SU1352427A1 - Magnetic field digital meter - Google Patents

Abstract

The invention can be used in magnetometers intended to measure a magnetic field in instrument making, magnetic flaw detection and shipbuilding. The aim of the invention is to improve the measurement accuracy. CT achieve this goal in the digital magnetic field meter additionally introduced the counter-divider 11 to N, the trigger 12, the element OR 10, the inverter 14 and the driver 13 pulses. In addition, the device contains a clock generator 1, a reversible counter 2, an analog converter 3, a register 4, a flux probe 5, a differentiator 6, a comparator 7, an arithmetic adder 8, a register 9. In the presence of an external field, the excitation current in the flux probe is shifted the size of the measured field, which is ensured by the introduction of negative feedback on the measured field into the device. 2 Il. S S (L from 01 th

Description

The invention relates to a measurement technique and can be used in magnetometers for measuring magnetic fields in instrument making, magnetic flaw detection and shipbuilding.

The purpose of the invention is to increase accuracy.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - device voltage diagrams.

Pre, p; lagged device contains a clock generator 1, a reversible counter 2, a digital-analog converter (PAH) 3, register 4, ferrozond 5, differential ator 6, comparator 7, arithmetic adder 8, register 9, element OR 10, counter-divider 11 on N, the trigger 12, the shaper 13 pulses and the inverter 14.

The output of the clock generator EA 1 is connected to the counting input of the reversible counter 2 and the first input of the element OR 10, the output of which is connected to the counting input of the counter-divider 11, the output of which is connected to the second input

Thus, at the output of the LPP 3, a signal Uj of a triangular excitation current of ferro ond 5 is formed (Fig. 2). At the moment of magnetic reversal of the core of the fluxgate, pulses Uj. Appear at the output of the latter, which after differentiation on the differentiator 6 (U,) are fed to the input of the comparator 7. At the output of the comparator 7 a rectangular impulse Vj is formed, the positive edge of which records the state of the outputs reversible counter 2 in register 4. This information corresponds to the hysteresis of the core Hf. ferrosonde 5. At the same time, a positive pulse with a duration of less than half of the clock generator U, j, wrapping the counter-divider 11 by N, is generated at the output front of the U-, comparator 7, and then it counts the specified number of pulses of the clock generator. When a given number of pulses is reached, a pulse appears at the output of divider 11, and through the element OR 10 it blocks the counting input of the counter divider 11 to N, a by the OR 10 element and the counting input of trigger 12, the output of which is connected to 30 the front of this pulse changes to the control input of the reversible counter 2, the output of which is connected to the inputs of registers 4, 9 and inputs of the DAC 3, the output of which is connected to the winding state of the trigger 12, according to the signal of which the counting direction of the reversible counter 2 is switched.

When the remagnetizing of the core of the fluxgate 5 (Uj) is repeated at the output of the comparator 7, a negative front U- is formed, along which the pulse shaper 13 forms a second pulse that flushes the exciter counter of the fluxgate 5. The output 35 of the fluxgate 5 is connected to the input of the differential gear 6, output connected to

When re-magnetizing the core of the fluxgate 5 (Uj) at the output of the comparator 7, a negative front U- is formed, along which the pulse shaper 13 forms a second pulse that flushes the counter-offset of the comparator 7, while the output of the comparator 7 is connected to the control input of register 4, input form 40 liter 11 per N, Simultaneously ot 13 pulses and input to the inverter edge of the comparator 7 at 14, the outputs of register 4 are connected to the first group of inputs of the arithmetic adder 8, and the outputs of register 9 - from

the output of the inverter 14 forms a pulse and

(four-

on the positive front

which records the second group of inputs of arithmetic 45 Zi Uj about the status of the inputs of the reversing-adder 8, the output of which is connected to the output 15, the output of the pulse shaper 13 is connected to the zeroing divider counter input to N, and the output of the inverter 14 is controlled by Incoming gg register house 9.

The device works as follows.

In the absence of a measurable magnetic field, an increase or decrease in the state of the V outputs of the reversible counter 2 occurs according to the signals

55

counter 2 in register 9. This information corresponds to N. Thus, in the arithmetic adder 8 the signal of registers 4 and 9 is added

NG + (-Ig) a

and at the output of the adder 8 a device output signal appears, which is equal to zero in the absence of the measured field.

