CN109343374B - LabVIEW-based pulse synchronization control two-dimensional scanning and signal acquisition method - Google Patents

Abstract

The invention discloses a method for realizing pulse synchronization control two-dimensional scanning and signal acquisition based on LabVIEW. The method includes a hardware structure and a software module; the hardware structure is composed of a workstation, an onboard data acquisition card, a signal amplifier, a workstation power supply, a motion control module, a motion control module power supply and an ultrasonic sensor; the software module is developed based on the LabVIEW platform , through the hardware to control two motors to perform two-dimensional grid scanning, and realize the acquisition of electrical signals at the same time; the software module is composed of a control panel and a display panel, the control panel includes a position adjustment module, a parameter setting module and a signal acquisition module, and the display panel includes Two-dimensional real-time signal display module, real-time signal display module and signal position display module. The method can realize the independent and joint control of the X-axis motor and the Y-axis motor, set the signal acquisition distance with high precision, quickly and accurately locate the signal acquisition point, and effectively improve the efficiency and stability of the signal acquisition.

Description

LabVIEW-based pulse synchronization control two-dimensional scanning and signal acquisition method

technical field

The invention belongs to the technical field of automatic control and signal acquisition and storage, and in particular relates to a LabVIEW-based pulse synchronization control two-dimensional scanning and signal acquisition implementation method.

Background technique

In the signal acquisition technology, it is extremely important to use the control system to acquire and store time-varying signals in real time. The operation platform is designed based on the LabVIEW (Laboratory Virtual Instrument Engineering Workbench) graphical programming language. Compared with other programming languages, the programming interface is intuitive and easy to understand, and the user interface is friendly. Compared with other forms of motor control, such as single-chip microcomputer, special programming knowledge is required, and the professional threshold is higher. The operation interface of LabVIEW is more concise, and the visual programming language is easy to understand and control. The combination of the coordinated motion of the motors and the collection of signals during the motion is missing from the patent application. For example, in the patent "a multi-motor control system based on LabVIEW" applied by Jia Zhenyuan of Dalian University of Technology in December 2015, this method realizes fast and stable control of multiple motors, but the implementation process of this method is complicated and cannot satisfy The requirement for simultaneous signal acquisition during motion. The signal analysis in the movement process is in line with the actual needs of production in the field of signal acquisition and storage. Therefore, a new method is needed to solve the problem of multi-motor fast and stable control cooperative signal acquisition.

LabVIEW is a program development environment developed by National Instruments (NI), similar to C and BASIC development environments, but the significant difference between LabVIEW and other computer languages is that other computer languages use text-based languages to generate code , and LabVIEW uses the graphical editing language G to write programs, and the resulting programs are in the form of block diagrams. LabVIEW software is at the heart of the NI design platform and is ideal for developing measurement or control systems. The LabVIEW development environment integrates all the tools engineers and scientists need to rapidly build a variety of applications designed to help engineers and scientists solve problems, increase productivity, and innovate.

Like C and BASIC, LabVIEW is a general-purpose programming system with a large library of functions that can be used to accomplish any programming task. The function library of LabVIEW includes data acquisition, GPIB, serial port control, data analysis, data display and data storage, and so on. LabVIEW also has traditional program debugging tools, such as setting breakpoints, displaying data and its subprograms (subVI (Virtual Instrument, virtual instrument)) results in animation, single-step execution, etc., which is convenient for program debugging.

LabVIEW is a graphical programming language that uses icons instead of lines of text to create applications. Traditional text programming languages determine the program execution order according to the sequence of statements and instructions, while LabVIEW uses data flow programming. The data flow between nodes in the block diagram determines the execution order of VIs and functions. VI refers to a virtual instrument and is a program module of LabVIEW.

LabVIEW provides many controls that look similar to traditional instruments (eg, oscilloscopes, multimeters) and can be used to easily create user interfaces. The user interface is called the front panel in LabVIEW. Objects on the front panel can be controlled programmatically using icons and wires. This is the graphical source code, also known as G-code. LabVIEW's graphical source code is somewhat similar to flowcharts and is therefore also referred to as block diagram code. The characteristics of LabVIEW are: use general hardware as much as possible, and the difference between various instruments is mainly software; it can give full play to the capabilities of the computer, has powerful data processing functions, and can create more powerful instruments; users can according to their own needs. Define and manufacture various instruments.

