Negative ion detector and online self-checking and measuring method thereof

Abstract

The invention discloses a negative ion detector and an on-line self-checking and measuring method thereof, and solves the problems of strong manpower dependence and low-concentration detection inaccuracy. The negative ion detector comprises a negative ion acquisition probe interface, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit, an amplifying circuit and a controller, the first end of the resistor R2, the first end of the resistor R3, the input end of the amplification circuit and the negative ion acquisition probe interface are connected; the negative ion acquisition probe interface is externally connected with a negative ion acquisition probe arranged in the acquisition air duct, and a fan for driving airflow is arranged in the acquisition air duct; the second end of the resistor R3, the first end of the resistor R5 and the first end of the resistor R4 are connected; the second end of the resistor R2 and the second end of the resistor R5 are both grounded. The second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit; the output end of the amplifying circuit, the control end of the auxiliary power supply circuit and the control end of the fan are all connected to the controller.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a negative ion detector and an online self-test and measurement method thereof. Background Art

[0002] A negative ion detector is a professional instrument used to quantitatively measure the concentration of negative ions (primarily negative oxygen ions) in the air. It captures negative ions in the air through a negative ion collection probe and converts the negative ion concentration into a readable electrical signal. After amplification and analog-to-digital conversion, the number of negative ions per unit volume is displayed in digital form. In the field of environmental monitoring, negative ion detectors, as equipment for detecting characteristic values ​​of negative ion concentration in the air, can assess the self-purification capacity of the environment and the health of the ecology. In addition, in meteorological science, it can analyze the contribution of the distribution of charged particles in the atmosphere to the local electric field; in environmental protection engineering, it can provide key indicators for the performance verification of air purification devices; and in the field of forestry, it can support ecological benefit assessment by quantifying the flux of negative ions released by forest vegetation.

[0003] Negative ion detectors are often deployed outdoors in complex operating environments, susceptible to a variety of factors. For example, during long-term operation, negative ion detectors may be subjected to mechanical stresses such as vibration and collision; they must also withstand environmental factors such as drastic changes in temperature and humidity, and electromagnetic interference. These factors can cause changes in the performance of internal components and, in turn, lead to inaccurate measurement data. Therefore, it is necessary to periodically inspect negative ion detectors and, if inaccurate measurements are confirmed, calibrate them immediately to ensure the continued accuracy of measurement data.

[0004] Currently, on-site testing of negative ion detectors generally relies on a standard instrument comparison method. This involves personnel carrying a traceable and calibrated standard negative ion detector to an outdoor observation site and performing simultaneous measurements and comparisons with the device under test. However, this method has two technical limitations: first, it requires significant manpower for equipment transportation and on-site operation; second, in environments with low negative ion concentrations, the signal-to-noise ratio decreases significantly, leading to significantly increased comparison errors and seriously affecting the validity of the test results. Summary of the Invention

[0005] In view of the above problems, this application provides a negative ion detector and its online self-test and measurement method to solve the problems of strong dependence on manpower and inaccurate low-concentration testing. The specific solution is as follows:

[0006] In a first aspect, the present application provides a negative ion detector, comprising: a negative ion collection probe interface, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit, an amplifier circuit, and a controller;

[0007] The first end of the resistor R2, the first end of the resistor R3, the input end of the amplifier circuit and the negative ion collection probe interface are connected; the negative ion collection probe interface is externally connected to the negative ion collection probe placed in the collection air duct, and the collection air duct is provided with a fan for driving the airflow;

[0008] The second end of the resistor R3, the first end of the resistor R5, and the first end of the resistor R4 are connected;

[0009] The second end of the resistor R2 and the second end of the resistor R5 are both grounded;

[0010] The second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit;

[0011] The output end of the amplifier circuit, the control end of the auxiliary power supply circuit and the control end of the fan are all connected to the controller;

[0012] The controller is used to control the auxiliary power supply circuit to maintain a zero voltage output state and control the fan to remain in a stopped state when receiving a test instruction, collect the output signal of the amplifier circuit and perform analog-to-digital conversion to obtain a first voltage value; then, control the auxiliary power supply circuit to output a preset voltage and control the fan to continue to remain in a stopped state, collect the output signal of the amplifier circuit again and perform analog-to-digital conversion to obtain a second voltage value; calculate the difference between the second voltage value and the first voltage value, and determine whether the difference between the difference and the calibration threshold exceeds the allowable error range. If so, it is determined that the negative ion detector is inaccurate in measurement; wherein, the controller can adjust and set the amplitude of the preset voltage.

[0013] In one possible implementation, the controller is also used to control the auxiliary power supply circuit to maintain a zero voltage output state and control the fan to remain in a stopped state again when it is determined that the negative ion detector is not inaccurate and a measurement instruction is received, collect the output signal of the amplifier circuit and perform analog-to-digital conversion to obtain the first voltage value; then, control the fan to turn on and control the auxiliary power supply circuit to continue to maintain a zero voltage output state, collect the output signal of the amplifier circuit again and perform analog-to-digital conversion to obtain a third voltage value; calculate the difference between the third voltage value and the first voltage value, and calculate the negative ion concentration value in the air based on the difference between the third voltage value and the first voltage value.

