DE2226639C3 - Non-linear device for detecting magnetic flux - Google Patents

Description

Circumferential direction is easily magnetizable, further

with a coil wound on the thin film, "with the wire being sent a signal from an exciter the frequency / is fed and to the

Coil sin measuring part for measuring a through the The invention relates to a non-linear

to be detected magnetic flux caused device for detecting a magnetic flux output signal of frequency 2 / connected 15 with at least one element made of a wire, which is characterized in that the with a uniaxial magnetically anisotropic thin amplitude of the exciter (6) supplied - Layer is plated, which is limited in the axial direction of the wire th signal of the frequency / to such a difficult and in the circumferential direction easily magnetizable value that the thereby generated is bar, furthermore with a magnetic field [H _x ) weaker on the thin layer , preferably only 20 celts coil, whereby a signal of the frequency / is fed to the wire from an exciter slightly weaker than the anisotropic magnetic field and on

the coil is a measuring part for measuring an output signal caused by the magnetic flux to be detected frequency 2 / is connected.

There are many possible uses for such devices, z. B. the acquisition and measurement of a magnetic field, the signal conversion of a mechanical one Shift into an electrical signal using a magnetic field and the displacement

2. Apparatus according to claim 1, marked 30 turn in a ternary control system, d. H. in teichnet through one to the output (4, 4 ') of the one working with three values, namely +1, 0 and - 1 System.

By Japanese patent application 45-10031 is an apparatus for detecting an uneven magnetic field has become known, which has a parametrically excited oscillator for the second Contains harmonics and has two magnet wires, each of which is a straight electrical Conductor with a thin ferromagnetic cover

0.2 mm, the coil (3) has a number of turns of 60 40 train, the so in the circumferential direction and in axia- And the amplitude of the signal in the Freler direction is applied to the conductor that frequency / is about 70 milliamps. the coating is slightly magnetized in the circumferential direction

4. Device according to one of claims 1 ren can, in which an inductance is also provided to 3, characterized in that the measuring part is the two coils with the same number of tines connected to the coil output (4, 4 ') are isolated around one of the two magnetic wires Amplifier (12) and one on the amplifier has windings and the coils for

Detecting an external magnetic field are differentially connected in series, also a Supply source for the excitation current of the two coils

5. Device according to one of claims 1 5 ° is present, further parallel to the two coils fcis 4, characterized by a capacitor connected to a parallel resonant circuit for the second harmonic of the frequency of the excitation current and finally

. >. ".. ,, .. -j, ... .. measuring elements are connected to the resonance circuit,

b) an excitation part (6) which is connected in series _{to the phase of the second harmonic chen compo} .

switched clad wires simultaneously en _{nente m} ^^ _{dje in the resonance circuit generated} J _hd

and one of the two possible phases depending on the presence or absence

_ _r . . _f , one unevenly on the two magnetic

to detect the occurrence of several von- _{6o wires} acting magnetic field occupies, mutually independent external magnetic fields _Nights in _g on this known device is the

unstable operation of the measuring device due to a small excitation current, the differential operation when using two coils and using them as a temporary control system on the 65 too high sensitivity.

Output of the exciter part (6) a doubler (31) The object of this invention is to

for generating an output signal of the reference direction for detecting a magnetic flux this phase and the frequency 2 / is connected to eliminate that disadvantages and a device with

{H _k ) of the clad wire (1, 2), and that the measuring part (10, 13, 14) is designed so that it hits an output signal of the frequency 2 / the coil (3) which occurs suddenly when the Field strength (H _y ) of the external magnetic field in the direction of the difficult-to-magnetize axis! Exceeds predetermined threshold value lying above zero.

Coil (3) capacitor (5) connected in parallel, Jessen capacitance together with the inductance ier coil gives a resonance at frequency 2 /.

3. Apparatus according to claim 1 or 2, characterized characterized in that the magnetically anisotropic thin layer (2) has a thickness of approximately 1 μ, the wire (1) has a diameter of about

• output connected counter (13) has to tu record how often the external magnetic field exceeds the threshold value (Fig. 6).

a) several elements (10), the clad wires (1, 2) of which are connected in series,

Excitation signal of frequency / supplies,

c) several each to the output of the coils

(3) connected amplifiers (20 a, 20 b. ..)

(Fig. 7).

