Calibrating instrument of steel rail ultrasonic flaw detector

Abstract

The utility model provides a calibrator for a steel rail ultrasonic flaw detector, which relates to the field of steel rail ultrasonic flaw detection and comprises a time interval trigger, a signal generator and an attenuator, the output end of the time interval trigger is electrically connected with the input end of the signal generator, and the output end of the signal generator is electrically connected with the input end of the attenuator. And the output end of the attenuator is electrically connected with the input end of the to-be-calibrated steel rail ultrasonic flaw detector. The calibration device has the advantage of improving the calibration efficiency of the steel rail ultrasonic flaw detector.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic flaw detection of rails, and in particular to a calibration instrument for ultrasonic flaw detectors of rails. Background Technology

[0002] Ultrasonic rail flaw detectors are specialized ultrasonic testing devices for rails. They can simultaneously emit ultrasonic beams at different angles to detect and record damage to the rails. The characteristics of using ultrasonic rail flaw detectors include harsh working environments, long operating times, and dispersed deployment, making it difficult to detect problems in a timely manner. Therefore, the calibration of ultrasonic rail flaw detectors is crucial. Ultrasonic rail flaw detectors are railway-specific measuring instruments and require regular calibration. Calibrating the ultrasonic rail flaw detectors according to calibration specifications is a necessary guarantee for early detection of problems and reduction of malfunctions.

[0003] In existing technologies, operators need to carry multiple devices (such as digital storage oscilloscopes, function generators, electronic attenuators, and step attenuators) to calibrate the ultrasonic flaw detector for rails, which is cumbersome.

[0004] Therefore, there is a need to provide a calibration instrument for ultrasonic flaw detectors of rails to improve the efficiency of ultrasonic flaw detector calibration. Utility Model Content

[0005] This utility model provides a calibration instrument for an ultrasonic flaw detector for rails, comprising: a time interval trigger, a signal generator, and an attenuator, wherein the output terminal of the time interval trigger is electrically connected to the input terminal of the signal generator, the output terminal of the signal generator is electrically connected to the input terminal of the attenuator, and the output terminal of the attenuator is electrically connected to the input terminal of the ultrasonic flaw detector for rails to be calibrated.

[0006] Furthermore, the signal generator includes a D / A converter.

[0007] Furthermore, the model of the D / A converter is selected based on a plurality of first performance indicators, wherein the plurality of first performance indicators include at least resolution, linearity, absolute accuracy, relative accuracy and settling time.

[0008] Furthermore, the model of the attenuator is selected based on multiple second performance indicators, wherein the multiple second performance indicators include attenuation, frequency range, insertion loss, VSWR, temperature coefficient and bandwidth.

[0009] Furthermore, it also includes a control button matrix, which is used to control the operation of the time interval trigger, the signal generator, and the attenuator.

[0010] Furthermore, it also includes an attenuator control board, wherein the attenuator control board is used to set the attenuation value of the attenuator based on the output signal of the control button matrix.

[0011] Furthermore, the control button matrix is ​​also used to control the parameters of the time interval trigger.

[0012] Furthermore, the testing instrument also includes a display screen. Attached Figure Description

[0013] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0014] Figure 1 This is a structural schematic diagram of a calibration instrument for an ultrasonic flaw detector for rails, as shown in some embodiments of this specification.

[0015] Figure 2 This is a circuit diagram of the program interface shown in some embodiments of this specification;

[0016] Figure 3 This is a circuit diagram of a control key matrix according to some embodiments of this specification. Detailed Implementation

[0017] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0018] A calibration instrument for an ultrasonic flaw detector for rails is used to perform at least one calibration item. In some embodiments, the at least one calibration item includes attenuator calibration, dynamic range calibration, vertical linearity error calibration, the influence of suppression state on measurement results calibration, time baseline linearity error calibration, sampling error calibration, and response time calibration.

[0019] By way of example only, at least one calibration item may be shown in Table 1.