[0014] In a possible implementation, the inspection instruction and the measurement instruction support any one or any combination of three modes: timed triggering, local manual triggering, and remote instruction triggering.

[0015] In a possible implementation, the negative ion detector further includes a capacitor C1; the capacitor C1 is connected in parallel with the resistor R5.

[0016] In one possible implementation, the auxiliary power supply circuit includes: a relay SW1, an optocoupler U2, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C2, a switch tube Q1, and a switch tube Q2;

[0017] The control end of the switch tube Q1 is connected to the first output end of the controller via the resistor R8. The output end of the switch tube Q1 is grounded. The light emitting module in the optocoupler U2 is connected in series with the resistor R9 and then connected between the first power supply and the input end of the switch tube Q1.

[0018] The light receiving module in the optocoupler U2 is connected in series with the resistor R10 and then connected between the second power supply and the first end of the capacitor C2, and the second end of the capacitor C2 is grounded;

[0019] The first end of the capacitor C2 is connected to the output end of the auxiliary power circuit via the normally open contact of the relay SW1;

[0020] One end of the coil of the relay SW1 is connected to the first power supply via the resistor R6, the other end of the coil of the relay SW1 is connected to the input end of the switch tube Q2, the output end of the switch tube Q2 is grounded, and the control end of the switch tube Q2 is connected to the second output end of the controller via the resistor R7;

[0021] The controller controls the auxiliary power supply circuit to maintain a zero voltage output state, and is specifically configured to: output a signal for controlling the switch tube Q2 to be turned off through the second output terminal;

[0022] The controller controls the auxiliary power supply circuit to output a preset voltage, and is specifically configured as follows: by adjusting the duty cycle of the PWM signal output from the first output terminal, the voltage across the capacitor C2 reaches and is maintained at the preset voltage; when the voltage across the capacitor C2 is at the preset voltage, a signal for controlling the conduction of the switch tube Q2 is output through the second output terminal.

[0023] In a possible implementation, the auxiliary power supply circuit further includes: a capacitor C3; the capacitor C3 is connected in parallel with the capacitor C2.

[0024] In a possible implementation, the switch tube Q1 and the switch tube Q2 are both triodes.

[0025] In a possible implementation, the controller is further configured to trigger an alarm when determining that the negative ion detector has made an inaccurate measurement; the alarm includes a local alarm and / or a remote alarm.

[0026] According to a second aspect of the present application, there is provided an online self-test method for a negative ion detector, which is applied to a controller in the negative ion detector. The negative ion detector includes a negative ion collection probe interface, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit, an amplifier circuit, and the controller. The first end of the resistor R2, the first end of the resistor R3, the input end of the amplifier circuit, and the negative ion collection probe interface are connected. The negative ion collection probe interface is externally connected to a negative ion collection probe placed in a collection air duct, and a fan for driving airflow is provided in the collection air duct. The second end of the resistor R3, the first end of the resistor R5, and the first end of the resistor R4 are connected. The second end of the resistor R2 and the second end of the resistor R5 are both grounded. The second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit. The output end of the amplifier circuit, the control end of the auxiliary power supply circuit, and the control end of the fan are all connected to the controller.

[0027] The method comprises:

[0028] Upon receiving the inspection instruction, controlling the auxiliary power supply circuit to maintain a zero voltage output state and controlling the fan to remain in a stopped state, collecting the output signal of the amplifier circuit and performing analog-to-digital conversion to obtain a first voltage value;

[0029] Then, the auxiliary power supply circuit is controlled to output a preset voltage and the fan is controlled to remain in the shutdown state, and the output signal of the amplifier circuit is collected again and analog-to-digital converted to obtain a second voltage value;

[0030] Calculate the difference between the second voltage value and the first voltage value, and determine whether the difference between the difference and the calibration threshold exceeds the allowable error range. If so, determine that the negative ion detector is inaccurate; wherein, the controller can adjust and set the amplitude of the preset voltage.

[0031] The third aspect of the present application provides a negative ion detector measurement method, comprising:

[0032] When it is determined according to the online self-test method for a negative ion detector described in the second aspect that the negative ion detector is not inaccurate and a measurement instruction is received, the auxiliary power supply circuit is again controlled to maintain a zero voltage output state and the fan is controlled to remain in a stopped state, and the output signal of the amplifier circuit is collected and analog-to-digital converted to obtain the first voltage value;

[0033] Then, the fan is controlled to be turned on and the auxiliary power supply circuit is controlled to continue to maintain a zero voltage output state, and the output signal of the amplifier circuit is collected again and analog-to-digital converted to obtain a third voltage value;

[0034] The difference between the third voltage value and the first voltage value is calculated, and the concentration of negative ions in the air is calculated according to the difference between the third voltage value and the first voltage value.