6. Device according to one of claims 1 to 5, characterized in that at his

of adequate sensitivity and simple structure Fig. 2 shows the waveforms of the magnetic field

m create which is used in a switching element and the output voltage;

can be whose mode of operation by external ma- Fig.3 (A) and 3 (B) represent the change of the main tables Interfering fields is not influenced. With the gnetisierung dar;

The device is intended to give a signal as a result of a 5 Fig.4 is an Astiroid curve and shows the limit

Change in magnetic flux due to a median magnetic change;

chanical shift be possible. The previous Fig. 5 (A) shows a circuit diagram of EI-

direction should be used as a contactless switch or as a resting moment for detecting the magnetic flux according to the

contact switches can be used. She is supposed to be invention;

also used in a ternary control system io F i g. 5 (B) shows another embodiment of a

can be, depending on the presence and Po circuit diagram of an element to detect

larity of a magnetic field works of the magnetic flux according to the invention;

The device according to the invention is thereby shown. 6 shows a block diagram of an embodiment

kennzeicb.net that the amplitude of the form and represents a binary control system according to

Regerteii supplied signal of the frequency / on a 15 of the invention;

is limited to such a value that FIG. 7 generated thereby shows a block diagram of another

Magnetic field H _x weaker, preferably just some embodiment and represents a binary control system

weaker than the anisotropic magnetic field H _k according to the invention;

clad wire, and that the measuring part is so formed- Figs. 8 (A) to 8 (C) are diagrams showing the

is placed that there is an output signal of the frequency »o explain the principle of a ternary control system, and

2 / the coil is detected, which occurs suddenly when Fig. 9 shows the block diagram of an embodiment

the field strength H _{x of} the external magnetic field in the shape of the ternary control system according to the

The hard-to-magnetize axis is a presence.

given, above zero threshold value F i g. 1 shows a typical magnetization curve

exceeds. * 5 of a ferromagnetic-plated wire with one

A further development of the axial, magnetic anisotropy according to the invention. In Fig. 1 is with

direction shows a parallel to the exit of the coil- »α« the magnetization curve along the slightly ma-

switched capacitor, the capacity of which can be assigned axis, z. B. in the circumferential direction and

together with the inductance of the coil a resonance with "6" the magnetization curve along the difficult

at frequency 2 / results. 3 ° magnetizable axis, e.g. B. in the axial direction

A further embodiment of the invention-referred. For better understanding, the device provides that the magnetic direction of the easily magnetizable axis with * and isotropic thin film has a thickness of about 1 μm, the direction of the hard-to-magnetize axis wire has a diameter of about 0.2 mm, the denoted by y. The strength of the magnetization, the coil has a number of turns of 60 and which 35 occurs at saturation or at the point of change to the amplitude of the signal of the frequency / approximately 70 multiples, ie the anisotropic magnetic field H,., Is in amps. the same in the directions. The coercive force H _c is

A further advantageous embodiment of the device according to the invention, normally slightly smaller than the anisotropic device according to the invention, is characterized by the magnetic field H _k . If the magnetic film of the net, that the measuring part has a wire clad to the coil output, is so thin that the magnetic field is connected to the amplifier and a counter connected to the output is only in a flat plane, it is sufficient to have the counter connected to the master output to examine gnetization only two-dimensionally,
to detect how often the external magnetic field exceeds an input threshold when passing through the clad wire. Excitation current flows, occurs in a two-dimensional

Another embodiment of the 45 plane according to the invention shown in FIG. 2 (a). Device is characterized by several EIe- If along the y-axis of the clad wire no mente, the clad wires of which are connected in series magnetic field is caused, the magnetization must be, an excitation part that is low in the series connected so that none on the winding Output plated wires at the same time an excitation signal of the voltage occurs, as shown in FIG. 2 (b) illustrated frequency / feeds, and several are each at the output 5 °. F i g. 2 (c) shows the waveform of the output response of the amplifiers connected to the coil for voltage E when there is a magnetic detection of the occurrence of several independent of one another along the y-axis.
pending external magnetic fields. F i g. 3 shows the process of magnetization in FIG

Furthermore, when using the invention, a two-dimensional plane. When the ma-

according to the device as a ternary control system on 55 gnetfeld H _x , as in F i g. 2, at the time

the output of the exciter part a doubler at point t, shifts from positive to negative.

To generate an output signal for the reference phase, the magnetic vector M either goes through

and the frequency 2 / connected and a connection path (1) or through path (2) of FIG. 3 (A). the

equalization for comparing the phase between Eahn the vector M is at the times /

see the doubler output and the spu- 60 and Λ, through the weak magnetic field | // ,, | in Rieh

len output signal and determined for detecting the amplitude device of the y-axis. Depending on the train:

of the output signal of the element for detecting the vector M can be the one shown in FIG. 3 (B)

Magnetic flux be provided. output voltage at these times E ₁ or E

Other features and advantages of the present will be. The voltages E ₁ and E ₂ have the same

Invention go from the following description 65 amplitude and waveform and opposite

and the drawings. Polarity.