LabVIEW is widely accepted by industry, academia, and research laboratories as a standard data acquisition and instrument control software. LabVIEW integrates all functions for communicating with hardware and data acquisition cards that meet GPIB, VXI, RS-232 and RS-485 protocols. It also has built-in library functions that facilitate the application of software standards such as TCP/IP and ActiveX. This is a powerful and flexible software. Using it, you can easily build your own virtual instrument, and its graphical interface makes the programming and use process lively and interesting.

Graphical programming language, also known as "G" language. When programming in this language, program code is basically not written, but instead flowcharts or block diagrams. It utilizes as much as possible the terms, icons, and concepts familiar to technicians, scientists, and engineers, so LabVIEW is an end-user-facing tool. It enhances your ability to build your own scientific and engineering systems, providing a convenient way to implement instrument programming and data acquisition systems. When using it for principle research, design, test and realization of instrument system, work efficiency can be greatly improved. With LabVIEW, a stand-alone executable can be produced, which is a true 32-bit/64-bit compiler. Like many important software, LabVIEW provides Windows, UNIX, Linux, Macintosh versions. Its main convenience is that in the case of the same hardware, the functions of different instruments can be realized by changing the software.

SUMMARY OF THE INVENTION

In order to solve the problems of weak real-time performance and low accuracy in the existing real-time acquisition and storage methods of time-varying signals, the present invention provides a LabVIEW-based pulse synchronization control two-dimensional scanning and signal acquisition implementation method. The method constructs a control system that realizes two-dimensional scanning through the combination of single-dimensional motors and a signal storage system that performs signal acquisition at the same time. The method can realize the separate and joint control of the X-axis motor and the Y-axis motor, and set the signal acquisition distance with high precision , quickly and accurately locate the signal acquisition point, effectively improving the efficiency and stability of signal acquisition.

To achieve the above-mentioned goals, the present invention adopts the following technical solutions:

A LabVIEW-based pulse synchronization control two-dimensional scanning and signal acquisition implementation method, the method includes a hardware structure and a software module. The hardware structure consists of a workstation, an onboard data acquisition card, a signal amplifier, a workstation power supply, a motion control module, a motion control module power supply and an ultrasonic sensor; the onboard data acquisition card, the signal amplifier and the ultrasonic sensor are connected in sequence , the ultrasonic sensor is connected to the onboard data acquisition card after signal amplifier for data acquisition, analog-to-digital conversion and data storage; the onboard data acquisition card is installed in the workstation motherboard. The software module is developed based on the LabVIEW platform, and the hardware controls two motors to perform two-dimensional grid scanning, and simultaneously realizes the acquisition of point source signals; the software module is composed of a control panel and a display panel. The control panel includes a position adjustment module, a parameter setting module and a signal acquisition module, and the display panel includes a two-dimensional real-time signal display module IV, a real-time signal display module V and a signal position display module VI.

The problem to be solved by the present invention is to construct a set of control system for combining single-dimensional motors to realize two-dimensional scanning and a signal storage system for simultaneous signal acquisition. The control system consists of software modules and hardware parts. The software module is based on the control program and system operation interface written by the LabVIEW graphical programming platform. Using this control program, two stepper motors are used to perform high-precision two-dimensional raster scanning on the X-axis and the Y-axis. , so that the combined signal acquisition device can quickly and stably acquire point-to-point signals, and at the same time cooperate with the onboard multi-channel data acquisition card for data acquisition, transmission and storage. In addition, the control system can realize the independent and joint control of the motors of the X-axis and the Y-axis, and set the signal acquisition distance with high precision, quickly and accurately locate the signal acquisition point, and effectively improve the efficiency and stability of the signal acquisition.

The software module consists of a control panel and a display panel. The control panel includes a position adjustment module I, a parameter setting module II, and a signal acquisition module III; the display panel includes a two-dimensional real-time signal display module IV, a real-time signal display module V, and a signal position display module VI.