[0035] By means of the above technical solution, the present application realizes the online self-test function of the negative ion detector by co-optimizing the software and hardware of the negative ion detector. The self-test process is divided into three stages: first, the auxiliary power supply circuit is controlled to maintain a zero voltage output state and the fan is controlled to remain in a shutdown state. At this time, the output signal of the amplifier circuit is collected and a first voltage value is obtained after analog-to-digital conversion; then, the auxiliary power supply circuit is controlled to output a preset voltage, and a standard excitation signal is injected through the voltage divider network to simulate a negative ion signal of a specific concentration. At this time, the output signal of the amplifier circuit is collected again and a second voltage value is obtained after analog-to-digital conversion; finally, the difference between the second voltage value and the first voltage value is calculated and compared with the calibration threshold to determine whether the negative ion detector is inaccurate. The entire process does not require manual intervention, saving labor costs. Moreover, the controller can simulate negative ion signals of different concentrations by dynamically adjusting the preset voltage, so that the negative ion detector maintains measurement accuracy within the full range. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other features, advantages, and aspects of the various embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the originals and elements are not necessarily drawn to scale.

[0037] Figure 1 A schematic diagram of the circuit structure of a negative ion detector provided in this application;

[0038] Figure 2 A schematic diagram of the circuit structure of another negative ion detector provided in this application;

[0039] Figure 3 A flow chart of an online self-test method for a negative ion detector provided in this application;

[0040] Figure 4 This is a flow chart of the measurement method of a negative ion detector provided in this application. DETAILED DESCRIPTION

[0041] In the following explanation, in order to ensure the accuracy of citations and the fluency of reading, the key technical terms, abbreviations or abbreviations involved in the article are summarized and explained as follows:

[0042] PWM: Pulse Width Modulation.

[0043] MOSFET: Metal-Oxide-Semiconductor Field-Effect Transistor, metal-oxide semiconductor field-effect transistor, referred to as MOS tube;

[0044] IGBT: Insulated Gate Bipolar Transistor.

[0045] The embodiment of the present application provides a negative ion detector and its online self-test and measurement method, which breaks through the on-site operation limitations of the traditional standard instrument comparison method, and realizes online self-test of the operating status of the negative ion detector through the integrated design of the hardware circuit, fundamentally solving the technical problems of the traditional standard instrument comparison method, such as strong dependence on manpower and inaccurate low-concentration testing.

[0046] Below, in conjunction with the accompanying drawings, a negative ion detector provided by an embodiment of the present application is first described in detail. Those skilled in the art will appreciate that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0047] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, and this is merely a way of distinguishing the objects of the same attributes when describing them in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0048] See also Figure 1 , a negative ion detector provided in an embodiment of the present application includes: a negative ion collection probe interface TP1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit 100, an amplifier circuit 200 and a controller;

[0049] The first end of the resistor R2, the first end of the resistor R3, the input end of the amplifier circuit 200 and the negative ion collection probe interface TP1 are connected; the negative ion collection probe interface TP1 is externally connected to the negative ion collection probe placed in the collection air duct ( Figure 1 Not shown), a fan for driving air flow is provided in the air collection duct ( Figure 1 (not shown);

[0050] The second end of the resistor R3, the first end of the resistor R5, and the first end of the resistor R4 are connected;

[0051] The second end of the resistor R2 and the second end of the resistor R5 are both grounded;

[0052] The second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit 100;

[0053] The output end of the amplifier circuit 200, the control end of the auxiliary power supply circuit 100 and the control end of the fan are all connected to the controller;

[0054] The controller is used to control the auxiliary power supply circuit 100 to maintain a zero voltage output state and control the fan to remain in a stopped state when receiving a test instruction, collect the output signal of the amplifier circuit 200 and perform analog-to-digital conversion to obtain a first voltage value V1; then, control the auxiliary power supply circuit 100 to output a preset voltage and control the fan to continue to remain in a stopped state, collect the output signal of the amplifier circuit 200 again and perform analog-to-digital conversion to obtain a second voltage value V2; finally, calculate the difference between the second voltage value V2 and the first voltage value V1, and determine whether the difference between the difference and the calibration threshold exceeds the allowable error range. If so, it is determined that the negative ion detector is inaccurate in measurement; wherein, the controller can adjust and set the amplitude of the preset voltage.

[0055] The working principle of the embodiment of the present application is described in detail below:

[0056] The negative ion collection probe interface TP1, resistor R2, amplifier circuit 200, fan, and controller are the essential components of the negative ion detector for quantitatively calculating negative ion concentration. The negative ion collection probe interface TP1 connects to an external negative ion collection probe (such as a copper rod electrode), and the two are electrically connected to form the negative ion signal acquisition front end. The negative ion collection probe utilizes the conductivity and high surface area of ​​the metal conductor to adsorb negative ions from the air. When the negative ions come into contact with the surface of the negative ion collection probe, charge transfer occurs, generating a weak current signal, referred to as the probe signal. After inputting through the negative ion collection probe interface TP1, this probe signal is first converted to a voltage signal by resistor R2 and then transmitted to amplifier circuit 200 for gain adjustment. After conversion to a standard analog voltage by amplifier circuit 200, it is input into the controller's built-in analog-to-digital conversion module. Digital quantization and algorithmic processing enable quantitative calculation of negative ion concentration.