Fig. 1 shows the hysteresis line of a thin ferro- Fig.4 shows an astroid curve showing the ratio

Maoneian layer with uniaxial anisotropy; between the change of magnetization and de

respective strength of the magnetic fields \ H _X \ and | // ,. | A capacitor 5 is connected in the magnetic flux 10 'between the terminals 4 and 4' in the direction of the easy and difficult to magnetize coil 3. The Kapa axis reproduces. If, as shown in FIG. 4, this capacitor 5 is designed in such a way that the alternating magnetic field | // J in the direction of the resonance circuit from this capacitor and the .v-axis is weaker than the anisotropic field \ H _k \ and coil 3 has a resonance frequency of 2 / has. In which the magnetic field in the direction of the y-axis is zero, embodiment according to FIG. 5 (B), the magnetization vector M in area (1) is balanced so that the output voltage between terminals 4 and 4 'does not change. If the has a large amplitude, e.g. B. 0.3 V.
clad wire with the magnetic field \ H _y \, whose output voltage of the circuit according to strength outside the borderline of F i g. 4 in the io F i g. 5 (A) or 5 (B) is located by the process part (3) or (4), works in the direction of the y-axis, which is connected to the coil and acted upon in such a way that the magnetization of the is designed so that it changes a clad wire induced in the coil depending on the polarity of the magnetic hopping signal of frequency 2 / processed. The profeldes in the direction of the y-axis, and it is the zeßteil represents the presence and polarity of the output voltage shown in Fig. 3 (B) in the 15 external magnetic field and processed coil induced. If \ H _X \ is equal or slightly to this information for the evaluation odei weaker than H _lr , ie the strength of the magnet control suitable, the information corresponding field in area (2) of FIG. 4 is carried out on corresponding electrical signals.
The reason for the movement of the Bloch walls is a change. The device for detecting the magnetic flux of the magnetization, although in the direction of the y-axis 20 according to the present invention, can only be a very small magnetic field. If binary Ix) gik elements are used. F i g. 6, however, the value of \ H _X \ increases and becomes larger shows the block diagram of an embodiment of the invention as the value of H _k \ and in the direction of the y-axis where, using this logic, there is no magnetic field, the phase of the elements the speed is detected. In Fig. 6, the output voltage is unstable because area (3) or (4) 35 magnet M 16 is arranged on a turntable 15 in the vicinity of its circumference, arbitrarily detected by the magnetic stray field, that in the longitudinal direction. device of the measuring element DET 10 a constant magnetic

F i g. 5 (A) and 5 (B) show two execution tables that generate a constant field. That through the Ma-

Examples of a circuit diagram of the magnetic field induced by the magnet M 16 in the coil 3

the invention. 30 output signal is fed to an amplifier AMP 12

In Fig. 5 (A) is the element for detecting the out, the output signal of which is provided with the reference numeral 10 after the rectifying magnetic flux. device is input to a counter COU 13. The element for detecting the magnetic flux 10 output signal of this counter COU 13 is fed to a stand of a plated wire with a conductor display device WD14, which shows the number of cores 1, on the surface of which a thin film 2 35 revolutions of the disk 15 is displayed . The structure was applied by electrolytic precipitation and according to FIG. 6 can also be used for the automatic on a reel 3 wound on the wire. In the case of a display of a measuring device, the preferred embodiment of this invention is turned over the signal displayed on the display device / ND14 by means of data transmission lines for the thin magnetic film 2 permalloy to a remote, in which the easily magnetizable axis is fed into the process system.
Circumferential direction and the difficult to magnetize When the circuit according to F i g. 6, the off axis in the direction of the axis of the plated wire output signal of the measuring element DET 10 is processed by a tes or the difficultly magnetizable axis in amplifier AMP 12, a counter COU 13 and a circumferential direction and the easily magnetizable display device IND 14, so that each this axis in the direction of the axis of the clad wire 45 parts 12, 13 and 14 is an element of the process part. runs. For example, the thickness of the thin F i g. 7 shows a further embodiment of the film 1 μ, the diameter of the conductor core 1 0.2 mm, invention in which several measuring elements 10 or 10 and the coil 3 has sixty turns. Let g 10 'according to F i. 5 (A) or 5 (B) can be used, assuming that a current In F i g. 7 are the conductor cores of the magnetic platvcwi certain amplitude and frequency, z. B. 50 oriented wires 10 α, 10 b, 10 c and 10 d in series ge 70 mA and 1 MHz, switched through the conductor core 1 and are sent through a single exciter part ί to generate a magnetic field that The attenuator induced in the coil 3 as the anisotropic field H _t in the plateau signal of each measuring element is generated by the wire and thus the plated wire is in the range of the respective amplifier AMP 20 α, 206, 20 c or 20 £ (1) of FIG. 4 is amplified - amplified at this 5s. In this case, the amplifiers represent the time, the voltage-shaped output signal between 20 a, 206, 20 c or 20 a * represents the process part, which is output terminals 4 and 4 'of the coil 3 ches the output signal of the coil 3 processed Di <HoIl when the external magnetic field in the longitudinal embodiment according to FIG. 7 can be at a kon tong NnO. B. is more tactless switch or with a break contact than 2 Gajiss, appears between the output switches 60 used, if in the longitudinal direction terminals 4 and 4 'an abrupt output was pre-magnetized and an additional magnet signal. The frequency of this output signal is from the opposite direction and the same 2 / (2 MHz) sad its phase is (0) or (α), depending on the strength of the premagnetization. Ii the polarity of the external magnetic field, as before this fail, an output voltage is normally shown in FIG. 3 explains 65 tion reached, which when applying the additional measure

