RU3998U1 - ELECTROMAGNETIC THICKNESS METER - Google Patents

Abstract

An electromagnetic thickness gauge containing a microcontroller, an indicator connected to it, and a measuring transducer, including a programmable frequency divider, the inputs of which are connected to the corresponding outputs of the microcontroller, a repeater, a comparator and logical element And connected in series, the output of which is connected to the microcontroller input, an integrator consisting of a resistor and parallel connected capacitor and operational amplifier, as well as a measuring transformer transducer, consisting of and a radiating coil connected by one output to the corresponding output of the first key, to the second output of which a supply voltage is applied, and two receiving coils, each of which is connected to the second and third keys, respectively, by one of its terminals, the other leads of which are combined with one of the fourth key outputs , to the other terminal of which a constant voltage is applied, and connected to one of the inputs of the repeater, the other input of which is combined with its output and connected to one of the terminals of the integrator resistor, the other terminal the resistor is connected to one of the terminals of the fifth key, the second terminal of which is connected simultaneously with the capacitor, the operational amplifier of the integrator and one of the terminals of the sixth key, the other terminal of the latter is connected to the second terminal of the capacitor, the output of the operational amplifier and one of the inputs of the comparator, the second inputs of the operating the amplifier and the comparator are grounded, the control terminals of the second, third, fourth and sixth keys are connected to the corresponding outputs of the microcontroller, the control terminal of the fifth key is connected to

Description

Electromagif Thickness Gauge

The utility model relates to test equipment, namely, devices for measuring the thickness of various coatings on metal substrates.

A known thickness gauge (see the description of the invention to ed. St. N 1796885, class G01B 7/06, published in 1993) containing a generator, an inductive converter connected to it, a voltage reference source, adder, indicator, synchronizer, device sampling-storage, comparator and amplifier.

This design of the thickness gauge made it possible to eliminate the influence of drift of the amplitude value of the output signal of the amplifier on the measurement results, however, eliminating this drawback in the known design did not sufficiently improve the accuracy of measuring the thickness gauge, due to the inability to eliminate drifts of the generator amplitude, reference voltage, and comparator bias, i.e. drift of the entire measuring path.

Known Eddy current thickness gauge see article by V.A.Syas'ko and S.V. Ilyushin. Pulse eddy current thickness gauge of dielectric coatings. Defectoscopy, N4, 1989, p. 52-58, Fig. 3 Appendix 1), containing a microcontroller, an indicator and a measuring transducer, including a programmable frequency divider (timer), a single vibrator, a logic element, a peak detector, operational amplifiers, keys, a primary transformer converter, consisting of a radiating coil and two receiving coils.

A disadvantage of the known thickness gauge is that in the process of measuring the thickness of the dielectric coatings, it becomes necessary to raise the measuring transformer transducer above the coating at regular intervals to update the internal parameters of the system.

As a prototype, the well-known Induction

integrating thickness gauge (see author's article Syasko VA Induction integrating thickness gauge. Defectoscopy. N 12, 1990, p. 47-52, Appendix 2). It contains a microcontroller, an indicator and a measuring converter, including a programmable frequency divider, a measuring transformer converter, a repeater, a comparator, a logic element, keys and an integrator, including a resistor and a capacitor and an operational amplifier connected in parallel.

A disadvantage of the known induction integrating thickness gauge is that in the process of measuring the thickness of coatings on metal substrates at certain intervals, it becomes necessary to raise the measuring transformer transducer above the coating to update the internal parameters of the system, which limits the scope of the thickness gauge.

In addition, in the case when the operator does not provide the conditions for the lifting height of the measuring transformer transducer, additional measurement errors appear.

The objective of the proposed technical solution is to create a thickness gauge that allows you to expand the scope of its application by eliminating the need for periodic lifting of the measuring transformer transducer over a controllable BS coating.