The position adjustment module I can adjust each stepping motor individually, including the distance adjustment of the X-axis motor, the distance adjustment of the Y-axis motor, and the synchronous adjustment of the two-dimensional motor; at the same time, the initial position point can also be set, which is convenient for the two-axis motor to be adjusted in the future. Restore during scanning. The position adjustment module includes the following structure and operation steps: a serial port sequence selection window, X-axis and Y-axis motor position adjustment input and position adjustment confirmation buttons; general operation steps: first, select the serial port corresponding to the motor and the workstation to connect the serial port in the serial port sequence selection window, In order to realize serial port communication functions such as serial port initialization, serial port reading and writing, and serial port closing, after completing serial port communication, adjust the serial port input motor displacement distance in millimeters in the X-axis and Y-axis motor positions, and check the selection box of the corresponding axis, Click the position adjustment button to realize one-dimensional or two-dimensional spatial position adjustment.

The parameter setting module II is used to set the size of the X-axis and Y-axis area of the two-dimensional operation of the motor, the raster scan spacing and the adjustment of the motor stepping speed; the built-in emergency stop control is used to quickly cut off all signals and stop all signals before an accident occurs. The motor runs and the data acquisition card is collected, and after the motor stops, it automatically returns to the initial position set, and the data of the acquisition card is cleared. After the parameter setting is completed, click the start button, and the motor will move according to the given parameters. The parameter setting module includes the following structures and operation steps: X-axis and Y-axis scan length input windows, scan spacing input windows, data storage location selection windows and file naming windows; general operation steps are: first determine the size of the signal acquisition range, and then sequentially. Enter the X-axis and Y-axis scan lengths in millimeters, and then determine the X-axis scan spacing. The smaller the spacing setting, the finer the signal acquisition, the more the corresponding acquisition cycles, the longer the completion time for one acquisition, and the input scan spacing. The parameters are set according to the actual situation. Finally, set the name and storage location of the pre-collected data file.

The signal acquisition module III is used to set the parameters of signal acquisition. Taking into account the characteristics of the collected signal itself, this module can adjust the data acquisition card, and by setting the sampling frequency, sampling length, sampling starting point and other parameters, efficiently and accurately collect the required signal segments and store them. The signal acquisition module includes the following structures and operation steps: sampling rate, sampling length, clock mode, trigger timeout, acquisition mode, trigger wait, sampling depth, trigger delay and other input or selection windows; the general operation steps are: Starting from the frequency, select the appropriate sampling rate according to the Nyquist theorem; select the sampling length, clock mode, trigger delay, acquisition mode, trigger wait and other parameters according to the amplitude, length, period and frequency of different signals, so that the final signal The collection accuracy and efficiency are optimized. Built-in emergency stop control is used to quickly cut off all signals, stop all motor operation and data acquisition card acquisition before an accident occurs, and make the motor automatically return to the initial position after the motor stops, and the data of the acquisition card is cleared.

The two-dimensional image real-time display module IV, as an auxiliary module, mainly provides the experimenter with a preview of the collected signals. By displaying the signal waveform and the combination and processing of the signal, the experimenter can intuitively observe whether the acquired signal is the content of interest, so as to adjust the control and acquisition process in time. The two-dimensional image real-time display module includes the following structures and operation steps: the X-axis and Y-axis coordinates respectively represent the X-axis and Y-axis scanning lengths in the parameter setting module. Through the positioning of the two coordinates, the real-time reconstruction of the acquired signal can obtain the real-time display of the two-dimensional image; further, by adjusting the maximum and minimum values of the coordinate axis, the range of the image area of interest can be adjusted in this module; in addition , by changing the value of the color intensity of the right color bar, the optimal display contrast of the two-dimensional image can be obtained by adjusting the signal intensity.