Fig. 5 (B) shows a circuit diagram of a zero field.

further embodiment of the invention. In a device for detecting the magnetic flasse

Fig. 5 (B) is in the device for detecting according to this invention can in an Elemen

2 26

with three states or a ternary control system can be used as a phase detector which compares the output of the double frequency of the doubler and the measuring element. The principle of this trivalent element is from FIG. 8 (A) to 8 (C) can be seen. The trivalent element has three types of output signals, (O) phase, (? I) phase and zero voltage, corresponding to its three states. In Fig. 3 (B), for example, the signal E ₁ (+) represents the (0) phase and the signal E ₂ {- ) represents the (.-I) phase. It is assumed that a for the external magnetic field Bar magnet M is used, as shown in FIGS. 8 (A) through 8 (C) is shown. F i g. Fig. 8 (A) shows that the coil 3 gives an output of the (O) -phase when the magnet M points in the longitudinal direction with the north pole to the coil; Fig. 8 (B) shows that the output voltage of the coil 3 is zero when there is no magnetic field in the longitudinal direction to it, and F i g. Fig. 8 (C) shows that the coil 3 gives an output of the (Tr) phase when the south pole of the magnet M points in the longitudinal direction of the coil.

F i g. 9 shows the distinction between the (O) phase and the (^) phase. A according to FIG. 9 doubler DUB 31 connected to the output of the exciter part 6 emits a reference signal of a standard »5 phase and a frequency 2 /. A comparison circuit COM 32 compares the phase between the reference phase of the doubler DUB 31 and the variable phase of an element 10 and outputs three types of output signals corresponding to the three states of the magnetic field in the longitudinal direction of the element 10. A display device IND 33 indicates one of the three values as a visible or as an electrical signal. In this case, the doubler DUB 31, the comparison circuit COM 32 and the display device IND 33 represent the elements of the process part. A ternary control system according to this invention thus works depending on the presence and on the polarity of a magnetic field in the longitudinal direction. This ternary tax system can e.g. B. can be used for a computer that works with three values f 1, 0 and -1, while the known device only works with the values 1 and 0 in binary systems. The ternary system can e.g. B. can be used for an automatic adjustment.

From the above it can be seen that a device according to the invention for detecting the magnetic flux is not influenced by external weak magnetic fields, since in the area (1) of FIG so that no magnetic shielding of the element is required. The structure and the process facilities are simple and the cost is low because the output voltage is direct and not as with the known devices - the phase is detected; it should also be noted that heat dissipation and low power consumption due to energy loss due to the magnetic material because the element 10 does not provide a continuous output voltage and only a weak excitation current needed. Since the principle of this invention, as explained above, depends on the properties of the Depending on the magnetic material, this invention provides an apparatus for detecting magnetic flux of great reliability and long service life.

A device for detecting the magnetic flux according to the invention can be used as a sensor or Switching element of low sensitivity not only in the binary or ternary control systems mentioned can be used, but also generally in conventional switching systems.

For this purpose 3 sheets of drawings

Claims (1)

a comparison circuit (32) for comparing claims: the phase between the doubler output signal and the coil output signal and zurr. 1. Non-linear device for detecting a detection of the amplitude of the output signal of the magnetic flux with at least one EIe- 5 element for detecting the magnetic flux vorment from a wire that is seen uniaxially with a. magnetically anisotropic thin film is plated, which is heavy and in the axial direction of the wire