation. The time for preheating and self-test is set according to the characteristics of the sensor unit and the external environment.

6. A sensor system based on a rotation mode according to claim 5, characterized in that: When the automatic switching module encounters one of the following special situations, it will force the next sensor unit to work and output a warning message: (1) When the preset limit working time is reached, the limit working time is set to 2 times the effective working time; (2) The resistance of the currently working sensor unit is short-circuited, open-circuited, or has serious abnormalities in the electrical signal; (3) Other systemic failures.

7. A sensor system based on a rotation mode according to claim 6, characterized in that: When the automatic switching module encounters one of the following situations, the automatic program switching mechanism is not activated, and the currently working sensor unit suspends the execution of the switching function and continues to work: (1) Excluding baseline drift and determining the trigger response state: within a fixed time interval, the resistance drift, conductance drift or current drift of the currently working sensor unit is greater than or equal to 10%, and the state is continuously triggered more than the set number of times; (2) The currently operating sensor unit has detected a response and is in the measurement process; When the above situation disappears, the automatic program switching mechanism is reactivated.

8. A sensor system based on a rotation mode according to claim 6, characterized in that: The automatic program switching mechanism is activated and will automatically switch to the next sensor unit to work when one of the following situations occurs: (1) When the preset effective working time is reached; (2) When the resistance drift, conductance drift or current drift of the currently operating sensor unit is greater than or equal to 3-5%; Among them, situation (1) is a regular switching condition, and situation (2) is an unconventional switching condition. When situation (2) is triggered, the automatic switching module performs cumulative counting. When the count value reaches a preset value, the automatic switching module will give a prompt to replace the sensor unit.

9. A method for using a sensor system based on a rotation mode, characterized in that: The method comprises using the sensing system based on the rotation mode as described in any one of claims 1 to 8, wherein the specific steps include: S1. When starting, first select the first sensor unit to enter preheating and self-testing. After the preheating and self-testing, it enters the working state to detect the type and concentration of the target object to be tested; S2. During the operation of the first sensor unit, real-time monitoring of operating parameters, including resistance drift, conductance drift, and current drift, etc., to determine in real time whether the first sensor unit exceeds a predetermined limit. When a preset effective working time is reached or the resistance drift, conductance drift, or current drift of the first sensor unit is greater than or equal to 3-5%, the first sensor unit automatically stops working and is placed in a dormant state; S3, before the first sensor unit stops working, the second sensor unit is started in advance to perform a preheating self-test. When the first sensor unit stops working, the second sensor unit immediately takes over its work and continues to detect according to the detection mode of the first sensor unit, and then takes over in sequence; S4. During the entire operation cycle, multiple sensor units are periodically rotated. If the second sensor unit is dormant, a new third sensor unit can be started or the first sensor unit can be started again to work.

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