The signal display module V can provide relevant information such as waveform, amplitude and peak position of the measured point source signal in real time, and includes the following structure and operation steps: the X and Y axis coordinates respectively represent the sampling length and signal amplitude of the time domain signal. The length of the X-axis is mainly determined by the sampling length in the signal acquisition module, and the starting sampling point is determined by the trigger delay, that is, after the trigger delay expires, the acquisition card starts to collect signals, and the real-time signal display module displays the signal waveform of the sampling length.

The signal position display module VI can display in real time the signal position of the line of signals in the Z-axis direction after one X-axis scan is completed, and determine the relative positional relationship between the signal generating point source and the sample surface and the different signal generating point sources in the line. relative positional relationship. The signal position display module includes the following structure and operation steps: the X and Y axis coordinates respectively represent the X axis length and the signal depth, which are respectively determined by the X axis scanning length of the parameter setting module and the sampling length of the signal acquisition module. The length of the X-axis can be adjusted to display the signal depth in different scanning ranges; the signal depth of the Y-axis is obtained by inversion from the sampling rate, sampling length, and signal transmission rate, so as to observe the depth information of the deep signal and the surface signal.

The control flow of the control software is: serial port initialization, testing whether the communication between the workstation and the controller and the acquisition board is normal, if not, debugging until normal. When the port detects a high-level trigger signal, the motor controller sends an instruction to control the X-axis motor to travel a specified distance. Simultaneously, the acquisition card is triggered by the trigger signal to trigger the data acquisition process. When the X-axis motor stops moving after the specified distance, the acquisition board stops data acquisition, uploads the data to the workstation, and writes the storage file. At the same time, the Y-axis motor travels the specified distance until it stops. At this time, the X-axis motor moves in the opposite direction for the specified distance, and synchronously, the acquisition card is triggered by the trigger signal to trigger the data acquisition process. When the X-axis motor stops moving after completing the specified distance, the acquisition board stops data acquisition, uploads the data to the workstation, and writes the storage file. At the same time, the Y-axis motor travels the specified distance until it stops, and the X-axis motor moves in the opposite direction again, and the data acquisition and storage process occurs synchronously. Finally, the collected data is all saved in one file, and the software control process ends.

The advantages and beneficial effects of the present invention are:

1) Based on LabVIEW, a collaborative control system of two-dimensional motor and signal acquisition is designed and developed. The program is simple and the operation is convenient. Compared with the control of single-chip microcomputer, PLC and other equipment, it has better portability and can efficiently control the two-dimensional motor. Coordinate control with signal acquisition card;

2) The independent and coordinated control of the two-dimensional spatial position of the X-axis and the Y-axis and the acquisition and storage of time-varying pulse signals are realized, which improves the accuracy and efficiency of signal acquisition.

Description of drawings

1 is a hardware connection diagram of a control system constructed by the present invention, wherein 1 is a workstation, 2 is a signal acquisition card, 3 is a signal amplifier, 4 is a workstation power supply, 5 is a motion control module power supply, 6 is a motion control module, 7 is an ultrasonic sensor;

Fig. 2 is the software interface of the control panel of the present invention;

Fig. 3 is the software interface of the display panel of the present invention;

Fig. 4 is the control flow chart of the control software of the present invention;

FIG. 5 is a schematic diagram of the two-dimensional grid scanning method according to the present invention.

Fig. 6 is the structure and execution flow chart of the position adjustment module of the present invention;

Fig. 7 is the structure and execution flow chart of the parameter setting module of the present invention;

Fig. 8 is the structure and execution flow chart of the signal acquisition module of the present invention;

Fig. 9 is the structure and execution flow chart of the two-dimensional image real-time display module of the present invention;

Fig. 10 is the structure and execution flow chart of the signal display module of the present invention;

Fig. 11 is the structure and execution flow chart of the signal position display module of the present invention;

Detailed ways

The present invention will be further described below in conjunction with the examples.