[0057] The present embodiment integrates resistors R3, R4, and R5 and an auxiliary power supply circuit 100 within a conventional negative ion detector, optimizes the controller program logic, and constructs an online self-test system. Upon receiving a test command, the online self-test system performs an online self-test through three stages: background signal acquisition, standard stimulus injection, and error assessment. The details are as follows:

[0058] 1. Background signal acquisition stage

[0059] During the background signal acquisition phase, the controller controls the auxiliary power supply circuit 100 to maintain a zero-voltage output and keeps the fan off to prevent external airflow from interfering with the collection duct. As external air ceases to enter, the residual ionic charge on the surface of the negative ion collection probe (equivalent to a high-resistance current source) gradually decreases and stabilizes. As a result, the weak current output by the negative ion collection probe also decreases and stabilizes. This weak current is converted to a voltage signal via a resistor network consisting of resistors R2, R3, and R5 (resistors R3 and R5 are connected in series and then in parallel with resistor R2). This current is then transmitted to the amplifier circuit 200 for gain adjustment and finally to the analog-to-digital conversion module for digital quantization. As the weak current output by the negative ion collection probe decreases and stabilizes, the output voltage of the analog-to-digital conversion module also gradually decays and stabilizes. Through real-time monitoring, the controller confirms that the output voltage of the analog-to-digital conversion module has entered a stable state, and then reads the output voltage value (first voltage value V1) of the analog-to-digital conversion module as the reference zero point value for subsequent measurement of air negative ion data, thereby establishing an initial reference standard for accurately quantifying the environmental ion concentration.

[0060] The reference zero value is the background signal. Background signal refers to the signal output generated by the detection system itself under specific detection conditions, even when no target stimulus is applied and no sample or target signal is present. Because background signal is a background interference that cannot be completely eliminated in a detection system, it is necessary to first measure the background signal value and then subtract the actual detection signal from the background signal to eliminate background interference and restore the true characteristics of the actual detection signal.

[0061] 2. Standard Incentive Injection Phase

[0062] During the standard excitation injection phase, the controller sends a control signal to the auxiliary power supply circuit 100, causing it to output a preset voltage. The output current from the auxiliary power supply circuit 100 flows through resistor R4 and is then split into two paths. By designing resistors R2 and R3 to have essentially equal resistance values ​​and significantly greater resistance values ​​than resistor R5 (|R2-R3| < first preset value, R3-R5 > second preset value), the test current flows through resistor R4, with the vast majority of the current flowing directly to the reference ground via resistor R5 (the main path). A very small portion of the current flows through resistor R3 and then through resistor R2 to the reference ground (the microcurrent path). The microcurrent flowing through resistor R2 generates a voltage drop across resistor R2, which is directly transmitted to the input of the amplifier circuit 200 (i.e., the standard excitation injection), simulating a negative ion signal at a specific concentration. After the amplifier circuit 200 performs gain processing on the input signal, it outputs it to the analog-to-digital conversion module built into the controller. The controller reads the output voltage value (second voltage value V2) of the analog-to-digital conversion module. The output voltage value is recorded as the response value of the online self-test system to the injection of a negative ion signal of a specific concentration, and is used for subsequent comparison and analysis with the theoretical calibration value to verify the measurement accuracy of the negative ion detector.

[0063] Resistor R4 primarily serves as a current limiter, preventing overcurrent damage to amplifier circuit 200. Resistor R3 is designed to be a high-value resistor of the same magnitude as resistor R2 (for example, R2 = R3 = 10 GΩ) to prevent significant shunt interference on the probe signal during actual measurement of negative ion concentration in the air. This ensures that probe signal attenuation remains within an acceptable range (e.g., approximately 50%).

[0064] In addition, during the standard excitation injection phase, the controller can simulate negative ion signals of different concentrations by adjusting the preset voltage output by the auxiliary power supply circuit 100, allowing the negative ion detector to adapt to different negative ion concentration ranges. Specifically, in low-concentration scenarios, the preset voltage is increased to simulate a stronger negative ion signal, allowing the negative ion detector to capture weak changes in negative ion concentration; in high-concentration scenarios, the preset voltage is lowered to avoid signal overload or saturation, ensuring that the detection data is within the linear quantization range of the analog-to-digital conversion module. In this way, the negative ion detector can adapt to different negative ion concentration ranges from low to high, greatly broadening the detectable concentration range.

[0065] 3. Error Assessment Phase

[0066] In the error evaluation stage, the controller calculates the difference V2-V1 between the second voltage value V2 and the first voltage value V1, and compares the difference V2-V1 with the calibration threshold. If the two are basically equal, it means that the measurement result of the negative ion detector is accurate; otherwise, if there is a significant difference between the two, it means that the negative ion detector test is inaccurate.

[0067] Among them, the calibration threshold is the voltage value that the analog-to-digital conversion module should theoretically output under the conditions of injecting standard excitation and no background interference; the calibration threshold is uniquely determined by the nominal parameters and circuit topology of the internal circuit components of the negative ion detector, and is pre-calculated and stored in the memory of the controller during the design stage of the negative ion detector.

