SU1422127A1 - Eddy-current measuring device - Google Patents

Abstract

 The invention can be used in systems for automatic control and monitoring of product parameters. The purpose of the invention, which is to measure measurement reliably, is achieved by periodically testing the parameters of blocks of the eddy current device, detecting invalid signals of the device by modulating the output signal of the synchronous detector 9. The signal is modulated by periodically connecting to converter 4 unit 18 for testing, inductively coupled to it through coil 7. The frequency of testing is set by divider 13 frequently-. you. When the parameters of the device blocks deviate from the nominal output signal of the synchronous detector 14, it exceeds the level specified by the threshold element 15, and the output signal of the device generated at the output of the low-frequency filter 10 does not go to the indicator 12. 1 sludge. (L

Description

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This invention relates to a control; measurement technique and can be used in automated control and monitoring systems for determining the geometric and electrophysical parameters of non-ferromagnetic products and their movements; the invention is to increase the reliability of measurement results by introducing a periodically tested ; measuring device and automatic indicator off; when its operation fails. The drawing shows a block diagram of an eddy current measuring device.

; The iCTBo eddy current measuring device contains a series-connected rectangular generator 1, a pulse, a driver 2 pulses, a power Yci 3, a eddy current transducer 4, consisting of: - inductance measuring coil 5, inductance compensation coil 6, and auxiliary coil 7 : inductance5 second amplifier 8, first synchronous detector 9, low-pass filter 10, switch 11 and. Indicator 12, a serially connected frequency divider 13, whose input is connected to the output of a square-wave generator 1, a second synchronous detector 14, the second input of which is connected to the output of the first synchronous detector 9, and a threshold element 15 whose output is connected to the second input of the switch 11 ;, phase shifter 16, switched on by the output of the pulse former 2 and the second input of the first synchronous detector 9, the compensator 1 7 connected between the output of the pulse former 2 and the input of the amplifier 8, and block 18 is tested and, the state of connected in a closed circuit of the auxiliary coil 7 of the inductance of the resistor 19 and the electronic switch 20 ,. the control input of which is connected to the output of the frequency divider 13

The device works as follows.

The generator 1 generates rectangular pulses of constant high frequency, which are fed to the shaper of 2 pulses. At the output of the latter, sequences of symmetric rectangular pulses are formed.

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a predetermined frequency, arriving simultaneously to the power amplifier 3, the compensator 17 and the phase shifter 16. A sequence of pulses from the power amplifier 3 is fed to the vortex converter 4 mounted above the product under test (not shown). At the same time, the sequences of pulses from the compensator 17, operating in the rectangular coordinate system, are fed to the input of the amplifier 8, where the voltage caused by non-identical, coils 5 and 6 of the inductance of the eddy current converter 4 is compensated, as well as the initial voltage applied the output of the eddy current transducer 4, when installed above the reference product at the extreme point of the range of variation of the measured parameter, adds detuning from the interfering factor. The phase shifter 16 forms the necessary shift of the reference voltage supplied to the reference input of the first synchronous detector 9, C of the eddy current transducer 4 to the amplifier 8 receives a modulated signal arising from a periodic (with a frequency determined by the divider 13) frequency that is significantly less than the frequency of the pulses shaper 2) closure through resistor 19 and electronic key 20 of calls of auxiliary coil 7 of test unit 18; From the output of amplifier 8, the modulated signal goes to the first „synchronous, detectable p 9, the output of which is constant component, .modul lation on amplitude rectangular voltage with a frequency testkro Vani ™. The second synchronous detector 14 rectifies the signal arriving at it from the first synchronous detector 9. The output signal of the second synchronous detector 14, proportional to the modulation depth, passes through the threshold element 15 to the co-driver 11, to the other input through the filter 10 lower parts that output signal of the first synchronous detector 9, the threshold element 15 is set to the depth level of the module -. : In this case, the operating parameters of all blocks of the inverter: measuring instrument do not go beyond the limits of allowable deviations from the nominal ones. In this case - from the switch 314221

The torus 11 receives a signal determined by the value of the measured parameter of the monitored product, which is fed to various external devices (not shown) and indicator 12. If the output signal of the detector 14 exceeds the value specified by the threshold element 15, the switch 11 triggers and the indicator 12 turns off from the rest of the device.

Formula of invention

An eddy current measuring device, containing a series-connected square pulse generator, a pulse shaper, a power amplifier, and a eddy current converter consisting of sequentially connected and coaxially arranged measuring and compensation coils of inductance, the output of which is a common point of inductance carcasses second effort- 25

Tel and synchronous detector, a compensator connected between the second output. pulse driver and input b27

an amplifier, a phase shifter connected between the second output of the pulse generator and the second input of the synchronous detector, and an indicator characterized in that, in order to increase the reliability of the measurement results, it is equipped with series-connected frequency divider whose input is connected to. generator output, rectangular pulses, a second synchronous detector, the second input of which is connected to the output of the first synchronous detector, a threshold element and a switch, the output of which is connected to the indicator side, a low-pass filter connected between the output of the first synchronous detector and the second input of the switch, and testing unit, made in the form of auxiliary coil connected in series in a closed circuit, connected to the compensation coil of the converter, resistor, and Foot switch, the actuating input of which is connected to the output of the frequency divider.

Claims (1)

Formula of the invention Eddy current measuring device comprising a rectangular pulse generator, a pulse shaper, a power amplifier, connected in series; eddy-current transducer, consisting of series-connected and coaxially arranged measuring and compensation inductance coils, the output of which is the common point of the inductance coils, the second amplifier ^{: an} amplifier and a synchronous detector, a compensator connected between the second output. of the pulse shaper and the input of the second amplifier, a phase shifter connected between the second output of the pulse shaper and the second input of the synchronous detector, and an indicator, characterized in that, in order to increase the reliability of the measurement results, it is equipped with a series-connected frequency divider, the input of which is connected to the output generator, rectangular pulses, a second synchronous detector, the second input of which is connected to the output of the first synchronous detector15, a threshold element and a switch, the output of which о is connected to the indicator input *, a low-pass filter connected between the output of the first synchronous detector and the second 2o input of the switch, and the testing unit, made in the form of an auxiliary inductor connected in series to a closed circuit connected to the compensation coil of the converter, resistor, and electronic key controlling the input of which is connected to the output of the frequency divider. Compiled by V. Krapivin Editor I. Schull Tehred L. Oliinyk Proofreader V. Girnyak Order 4423/43 Circulation 847 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and printing company, Uzhhorod, st. Project, 4