In the specific implementation process, according to the principle of photoacoustic effect, a focused pulsed laser is used to excite the sample to generate a pulsed ultrasonic source as the acquisition signal. The two-dimensional mechanical scanning device scheme is to place two stepping motors perpendicular to each other, and the signal source and the two-dimensional motor are relatively fixed and move with the motor to construct a pulsed ultrasonic signal source in a two-dimensional plane. In order to realize the flexible and coordinated control of the entire mechanical device and simultaneously acquire the pulsed ultrasonic signals, a method of coordinated control of the two-dimensional motor and the signal acquisition card is required to complete the independent and coordinated control and adjustment of the scanning range, speed, and distance of the motor in the two-dimensional plane. And point-to-point pulse signal acquisition.

Example 1

See Figures 1, 2, and 3. A LabVIEW-based pulse synchronization control two-dimensional scanning and signal acquisition implementation method, the method includes a hardware structure and a software module. The hardware structure consists of a workstation 1, an onboard data acquisition card 2, a signal amplifier 3, a workstation power supply 4, a motion control module power supply 5, a motion control module 6, and an ultrasonic sensor 7; the workstation power supply 4 is connected to the workstation 1 and is It supplies power; the data acquisition card 2 is onboard on the workstation 1 and is connected with the signal amplifier 3 and the ultrasonic sensor 7 to realize signal acquisition, amplification and storage; the power supply 5 is connected to the power supply stepper motor combination to drive the ultrasonic sensor to perform X-ray operation. Axes and Y-axis motion sweep.

The software module is written and developed based on the LabVIEW graphical programming platform, and together with the hardware part, it realizes the control of the stepping motor and the data acquisition card. The software module consists of a position adjustment module I, a parameter setting module II, a signal acquisition module III, a two-dimensional real-time signal display module IV, a real-time signal display module V, and a signal position display module VI in the control panel and the display panel.

Accompanying drawing 2 shows the control interface of the position adjustment module I, which includes the independent and coordinated position adjustment control of the X-axis and Y-axis motors; the parameter setting module II, which includes the X-axis and Y-axis scanning length, scanning distance, Related parameter settings of storage location and file naming; signal acquisition module III, this module implements the settings of parameters such as sampling frequency, sampling length and sampling starting point according to different signal characteristics.

The two-dimensional real-time signal display module IV shown in accompanying drawing 3 is used to display the signal image of each X-axis scanning line in real time; It is convenient to adjust the scanning position in time; the signal position display module VI, this module can be used to clarify the positional relationship between the signal point relative to the detection surface depth and the multi-point signal.

When the system is running, open the system operation interface on the workstation 1. The control process of the software includes: first, set the adjustment distance of X-axis and Y-axis in position adjustment module I, for example, set the adjustment distance of X-axis and Y-axis to 5 mm and 3 mm, respectively. Position the scanning initial position to the distance adjustment initial origin X-axis 5mm, Y-axis 3mm preset position. Then enter the X-axis and Y-axis scan length and scan interval in the parameter setting module II, and set the data drive letter position and file name in the data storage and workstation. Then in the signal acquisition module III, the system sampling rate is set based on the Nyquist theorem, and the acquisition card parameters such as sampling length, clock mode, trigger delay, acquisition mode, and trigger wait are selected according to the characteristics of the measured signal. Click the start button, the Boolean button judges to be true and then sends out a command, including the position adjustment, scanning distance and relevant parameters of the capture card, enter the stacked sequence structure, first initialize the capture card and motor, obtain the basic parameters of the workstation operating system, and then set the Set the panel parameter command and send it to the stepper motor and acquisition card driver to start data acquisition. The while loop structure is nested in the sequence structure to receive the trigger signal repeatedly until the data acquisition is completed. If you need to adjust the scan acquisition during the acquisition process, click the stop button, and the Boolean button is true, the system stops the data acquisition card acquisition after the current line scan ends, and transmits and stores the currently completed data acquisition results to the preset workstation drive letter. If there is an emergency during the acquisition process, press the emergency stop button, after the Boolean button is True, the system global variable will be converted to False, all signals will be interrupted, and the system will stop working.

