SU1224704A1 - Apparatus for eddy-current inspection - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to measure the thickness of dielectric coatings on an electrically conductive base. The invention makes it possible to increase the control accuracy by amplitude-phase processing of the signal of the eddy-current transducer using only amplitude detection and computational operations using a microprocessor. The signal from the output of the buffer amplifier enters the input of the amplitude detector and the second input of the adder, where the vector is summed with the signal from the output of the voltage divider. In the course of processing, according to the received value of the signal at the output of the adder, as well as the size of the signal from the buffer amplifier, an informative signal is obtained. 1 il. i (L S to yu 4 4j

Description

I

The invention relates to a non-fracture Nfy control and can be used to measure the thickness of dielectric coatings on an electrically conductive base.

The purpose of the invention is to increase the accuracy of the control.

The drawing shows a block diagram of a device for an eddy current monitor,

The device for eddy current testing consists of series-connected frequency and amplitude generator 1, eddy current converter 2, buffer amplifier 3, amplitude detector 4, switch 5, analog-digital converter 6, microprocessor 7 and indicator 8, as well as series-connected controlled the voltage divider 9 connected by the input to the output of the generator 1, the adder 10 connected by the second input to the output of the buffer amplifier 3 and the amplitude detector 11 connected to the second input of mutator 5, wherein the control inputs of the oscillator 1, a controllable voltage divider 9 and the switch 5 are connected to the output of microprocessor 7.

The device for eddy current testing works as follows.

Frequency and amplitude controlled oscillator 1 drives the eddy current transducer 2. The choice of frequency and amplitude of the excitation current is determined by the operator in accordance with the type of task being solved. The signal from the output of the eddy current transducer 2 is fed to the input of the buffer amplifier 3, where it is amplified and fed to the input of the amplitude detector 4 and to the second input of the adder 10, where the vector is summed with some signal (AQ) from the output of the controlled voltage divider 9, input the signal for which is the output of controlled oscillator 1,

The signal is proportional to the modulus of the vector inserted into the eddy current transducer 2, voltage (A), is removed from the output of the amplitude detector 4, Signals proportional to

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vector module

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alternately with

five

0

five

five

0

five

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switch 5 is fed to the input of analog-to-digital converter 6, where it is converted into binary code and entered into microprocessor 7, the result of processing information of microprocessor 7 is displayed on indicator 8,

In the process of processing, the result is L, A „compute- where h - At the same time

n1m values

The value of A is SoC, the phase applied to the yarn uses the ratio

A cos H - A,

yA

where what is achieved is correspondingly. by selecting the transfer coefficients of the vector adder 10,

The value, along with the value A, is used to calculate the measurement result. The accuracy of the measurement is provided by eliminating phase detection in determining the value of A.cos,

Claims (1)

Formula inventions. An eddy current control device containing a series-connected frequency and amplitude generator, eddy current transducer, buffer amplifier, amplitude detector, switch,: analog-digital converter, microprocessor and indicator, the second and third outputs of the microprocessor are connected to the control input of the generator and to the control input of the switch, respectively, characterized in that, with whole improvements in the control accuracy, it is provided with series-connected controlled divider, for example A summation connected by a second input to the output of the buffer amplifier and a second amplitude detector connected to the second input of the switch, and a controlled voltage divider connected by a signal input to the output of the generator and the control input to the fourth output of the microprocessor. Editor N. Volovik Order 1944/43 Circulation 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Compiled by P. Shkatov Tehred I. Veres Proofreader E, Sirohman