If there is an external field when a positive edge of a pulse U-, the comparator 7 arrives, the state of the reverse counter 2

and

 clock generator 1 depending on the direction of counting. So

Thus, at the output of the LPP 3, a signal Uj of a triangular excitation current of ferro ond 5 is formed (Fig. 2). At the moment of magnetic reversal of the core of the fluxgate, pulses Uj. Appear at the output of the latter, which after differentiation on the differentiator 6 (U,) are fed to the input of the comparator 7. At the output of the comparator 7 a rectangular impulse Vj is formed, the positive edge of which records the state of the outputs reversible counter 2 in register 4. This information corresponds to the hysteresis of the core Hf. ferrosonde 5. At the same time, a positive pulse with a duration of less than half of the clock generator U, j, wrapping the counter-divider 11 by N, is generated at the output front of the U-, comparator 7, and then it counts the specified number of pulses of the clock generator. When a specified number of pulses is reached, a pulse appears at the output of divider 11, and through the element OR 10 it blocks the counting input of divider 11 by N, a on the positive front of this pulse

front of this pulse is changed

The state of the trigger 12, according to the signal of which the counting direction of the reversible counter 2 is switched.

When the re-magnetization of the core of the fluxgate 5 (Uj) at the output of the comparator 7 is formed, a negative front U- is formed, along which the pulse shaper 13 forms a second pulse that flushes the counter-divider 11 by N, simultaneously along the negative front of the comparator 7 on

11 on N, at the same time on the negative front of the comparator 7 on

the output of the inverter 14 is formed immitel 11 on N, at the same time on the negative front of the comparator 7 on

pulse and

(four-

on the positive front

Ui Uj about the state of the reversible inputs

counter 2 in the register 9. This information corresponds to N. Thus, at the same time, in the arithmetic adder 8 the signal of registers 4 and 9 is added

NG + (-Ig) a

and at the output of the adder 8 a device output signal appears, which is equal to zero in the absence of the measured field.

If there is an external field when a positive edge of a pulse U-, the comparator 7 arrives, the state of the reversible counter 2

5 and. "This state is written to register 4.

Upon receipt of a negative pulse front U of the comparator 7, the state of the reversible counter 2

Not

FROM and

This state is recorded in register 9.

Thus, at the output 15 of the arithmetic adder 8 there is information that is proportional to the measured field:

8 meas +

Ng

Hjm -

As can be seen from FIG. 2, in the presence of an external field, the excitation current of the fluxgate is shifted by the measured field, which corresponds to the introduction of negative feedback to the measured field in the device.

Claims (1)

Invention Formula A digital magnetic field meter containing a clock generator, a reversible counter, a digital-to-analog converter, two registers, an arithmetic adder, a ferrozond, a differentiator, and a comparator, and you- 0 five 0 5 0 5 the stroke of the clock generator is connected to the counting input of a reversible counter, the output of the D / A converter is connected to the excitation winding of the fluxgate, the output of the signal winding of which is connected to the input of the differentiator, the output connected via a comparator to the control input of the first register, the outputs of the first register are connected to the first group of inputs of the arithmetic totalizer, characterized in that, in order to increase accuracy, a counter-divider by N, a trigger, an OR element, an inverter and a pulse shaper, p are introduced into it At the same time, the clock generator output is connected to the first input of the OR element, the output of which is connected to the counting input of the divider counter to N, the output of which is connected to the second input of the OR element and the counting trigger input, the output of the latter is connected to the control input of the reversible counter, the outputs connected to inputs of two registers and a digital-analog converter, the output of the comparator is connected via a pulse shaper to the reset input of the counter-divider to N, and through an inverter to the control input of the second register, output and connected with the second group of inputs of the arithmetic adder, the output of which is connected to the output bus. I8 U us Ufi r Jh Compiled A. Sazonov Editor L. Pcholinsk Tehred L. Serdyukova Proofreader A. Obruchar Order 5563/45 Circulation 730. Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul. Proektna, 4  - L  / V / fie.g