SU1295208A1 - Digital electromagnetic thickness gauge - Google Patents

Abstract

This invention relates to methods for non-destructive testing of materials and products and can be used in mechanical engineering in determining the thickness of various materials. The purpose of the invention is to improve the accuracy of the edges by linearizing the measurement results of the block of permanent memory. The current source 1 is connected to the electromagnetic field source 2, the magnitude of which is recorded by the electromagnetic field converter 3. The thickness converter 4 in the time interval forms a pulse whose duration is a function of the thickness. The received pulse is filled with gating pulses, the number of which is recorded by the counter 7. In order to correct the measurement result, the permanent memory 10 generates a signal triggering one - a vibrator 11, which generates an additional impulse, correcting the readings of the counter 7. The result of the linearization is visualized by the indicator 8, 2 Il. i (About ig. /

Description

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The invention relates to non-destructive testing methods and can be used in measuring the thicknesses of materials and products.

The purpose of the invention is to improve the measurement accuracy due to the linearization of measurement results using a block of permanent memory

Fig, 1 shows a structural diagram of the thickness gauge; in fig. 2 - timing charts of the elements of linearization.

The thickness gauge contains current sources 1 and electromagnetic field 2 connected in series, electromagnetic field converter 3 connected in series, time thickness converter 4, the second input of which is connected to the current source 1, element 5, equivalence element 6, counter 7 and indicator 8 .

The thickness gauge also contains an automatic frequency control circuit 9, the outputs of which are connected to the inputs of the current source, counter 7 and indicator 8, and the second input of element 5, and connected in series permanent memory 10 and one-shot 11 connected between the outputs of counter 7 and the second input of element 6 equivalences

The device works as follows.

The source 2 and the transducer 3 of the electromagnetic field are placed on opposite sides of the control object (not shown). Depending on the thickness of the product under test, the transducer 4 of thickness in the time interval forms a square pulse, the duration of which is a function of the thickness. Then the element And 5 forms a pack of counting pulses, the number of which is proportional to the duration of the input pulse. The formation of the counting pulses is carried out by the frequency control circuit 9, which in the steady state produces pulses whose frequency is

ten

f5

0

Q

the first output is two times higher than on the second and 1000-5000 times higher than the network frequency.

Synchronous adjustment of the frequency to the frequency 5 of the industrial network (50 g) eliminates the effect of network interference on the measurement results and compensates for the dependence of the output pulse duration of the converter D thickness in the time interval on the network frequency. Next, a pack of counting and fflyls through the element 6 of equivalence goes to counter 7.

The measurement process is linearized as follows. When a value requiring correction appears in counter 7, a signal appears at the output of the permanent memory 10 that triggers a one-shot 11, adding a positive pulse to the input of counter 7.

At the end of the counting, the measurement results are recorded by the indicator 8 according to the signal received from the circuit: 9

five

five

0

five

Claims (1)

auto-tuning frequency. Invention Formula Digital electromagnetic thickness gauge containing a current source connected in series and an electromagnetic field source connected in series by an electromagnetic field converter, a thickness to time converter and an And element connected in series by a counter and an indicator and a frequency auto-tuning circuit whose outputs are connected to the current source, counter s to an indicator and the second input element And, characterized in that, in order to increase the measurement accuracy, it is provided with connected in series permanently memory connected to the counter, one-shot and equivalence element, the second input of which is connected to the output of the element I, and the output is connected to the input of the counter. Logout ROM9 08 i1 8khodSch8 Compiled by I. Keso N. Editor M. Blanlan Tehred A. Kravchuk Proofreader-O. Lugova 608/46 Circulation 678 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 FIG. 2