SU1298631A1 - Eddy-current device for nondestructive checking - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to control the quality of electrically conductive objects. Reliability control is achieved by automatically adjusting the reference voltages of the quadrature channels with a smooth change in the operating frequency of the device. The operation mode of the device is set by installing a reversible counter 19, defining permanent integration of integrators 13 and 16. The outputs of the latter are quadrature channels connected to the reference inputs of the synchronous detectors 7 and B. 1 Il. (O (L y from 00 O5 CO

Description

one

The invention relates to non-destructive testing and can be used to control the quality of electrically conducting objects.

The purpose of the invention is to increase the reliability of control, achieved by automatically adjusting the reference voltages of the quadrature channels with a smooth change in the operating frequency of the device.

The drawing shows a block diagram of the device.

The eddy current device contains serially connected tunable harmonic current generator 1, phase shifter 2, power amplifier 3, eddy current converter 4, compensator 5, amplifier 6, synchronous detectors 7 and 8 connected by signal inputs to the output of amplifier 6, oscillographic indicator 9 and recorder 10 connected the first and second inputs to the outputs of the synchronous detectors 7 and 8, respectively, and the meter- 11 frequencies.

The tunable harmonic current generator 1 consists of a series-connected digital-analog converter 12, an integrator 13, an inverter 14, a D / A converter 15, and an integrator 16 connected in series

This reversible counter 19 for a given frequency generator frequency change mode 1, the command block 17 connects the clock generator 18 to the counting input of the reversible counter 19, the output of which forms a n-modend block 17, a clock pulse generator 18 and a reversible counting descending binary code 19, logic switch AND 20, which feeds on the control inputs of digital OR 21 and OR-NOT 22, respectively, analogue converters 12 and 15. Trigger 23, connected between the control- At the same time, the integrator integrates the counter input 19 and the output of the integrators 13 and 16 are changed by the logic element OR 21, connected by smoothly changing the output data by their inputs, respectively, from the digital-to-analog converters, the second output of the command block 17, the outputs of the logic elements 20 and 22 , the outputs of each of the bits of the reversible counter 19 are connected to the inputs 45 F to F, the inputs of logic elements 20 and 22, and the control inputs of the digital-analogue converters 12 and 15, the outputs of the integrators 13 and 16 are the reference and main outputs 50 ia, ix voltage integra Ators 13 and 16 of my 1 harmonic generator 90 ° and the inclusion of an inverter 14 between the output of the first integrator 13 and the series-connected digital-analog converter 15 and the integrator 16. When the maximum frequency of the generator is reached, which corresponds to the maximum code at the output of the reverse counter 19, at the output of the logical element OR-NOT 22 formers 12 and 15 in accordance with the incoming code, which leads to a smooth change in the frequency of the generator from .l ,. on cooTBeTCTBVKHiiHX quad MQivC. cc

Routing (shifted to 90) outputs

 e-bixt 8х2 with the phase generation condition (phase balance) provided by the phase shift of the trick and connected to the reference inputs of the synchronous detectors 7 and 8, respectively, and the output of the second integrator is connected to the inputs of the digital-to-analog converter 12 and the frequency meter 11.

The device works as follows.

To provide control over a wide frequency range and to use amplitude-phase analysis of the signal by quadrature components, it is necessary to have quadrature voltages at the output of generator 1 in a given operating frequency range. At the moment of switching on the device, the reversible p-bit counter 19 and the trigger 23 are reset, in which at the reference output from the integrator 13 U and the main output from the integrator

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generator 1 is provided

OUT 1

set value of the original frequency. The setting of the required frequency of the generator 1 is effected by the signal of the command unit 17. When the signal is applied, the reversible p-bit counter 19 through the logic element OR 21 sets the trigger 23 to a state that provides the forward or reverse counting mode of the reversible p-discharge of the counter nineteen.

