SU1350495A1 - Ultrasonic echo-pulse thickness gauge - Google Patents

Abstract

The invention relates to a measurement technique, namely to non-destructive testing of the thickness of products with one-sided access to their surface. The aim of the invention is to improve the measurement accuracy. To achieve this goal, a RAM trigger, a decoder 11, a code comparator 13, a digital-to-analog converter 12 are entered into the thickness gauge, and the RAM trigger trigger 10 is connected to the higher bit output of the digital block 7, and the RAM trigger output 10 is connected to the input of the decoder 11, the output of which is connected to the input of the digital-to-analog converter 12, the output of which changes the frequency of the generator 9 of counting pulses. The inputs of the comparator 13 code are connected to the output of the digital unit 7, and the output of the comparator 13 code to the input of the digital-to-analog converter 12. 2 Il. b (L 00 ate about 4 g sd

Description

The invention relates to a measurement technique, namely to a non-waving control of the thickness of products with one-sided access to their surface.

The purpose of the invention is to show measurement accuracy.

FIG. Figure 1 shows the dependence of the measurement error on the thickness of the product; in fig. 2 is a structural diagram of an ultrasonic echo-pulse thickness gauge.

The thickness gauge contains synchronizer 1 connected in series, a generator of 2 probe pulses, an ultrasonic split-transducer 3, an amplifier 4, a driver 5, a measuring gate driver 6, a digital block 7, a digital indicator 8, and a generator 9 of counting pulses, the output connected one of the inputs of the digital block 7, sequentially connected trigger 10 of the RAM, decoder 11 and digital-to-analog converter (DAC; 12, comparator 1 :) of the code, the input of which is connected to one of the outputs digital block 7. The inputs of the imager 6 of the measuring gate and the digital block 7 are connected to the output of the synchronizer 1. The second output of the digital block 7 is connected to. the inputs of the trigger 10 and comparator 13, the output of the comparator 13 code is connected

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to the second input of the DAC 12, the output of which is,. according to the law of dependence

go is connected to the generator 9 counting

pulses.

The thickness gauge works as follows.

The synchronizer 1 front of the pulse triggers the generator 2 probe pulses and at the same time generates a starting pulse arriving at the input of the imaging unit 6 of the measuring gate. The probe pulse generator 2 excites a separately-combined ultrasonic transducer 3, which sends an acoustic probe pulse into the product through a layer of contact liquid (not shown; the probe pulse passes through the product and, reflected from the bottom surface, enters the converter 3, is converted into electrical pulses. and enters the amplifier 4. Amplified

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50

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error presented in figure 1, the change in the frequency of sending pulses of the generator 9 counting pulses. In the code comparator 13, the values represented in the higher bit of the digital block 7 are compared with two consecutive cycles of correction of the measurement result. In the case of a mismatch of codes for two consecutive correction results, a signal for the DAC 12 is generated at the output of the code comparator 13, producing the next correction of the frequency of the counting pulses on this signal. The correction is made until the coincidence of the number codes for two consecutive measurements.

The measurement results are indicated by a digital indicator 8.

Claims (1)

Invention Formula the pulses go to shaper 5, where they are converted into square pulses normalized by amp five lituda. From the output of the imaging unit 5, the pulses are fed to the input of the imaging unit 6 of the measuring gate, previously triggered by the siy-tronizator 1 signal. The imaging unit 6 of the measuring gate operates on the leading edge of the first pulse that came from the imaging unit 5. At the output of the former 6, the measuring gate receives a rectangular pulse of positive polarity, the duration of which is directly proportional to the measured thickness. From the output of the imaging unit 6 of the measuring gate, the pulse arrives at one of the inputs of the digital unit 7, to the second input of which high-frequency pulses come from the generator 9 of counting pulses. The process of counting pulses occurs only when a strobe pulse is received from the imaging unit 6 of the measuring gate. Signal from the senior (units of mm) 5 bits of the digital block / goes to the comparator 13 and the trigger 10 of the RAM, from the output of which the signal goes to the decoder 11, the output of which forms 0 the low potential of that digit, which is represented in the high-order bit of the digital block 7. By this value of the signal coming from the output of the decoder 11, the DAC 12 produces in co0 0 five 0 five error presented in figure 1, the change in the frequency of sending pulses of the generator 9 counting pulses. In the code comparator 13, the values presented in the higher bit of the digital block 7 are compared with two consecutive cycles of the measurement result correction. If the codes for two consecutive correction results do not match, the signal for the DAC 12 is generated at the output of the code comparator 13, producing the next correction of the frequency of the counting pulses on this signal. Correction is made until the coincidence of the number codes for two consecutive measurements. An indication of the measurement results is produced by a digital indicator 8. Invention Formula Ultrasonic echo pulse thickness gauge containing sequentially 3 1 connected synchronizer, probe pulse generator, separately-combined ultrasonic transducer, amplifier, driver, measuring gate driver, digital block, digital indicator, as well as counting pulse generator, output connected to digital unit, second synchronizer output connected to measuring gate driver and a digital unit, characterized in that, in order to improve the accuracy of measurements, it is provided with series-connected operating memory trigger, a decoder and a digital-to-analog converter, a code comparator whose input is connected to the second output of a digital unit, and an output to a digital-to-analog converter, the RAM trigger input connected to the digital output of the digital unit, and a digital-to-digital converter output - with the input of a counting pulse generator designed to control the frequency of sprinkling. Imp Yu Editor S. Patrushev Compiled by D. Shirochin Tehred L. Oliynyk Proofreader M. Demchik Order 5249/40 Circulation 677. Subscription VNR1IPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4