SU1096565A1 - Pulse eddy-current device - Google Patents

Abstract

An impulse eddy current device containing a pulse current generator, a series-connected eddy current transducer, a peak detector connected by a reference input to the generator, and a comparator, and an indicator that, in order to improve measurement accuracy, is equipped with a matching circuit connected output to the indicator, an inertial link connected between the pulse current generator and the input of the eddy current transducer, a resistive divider and a second comparator connected by the first input es resistive divider to the output of the peak detector, the second inputs of each comparator connected to the output of the eddy current transducer avhody matcher circuit connected to the outputs of respective comparators.

Description

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about

The invention relates to a non-destructive control and can be used to measure parameters of electrically conductive objects. A pulsed incurrent device is known that contains a pulse generator connected in series, an eddy current transmitter, a full-wave rectifier, an average signal determination unit and an indicator, the output of the full-wave rectifier is connected to the control unit. generator through a series-connected peak detector and comparison unit connected by a second input block output reference voltage tlj. The disadvantage of this device is low measurement accuracy, which is associated with the influence of the parameters of the eddy current transducer on the control results and the nonlinear dependence of the measured signal parameter on the controlled parameters of the test object. The closest to the invention in its technical essence is a pulsed eddy current device containing a series-connected pulse current generator, a eddy current transducer, a peak detector, a connected reference input to the generator, a comparator and an indicator, as well as a standard amplitude unit connected to the second C21 comparator. However, the known device does not have the required accuracy of control, which is associated with a nonlinear relationship between the measurement results and the measured value, as well as with the complexity of adjusting the device to the parameters of the eddy current transducer. The purpose of the invention is to improve the measurement accuracy. The goal is achieved by the fact that a pulsed eddy current device containing a pulsed current generator, a series-connected eddy current converter, a peak detector connected by a reference input to the generator, and a comparator, and an indicator equipped with a coincidence circuit connected to the output of the indicator, an inertial link connected between pulsed current generator and input of eddy current transducer, resistive divider and second-5 comparator connected by the first input through a resistive divider to the output at the peak detector, the second inputs of each comparator are connected to the output of the eddy current transducer, and the inputs of the coincidence circuit are connected to the outputs of the corresponding comparators. FIG. 1 shows a flowchart of a pulsed eddy current device; in fig. 2 - diagrams of output voltages U in blocks of the device; The device consists of a series-connected pulse current generator 1, inertial link 2, eddy current transducer 3, on-switch; :: its exciting 4 and measuring winding 5, peak detector 6, connected by a reference input to –pulse generator 1, and resistive voltage detector 7, comparators 8 and 9, connected by outputs to coincidence circuit 10, second inputs to the output of eddy current transducer 3, and first inputs to output of the peak detector 6 and resist Divider 7, for example, respectively. The device works as follows. The pulses from the pulse generator 1 through, the inertial link 2 prokod t on the exciting winding A and simultaneously gated the peak detector Oj which remembers the maximum values of the signal at the output of the measuring winding 5. Comparator 8 compares the signals at the input and output of the peak detector 6 and fires at maximum voltage values on the measuring winding 5. The operation of the comparator 9 occurs in moments of equality of the signal at the output of the measuring winding 5 with a certain part of the maximum value This signal is taken from the output of the resistive voltage divider 7. By the circuit 10, coincidences are formed, the duration of which corresponds to the time intervals between the trigger times of the compass 8 and 9. At the end of each pulse coming from the pulse generator 1j, the peak etector 6 is reset and the circuit 1 1 is returned to its initial state.

Changing the time constant of the inertial link 2, you can adjust the duration of the fronts of the exciting current pulses, eliminating the occurrence of spurious emissions or high-frequency oscillations in the output signal of the eddy current transducer 3. This makes it possible to use eddy current transducers with large internal winding resistance and a relatively large parasitic capacitance, resulting The output signal level rises and the hardware error of the low power consumption decreases accordingly. emoy power.

Separating the time i of the output signal of the sensor from the moment of its maximum to a certain part of its maximum value allows a highly accurate measurement of the parameters of monitored products with a wide range of variation of these parameters and an unstable amplitude of the exciting current pulses.

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Claims (1)

A PULSED EDGE-CURRENT DEVICE containing a pulsed current generator, a eddy-current transducer connected in series, a peak detector connected to a reference input to the generator, and a comparator and indicator, characterized in that, in order to increase the accuracy of measurements, it is. equipped with a matching circuit connected by an output to the indicator, an inertial link connected between the pulsed current generator and the input of the eddy current transducer, a resistive divider and a second comparator connected by the first input through a resistive divider to the output of the peak detector, the second inputs of each comparator are connected to the output of the eddy current transducer, and The inputs of the matching circuit are connected to the outputs of the corresponding comparators. FIG. 1