Method and system for automatically testing icing sensor based on LabVIEW

Abstract

The invention provides an icing sensor automatic test method and system based on LabVIEW. The method comprises the steps that initialization parameters of icing sensor test software and communication addresses of hardware ports are written into a configuration file; acquiring an initialization parameter and a communication address of each hardware port from the configuration file; switch states are set, and the corresponding relays are switched on; frequency sweeping parameters of the signal generator are set, and frequency sweeping is started; setting oscilloscope card acquisition parameters, starting acquisition, and drawing a spectrogram according to an acquisition result; setting acquisition parameters of the data acquisition instrument, analyzing data and obtaining a test result; according to the drawn spectrogram, the maximum amplitude point is the output signal amplitude of the icing sensor, and the corresponding frequency point is the resonant frequency; the signal amplitude corresponding to 1KHz before and after the resonant frequency point in the drawn spectrogram is the zero signal value of the sensor; according to the drawn spectrogram, the curve before the resonant frequency point is monotonically increased, and the curve after the resonant frequency point is monotonically decreased.

Description

Technical Field

[0001] The present application belongs to the field of aviation testing technology, and specifically relates to an automatic testing method and system for an icing sensor based on LabVIEW. Background Art

[0002] The ice sensor is a special sensor used to detect whether there is ice on the aircraft surface when the aircraft is flying in icing weather conditions. When the ice thickness seriously affects flight safety, the ice sensor can detect the ice thickness and send the corresponding signal to the flight control system.

[0003] The production quantity of a certain type of ice sensor is large and the testing items are complex. During the testing process, each peripheral testing instrument (such as signal generator, digital multimeter, etc.) is operated independently, which makes the work cumbersome and fails to achieve automatic testing, seriously affecting the production and delivery efficiency of the product. Summary of the invention

[0004] Purpose of the invention: In view of the existing cumbersome manual testing, the present invention provides a LabVIEW-based automatic testing method and system for a certain type of ice sensor.

[0005] In a first aspect, the present application provides an automatic testing method for an ice sensor based on LabVIEW, the method comprising:

[0006] Step 1: Write the initialization parameters of the ice sensor test software and the communication addresses of each hardware port into the configuration file;

[0007] Step 2: Get the initialization parameters and the communication addresses of each hardware port from the configuration file;

[0008] Step 3: Set the switch state, and the corresponding relay in the switch module is turned on;

[0009] Step 4: Set the signal generator sweep parameters, oscilloscope card acquisition parameters and data acquisition instrument acquisition parameters;

[0010] The signal generator starts frequency sweeping to send an excitation signal to the icing sensor, and the icing sensor feeds back a sinusoidal signal according to the excitation signal;

[0011] The oscilloscope card collects the sinusoidal signal, draws a spectrum diagram according to the sinusoidal signal, analyzes the spectrum diagram, obtains the maximum amplitude point, determines the resonance frequency according to the maximum amplitude point, and uses the signal amplitude corresponding to 1KHz before and after the resonance frequency point as the zero signal value of the ice sensor; wherein the maximum amplitude point is the output signal amplitude of the ice sensor, and the resonance frequency is the frequency point corresponding to the maximum amplitude point; the curve before the resonance frequency point is monotonically increasing, and the curve after the resonance frequency point is monotonically decreasing;

[0012] The data acquisition instrument monitors the loop current of the signal generator in real time, and adjusts the output amplitude of the signal generator in a timely manner according to the loop current;

[0013] Step 5: Stop the test and output the report;

[0014] Step 6: After the test is completed, restore the initial state.

[0015] Preferably, the step 1 comprises:

[0016] Step 1.1: The test system is powered on, each test module automatically starts, and the hardware is initialized;

[0017] Step 1.2: The user starts the test software interface on the computer, and the software reads the information preset in the configuration file, which includes the serial port number and communication address of each hardware device;

[0018] Step 1.3: The test software reads the serial port number and communication address in the previous step, communicates with the data acquisition instrument, signal generator, and programmable DC power supply through the VISA protocol, and communicates with the data acquisition card and oscilloscope card through the PCIe protocol.