Figure 5 shows the two-dimensional grid scanning motion mode of signal acquisition: the ultrasonic sensor is driven by the stepping motor to perform grid scanning motion of the XY axis; the scanning range x × y can be set in the motion control module, and the scanning accuracy is dx and dy, where x controls scan length and data storage. The detailed process is as follows: The ultrasonic sensor moves synchronously with the motor. During the X-axis scanning process, the scanning accuracy is every dxμm step. After each X-axis scanning is completed, the full-waveform x scanning signal is recorded and stored and stored in the program file; After the length scan, the probe makes a vertical step of dyμm, and then performs a negative horizontal scan after the step, and records the data and buffers it in the program file in the above-mentioned manner. The data acquisition module collects ultrasonic scan signals after each X-axis scan is completed and records them to the data lines of the program file in turn. After all X-axis scans are completed, the data is stored in the workstation at one time, the number of data columns=x/dx, data lines =y/dy.

See Figure 6. The position adjustment module I can adjust each stepping motor individually, including the distance adjustment of the X-axis motor, the distance adjustment of the Y-axis motor, and the synchronous adjustment of the two-dimensional motor; at the same time, the initial position point can also be set, which is convenient for the two-axis motor to be adjusted in the future. Restore during scanning. The position adjustment module includes the following structure and operation steps: serial port sequence, X-axis motor adjustment parameter input window, Y-axis motor adjustment parameter input window and position adjustment button. First, select the serial port sequence of the motor to realize the communication between the lower computer (motor controller) and the upper computer (workstation). After the adjustment parameters of the X axis and the Y axis are input, check the box at the front of the corresponding axis parameter input line, and click the position The adjustment button can realize one-dimensional or two-dimensional position adjustment function.

The parameter setting module II is used to set the size of the X-axis and Y-axis area of the two-dimensional operation of the motor, the raster scan spacing and the adjustment of the motor stepping speed; after the parameter setting is completed, click the start button, and the motor will move according to the given parameters. Described parameter setting module comprises following structure and operation steps: X-axis scanning length parameter input window, Y-axis scanning length parameter input window, acquisition cycle display window, scanning interval parameter input window, data storage location selection window and file naming window; Enter the corresponding millimeter (mm) unit length in the X-axis and Y-axis scanning length input windows to determine the size of the scanning area, that is, the size of the signal detection area. By selecting the storage location and naming the corresponding file, it is convenient to distinguish and save the data.

The signal acquisition module III is used to set the parameters of signal acquisition. Considering the characteristics of the collected signal itself, this module can adjust the data acquisition card, by setting the sampling rate, sampling length, clock mode, trigger delay, sampling starting point and other parameters, efficiently and accurately collect the required signal segments and be stored. Built-in emergency stop control is used to quickly cut off all signals, stop all motor operation and data acquisition card acquisition before an accident occurs, and make the motor automatically return to the initial position after the motor stops, and the acquisition card data is cleared. The signal acquisition module includes the following structures and operation steps: sampling rate, sampling length, clock mode, trigger timeout, acquisition mode, trigger wait, sampling depth, trigger delay and other input or selection windows; the general operation steps are: Starting from the frequency, select the appropriate sampling rate according to the Nyquist theorem; select the sampling length, clock mode, trigger delay, acquisition mode, trigger wait and other parameters according to the amplitude, length, period and frequency of different signals, so that the final signal The collection accuracy and efficiency are optimized. Built-in emergency stop control is used to quickly cut off all signals, stop all motor operation and data acquisition card acquisition before an accident occurs, and make the motor automatically return to the initial position after the motor stops, and the data of the acquisition card is cleared.

The two-dimensional image real-time display module IV, as an auxiliary module, mainly provides the experimenter with a preview of the collected signals. By displaying the signal waveform and the combination and processing of the signal, the experimenter can intuitively observe whether the acquired signal is the content of interest, so as to adjust the control and acquisition process in time. The two-dimensional image real-time display module includes the following structures and operation steps: the X-axis and Y-axis coordinates respectively represent the X-axis and Y-axis scanning lengths in the parameter setting module. Through the positioning of the two coordinates, the real-time reconstruction of the acquired signal can obtain the real-time display of the two-dimensional image; further, by adjusting the maximum and minimum values of the coordinate axis, the range of the image area of interest can be adjusted in this module; in addition , by changing the value of the color intensity of the right color bar, the optimal display contrast of the two-dimensional image can be obtained by adjusting the signal intensity.