[0068] In summary, the embodiment of the present application realizes the online self-test function of the negative ion detector by co-optimizing the software and hardware of the negative ion detector. The self-test process is divided into three stages: first, the auxiliary power supply circuit 100 is controlled to maintain a zero voltage output state and the fan is controlled to remain in a shutdown state. At this time, the output signal of the amplifier circuit 200 is collected and a first voltage value V1 is obtained after analog-to-digital conversion; then, the auxiliary power supply circuit is controlled to output a preset voltage, and a standard excitation signal is injected through the voltage divider network to simulate a negative ion signal of a specific concentration. At this time, the output signal of the amplifier circuit 200 is collected again and a second voltage value V2 is obtained after analog-to-digital conversion; finally, the difference between the second voltage value V2 and the first voltage value V1 is calculated and compared with the calibration threshold to determine whether the negative ion detector is inaccurate. The entire process does not require manual intervention, saving labor costs. Moreover, the controller can simulate negative ion signals of different concentrations by dynamically adjusting the preset voltage, so that the negative ion detector maintains measurement accuracy within the full range.

[0069] Based on any of the negative ion detectors provided in the above embodiments, the controller can also trigger an alarm when determining that the negative ion detector is measuring inaccurately, including: a local alarm and / or a remote alarm. The local alarm may, for example, be: controlling the sound and light alarm module of the negative ion detector to emit a beeping tone, and displaying an inaccuracy alarm pop-up window on the human-computer interface of the negative ion detector. The remote alarm may, for example, be: sending an inaccuracy alarm protocol frame to a host computer via the communication interface of the negative ion detector, and / or triggering a cloud platform to push an alarm text message / email, etc.

[0070] Based on any of the negative ion detectors provided in the above embodiments, the controller can also control the auxiliary power supply circuit 100 to maintain a zero voltage output state and control the fan to remain in a stopped state when it is determined that the negative ion detector is not inaccurate and a measurement instruction is received, collect the output signal of the amplifier circuit 200 and perform analog-to-digital conversion to obtain the first voltage value V1; then, control the fan to turn on and control the auxiliary power supply circuit 100 to continue to maintain a zero voltage output state, collect the output signal of the amplifier circuit 200 again and perform analog-to-digital conversion to obtain a third voltage value V3; finally, calculate the difference V3-V1 between the third voltage value V3 and the first voltage value V1, and calculate the negative ion concentration value in the air based on the difference V3-V1.

[0071] Specifically, when actual measurement of negative ion concentration in the air is required, a first voltage value V1 must still be determined (the negative ion detector is deployed in an outdoor observation field, where the operating environment is complex and changeable. Therefore, it is recommended to redetermine the first voltage value V1 for each test and actual measurement). Then, the fan is turned on to draw outside air into the collection duct. The negative ion collection probe utilizes the conductivity and high specific surface area of ​​the metal conductor to adsorb negative ions in the air. When the negative ions come into contact with the surface of the negative ion collection probe, charge transfer occurs, generating a weak current signal, or the probe signal. This probe signal is converted into a voltage signal via a resistor network consisting of resistors R2, R3, and R5 (resistors R3 and R5 are connected in series and then in parallel with resistor R2). The voltage signal is then transmitted to amplifier circuit 200 for gain adjustment. After conversion to a standard analog voltage by amplifier circuit 200, it is input into a controller for analog-to-digital conversion to obtain a third voltage value V3. Finally, the difference V3-V1 is calculated, and the negative ion concentration value in the air can be converted accordingly.

[0072] The inspection and measurement instructions support any one of three modes, or any combination of several, including timed triggering, local manual triggering, and remote command triggering. In the timed triggering mode, the inspection and measurement instructions are automatically generated and periodically sent by the controller according to a preset program. The inspection instruction sending period can be configured to, for example, 2 hours, and the measurement instruction sending period can be configured to, for example, 10 minutes. Local manual triggering is achieved through the human-computer interaction interface (e.g., touch screen / button) of the negative ion detector. Remote command triggering receives corresponding instructions issued by the host computer through the negative ion detector's communication interface.

[0073] Based on any of the negative ion detectors provided in the above embodiments, see Figure 1 The negative ion detector may further include a capacitor C1; the capacitor C1 is connected in parallel with the resistor R5, and is used to filter and stabilize the output voltage of the auxiliary power supply circuit 100 to eliminate ripple interference and stabilize the voltage output.

[0074] Based on any of the negative ion detectors provided in the above embodiments, see Figure 2 The auxiliary power supply circuit 100 may include: a relay SW1, an optocoupler U2, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C2, a switch tube Q1 and a switch tube Q2;

[0075] The control end of the switch tube Q1 is connected to the first output end PWM_1 of the controller via the resistor R8. The output end of the switch tube Q1 is grounded. The light emitting module in the optocoupler U2 is connected in series with the resistor R9 and then connected between the first power supply VCC1 and the input end of the switch tube Q1.

[0076] The light receiving module in the optocoupler U2 is connected in series with the resistor R10 and then connected between the second power supply S_VCC and the first end of the capacitor C2, and the second end of the capacitor C2 is grounded;

[0077] The first end of the capacitor C2 is connected to the output end of the auxiliary power circuit 100 via the normally open contact of the relay SW1;

[0078] One end of the coil of the relay SW1 is connected to the first power supply VCC1 via the resistor R6, the other end of the coil of the relay SW1 is connected to the input end of the switch tube Q2, the output end of the switch tube Q2 is grounded, and the control end of the switch tube Q2 is connected to the second output end GPIO_1 of the controller via the resistor R7;

[0079] The controller controls the auxiliary power supply circuit 100 to maintain a zero voltage output state, and is specifically configured as follows: outputting a signal for controlling the switch tube Q2 to be turned off through the second output terminal;

[0080] The controller controls the auxiliary power supply circuit 100 to output a preset voltage, and is specifically configured as follows: by adjusting the duty cycle of the PWM signal output from the first output terminal, the voltage across the capacitor C2 reaches and is maintained at the preset voltage; when the voltage across the capacitor C2 is at the preset voltage, a signal for controlling the conduction of the switch tube Q2 is output through the second output terminal.