[0020] Table 1

[0021]

[0022]

[0023] Figure 1 This is a structural schematic diagram of a rail ultrasonic flaw detector calibration instrument according to some embodiments shown in this specification, such as... Figure 1 As shown, a calibration instrument for an ultrasonic flaw detector for rails includes: a time interval trigger, a signal generator, and an attenuator. The output terminal of the time interval trigger is electrically connected to the input terminal of the signal generator, the output terminal of the signal generator is electrically connected to the input terminal of the attenuator, and the output terminal of the attenuator is electrically connected to the input terminal of the ultrasonic flaw detector for rails to be calibrated.

[0024] In some embodiments, the signal generator includes a D / A converter. The model of the D / A converter is selected based on several first performance indicators, which include at least resolution, linearity, absolute accuracy, relative accuracy, and settling time. Resolution refers to the change in the output analog quantity (voltage or current) corresponding to a change in the least significant bit (LSB) of the input digital quantity. It reflects the minimum change in the output analog quantity. Resolution has a definite relationship with the number of bits of the input digital quantity, which can be expressed as FS / (2^n). FS represents the full-scale input value, and n is the number of binary bits. For a full-scale of 5V, using an 8-bit DAC, the resolution is 5V / 256 = 19.5mV; when using a 12-bit DAC, the resolution is 5V / 4096 = 1.22mV. Obviously, the more bits, the higher the resolution. Linearity (also known as nonlinearity error) is the maximum deviation between the actual conversion characteristic curve and the ideal linear characteristic. It is often expressed as a percentage relative to the full scale. For example, ±1% means that the difference between the actual output value and the theoretical value is within ±1% of the full scale. Absolute accuracy (or simply accuracy) refers to the maximum error between the actual output value and the theoretical value of the analog signal corresponding to any input digit across the entire scale range. Absolute accuracy is caused by the DAC's gain error (the difference between the actual and ideal output values ​​when all input digits are 1), zero-point error (the non-zero output value of the DAC when all input digits are 0), nonlinearity error, and noise. Absolute accuracy (i.e., the maximum error) should be less than 1 LSB. Relative accuracy has the same meaning as absolute accuracy, expressed as a percentage of the maximum error relative to full scale. Settling time refers to the time required for the output analog signal to reach ±1 / 2 LSB of the full-scale value when the input digital signal changes to full scale. It is a dynamic indicator describing the D / A conversion rate. Current-output DACs have short settling times. The settling time of voltage-output DACs is mainly determined by the operational amplifier's response time. Based on settling time, DACs can be divided into ultra-high speed (<1μS), high speed (10~1μS), medium speed (100~10μS), and low speed (≥100μS).

[0025] Figure 2This is a circuit diagram of the program interface shown in some embodiments of this specification, such as... Figure 2 As shown, the programmable interface can use either a network port or a serial port, depending on the interface resources provided by the core board. Considering that using a network port would occupy one network port resource of the PC, and that there would be a requirement for the number of network ports on the computer in the case of remote access, it is more reasonable to use RS-232.

[0026] Figure 3 This is a circuit diagram of a control key matrix shown in some embodiments of this specification, such as... Figure 3 As shown, the matrix key row-column scanning method is a simple and intuitive key scanning method. In this method, the keyboard keys are connected by intersecting rows and columns to form a matrix. Each key is located at the intersection of a row and a column. The state of each key is detected one by one through a polling scan. When a key is pressed, the corresponding row and column are determined to identify which key was pressed.