[0019] Preferably, step 2 comprises:

[0020] Step 2.1: Clear the test status process description box on the test software test interface;

[0021] Step 2.2: Set the output display control on the test software test interface to zero;

[0022] Step 2.3: After clicking the "Start Test" control, the "Exit" control is disabled;

[0023] Step 2.4: After clicking the "Start Test" control, reset the signal generator output parameters and stop output, reset the programmable DC power supply output parameters and stop output, and reset the data acquisition card DO state to restore to low level output;

[0024] Step 2.5: Write the different execution states of steps 2, 3, 4, 5, and 6 into the array to form a state set, set the execution state sequence, and the program will be executed in the set state set sequence when the automatic test starts.

[0025] Preferably, the step 3 comprises:

[0026] Step 3.1: Set the data acquisition card slot number, set the DO port number that the data acquisition card needs to output high level, convert the number cluster into an array, and input it to the data acquisition card subroutine port number;

[0027] Step 3.2: Set the DO port with the above number to output high level;

[0028] Step 3.3: Set the DO port output state in the test state process description box, corresponding to the relay open state description;

[0029] Step 3.4: Set the delay time to ensure that all relays are turned on before the next frequency sweep begins.

[0030] Preferably, step 4 comprises:

[0031] Step 4.1: Set the oscilloscope card acquisition parameters, including the oscilloscope card slot number, sampling channel number, sampling range, sampling rate, sampling point number, impedance matching method, and coupling method;

[0032] Step 4.2: Set the signal generator sweep parameters, including the signal generator output channel number, sweep start frequency, sweep end frequency, sweep duration, output signal phase, and sweep hold time; in particular, the sweep duration affects the final frequency point acquisition; set the parameters according to the test sweep range required by the ice sensor being tested;

[0033] Step 4.3: Set the amplitude adjustment control, detect the current in real time during the frequency sweep process, and adjust the output voltage; specifically, set the data acquisition card acquisition parameters, including the acquisition card AI acquisition channel number, sampling rate and sampling point number, and sampling method; obtain the data of the corresponding channel number of the AC current transmitter, multiply it by the conversion coefficient to obtain the actual current value, write this current value into the comparison function of range judgment and forced conversion, and use the output Boolean value as the branch selection of the next conditional structure. When it is less than the current setting range, increase the signal generator output amplitude; when it is greater than the current setting range, reduce the signal generator output amplitude;

[0034] Step 4.4: Set the state description in the test state process description box to start frequency sweeping, data collection and result analysis;

[0035] Step 4.5: Set up the oscilloscope card acquisition result capture subroutine, use the array maximum and minimum functions, capture the group of data with the largest amplitude in the array acquired by the oscilloscope, set this group of data as the output control, and display it as the resonance frequency and output signal amplitude; at the same time, take the points 1KHz before and after the resonance frequency as the index in the subroutine, and get the amplitude in the array as the zero signal value;

[0036] Step 4.6: Compare the resonance frequency, output signal amplitude and zero signal value with the preset values ​​respectively, and judge whether the test results are qualified;

[0037] Step 4.7: Set the spectrum monotonicity check control to perform monotonicity analysis on the spectrum of the ice sensor output signal. Specifically, grab the array of acquisition results from the oscilloscope card, set a For loop, use the method of dividing the quotient and taking the remainder, take an amplitude every 50 groups of numbers, and then set another For loop. Set the shift register in the loop to shift the previous data as the subtracted value. Subtract the data obtained in the previous step in sequence in the loop. When the differences are all negative, it is judged to be monotonically decreasing. When the differences are all positive, it is judged to be monotonically increasing.

[0038] Preferably, step 5 comprises:

[0039] Step 5.1: Capture the output data of the test items in the above steps and add them to the specified style table;

[0040] Step 5.2: Set the table save control and save the table to the local disk;

[0041] Step 5.3: Set the description of the test stop in the Test Status Process Description box.

[0042] Preferably, step 6 comprises:

[0043] Step 6.1: Reset the output parameters of the signal generator and stop the output, reset the output parameters of the programmable DC power supply and stop the output, reset the DO state of the data acquisition card to restore to low level output;

[0044] Step 6.2: Merge the error clusters and set the error type description in the test status process description box;

[0045] Step 6.3: Close the configuration file information reference, close the loop, and the test ends.