[0081] Figure 2 The working principle of the auxiliary power supply circuit 100 is as follows:

[0082] An optocoupler, or photoelectric coupler, is an electrical-to-optical-to-electrical conversion device that uses light as a medium to transmit electrical signals. It consists of a light emitting module and a light receiving module. The light emitting module is typically a light-emitting diode (LED), while the light receiving module is a photosensitive device, including but not limited to a photodiode or phototransistor. The pins of the light emitting module serve as the optocoupler's input, while the pins of the light receiving module serve as the optocoupler's output. When an electrical signal is applied to the optocoupler's input and the voltage of that signal exceeds the conduction voltage drop of the light emitting module, the light emitting module turns on and emits light. The resulting light signal is received by the light receiving module and converted into an electrical signal (i.e., the light receiving module turns on when exposed to light), thus achieving electrical-to-optical-to-electrical conversion.

[0083] When the PWM signal output by the controller's first output terminal PWM_1 is at a high level, the switch Q1 turns on. At this point, an electrical signal is applied to the optocoupler's input terminal, and the voltage of this electrical signal exceeds the conduction voltage drop of the optical transmitter module. Therefore, the optical transmitter module turns on and emits light, thereby turning on the optical receiver module. After the optical receiver module turns on, the second power supply S_VCC charges capacitor C2 through the optical receiver module and resistor R10, increasing the voltage across capacitor C2. When the PWM signal output by the controller's first output terminal PWM_1 is at a low level, the switch Q1 turns off. At this point, no electrical signal is applied to the optocoupler's input terminal, so the optical transmitter module turns off, and thus the optical receiver module. After the optical receiver module turns off, charging of capacitor C2 stops. The duty cycle of the PWM signal is positively correlated with the voltage across capacitor C2. By controlling the duty cycle of the PWM signal, the charging time of capacitor C2 can be precisely adjusted, thereby controlling the voltage across capacitor C2. When the duty cycle of the PWM signal increases, the charging time of capacitor C2 is prolonged, and the voltage across capacitor C2 increases. When the duty cycle of the PWM signal decreases, the charging time of capacitor C2 is shortened, and the voltage across capacitor C2 decreases.

[0084] When the controller outputs a high-level signal through the second output terminal GPIO_1, the switch tube Q2 is driven to turn on through the resistor R7. At this time, the coil of the relay SW1 is energized, and the normally open contact of the relay SW1 is closed, connecting the first end of the capacitor C2 to the output end of the auxiliary power supply circuit 100. At this time, the output voltage of the auxiliary power supply circuit 100 is equal to the voltage across the capacitor C2; when the controller outputs a low-level signal through the second output terminal GPIO_1, the switch tube Q2 is turned off, the coil of the relay SW1 is de-energized, and the normally open contact of the relay SW1 is opened. At this time, there is no voltage output from the auxiliary power supply circuit 100.

[0085] Therefore, by adjusting the duty cycle of the PWM signal to control the voltage of the capacitor C2 and combining the on-off control of the relay SW2, the output voltage of the auxiliary power supply circuit 100 can be accurately adjusted, thereby simulating negative ion signals of different concentrations.

[0086] The switch Q1 can be a transistor, MOSFET, or IGBT, but is not limited to these. When the switch Q1 is a MOSFET, the input end of the switch Q1 is the drain of the MOSFET, the output end of the switch Q1 is the source of the MOSFET, and the control end of the switch Q1 is the gate of the MOSFET. When the switch Q1 is a transistor, the input end of the switch Q1 is the collector of the transistor, the output end of the switch Q1 is the emitter of the transistor, and the control end of the switch Q1 is the base of the transistor. When the switch Q1 is an IGBT, the input end of the switch Q1 is the collector of the IGBT, the output end of the switch Q1 is the emitter of the IGBT, and the control end of the switch Q1 is the gate of the IGBT. Figure 2The switch tube Q1 is a triode as an example for illustration.

[0087] Similarly, the switch Q2 can be a transistor, MOSFET, or IGBT, without limitation. When the switch Q2 is a MOSFET, the input terminal of the switch Q2 is the drain of the MOSFET, the output terminal of the switch Q2 is the source of the MOSFET, and the control terminal of the switch Q2 is the gate of the MOSFET. When the switch Q2 is a transistor, the input terminal of the switch Q2 is the collector of the transistor, the output terminal of the switch Q2 is the emitter of the transistor, and the control terminal of the switch Q2 is the base of the transistor. When the switch Q2 is an IGBT, the input terminal of the switch Q2 is the collector of the IGBT, the output terminal of the switch Q2 is the emitter of the IGBT, and the control terminal of the switch Q2 is the gate of the IGBT. Figure 2 The switch tube Q2 is a triode as an example for illustration.