[0027] In some embodiments, the attenuator model is selected based on multiple secondary performance indicators, including attenuation, frequency range, insertion loss, VSWR, temperature coefficient, and bandwidth. Attenuation is a crucial performance indicator of an attenuator, representing the degree to which the attenuator reduces the amplitude of the signal. Attenuation is typically expressed in decibels (dB), calculated as: A(dB) = 10lg(P2 / P1), where P1 and P2 represent the power of the input and output signals, respectively. In practical applications, the attenuation magnitude needs to be determined based on circuit requirements. Generally, the attenuation should remain stable within a certain frequency range, while also considering factors such as signal distortion and noise. The frequency range of an attenuator refers to the range of frequencies within which it can effectively operate. When designing and selecting an attenuator, its frequency range must be determined based on the circuit's operating frequency range. Insufficient frequency range can lead to signal distortion and uneven attenuation during transmission. Insertion loss refers to the loss in amplitude caused by the attenuator during operation. Lower insertion loss results in less signal attenuation and better signal quality. In practical applications, attenuators with low insertion loss need to be selected based on circuit requirements. Standing Wave Ratio (VSWR) is the ratio of the reflection coefficients at the attenuator's input and output, reflecting the attenuator's matching degree. A VSWR of 1 indicates perfect matching between the attenuator's input and output, resulting in optimal attenuator performance. An excessively high VSWR leads to signal reflection and loss, affecting signal transmission quality. Temperature coefficient refers to the degree to which the attenuation of the attenuator changes with temperature. In practical applications, attenuator performance changes due to variations in ambient temperature. Therefore, attenuators with low temperature coefficients should be selected to ensure stability at different temperatures. Bandwidth refers to the frequency range within which the attenuator can operate. In practical applications, attenuators with appropriate bandwidth need to be selected based on circuit requirements to ensure stability and signal quality at different frequencies.

[0028] In some embodiments, a calibration instrument for an ultrasonic flaw detector for rails further includes a controller. The controller is connected to a programmable interface and electrically connected to a signal generator and an attenuator. The controller includes an S5P4418 processor. Before performing attenuator calibration, the controller adjusts waveform parameters, pulse count parameters, frequency parameters, amplitude parameters, attenuator parameters, and zero-point delay parameters based on a calibration procedure.

[0029] In some embodiments, the calibration instrument for an ultrasonic flaw detector for rails further includes a control button matrix and an attenuator control board. The attenuator control board is used to set the attenuation value of the attenuator based on the output signal of the control button matrix. It communicates with the controller via a serial port. The controller can then set the attenuation value via the serial port. The control board uses an STM32F103 as the main control chip. This STM32F series chip belongs to the mid-to-low-end 32-bit ARM microcontroller family, integrating various peripheral functions such as a timer, CAN, ADC, SPI, I2C, USB, and UART.

[0030] When calibrating the attenuator of the ultrasonic flaw detector for rails, the parameter loading operation is performed first. The programmable control system switches the scheduled inspection signal generator to general signal parameter settings via communication protocol commands, and simultaneously sends commands to read waveform, pulse count, frequency, amplitude, attenuator, and zero-point delay parameters. The scheduled inspection signal generator returns the parameter values. The waveform, pulse count, frequency, amplitude, attenuator, and zero-point delay parameters of the device are checked against the parameters set by the host computer to ensure they meet the requirements of this calibration. If they do not meet the requirements, the parameters can be manually modified. After parameter adjustment, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0031] The supported range for setting the number of pulses, delay, frequency, attenuation, amplitude, and dynamic waveform display for attenuator calibration is as follows:

[0032] Frequency f: 0~15.0MHz.

[0033] Delay T: 0~9000us.

[0034] Number of pulses N: 1 to 99.

[0035] Amplitude: 0-10V.

[0036] Attenuator: 0~90dB.

[0037] Waveform: Pulse wave, sine wave.

[0038] When calibrating the dynamic range of the ultrasonic flaw detector for rails, the parameter loading operation is performed first. The programmable control system switches the scheduled inspection signal generator to general signal parameter settings via communication protocol commands, and simultaneously sends commands to read waveform, pulse count, frequency, amplitude, attenuator, and zero-point delay parameters. The scheduled inspection signal generator returns the parameter values. The waveform, pulse count, frequency, amplitude, attenuator, and zero-point delay parameters of the device are checked against the parameters set by the host computer to ensure they meet the requirements of this calibration. If they do not meet the requirements, the parameters can be manually modified. After parameter adjustment, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0039] The supported ranges for dynamic range calibration, including the number of pulses, delay, frequency, attenuation, amplitude, and dynamic waveform display, are as follows:

[0040] Frequency f: 0~15.0MHz.