Consider the case of changing the frequency of the output signal from F to the corresponding inverse counting mode. Simultaneously with the installation of the reversible counter 19 for a given mode of changing the frequency of the generator 1, the command block 17 connects the clock generator 18 to the counting input of the reversible counter 19, the output of which forms an n-bit decreasing binary code going to the control inputs of the digital analog converters 12 and 15. At the same time, the constant integrations of the integrators 13 and 16 are changed by smoothly changing the output voltages of the digital-analog conversions F to F, ia, ix of the voltages of the integrators 13 and 16 by 90 ° and turning on the inverter ora 14 between the output of the first integrator 13 and the series-connected digital-to-analog converter 15 and the integrator 16. When the maximum frequency of the generator, which corresponds to the maximum code at the output of the reversible counter 19, is reached, the output of the logical element OR-HE 22 forms a decreasing binary code input to the control inputs of the digital-to-analog converters 12 and 15. In this case, the constant integrations of the integrators 13 and 16 are changed due to the smooth variation of the output voltages of the digital-analog converters Z-F to F, ia, ix of the voltage of the integrator 13 and 16 by 90 ° and the inclusion of the inverter 14 between the output of the first integrator 13 and the series-connected digital-to-analog converter 15 and the integrator 16. When the maximum frequency of the generator is reached, which corresponds to the maximum the code at the output of the reversible counter 19, at the output of the OR-NOT logic element 22 formers 12 and 15 in accordance with the incoming code, which leads to a smooth change of the generator frequency from the l. on cooTBeTCTBVKHiiHX quad MQivC. cc

Routing (shifted to 90) outputs

 e-bixt 8х2 and the condition of phase generation (phase balance) is provided by phase shift output3I

A pulse is triggered, which through the logical element OR 21 switches the trigger 23, which causes the reversing counter 19 to be switched to the reverse counting mode and, in accordance with the increasing code, leads to a smooth change in the frequency of the generator I

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When the frequency at the output of the reversible counter 19 is reached, the maximum value of the binary n-bit code is set, and a pulse is generated at the output of the AND 20 logic element, which OR 21 switches the trigger 23. The output signal of the trigger 23 changes the counting direction of the reversible counter 19 and the control inputs of digital-to-analog converters 12 and 15 receive an incremental code, which leads to a smooth change in frequency from T to f, the frequency of the generator is monitored by measuring 11 you. The frequency of the oscillator 1 in the device can vary in both the forward and reverse directions relative to the initially set, and the desired direction of change is set by the command unit 17,

Settable output quadrature components of voltage Ug ,, and generator 1 of a given frequency

LOW 2

served as reference voltages to synchronous detectors 7 and 8. At the same time, one of the quadrature components, for example, is fed through a phase shifter 2 to a power amplifier and a eddy current transducer 4, the output of which is fed through the compensator 5 to the amplifier input 6, Compensator 5 compensates for the initial signal of the eddy current transducer when it is installed on the reference section of the tested product. When the eddy current transducer is installed during scanning onto the monitored section, the output of amplifier 6 generates a signal that goes to the inputs of synchronous detectors 7 and 8. Synchronous detectors split the original useful signal from the output of amplifier 6 into quadrature components, which arrive at

VNIIPI Order 881/45

Random polygons pr-tie, Uzhgorod, st. Project, 4

986314

oscillographic indicator 9, which provides information on the complex plane, as well as to the recorder 10, which produces an analytical data sheet and the signal components.

Claims (1)

Invention Formula Eddy current device dp nonfO destructive control, containing serially tunable tunable harmonic current generator, phase shifter, power amplifier, eddy current converter, 15 compensator and amplifier, first and second synchronous detectors connected by signal inputs to the amplifier output, oscillographic indicator and recorder connected 0 by the first and second inputs to the outputs of the first and second synchronous detectors, respectively, and a frequency meter, characterized in that, in order to increase the reliability of control, the tunable oscillator is made in the form of serially connected first digital-analog converter, first integrator, inverter, second 0 digital-to-analog converter and the second integrator, serially connected command block, clock generator and reversible counter, logic elements or. AND, SHSh-NOT, a trigger connected between the control input of the counter and the output of an OR gate connected with its inputs respectively to the second output 0 of the command block and the outputs of the logical elements AND and OR-NOT, the outputs of each of the bits of the reversible counter are connected to the inputs of the logical elements AND, OR-NOT and to the control inputs of the first and second digital-to-analog converters, the outputs of the first and second integrators are reference and main outputs of a tunable generator 0 harmonic current and are connected to the reference inputs of the first and second synchronous detectors, respectively, and the output of the second integrator is connected to the inputs of the first digital-to-analogue 5 converter and frequency meter. Circulation 777 Subscription