[0088] In low-power switching scenarios, since the cost of transistors is significantly lower than that of MOSFETs and IGBTs, transistors are generally used as switch tubes Q1 and Q2.

[0089] Alternatively, see Figure 2 The auxiliary power supply circuit 100 further includes a capacitor C3; the capacitor C3 is connected in parallel with the capacitor C2 to achieve filtering and voltage stabilization.

[0090] In addition, corresponding to the above embodiment, the embodiment of the present application also provides an online self-test method for a negative ion detector, which is applied to a controller in a negative ion detector, wherein the negative ion detector includes a negative ion collection probe interface TP1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit 100, an amplifier circuit 200 and the controller; the first end of the resistor R2, the first end of the resistor R3, the input end of the amplifier circuit 200 and the negative ion collection probe interface TP1 are connected; the negative ion collection probe interface TP1 is externally connected to a negative ion collection probe placed in a collection air duct, and a fan for driving airflow is provided in the collection air duct; the second end of the resistor R3, the first end of the resistor R5 and the first end of the resistor R4 are connected; the second end of the resistor R2 and the second end of the resistor R5 are both grounded; the second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit 100; the output end of the amplifier circuit 200, the control end of the auxiliary power supply circuit 100 and the control end of the fan are all connected to the controller;

[0091] like Figure 3 As shown, the online self-test method of the negative ion detector includes:

[0092] Step S01: upon receiving the inspection instruction, controlling the auxiliary power supply circuit 100 to maintain a zero voltage output state and controlling the fan to remain in a shutdown state, collecting the output signal of the amplifier circuit 200 and performing analog-to-digital conversion to obtain a first voltage value V1;

[0093] Step S02: Controlling the auxiliary power supply circuit 100 to output a preset voltage and controlling the fan to remain in the shutdown state, again collecting the output signal of the amplifier circuit 200 and performing analog-to-digital conversion to obtain a second voltage value V2; wherein the controller is capable of adjusting the amplitude of the preset voltage;

[0094] Step S03: Calculate the difference V2-V1, and determine whether the difference between V2-V1 and the calibration threshold exceeds the allowable error range. If so, it is determined that the negative ion detector is inaccurate.

[0095] Based on the above-mentioned negative ion detector online self-test method, the embodiment of the present application also provides a negative ion detector measurement method, such as Figure 4 Shown, including:

[0096] Step S11: When it is determined that the negative ion detector is not inaccurate and a measurement instruction is received, the auxiliary power supply circuit 100 is controlled again to maintain a zero voltage output state and the fan is controlled to remain in a shutdown state, and the output signal of the amplifier circuit 200 is collected and analog-to-digital converted to obtain a first voltage value V1;

[0097] Step S12: Control the fan to start and control the auxiliary power supply circuit 100 to continue to maintain a zero voltage output state, collect the output signal of the amplifier circuit 200 again and perform analog-to-digital conversion to obtain a third voltage value V3;

[0098] Step S13: Calculate the difference V3-V1, and calculate the concentration of negative ions in the air based on the difference V3-V1.

[0099] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present application. Therefore, the embodiments of the present application are not limited to the embodiments shown herein, but are intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A negative ion detector, characterized in that: include: A negative ion collection probe interface (TP1), a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit (100), an amplifier circuit (200), and a controller; The first end of the resistor R2, the first end of the resistor R3, the input end of the amplifier circuit (200), and the negative ion collection probe interface (TP1) are connected; the negative ion collection probe interface (TP1) is externally connected to a negative ion collection probe placed in a collection air duct, and a fan for driving airflow is provided in the collection air duct; The second end of the resistor R3, the first end of the resistor R5, and the first end of the resistor R4 are connected; The second end of the resistor R2 and the second end of the resistor R5 are both grounded; The second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit (100); The output end of the amplifier circuit (200), the control end of the auxiliary power supply circuit (100), and the control end of the fan are all connected to the controller; The controller is used to, upon receiving a test instruction, control the auxiliary power supply circuit (100) to maintain a zero voltage output state and control the fan to remain in a stopped state, collect the output signal of the amplifier circuit (200) and perform analog-to-digital conversion to obtain a first voltage value; then, control the auxiliary power supply circuit (100) to output a preset voltage and control the fan to continue to remain in a stopped state, collect the output signal of the amplifier circuit (200) again and perform analog-to-digital conversion to obtain a second voltage value; Calculate the difference between the second voltage value and the first voltage value, and determine whether the difference between the difference and the calibration threshold exceeds the allowable error range. If so, determine that the negative ion detector is inaccurate; wherein, the controller can adjust and set the amplitude of the preset voltage.

2. The negative ion detector according to claim 1, characterized in that The controller is further configured to, when it is determined that the negative ion detector is not inaccurate and a measurement instruction is received, control the auxiliary power supply circuit (100) again to maintain a zero voltage output state and control the fan to remain in a stopped state, collect the output signal of the amplifier circuit (200) and perform analog-to-digital conversion to obtain the first voltage value; then, control the fan to start and control the auxiliary power supply circuit (100) to continue to maintain a zero voltage output state, collect the output signal of the amplifier circuit (200) again and perform analog-to-digital conversion to obtain a third voltage value; The difference between the third voltage value and the first voltage value is calculated, and the concentration of negative ions in the air is calculated according to the difference between the third voltage value and the first voltage value.