[0046] In a second aspect, the present application also provides an automatic test system for an ice sensor based on LabVIEW, the test system comprising: a programmable DC power supply, a signal generator, an oscilloscope card, a data acquisition card, a switch module, an AC current transmitter, a computer and a display module;

[0047] Among them, the program-controlled DC power supply is used to power the product under test;

[0048] A signal generator is used to generate an excitation signal required for the test process. After the excitation signal enters the ice sensor to be tested, the matching electronic converter provides an AC voltage to a pressure element of the pressure assembly, thereby forming a mechanical vibration in the vibration converter. When the frequency of the AC voltage is equal to the longitudinal resonance frequency of the vibration converter, the vibration converter resonates;

[0049] Oscilloscope card, used to collect feedback signals from the ice sensor under test. When ice forms on the sensor vibrating head, its mass changes, which causes the resonant frequency of the vibration converter to change, and the output voltage signal also changes accordingly.

[0050] The data acquisition card is used to collect the output of the AC current transmitter and control the opening of the switch module. The real-time output voltage of the AC current transmitter is collected by using the analog input terminal (AI) of the data acquisition card, and converted into an AC current value; the high-level signal output by the switch output terminal (DO) of the data acquisition card is used to control the opening and closing of the switch module;

[0051] The switch module is used to control the on / off of the power supply circuit, signal input circuit, and signal output circuit. It is composed of a transistor, a current limiting resistor, a relay, a wiring terminal, and a circuit board. When the software controls the DO terminal of the data acquisition card to output a high level, the high-level signal drives the transistor to conduct, the driving circuit of the corresponding relay is conducted, the relay is turned on, and the corresponding main circuit is connected;

[0052] AC current transmitter is used to measure the current of the ice detector feedback loop and convert it into a DC voltage signal, which is collected by the AI ​​port of the data acquisition card;

[0053] A computer is used to provide a communication interface for the above-mentioned equipment and integrate the test software. When the test equipment is running, it controls the hardware operation according to the preset process, and at the same time accepts instructions from the operator and transmits key test information to the display module;

[0054] Display module, used to intuitively display the test results on the computer user interface developed with LabVIEW;

[0055] The program-controlled DC power supply and the signal generator communicate with the computer via VISA serial port, and the oscilloscope card and the data acquisition card communicate with the computer via PCIe.

[0056] This application has the following technical effects:

[0057] 1. LabVIEW programming language is used, which is concise, intuitive and easy to use. It can simplify tedious and complex programming into selecting functions in the form of menu prompts, replacing traditional text program codes. It is direct to run, easy to debug, and easy to understand programming identification;

[0058] 2. The test method of this invention solves the problem of synchronous interaction between the program-controlled DC power supply, signal generator, oscilloscope card, data acquisition card, switch module, AC current transmitter and computer, automates the test process and greatly improves production efficiency;

[0059] 3. The test method of this invention is adopted to automate the test with one key, solidify the test process and test parameters, reduce the operation process of manual testing, avoid the possible omissions in the manual testing process, and greatly improve the quality level of the product;

[0060] 4. The test system of this invention reserves communication interfaces for other hardware devices, and a hardware parameter modification window is reserved in the software. When testing other types of ice sensors, the universality of the test system can be achieved by modifying the hardware parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic diagram of the system framework of the present invention;

[0062] Figure 2 It is a schematic diagram of the software testing process of the present invention. DETAILED DESCRIPTION

[0063] See also Figure 1 and Figure 2 The present invention provides a certain type of ice sensor automatic testing method based on LabVIEW, referring to Figure 2 As shown, the specific steps of implementing this method are as follows:

[0064] Step 1: Start the software and write the initialization parameters of the ice sensor test software and the communication addresses of each hardware port into the configuration file;

[0065] Specifically, the step 1 includes:

[0066] Step 1.1: The test system is powered on, each test module automatically starts, and the hardware is initialized;

[0067] Step 1.2: The user starts the test software interface on the computer, and the software reads the information preset in the configuration file, which includes the serial port number and communication address of each hardware device. The configuration file has a unified save path, and different test steps apply different values ​​in the configuration file. The configuration file contains two categories, namely the hardware device communication address and the adjustment coefficient of the test item. In this method, the device communication address includes the programmable DC power supply communication address and the signal generator communication address, and the test item adjustment coefficient includes the AC current value conversion coefficient;

[0068] Step 1.3: The test software reads the serial port number and communication address in the previous step, communicates with the data acquisition instrument, signal generator, and programmable DC power supply through the VISA protocol, and communicates with the data acquisition card and oscilloscope card through the PCIe protocol.