The signal display module V can provide relevant information such as waveform, amplitude and peak position of the measured point source signal in real time, and includes the following structure and operation steps: the X and Y axis coordinates respectively represent the sampling length and signal amplitude of the time domain signal. The length of the X-axis is mainly determined by the sampling length in the signal acquisition module, and the starting sampling point is determined by the trigger delay, that is, after the trigger delay expires, the acquisition card starts to collect signals, and the real-time signal display module displays the signal waveform of the sampling length.

The signal position display module VI can display in real time the signal position of the line of signals in the Z-axis direction after one X-axis scan is completed, and determine the relative positional relationship between the signal generating point source and the sample surface and the different signal generating point sources in the line. relative positional relationship. The signal position display module includes the following structure and operation steps: the X and Y axis coordinates respectively represent the X axis length and the signal depth, which are respectively determined by the X axis scanning length of the parameter setting module and the sampling length of the signal acquisition module. The length of the X-axis can be adjusted to display the signal depth in different scanning ranges; the signal depth of the Y-axis is obtained by inversion from the sampling rate, sampling length, and signal transmission rate, so as to observe the depth information of the deep signal and the surface signal.

The control flow of the control software is: serial port initialization, testing whether the communication between the workstation and the controller and the acquisition board is normal, if not, debugging until normal. When the port detects a high-level trigger signal, the motor controller sends an instruction to control the X-axis motor to travel a specified distance. Simultaneously, the acquisition card is triggered by the trigger signal to trigger the data acquisition process. When the X-axis motor stops moving after the specified distance, the acquisition board stops data acquisition, uploads the data to the workstation, and writes the storage file. At the same time, the Y-axis motor travels the specified distance until it stops. At this time, the X-axis motor moves in the opposite direction for the specified distance, and synchronously, the acquisition card is triggered by the trigger signal to trigger the data acquisition process. When the X-axis motor stops moving after completing the specified distance, the acquisition board stops data acquisition, uploads the data to the workstation, and writes the storage file. At the same time, the Y-axis motor travels the specified distance until it stops, and the X-axis motor moves in the opposite direction again, and the data acquisition and storage process occurs synchronously. Finally, the collected data is all saved in one file, and the software control process ends.

Finally, it should be noted that: obviously, the above-mentioned embodiments are only examples for clearly illustrating the present invention, and are not intended to limit the implementation manner. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. However, the obvious changes or changes derived therefrom still fall within the protection scope of the present invention.

Claims (1)