The problem is achieved in that in an electromagnetic thickness gauge containing a microcontroller, an indicator connected to it and a measuring transducer including a programmable frequency divider, the inputs of which are connected to the corresponding outputs of the microcontroller, a repeater, sequentially connected comparator and logical element And, the output of which is connected to the input of the microcontroller , an integrator consisting of a resistor and a parallel-connected capacitor and operational amplifier, as well as a measuring nsformatorny converter, consisting of emitting coils connected with one terminal to a corresponding terminal of the first switch, the second terminal of which is energized pitanE1ya and two coils, each of which is one of its terminals connected

respectively, with the second and third switches, the other TopBix outputs are combined with one of the outputs of the fourth switch, the other output of which is supplied with a constant voltage, and connected to one of the inputs of the repeater, the other input of which is combined with its output and connected to one of the terminals of the integrator resistor, the other terminal of the resistor is connected to one of the terminals of the fifth key, the second terminal of which is connected simultaneously with the capacitor, an operational amplifier of the integrator and one of the terminals of the sixth switch, the other terminal of the last connection with the second output of the capacitor, the output of the operational amplifier and with one of the inputs of the comparator, the second inputs of the operational amplifier and the comparator are grounded, the control outputs of the second, third, fourth and sixth keys are connected to the corresponding outputs of the microcontroller, the control output of the fifth key is connected to the output of the programmable frequency divider, the second input of the logical element And is connected to one of the outputs of the microcontroller, the second logical element And, the second the first resistor and compensation transformer transducer, containing emitting and two receiving coils identical to the measuring transformer transducer, while the radiating coils of the compensation and measuring transformer transducers are connected in series according to, and the receiving coils of the compensation transformer transducer are connected in series-opposite to the receiving coils of the measuring transformer converter, other VBShody all coils comp The transformer converter is grounded, one of the terminals of the second resistor is connected to the connection point of the first resistor and the fifth key, the control terminal of which is also connected to one of the inputs of the second logic element AND, the second input of which is connected to the corresponding output of the microcontroller, and the output of the second logic element And is connected to the control terminal of the first key, a second voltage is applied to the second terminal of the second resistor.

New is the introduction of a second logical element And into the measuring transducer of electromagnetic thickness gauge And,

a second resistor and a compensation transformer transducer containing identical to the measuring transformer transducer, emitting and two receiving coils.

In contrast to the prototype RP, in which the first two conversion cycles are carried out directly on the surface of the coating, and the second two cycles - the third and fourth are carried out with the transformer transducer raised above the coating, and then only the first two measurement cycles are repeated for a fixed time and the thickness T is calculated in this case, after a specified time, the codes obtained earlier in the third and fourth cycles are updated, the proposed design of the electromagnetic thickness gauge p Allows you to carry out all four conversion cycles and the calculation of the thickness T continuously directly on the surface of the controlled coating, eliminating the need for lifting the measuring transformer transducer, thereby making it possible to expand the scope of the thickness gauge, for example, in conditions of limited volume.

In addition, this design made it possible to exclude additional measurement errors that are possible in the prototype, if the specified conditions of the lifting height of the measuring transformer transducer and a fixed time were not provided for updating the codes of the third and fourth conversion cycles due to the fault of the operator.

The inventive electromagnetic thickness gauge is illustrated by drawings:

figure 1 - presents a functional diagram of a thickness gauge;

figure 2 - presents diagrams illustrating the operation of the thickness gauge and a table of key conditions (. - closed state of the key).

The electromagnetic thickness gauge (Fig. 1) contains a microcontroller 1, an indicator 2, and a measuring transducer 3, including a transformer measuring transducer 4, consisting of a radiating coil 5 and two receiving coils 6 and 7, a compensation transformer transducer 4, containing identical to the coils 5,6 and 7 radiating coil 5

and two receiving coils 6 and T, a programmable frequency divider 8, a repeater 9, an iterator consisting of an operational amplifier 10, a capacitor 11 and a resistor 12, a second resistor 13, a comparator 14, the first logical element And 15, six keys 16,17,18 , 19,20 and 21, the second logical element And 22

The microcontroller 1 is made, for example, on a chip type KR1816VB51.

Programmable frequency divider 8 is made, for example, on a chip type KR580VI 53.

The repeater 9, the operational amplifier 10 and the comparator 14 are made, for example, on chips of the type KR544UD1.

Logic elements And 15 and 22 WB are full, for example, on K155LI type microcircuits.

The key 16 is electronic and is made, for example, on a transistor type KT818.

The keys 17-21 are analog and are made, for example, on chips type KR590KN2.