[0069] Step 2: Start the test and obtain the initialization parameters and the communication addresses of each hardware port from the configuration file.

[0070] Specifically, the step 2 includes:

[0071] Step 2.1: Clear the test status process description box on the test software test interface; remove the description message in the test status process description box during the previous test, and display the description of the test process that is about to begin;

[0072] Step 2.2: Set the output display control on the test software test interface to zero; remove the value in the output display control during the previous test;

[0073] Step 2.3: After clicking the "Start Test" control, the "Exit" control is disabled;

[0074] Step 2.4: After clicking the "Start Test" control, reset the signal generator output parameters and stop output, reset the programmable DC power supply output parameters and stop output, and reset the data acquisition card DO state to restore to low-level output. This step is mandatory after the test starts, and the test process fails due to hardware or switch state errors. This step is encapsulated as a separate subVI and runs once at the start and end of the test.

[0075] Step 2.5: Write the different execution states of steps 2, 3, 4, 5, and 6 into an array to form a state set, set the execution state sequence, and execute the set state set sequence when the program starts automatic testing. The above state set is input into the test process subVI as an event queue, and the state set sequence is executed by the start test control.

[0076] Step 3: Set the switch state and the corresponding relay is turned on.

[0077] Specifically, the step 3 includes:

[0078] Step 3.1: Set the data acquisition card slot number, set the DO port number that the data acquisition card needs to output a high level, convert the number cluster into an array, and input it to the data acquisition card subroutine port number; in this method, the DO port numbers that output a high level are P0.2, P0.3, and P1.1, and the corresponding S2, S3, and S9 relays are turned on, and the excitation signal circuit, feedback signal circuit, and power supply circuit of the product under test are connected;

[0079] Step 3.2: Set the DO port with the above number to output high level;

[0080] Step 3.3: Set the DO port output state in the test state process description box, corresponding to the relay open state description;

[0081] Step 3.4: Set the delay time to ensure that all relays are turned on before the next frequency sweep begins;

[0082] Step 4: Set the sweep frequency parameters of the signal generator and start the sweep frequency; set the acquisition parameters of the oscilloscope card, start the acquisition, and draw a spectrum diagram according to the acquisition results; set the acquisition parameters of the data acquisition instrument, analyze the data and obtain the test results; according to the drawn spectrum diagram, the point with the maximum amplitude is the output signal amplitude of this type of ice sensor, and the corresponding frequency point is the resonance frequency; the signal amplitude corresponding to 1KHz before and after the resonance frequency point in the drawn spectrum diagram is the zero signal value of this type of sensor; according to the drawn spectrum diagram, the curve before the resonance frequency point should be monotonically increasing, and the curve after the resonance frequency point should be monotonically decreasing. In this method, the resonance frequency point should be in the range of 22-25.2kHz, the output signal amplitude should be greater than 200mVrms, the zero signal value should be less than 50mVrms, the curve before the resonance point on the spectrum diagram should be monotonically increasing, and the curve after the resonance point should be monotonically decreasing.

[0083] Specifically, step 4 includes:

[0084] Step 4.1: Set the oscilloscope card acquisition parameters, including the oscilloscope card slot number, sampling channel number, sampling range, sampling rate, sampling points number, impedance matching mode, and coupling mode; in this method, the slot number is set to 1, the sampling channel is 1 channel, the sampling range is 0-10V, the sampling rate is set to 100ksps, the sampling points are 10k, the impedance matching is set to 1MΩ, and the coupling mode is selected as AC coupling;

