SU746360A1 - Apparatus for measuring magnetic properties of magnetically soft materials - Google Patents

Description

The invention relates to a measurement technique that can be applied to measure and digitally record the magnetic properties of samples of magnetic materials. Devices are known for determining the magnetic properties of samples of magnetic soft materials with the output of measurement results in a digital form. Such devices contain sources of magnetizing currents, an integrator, converting blocks, ani signals into digital form and indicators 1. However, their measurement accuracy is insufficient. Closest to the proposed device, which includes a magnetizing current generator, sequentially which includes the magnetizing winding of the test sample and a resistor serving as a signal sensor proportional to the magnetizing current; an integrator, to the input of which the measuring winding of the test piece is connected; the first key connected in series, the first reversible counter, the first converter; the code — the first comparator, to the second input of which the output of the integrator is connected; and the first selective driver, forming the induction measurement channel, the second key, connected in series, the second reversible counter, the second converter, code voltage, the second comparator , to the second input of which a resistor is connected, and the second selective driver, forming the channel for measuring the intensity of the magnetic field in the sample, the gene pulse puller, the output of which is connected to the first key inputs; logic device, the inputs of which are connected to the outputs of selective drivers and the output of the driver of the reference signal, the first input of which is connected to the output of the integrator, and the second to one of the outputs of the logic device, the other outputs of which are connected to the second inputs of keys, reversible counters and selections tivnyh shapers; a sampling unit and a digital printing device, the first inputs of which are connected to the output of the first reversible counter, and BTOptJe to the output of the second counter of the reversible counter; the output of the sampling unit is connected to the third input of the digital printer; analog recorder, the inputs of which are connected to the outputs of the corresponding converters of code-voltage 2 converters,

This device measures the magnetic properties of magnetic soft materials with high-frequency and pulsed magnetization (nano-microsecond range of pulse durations) with an unacceptably large error. This is due, in particular, to the lack of synchronization of the measuring part of the device and the magnetizing-current generator. This does not allow for the investigation of the short signals obtained when the samples are magnetized. The use of an analog integrator also introduces a significant margin of error. The latter is especially noticeable when determining the dynamic hysteus loop with pulsed magnetization reversal. .

The purpose of the invention is to improve the measurement accuracy.

The goal is achieved due to the fact that the device for measuring the magnetic properties of specimens made of soft magnetic materials containing a series-connected master oscillator, a magnetized magnetic current generator, a magnetizing winding and a resistor are sequentially

connected measuring winding, first comparison element, first logic element, first reversible counter And the first code-voltage converter, the output of which is connected to the second input of the first

Comparison elements connected to. The second element of the comparison, the second logic element, the second reversible counter and the second code-voltage converter, whose output

connected to the second input of the second element of the comparison, the unit shift and the formation of strobe pulses, the first

which yy is attached to the third

The inputs of the comparison elements, and the second to the second inputs of the logic elements, and the adder. The input of which is connected to the output of the first-turn counter, the coincidence element, controlled by the cumulative counter, is additionally introduced. the third code-voltage converter, the first input of the coincidence element is connected to the second output of the shift and strobe block, the second input is the second output of the first logic element, and the third - to the G-output of the second logic element, the output - with the counting input of the counters counter : a and a control of the adhUBWBXdaoM adder, the output of the controlled storage counter is connected to the input of the third converter. to one voltage, the power supply is connected to the second input of the unit and the formation of strobe pulses.

The drawing shows a structural electrical circuit of the device. The diagram shows: 1 - master oscillator; 2 - generator of magnetizing currents, 3 - magnetized wedge winding of the test sample 4 - test sample; 5 - resistor, 6 - measuring winding of the test sample, 7.8 - elements of comparison of channels for measuring induction and magnetic field strength, respectively, 9.10 logical elements of channels for measuring induction and magnetic field strength in sample, 11.12 - reversible channel counters measurements of induction and magnetic field strength in the sample, respectively, 13.14 code-voltage converters; channels for measuring the induction and magnetic field strength in the sample, respectively, 15 is a coincidence element, 16 is a controllable storage counter, 17 is an adder, 18 is a code-voltage converter for the shear channel and strobe shaping, 19 is the shear block and strobe pulse shaping.

The device works as follows.

The signals of the master oscillator 1 start the generator of magnetizing current pulses 2. Under the influence of current pulses / entering the magnetizing winding 3, the test sample 4 is reversal and an emf is induced in the measuring winding b proportional to the rate of change of the magnetic flux (induction) in the sample. This signal is fed to the reference element 7. The input of the comparison element 8 and the resistor 5, connected in series with the magnetizing winding, receives a voltage proportional to the magnetizing current (magnetic field strength).