The microcontroller 1 is connected to the indicator 2, the other outputs of the microcontroller are connected to the inputs of the programmable frequency divider 8. The comparator 14 is connected in series with the first logic element And 15, the output of which is connected to the input of the microcontroller 1. The radiating coil 5 of the transformer 4 is connected by one output to the corresponding output first key 16, on the second

whose output is powered. Each of the receiving coils 6 and 7 of the measuring transformer transducer 4 is connected by one of its terminals to the second 17 and third 18 keys, respectively, the other terminals of which are combined with one of the terminals of the fourth 19 key, the other terminal of which is supplied with constant voltage, and connected to one of the inputs repeater 9. The other input of the repeater 9 is combined with its output and connected to one of the terminals of the resistor 12, the other terminal of which is connected to one of the terminals of the fifth 20 key. The second terminal of the fifth key 20 is connected to a parallel-connected capacitor 11 and operational amplifier 10 and to one of the terminals of the sixth 21 key. Another conclusion of the sixth 21

the key is connected to the second output of the capacitor 11, the output of the operational amplifier 10 and with one of the inputs of the comparator 14. The second inputs of the operational amplifier 10 and the comparator 14 are grounded. The control outputs of the second 17, third 18, fourth 19 and sixth 21 keys are connected to the corresponding outputs of the microcontroller 1. The control output of the fifth 20 key is connected to the output of the programmable frequency divider 8. The second input of the first logic element And 15 is connected to one of the outputs of the microcontroller 1. Radiating the coil 5 of the compensation transformer converter 4 is connected in series with the radiating coil 5 of the measuring transformer converter 4. The receiving coils 6 and 7 of the compensation transformer nsformatornogo converter 4 connected in series with oppositely-priemnEshi coils b and 7 a measuring converter transformer 4. The other terminals of all coils 7 5,6i compensating inverter transformer 4 are grounded. One of the terminals of the second resistor 13 is connected to the connection point of the first resistor 12 and the fifth key 20, the control terminal of which is also connected to one of the inputs of the second logical element And 22, the second input of which is connected to the corresponding output of the microcontroller 1. The output of the second logical element And 22 is connected to the control output of the first 16 key. The second output of the second resistor 13 is supplied with a reference voltage.

An electromagnetic thickness gauge operates as follows.

The work of the thickness gauge is synchronized by the microcontroller 1 in accordance with the program of functioning recorded in the memory. The operation algorithm of the measuring transducer is illustrated by a time diagram and a state table of keys 16-21 in figure 2. The work of the programmable frequency divider 8 is synchronized by signals Up (t) with the repetition period. and Control permitting the operation of the programmable frequency divider 8. During the measurement, the measuring transformer converter 4 is installed on the coating of the product. To determine the coating thickness T, the operation of the measuring transformer transducer 4 is built in four cycles. IN

the first conversion cycle at the time before the start of the conversion (Fig. 2) an enable signal Up (t) is supplied to the input of the logical

of the element And 22, and the key 17 is closed, the switching output of the coils 6 and 6 connected in series to the input of the follower 9. At time t, the key 16 is closed and the current i (t) flows through the radiating coils 5 and 5 (Fig. 2d). At the same moment, the key 20 closes and the key 21 opens. On the coils 6 and 6 connected in series and opposite, the resulting EMF ei (t) is induced (Fig. 2e), inversely proportional

the thickness of the cover T supplied through the repeater 9 to the input of the inhaler. At time t.2, the voltage at the output of the integrator Uj is proportional to the area of the EMF ei (t) and the area of the bias voltages of the elements included in the transducer 4. When using identical transformer transducer 4 and compensation transformer transducer 4, identical in characteristics, that the compensation transformer transducer 4 is removed from the coating and the measuring transformer transducer 4 at a distance that excludes their mutual influence, area EMF ei (t) proportional to the flux current Insertion

Ygi (T). At time t.2, the enable signal Up (t) is taken,

the keys 16 and 17 open, the key 19 closes, the enable signal Uox (t) is supplied to the input of the logic element And 15, when

this at the output of the logical element And 15 the leading edge of the time interval Uox (t) is formed. At the same time, the voltage Ug (t) begins to decrease linearly, reaching zero at time 1; zg then triggers

comparator 14, and at the output of the logic element And 15 a trailing edge of the pulse and (t) is formed, the duration of which is inversely proportional to the thickness of the coating T. After that, the enable signal is removed) from the input of the logical element And 15,

the keys 19 and 20 open, the key 21 closes. The time interval t.2 - tj the microcontroller 1 quantizes with pulses of frequency f and counts the code N1 (t3-t2) f, proportional to the voltage at the output of the integrator and at time t.2 and, accordingly, the area EMF ei (t) and the area of the values of the bias voltages of the elements that make up the measuring transformer

transducer 4.