[0085] Step 4.2: Set the sweep parameters of the signal generator, including the signal generator output channel number, sweep start frequency, sweep end frequency, sweep duration, output signal phase and sweep hold time. In particular, the sweep duration affects the final frequency point acquisition; in this method, the signal generator output channel number is set to 1, the sweep start frequency is 21KHz, the sweep end frequency is 27.5KHz, the sweep time is set to 650s, the output signal phase is set to 0°, and the sweep hold time is set to 0.1s. In particular, during the equipment debugging process, the sweep hold time is initially set to 1s, that is, it increases by 10Hz per second. The value of the resonant frequency point in the test result is unstable, and the results show large deviations after continuous repeated measurements. After analysis, the output of the signal generator is not linear. It maintains a constant value during the set hold time, and changes to the next constant frequency value in the next hold time period, resulting in deviations in the reading of the resonance point of the spectrum graph. The solution is to increase the linearity of the signal generator output, that is, reduce the output holding time and adjust it to 0.1s. In this way, the frequency increases by 1Hz every 0.1s. Although the sweep range and sweep time do not change, the linearity of the signal generator output increases, and the deviation is smaller when close to the resonance point.

[0086] Step 4.3: Set the amplitude adjustment control, detect the current in real time during the frequency sweep, and adjust the output voltage. Specifically, set the data acquisition card acquisition parameters, including the acquisition card AI acquisition channel number, sampling rate and sampling point number, and sampling method. Take the data of the corresponding channel number of the AC current transmitter, multiply it by the conversion coefficient to get the actual current value, write this current value into the comparison function of range judgment and forced conversion, and use the output Boolean value as the branch selection of the next conditional structure. When it is less than the current setting range, increase the signal generator output amplitude, and when it is greater than the current setting range, reduce the signal generator output amplitude; in this method, set the acquisition card AI acquisition channel number to AI3, the sampling rate to 20ksps, the sampling point number to 2k, the sampling mode to single-ended sampling, the selected AC current transmitter input is 0-100mA, the output is 0-1VDC, and the conversion factor of the output voltage to the current value is 10, which is also saved in the configuration file. In the actual frequency sweep process, the current range is set to 19-21mA, the initial amplitude of the signal generator is 100mVrms, the initial frequency is 21KHz, the frequency is continuously increased, and the amplitude is also adjusted to maintain the current at 19-21mA;

[0087] Step 4.4: Set the state description of starting frequency sweep, data acquisition and result analysis in the test state process description box; the description box shows starting signal sweep, starting data acquisition and analysis;

[0088] Step 4.5: Set up the oscilloscope card acquisition result capture subroutine, use the array maximum and minimum functions, capture the group of data with the largest amplitude in the array acquired by the oscilloscope, set this group of data as the output control, and display it as the resonance frequency and output signal amplitude; at the same time, take the points 1KHz before and after the resonance frequency as the index in the subroutine, and get the amplitude in the array as the zero signal value;

[0089] Step 4.6: Compare the resonance frequency, output signal amplitude and zero signal value with the preset values ​​respectively, and judge whether the test result is qualified; if it is qualified, the output control will display passed and it will be displayed in green, and if it is unqualified, it will display failed and it will be displayed in red;

[0090] Step 4.7: Set the spectrum monotonicity check control to perform monotonicity analysis on the spectrum of the output signal of the ice sensor. Specifically, grab the array of acquisition results of the oscilloscope card, set a For loop, use the method of dividing the quotient and taking the remainder, take an amplitude every 50 groups of numbers, and then set another For loop. Set the shift register in the loop to shift the previous data as the subtracted value. Subtract the data obtained in the previous step in sequence in the loop. When the difference is negative, it is judged as monotonically decreasing, and when the difference is positive, it is judged as monotonically increasing. In this method, the spectrum curve from 21KHz to the resonance point should be monotonically increasing, and the spectrum curve from the resonance point to 27.5KHz should be monotonically decreasing.

[0091] Step 5: Stop the test and output the report.

[0092] Specifically, the step 5 includes:

[0093] Step 5.1: Capture the output data of the test items in the above steps and add them to the specified style table; in the table, you can manually fill in the product number, date, and operator information of the tested product. The table contains four items: test items, test results, reference range, and qualified judgment;

[0094] Step 5.2: Set the table save control, and save the table output values ​​to the local disk;

[0095] Step 5.3: Set the description of the test stop in the Test Status Process Description box.

[0096] Step 6: After the test is completed, restore the initial state.