[0041] Delay T: 0~9000us.

[0042] Number of pulses N: 1 to 99.

[0043] Amplitude: 0-10V.

[0044] Attenuator: 0~90dB.

[0045] Waveform: Pulse wave, sine wave.

[0046] When calibrating the vertical linearity error of an ultrasonic flaw detector for rails, the parameter loading operation is performed first. The programmable control system switches the scheduled inspection signal generator to general signal parameter settings via communication protocol commands, and simultaneously sends commands to read waveform, pulse count, frequency, amplitude, attenuator, and zero-point delay parameters. The scheduled inspection signal generator returns the parameter values. The waveform, pulse count, frequency, amplitude, attenuator, and zero-point delay parameters of the device are checked against the parameters set by the host computer to ensure they meet the requirements of this calibration. If they do not meet the requirements, the parameters can be manually modified. After parameter adjustment, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0047] The supported ranges for setting the number of pulses, delay, frequency, attenuation, amplitude, and dynamic waveform display for vertical linearity error detection are as follows:

[0048] Frequency f: 0~15.0MHz.

[0049] Delay T: 0~9000us.

[0050] Number of pulses N: 1 to 99.

[0051] Amplitude: 0-10V.

[0052] Attenuator: 0~90dB.

[0053] Waveform: Pulse wave, sine wave.

[0054] When calibrating the impact of the suppression state on the measurement results of the ultrasonic flaw detector for rails, the parameter loading operation is performed first. The programmable control system switches the function of the scheduled inspection signal generator to the suppression parameter setting via communication protocol commands, and simultaneously sends commands to read the parameters for frequency, attenuation, reference delay, high-wave position, and pulse interval. The scheduled inspection signal generator returns the parameter values. The personnel calibrating the inspected equipment verify whether the frequency, attenuation, reference delay, high-wave position, and pulse interval parameters of the equipment meet the requirements of this calibration. If not, the parameters can be manually modified. After the parameter adjustment is completed, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0055] When calibrating the time-base linearity error of an ultrasonic flaw detector for rails, the first step is parameter loading. The programmable control system switches the scheduled inspection signal generator to horizontal linear parameter setting via communication protocol commands, and simultaneously sends commands to read the center frequency, attenuation, zero-point delay, sound path range, and beam type parameters. The scheduled inspection signal generator returns the parameter values. The personnel calibrating the equipment under inspection verify whether the center frequency, attenuation, zero-point delay, sound path range, and beam type parameters of the equipment meet the requirements of this calibration. If not, the parameters can be manually modified. After parameter adjustment, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0056] The supported ranges for beam type, probe null point, center frequency, attenuation, and sound path range for baseline linearity error verification are as follows:

[0057] Center frequency fo: 0.0~15.0MHz.

[0058] Probe zero point T: 0.0~99.9us.

[0059] Sound path range S: 0~500mm.

[0060] Sound beam type: longitudinal wave or transverse wave.

[0061] Pulse interval ΔT: Automatically calculated by the formula ΔT=(1 / 20)×2S / V, where V is the speed of sound.

[0062] When calibrating the sampling error of an ultrasonic flaw detector for rails, the first step is parameter loading. The programmable control system (PCS) switches the scheduled inspection signal generator to sampling error parameter setting via communication protocol commands, and simultaneously sends commands to read the upper limit frequency, attenuation, reference delay, and step increment parameters. The scheduled inspection signal generator returns the parameter values. The personnel calibrating the inspected equipment verify whether the upper limit frequency, attenuation, reference delay, and step increment parameters of the equipment meet the requirements of this calibration. If not, the parameters can be manually modified. After parameter adjustment, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0063] The supported ranges for the upper limit frequency, reference delay, attenuation, and step increment of digital sampling error detection are set as follows:

[0064] Upper limit frequency fu: 0.0~15.0MHz.

[0065] Reference delay T: The delay value when the delay "step increment" is 0, ranging from 0.0 to 99.9 μs.