1. a pulse synchronization control two-dimensional scanning and signal acquisition implementation method based on LabVIEW, is characterized in that: The method includes a hardware structure and a software module; The hardware structure consists of a workstation, an onboard data acquisition card, a signal amplifier, a workstation power supply, a motion control module, a motion control module power supply and an ultrasonic sensor; the onboard data acquisition card, the signal amplifier and the ultrasonic sensor are connected in sequence , the ultrasonic sensor is connected with the on-board data acquisition card through the signal amplifier for data acquisition, analog-to-digital conversion and data storage; the on-board data acquisition card is installed in the workstation motherboard; the software module is based on Developed on the LabVIEW platform, the hardware controls two motors to perform two-dimensional grid scanning, and at the same time realizes the acquisition of electrical signals; The software module is composed of a control panel and a display panel, the control panel includes a position adjustment module, a parameter setting module and a signal acquisition module, and the display panel includes a two-dimensional image real-time display module, a real-time signal display module and a signal position display module; The software module is a control program and a system operation interface written based on the LabVIEW graphical programming platform, and the control program is used to realize the high-precision two-dimensional grid scanning of the X-axis and the Y-axis by two stepping motors, so that the combined The signal acquisition device can quickly and stably collect signals from point to point, and at the same time cooperate with the onboard multi-channel data acquisition card for data acquisition, transmission and storage; Among them, in the control panel: The position adjustment module includes the following structure and operation steps: a serial port sequence selection window, an X-axis and Y-axis motor position adjustment input and a position adjustment confirmation button; the operation steps are: first, in the serial port sequence selection window, select the corresponding connection port between the motor and the workstation, In order to realize serial port initialization, serial port reading and writing and close serial port serial port communication functions, after completing serial port communication, adjust the serial port input motor displacement distance in millimeters at the X-axis and Y-axis motor positions, check the selection box of the corresponding axis, and click The position adjustment confirmation button can realize one-dimensional or two-dimensional spatial position adjustment; The parameter setting module includes the following structures and operation steps: X-axis and Y-axis scan length input windows, scan spacing input windows, data storage location selection windows and file naming windows; the operation steps are: first determine the size of the signal acquisition range, and input successively X-axis and Y-axis scanning length in millimeters, and then determine the X-axis scanning spacing. The smaller the spacing setting, the finer the signal acquisition, the more the corresponding acquisition cycles, the longer the completion time for one acquisition, and the input scanning spacing. The parameters are set according to the actual situation; finally, the naming and storage location of the pre-collected data files are set; The signal acquisition module includes the following structures and operation steps: sampling rate, sampling length, clock mode, trigger timeout, acquisition mode, trigger wait, sampling depth, trigger delay input or selection window; the operation steps are: starting from the frequency of the signal , select the appropriate sampling rate according to the Nyquist theorem; select the sampling length, clock mode, trigger delay, acquisition mode, trigger waiting parameters according to the amplitude, length, period and frequency characteristics of different signals, so that the final signal acquisition accuracy and The efficiency is the best; the embedded emergency stop control is used to quickly cut off all signals, stop all motor operation and data acquisition card acquisition before an accident occurs, and make the motor automatically return to the initial position after the motor stops, and the data of the acquisition card is cleared. zero; Wherein, in the display panel: The two-dimensional image real-time display module includes the following structures and operation steps: the X-axis and Y-axis coordinates represent the X-axis and Y-axis scanning lengths in the parameter setting module respectively; through the positioning of the two coordinates, the collected signals are reconstructed in real time Two-dimensional images can be displayed in real time; further, by adjusting the maximum and minimum values of the coordinate axis, the range of the image area of interest can be adjusted in this module; in addition, by changing the value of the color intensity of the right color bar, you can Adjust according to the signal strength to obtain the best display contrast of the two-dimensional image; The real-time signal display module includes the following structures and operation steps: the X axis of the coordinate axis represents the sampling length value in the signal acquisition module, the Y axis is the signal amplitude value, the image of the module displays the position and signal amplitude of the point source signal, and the image is scanned along with it. Position change, reflecting the change of signal position and amplitude in real time; The signal position display module includes the following structure and operation steps: the X axis of the coordinate axis represents the X scan length in the parameter setting, and the Y axis is the sampling length value in the signal acquisition module, which can represent the position where the maximum value of each point source signal appears; complete After one X-axis scan, the display module can present the position where the maximum value of the point source signal of the line appears, and then it will enter the next scan cycle, and so on; in, The control flow of the software module is: 1) Initialize the serial port, test whether the communication between the workstation and the controller and the acquisition board is normal. If it is not normal, debug it until it is normal; 2) When the port detects a high-level trigger signal, the motor controller sends an instruction to control the X-axis motor to travel the specified distance. Simultaneously, the acquisition card is triggered by the trigger signal to trigger the data acquisition process; when the X-axis motor travels the specified distance, it stops moving , the acquisition board stops data acquisition, uploads the data to the workstation, and writes the data to the storage file; at the same time, the Y-axis motor travels the specified distance until it stops; at this time, the X-axis motor moves in the reverse direction for the specified distance, and the acquisition card is triggered synchronously. The signal triggers the data acquisition process; when the X-axis motor stops moving after the specified distance, the acquisition board stops data acquisition, uploads the data to the workstation, and writes the storage file; at the same time, the Y-axis motor travels the specified distance until it stops, and the X axis The motor moves in the reverse direction again, and the data acquisition and storage process occurs synchronously, and the cycle repeats until the coverage scanning of the designated area is completed; 3) Finally, the collected data are all stored in a file, and the software control process ends.

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