[0097] Specifically, the step 6 includes:

[0098] Step 6.1: Reset the output parameters of the signal generator and stop the output, reset the output parameters of the programmable DC power supply and stop the output, reset the DO state of the data acquisition card to restore to low level output;

[0099] Step 6.2: Merge the error clusters and set the error type description in the test status process description box;

[0100] Step 6.3: Close the configuration file information reference, close the loop, and the test ends.

[0101] In other embodiments of the present application, the present invention provides a certain type of automatic test system for ice sensors based on LabVIEW, and its specific hardware includes: a programmable DC power supply, a signal generator, an oscilloscope card, a data acquisition card, a switch module, an AC current transmitter, a computer and a display module. All hardware is integrated in a standard test cabinet and installed on the cabinet layer board.

[0102] The programmable power supply is used to power the product under test; the product is powered by 28V.

[0103] The signal generator is used to generate the excitation signal required for the test process. After the excitation signal enters the ice sensor to be tested, the matching electronic converter provides an AC voltage to a pressure element of the pressure assembly, thereby forming mechanical vibration in the vibration converter. When the frequency of the AC voltage is equal to the longitudinal resonance frequency of the vibration converter, the vibration converter resonates.

[0104] The oscilloscope card is used to collect the feedback signal of the ice sensor under test. When ice forms on the sensor vibration head, its mass changes, which causes the resonance frequency of the vibration converter to change, and the output voltage signal also changes accordingly.

[0105] The data acquisition card is used to collect the output of the AC current transmitter and control the opening of the switch module. The analog input terminal (AI) of the data acquisition card is used to collect the real-time output voltage of the AC current transmitter and convert it into an AC current value. The input of the selected AC current transmitter is 0-100mA, the output is 0-1VDC, and the conversion factor of the output voltage to the current value is 10; the high-level signal output by the switch output terminal (DO) of the data acquisition card is used to control the opening and closing of the switch module. The DO terminal outputs a 5V high level and continues until the control is closed;

[0106] The switch module is used to control the on and off of the power supply circuit, signal input circuit and signal output circuit. It is composed of a transistor, a current limiting resistor, a relay, a wiring terminal and a circuit board. When the software controls the DO end of the data acquisition card to output a high level, the high level signal drives the transistor to turn on, the driving circuit of the corresponding relay is turned on, the relay is turned on, and the corresponding main circuit is connected; the transistor, current limiting resistor, relay and wiring terminal are welded and installed on the circuit board, and the entire circuit board assembly is installed on the chassis layer.

[0107] The AC current transmitter is used to measure the current of the ice detector feedback loop and convert it into a DC voltage signal, which is collected by the AI ​​port of the data acquisition card;

[0108] The computer is used to provide a communication interface for the above equipment and integrate the test software. When the test equipment is running, it controls the hardware operation according to the preset process, and at the same time accepts instructions from the operator and transmits key test information to the display module;

[0109] The display module is used to intuitively display the test results on the computer user interface developed with LabVIEW;

[0110] The program-controlled DC power supply and the signal generator communicate with the computer via VISA serial port, and the oscilloscope card and the data acquisition card communicate with the computer via PCIe.

[0111] The present invention provides a LabVIEW-based automatic testing method and system for a certain type of ice sensor, comprising: step 1: starting the software, writing the initialization parameters of the ice sensor testing software and the communication addresses of each hardware port into a configuration file; step 2: starting the test, obtaining the initialization parameters and the communication addresses of each hardware port from the configuration file; step 3: setting the switch state, and the corresponding relay is turned on; step 4: setting the sweep frequency parameters of the signal generator, and starting the sweep frequency; setting the acquisition parameters of the oscilloscope card, starting the acquisition, and drawing a spectrum diagram according to the acquired results; setting the acquisition parameters of the data acquisition instrument, analyzing the data and obtaining the test results; according to the drawn spectrum diagram, the maximum amplitude point is the output signal amplitude of the ice sensor of this type, and the corresponding frequency point is the resonance frequency; the signal amplitude corresponding to 1KHz before and after the resonance frequency point in the drawn spectrum diagram is the zero signal value of the sensor of this type; according to the drawn spectrum diagram, the curve before the resonance frequency point should be monotonically increasing, and the curve after the resonance frequency point should be monotonically decreasing. Step 5: stop the test, and output a report; step 6: end the test, and restore the initial state. The present invention can simplify the test process and improve production efficiency.