[0066] Step increment N: The number of small incremental delays added on top of the "baseline delay", ranging from 0 to 50.

[0067] When calibrating the response time of an ultrasonic flaw detector for rails, the first step is parameter loading. The programmable control system (PCS) switches the scheduled inspection signal generator to response time parameter setting via communication protocol commands, and simultaneously sends commands to read parameters such as upper limit frequency, attenuation, delay, gate width, and trigger interval. The scheduled inspection signal generator returns the parameter values. The personnel calibrating the equipment under inspection verify whether the upper limit frequency, attenuation, delay, gate width, and trigger interval parameters of the equipment meet the requirements of this calibration. If not, the parameters can be manually modified. After parameter adjustment, the parameter values ​​of the scheduled inspection signal generator can be modified individually or in batches via communication protocol commands.

[0068] The supported ranges for setting the upper limit frequency, delay, attenuation, gate width, and trigger interval for response time verification are as follows:

[0069] Upper limit frequency fu: 0.0~15.0MHz.

[0070] Delay T: 0~99.9us.

[0071] Gate width W: 0~9.99ms.

[0072] Trigger interval: Manual / 0~9.9s.

[0073] A calibration instrument for ultrasonic flaw detectors of rails fully integrates the measurement functions of numerous conventional devices, simplifying the process. Custom-developed specifically for the calibration needs of ultrasonic flaw detectors of rails, it enables automatic calibration, significantly improving calibration efficiency. The control button matrix is ​​also used to control the parameters of the time interval trigger.

[0074] In some embodiments, the calibration instrument for an ultrasonic flaw detector for rails also includes a display screen. The screen interface, depending on the resources provided by the core board, can be either RGB or LVDS; a 6-inch industrial screen with an LVDS interface is selected. The screen displays waveform information and other parameter information. There are five function buttons on the right side of the screen, corresponding to five blue buttons in the button area. In addition to the five blue function buttons, the button area also includes six shortcut buttons, which can be used to jump to the corresponding page. The plus and minus buttons are used to modify parameter values, and the left and right buttons below the plus and minus buttons are used to move the setting digits.

[0075] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A calibrator for a rail ultrasonic flaw detector, characterized in that, The application relates to a signal generator for calibrating a rail ultrasonic flaw detector, which comprises a time interval trigger, a signal generator and an attenuator, wherein the output end of the time interval trigger is electrically connected with the input end of the signal generator, the output end of the signal generator is electrically connected with the input end of the attenuator, and the output end of the attenuator is electrically connected with the input end of the rail ultrasonic flaw detector to be calibrated. The signal generator comprises a D / A converter.

2. A calibrator for a rail ultrasonic inspection apparatus according to claim 1, characterised in that, The model of the D / A converter is selected based on a plurality of first performance indexes, wherein the plurality of first performance indexes at least include resolution, linearity, absolute accuracy, relative accuracy and establishment time.

3. A verification instrument for a rail ultrasonic inspection instrument as defined in claim 2, characterized in that The model of the attenuator is selected based on a plurality of second performance indexes, wherein the plurality of second performance indexes at least include attenuation amount, frequency range, insertion loss, standing wave ratio, temperature coefficient and bandwidth.

4. The verification device for a rail ultrasonic flaw detector according to claim 1, characterized in that, The application further comprises a control button matrix for controlling the operation of the time interval trigger, the signal generator and the attenuator.

5. A verification instrument for a rail ultrasonic inspection instrument according to any one of claims 1 to 4, characterised in that, The application further comprises an attenuator control panel, wherein the attenuator control panel is used for setting the attenuation value of the attenuator based on the output signal of the control button matrix.

6. A verification instrument for a rail ultrasonic inspection instrument as defined in claim 5, characterized in that The control button matrix is further used for controlling the parameters of the time interval trigger.

7. A verification unit for a rail ultrasonic inspection unit as defined in claim 5, characterized in that The application further comprises a display screen.

8. A verification device for a rail ultrasonic inspection device according to any one of claims 1 to 4, characterized in that, ​

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