Claims (2)

From the master oscillator 1, a shift and strobe pulse shaping circuit 19 is also triggered. Typically, such devices include a fast sawtooth voltage generator, a reference element and a short pulse shaper. At the moment of equality of the voltage of the INP-fast sawtooth and the code-voltage 18 coming from the converter, the pulses shifted in time with respect to the pulses of the driving oscillator appear at the output of the reference element. The time shift of the received pulses is proportional to the instantaneous values of the compared stresses. Since the rate of change of the fast sawtooth voltage is flux, m, therefore, the change in the time shift of the pulses is determined by the instantaneous voltage from the transducer 18. From the output of the comparison element, the pulses go to the gate driver. The latter arrive at elements of comparison 7 and 8. When the elements of comparison 7.8 are triggered, a pulse is generated, which is fed to the logic elements 9.10. Logic elements 9, 10 control the operation of reversible counters 11 12 by applying a pulse to the sum to the summing input, if the operation did not occur (this means that a compensating voltage needs to be increased), and to the subtracting input, if the comparison element operates (this means that the compensating voltage must be reduced). Thus, a system formed by a logic element, a reversible counter, and a code-voltage converter tends to keep the comparison element close to the unstable equilibrium position at the boundary. The circuit worked — the circuit did not work. Since the amplitude of the pulse is constant, it compensates for the voltage, and therefore the code of the reversible counter, has a proportional value of the signal under study at the time of gating. Logic elements 9,10 also express the signal following the matching element 15, If cxe№i compares transition t, the circuit did not operate the circuit, i.e., if the sum of the voltages of the code-voltage that compensates for the converter and the strobes became equal to or exceeded by (the minimum minimum value of the comparison element. The coincidence element 15 is triggered only in the case when all its inputs receive permission signals, then the pulse from the output of the coincidence element 15 enters the counter 16 and increases its content. This, in turn, leads to an increase in the output voltage of the code-voltage converter 18 and to the greatest displacement in time of the strobe pulse. The counter 16 has a control input 20. This makes it possible to set the number of accumulated pulses and, thus, set the measurement time. From the output of the reversing counter 11, information in the parallel code enters the adder 17. Information is entered into it only when the compensation moment arrives in the comparison elements 7.8, i.e., into the adder 17, the code from the reversible counter 11 can be entered only by a signal from the output of the coincidence element 15, the output of the sum of the mountain 17 is the value obtained by the magnetic properties of the test sample proportional to the magnetic flux (induction) - and at the output of the reversible counter 12 - a value proportional to the magnetizing current (magnetic field intensity) H. The introduction of the coincidence element 15, the counter 16, the transducer 18 and the adder it allows to measure the magnitude of the magnetic field intensity to the corresponding magnetic flux (induction) difference when a high-frequency or pulsed current is applied to the sample. Since the analog-digital stroboscopic transformation is applied, the durations of the studied signals can lie in the nano-microsecond range. Thus, the proposed technical solution allows one to increase the accuracy of measuring the magnetic properties of magnetic material samples when the sample is exposed to rapidly changing magnetizing fields (for example, pulsed) and to obtain the necessary information in digital form. Claims An apparatus for measuring the magnetic properties of magnetic soft materials, comprising a series-connected master oscillator, a magnetizing current generator, a magnetizing winding, and a resistor, successively connected to a measuring winding, the first element of comparison. the first logic element, the first reversible counter and the first converter, the code-voltage, the output of which is connected to the second input of the first element of the comparison, connect the resistor connected in series to the second element of the second element, the second logic element, the second reversible counter and the second code-voltage converter, 1 output of which is connected to the second input of the second comparison element, a unit for shifting and forming strobe pulses, the first output of which is connected to the third inputs of the comparison elements and the second to The second inputs of the logic elements, and an adder, the input of which is connected to the output of the first reversible counter, characterized in that, in order to improve the measurement accuracy. it additionally includes a coincidence element, a controllable storage counter and a third code-voltage converter, moreover, the first input of the coincidence element is connected to the second output of the shift and strobe unit, the second input is from the second (OUTPUT of the first logic element and the third - with the second output of the second logical element, the output with the counting input of the storage counter and the control driver Yzyod; the output of the controlled tGSHySHyy18yyyyyyyyyyy to the input of the third converter kyy-t e, the output of which is connected to a second input of shift pulses, and generating unit. Sources of information taken into account in the examination 1. USSR author's certificate 530293, G 01 R 33/12, 1975. 2. USSR author's certificate No. 437990, Q 01 R 33/12., 1974 (prototype).