Claims

1. An automatic testing method for ice sensors based on LabVIEW, characterized in that: The method comprises: Step 1: Write the initialization parameters of the ice sensor test software and the communication addresses of each hardware port into the configuration file; Step 2: Get the initialization parameters and the communication addresses of each hardware port from the configuration file; Step 3: Set the switch state, and the corresponding relay in the switch module is turned on; Step 4: Set the signal generator sweep parameters, oscilloscope card acquisition parameters and data acquisition instrument acquisition parameters; The signal generator starts frequency sweeping to send an excitation signal to the icing sensor, and the icing sensor feeds back a sinusoidal signal according to the excitation signal; The oscilloscope card collects the sinusoidal signal, draws a spectrum diagram according to the sinusoidal signal, analyzes the spectrum diagram, obtains the maximum amplitude point, determines the resonance frequency according to the maximum amplitude point, and uses the signal amplitude corresponding to 1KHz before and after the resonance frequency point as the zero signal value of the ice sensor; wherein the maximum amplitude point is the output signal amplitude of the ice sensor, and the resonance frequency is the frequency point corresponding to the maximum amplitude point; the curve before the resonance frequency point is monotonically increasing, and the curve after the resonance frequency point is monotonically decreasing; The data acquisition instrument monitors the loop current of the signal generator in real time, and adjusts the output amplitude of the signal generator in a timely manner according to the loop current; Step 5: Stop the test and output the report; Step 6: After the test is completed, restore the initial state.

2. The method according to claim 1, characterized in that The step 1 comprises: Step 1.1: The test system is powered on, each test module automatically starts, and the hardware is initialized; Step 1.2: The user starts the test software interface on the computer, and the software reads the information preset in the configuration file, which includes the serial port number and communication address of each hardware device; Step 1.3: The test software reads the serial port number and communication address in the previous step, communicates with the data acquisition instrument, signal generator, and programmable DC power supply through the VISA protocol, and communicates with the data acquisition card and oscilloscope card through the PCIe protocol.

3. The method according to claim 1, characterized in that The step 2 comprises: Step 2.1: Clear the test status process description box on the test software test interface; Step 2.2: Set the output display control on the test software test interface to zero; Step 2.3: After clicking the "Start Test" control, the "Exit" control is disabled; Step 2.4: After clicking the "Start Test" control, reset the signal generator output parameters and stop output, reset the programmable DC power supply output parameters and stop output, and reset the data acquisition card DO state to return to low level output; Step 2.5: Write the different execution states of steps 2, 3, 4, 5, and 6 into the array to form a state set, set the execution state sequence, and the program will be executed in the set state set sequence when the automatic test starts.

4. The method according to claim 1, characterized in that: The step 3 comprises: Step 3.1: Set the data acquisition card slot number, set the DO port number that the data acquisition card needs to output high level, convert the number cluster into an array, and input it to the data acquisition card subroutine port number; Step 3.2: Set the DO port with the above number to output high level; Step 3.3: Set the DO port output state in the test state process description box, corresponding to the relay open state description; Step 3.4: Set the delay time to ensure that all relays are turned on before the next frequency sweep begins.