3. The negative ion detector according to claim 2, characterized in that The inspection instruction and the measurement instruction support any one or any combination of three modes: timing triggering, local manual triggering and remote instruction triggering.

4. The negative ion detector according to any one of claims 1 to 3, characterized in that The negative ion detector further includes a capacitor C1; the capacitor C1 is connected in parallel with the resistor R5.

5. The negative ion detector according to any one of claims 1 to 3, characterized in that The auxiliary power supply circuit (100) comprises: a relay SW1, an optical coupler U2, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C2, a switch tube Q1, and a switch tube Q2; The control end of the switch tube Q1 is connected to the first output end (PWM_1) of the controller via the resistor R8. The output end of the switch tube Q1 is grounded. The light emitting module in the optocoupler U2 is connected in series with the resistor R9 and then connected between the first power supply (VCC1) and the input end of the switch tube Q1. The optical receiving module in the optical coupler U2 is connected in series with the resistor R10 and then connected between the second power supply (S_VCC) and the first end of the capacitor C2, and the second end of the capacitor C2 is grounded; The first end of the capacitor C2 is connected to the output end of the auxiliary power supply circuit (100) via the normally open contact of the relay SW1; One end of the coil of relay SW1 is connected to the first power supply (VCC1) via resistor R6, the other end of the coil of relay SW1 is connected to the input end of switch Q2, the output end of switch Q2 is grounded, and the control end of switch Q2 is connected to the second output end (GPIO_1) of the controller via resistor R7; The controller controls the auxiliary power supply circuit (100) to maintain a zero voltage output state, and is specifically configured as follows: outputting a signal for controlling the switch tube Q2 to be turned off through the second output terminal; The controller controls the auxiliary power supply circuit (100) to output a preset voltage, and is specifically configured as follows: by adjusting the duty cycle of the PWM signal output from the first output terminal, the voltage across the capacitor C2 reaches and is maintained at the preset voltage; when the voltage across the capacitor C2 is at the preset voltage, a signal for controlling the conduction of the switch tube Q2 is output through the second output terminal.

6. The negative ion detector according to claim 5, characterized in that: The auxiliary power supply circuit (100) further includes: a capacitor C3; the capacitor C3 is connected in parallel with the capacitor C2.

7. The negative ion detector according to claim 5, characterized in that The switch tube Q1 and the switch tube Q2 are both triodes.

8. The negative ion detector according to any one of claims 1 to 3, characterized in that: The controller is further configured to trigger an alarm when determining that the negative ion detector is out of measurement; the alarm includes a local alarm and / or a remote alarm.

9. A negative ion detector online self-test method, characterized in that: A controller for use in a negative ion detector, the negative ion detector comprising a negative ion collection probe interface (TP1), a resistor R2, a resistor R3, a resistor R4, a resistor R5, an auxiliary power supply circuit (100), an amplifier circuit (200) and the controller; the first end of the resistor R2, the first end of the resistor R3, the input end of the amplifier circuit (200) and the negative ion collection probe interface (TP1) are connected; the negative ion collection probe interface (TP1) is externally connected to a negative ion collection probe placed in a collection air duct, wherein a fan for driving airflow is provided in the collection air duct; the second end of the resistor R3, the first end of the resistor R5 and the first end of the resistor R4 are connected; the second end of the resistor R2 and the second end of the resistor R5 are both grounded; the second end of the resistor R4 is connected to the output end of the auxiliary power supply circuit (100); the output end of the amplifier circuit (200), the control end of the auxiliary power supply circuit (100) and the control end of the fan are all connected to the controller; The method comprises: When receiving the inspection instruction, controlling the auxiliary power supply circuit (100) to maintain a zero voltage output state and controlling the fan to maintain a shutdown state, collecting the output signal of the amplifier circuit (200) and performing analog-to-digital conversion to obtain a first voltage value; Then, the auxiliary power supply circuit (100) is controlled to output a preset voltage and the fan is controlled to continue to remain in the shutdown state, and the output signal of the amplifier circuit (200) is collected again and analog-to-digital conversion is performed to obtain a second voltage value; Calculate the difference between the second voltage value and the first voltage value, and determine whether the difference between the difference and the calibration threshold exceeds the allowable error range. If so, determine that the negative ion detector is inaccurate; wherein, the controller can adjust and set the amplitude of the preset voltage.

10. A negative ion detector measurement method, characterized in that, include: When the negative ion detector is determined to be not inaccurate and a measurement instruction is received according to the online self-test method for a negative ion detector according to claim 9, the auxiliary power supply circuit (100) is controlled again to maintain a zero voltage output state and the fan is controlled to remain in a stopped state, the output signal of the amplifier circuit (200) is collected and analog-to-digital conversion is performed to obtain the first voltage value; Then, the fan is controlled to be turned on and the auxiliary power supply circuit (100) is controlled to continue to maintain a zero voltage output state, and the output signal of the amplifier circuit (200) is collected again and analog-to-digital conversion is performed to obtain a third voltage value; The difference between the third voltage value and the first voltage value is calculated, and the concentration of negative ions in the air is calculated according to the difference between the third voltage value and the first voltage value.

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