Similarly, in the second conversion cycle, the N2 code is calculated, which is proportional to the EMF area e2 (t) and the area of quantities

the bias voltages of the elements that make up the measuring transformer 4. The difference is that at the beginning of the second conversion cycle, corresponding to the time to the beginning of the first conversion cycle

closes the key 18 instead of the key 17. At the end of the conversion, the code N2 is proportional to the EMF area) and the area

the bias voltages of the elements that make up the measuring transformer 4. In turn, the EMF area e2 (t) is proportional to the introduced flux linkage

UV2 (T).

In the third and fourth conversion cycles, codes N10 and N20 are calculated, which are proportional to the area of the bias voltage values of the elements included in the transmitter 4. In contrast to the first and second cycles, at the moment t, key 16 remains open, and keys 17 and

18 are locked in the third and fourth cycles, respectively, and the EMF on coils 6 and b, as well as 7 and 7 are not induced.

At the end of the fourth conversion cycle, the ratio is calculated by the microcontroller 1;

n (N1 - N10) / (N2 - N20).

Thus, in accordance with the above, n is equal to the ratio of the introduced flux linkages v1 () V to2 (),

the dependence of n on the additive and multiplicative components of the conversion characteristic is thereby excluded and the influence of the magnetic properties of the base on n is suppressed.

After that, the microcontroller 1, based on the previously taken and stored in the memory characteristic, VEL calculates the coating thickness T and gives the measurement result to digital indicator 2.

Thus, the proposed electromagnetic thickness gauge allows you to expand the scope of its application by eliminating the need for a periodic transformer

AOZT

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Chchk AETrra

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Syasko V.A.

Bulatov A.S.

Eliseeva N.A. Koroteev M.Yu. Syasko V.A. lifting measuring transnad controlled coverage.

Claims (1)

An electromagnetic thickness gauge containing a microcontroller, an indicator connected to it, and a measuring transducer, including a programmable frequency divider, the inputs of which are connected to the corresponding outputs of the microcontroller, a repeater, a comparator and logic element And connected in series, the output of which is connected to the microcontroller input, an integrator consisting of a resistor and parallel connected capacitor and operational amplifier, as well as a measuring transformer transducer, consisting of and a radiating coil connected by one output to the corresponding output of the first key, to the second output of which a supply voltage is applied, and two receiving coils, each of which is connected to the second and third keys, respectively, by one of its terminals, the other conclusions of which are combined with one of the fourth key outputs , to the other terminal of which a constant voltage is applied, and connected to one of the inputs of the repeater, the other input of which is combined with its output and connected to one of the terminals of the integrator resistor, the other terminal the resistor is connected to one of the terminals of the fifth key, the second terminal of which is connected simultaneously with the capacitor, the operational amplifier of the integrator and one of the terminals of the sixth key, the other terminal of the latter is connected to the second terminal of the capacitor, the output of the operational amplifier and one of the inputs of the comparator, the second inputs of the operating the amplifier and the comparator are grounded, the control terminals of the second, third, fourth and sixth keys are connected to the corresponding outputs of the microcontroller, the control terminal of the fifth key is connected to by the output of the programmable frequency divider, the second input of the logical element And is connected to one of the outputs of the microcontroller, characterized in that the second logical element And, the second resistor and the compensation transformer converter, containing emitting and two receiving coils identical to the measuring transformer converter, are additionally introduced into the measuring transducer this radiating coil compensation and measuring transformer transducers are connected in series but, and the receiving coils of the compensation transformer converter are connected in series and counterclockwise respectively to the receiving coils of the measuring transformer converter, the other terminals of all the coils of the compensation transformer converter are grounded, one of the terminals of the second resistor is connected to the connection point of the first resistor and the fifth key, the control terminal of which is also connected to one of the inputs of the second logical element AND, the second input of which is connected to the corresponding output ikrokontrollera, and the output of the second AND gate is connected to the control terminal of the first switch, the second terminal of the second resistor is supplied reference voltage.