5. The method according to claim 1, characterized in that The step 4 comprises: Step 4.1: Set the oscilloscope card acquisition parameters, including the oscilloscope card slot number, number of sampling channels, sampling range, sampling rate, number of sampling points, impedance matching method, and coupling method; Step 4.2: Set the signal generator sweep parameters, including the signal generator output channel number, sweep start frequency, sweep end frequency, sweep duration, output signal phase, and sweep hold time; in particular, the sweep duration affects the final frequency point acquisition; set the parameters according to the test sweep range required by the ice sensor being tested; Step 4.3: Set the amplitude adjustment control, detect the current in real time during the frequency sweep process, and adjust the output voltage; specifically, set the data acquisition card acquisition parameters, including the acquisition card AI acquisition channel number, sampling rate and sampling point number, and sampling method; obtain the data of the corresponding channel number of the AC current transmitter, multiply it by the conversion coefficient to obtain the actual current value, write this current value into the comparison function of range judgment and forced conversion, and use the output Boolean value as the branch selection of the next conditional structure. When it is less than the current setting range, increase the signal generator output amplitude; when it is greater than the current setting range, reduce the signal generator output amplitude; Step 4.4: Set the state description in the test state process description box to start frequency sweeping, data collection and result analysis; Step 4.5: Set up the oscilloscope card acquisition result capture subroutine, use the array maximum and minimum functions, capture the group of data with the largest amplitude in the array acquired by the oscilloscope, set this group of data as the output control, and display it as the resonance frequency and output signal amplitude; at the same time, take the points 1KHz before and after the resonance frequency as the index in the subroutine, and get the amplitude in the array as the zero signal value; Step 4.6: Compare the resonance frequency, output signal amplitude and zero signal value with the preset values ​​respectively, and judge whether the test results are qualified; Step 4.7: Set the spectrum monotonicity check control to perform monotonicity analysis on the spectrum of the ice sensor output signal. Specifically, grab the array of acquisition results from the oscilloscope card, set a For loop, use the method of dividing the quotient and taking the remainder, take an amplitude every 50 groups of numbers, and then set another For loop. Set the shift register in the loop to shift the previous data as the subtracted value. Subtract the data obtained in the previous step in sequence in the loop. When the differences are all negative, it is judged to be monotonically decreasing. When the differences are all positive, it is judged to be monotonically increasing.

6. The method according to claim 1, characterized in that The step 5 comprises: Step 5.1: Capture the output data of the test items in the above steps and add them to the specified style table; Step 5.2: Set the table save control and save the table to the local disk; Step 5.3: Set the description of the test stop in the Test Status Process Description box.

7. The method according to claim 1, characterized in that The step 6 comprises: Step 6.1: Reset the output parameters of the signal generator and stop the output, reset the output parameters of the programmable DC power supply and stop the output, and reset the DO state of the data acquisition card to restore to low level output; Step 6.2: Merge the error clusters and set the error type description in the test status process description box; Step 6.3: Close the configuration file information reference, close the loop, and the test ends.

8. An automatic test system for ice sensors based on LabVIEW, characterized in that: The test system includes: a program-controlled DC power supply, a signal generator, an oscilloscope card, a data acquisition card, a switch module, an AC current transmitter, a computer and a display module; Among them, the program-controlled DC power supply is used to power the product under test; A signal generator is used to generate an excitation signal required for the test process. After the excitation signal enters the ice sensor to be tested, the matching electronic converter provides an AC voltage to a pressure element of the pressure assembly, thereby forming a mechanical vibration in the vibration converter. When the frequency of the AC voltage is equal to the longitudinal resonance frequency of the vibration converter, the vibration converter resonates; Oscilloscope card, used to collect feedback signals from the ice sensor under test. When ice forms on the sensor vibrating head, its mass changes, which causes the resonant frequency of the vibration converter to change, and the output voltage signal also changes accordingly. The data acquisition card is used to collect the output of the AC current transmitter and control the opening of the switch module. The real-time output voltage of the AC current transmitter is collected by using the analog input terminal (AI) of the data acquisition card, and converted into an AC current value; the high-level signal output by the switch output terminal (DO) of the data acquisition card is used to control the opening and closing of the switch module; The switch module is used to control the on / off of the power supply circuit, signal input circuit, and signal output circuit. It is composed of a transistor, a current limiting resistor, a relay, a wiring terminal, and a circuit board. When the software controls the DO terminal of the data acquisition card to output a high level, the high-level signal drives the transistor to conduct, the driving circuit of the corresponding relay is conducted, the relay is turned on, and the corresponding main circuit is connected; AC current transmitter is used to measure the current of the ice detector feedback loop and convert it into a DC voltage signal, which is collected by the AI ​​port of the data acquisition card; A computer is used to provide a communication interface for the above-mentioned equipment and integrate the test software. When the test equipment is running, it controls the hardware operation according to the preset process, and at the same time accepts instructions from the operator and transmits key test information to the display module; Display module, used to intuitively display the test results on the computer user interface developed with LabVIEW; The program-controlled DC power supply and the signal generator communicate with the computer via VISA serial port, and the oscilloscope card and the data acquisition card communicate with the computer via PCIe.

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