System and method for measuring physical quantities and / or positions using a bistable magnetic wire - Patents.com

Abstract

A physical quantity measurement and / or position measurement system using a bistable magnetic wire (1), comprising an excitation element (2) for generating a magnetic field and a sensing element (3). Within the magnetic field of the excitation element (2), a bistable magnetic wire (1) having a first end (11) and an oppositely arranged second end (12) is arranged. The bistable magnetic wire (1) is adjusted in magnetization by a single Barkhausen jump from the first end (11) to the second end (12) or vice versa, the excitation element (2) and the bistable magnetic wire (1) are arranged in a mutual position with a magnetic field that is asymmetric with respect to the bistable magnetic wire (1), and the magnitude of the magnetic field excited by the excitation element (2) at the first end (11) is different from the magnitude of the magnetic field excited by the excitation element (2) at the second end (12). The asymmetry of the magnetic field arises due to the asymmetrical positions of the magnetic element (2) and the bistable magnetic wire (1) relative to one another and / or due to the asymmetrical structure of the magnetic element (2).

Description

[Technical field]

[0001] The present invention relates to a composition of a magnetizing element and a bistable magnetic wire, which is prepared for the measurement of various physical quantities and / or for the position measurement of the bistable magnetic wire. The novelty of this system and method lies mainly in the specific asymmetric position of the magnetic field of the magnetizing element and indeed of the magnetic field of the bistable magnetic wire, which significantly improves the interpretation value of the raw measurement data. [Background technology]

[0002] Bistable magnetic elements are used to measure a variety of physical quantities and positions. They are formed by a passive member that reacts to a change in position in a magnetic field or to a change in a physical quantity by changing its magnetization.

[0003] For example, GB2374084A describes an alloy with bistable magnetic properties and a microwire made of this alloy. The microwire can respond to various physical quantities, but response evaluation is problematic because the bistable magnetic elements of the prior art may have complex magnetic effects in which magnetization occurs in multiple regions (magnetic domains) within a single microwire, rather than a single wall jump. Applications of bistable magnetic wires to position, angle, and rotation measurements are also known.

[0004] The excitation of a bistable magnetic wire wound on a core is disclosed in US4484090A. This solution does not allow the evaluation of physical quantities. Some magnetic effects of bistable magnetic elements are described in JPH03252577A, but the problem of the interpretation of the measured nonlinear values ​​is not solved.

[0005] DE 2817169 A1, DE 3427582 A1 and SU 1753425 A1 describe systems with Wiegand wires with a level of magnetic bistability, which serve to determine the proximity of a bistable magnetic element to a sensor. Due to this configuration, it is not possible to measure the value of a physical quantity in the vicinity of the bistable magnetic element.

[0006] The position or rotation sensor according to EP 0 484 716 A1 uses a Wiegand wire which is approached by a rotating permanent magnet. This sensor only reacts to changes in the magnetic field and does not evaluate the magnitude of a physical quantity.

[0007] The Wiegand sensor according to DE 4107847 C1 is capable of contactlessly transmitting information about the closure of a switch which can react to changes in physical quantities such as temperature, pressure or acceleration, but requires a suitable sensor which then controls the switch, i.e. the physical quantity is not measured by the bistable magnetic element itself.

[0008] New technical solutions that are simple in construction, eliminate the influence of noise and secondary phenomena, and improve the reproducible interpretability of measurements of various physical quantities are desired but are not known. The bistable magnetic element must react to changes in the measured physical quantity on its own and generate a response that is contactlessly transmitted to a receiving element. Summary of the Invention

[0009] The above-mentioned drawbacks are substantially eliminated by a system for measuring physical quantities and / or for measuring position with a bistable magnetic wire, which comprises an excitation element for generating a magnetic field within the range in which the bistable magnetic wire is arranged. The bistable magnetic wire has a first end and a second end arranged on the opposite side, and is therefore not wound into a screw or a coil, the magnetization of which is adjusted by a single Barkhausen front jump from the first end to the second end or vice versa, according to the invention, the essence of which is that the excitation element and the bistable magnetic wire are arranged in a mutual position in which the magnitude (amplitude) of the magnetic field excited by the excitation element at the first end is different from the magnitude (amplitude) of the magnetic field excited by the excitation element at the second end. The magnetic field at the first end and the magnetic field at the second end are different at all moments of non-zero excitation and therefore at a given moment, the excitation being dynamic in time. The system also includes a receiving element for receiving a response from the bistable magnetic wire.

[0010] The terms first and second are used herein to refer to two different ends and are interchangeable, and therefore do not indicate superiority or importance of one end of the bistable magnetic wire to the other.

[0011] Different magnetic fields at the two ends at a given moment of excitation result in an asymmetric magnetic field and, together with the magnetization due to a single Barkhausen jump, in reproducible and interpretable measurement results. For practical measurement applications, it is important that the behavior of a bistable magnetic wire is fundamentally dependent on the measurand and the measurement position, and that other factors, including the action of the more complex magnetic properties of a bistable magnetic wire, can be ignored or at least identified in such a way that they can be compensated for when evaluating the raw data.

[0012] To ensure the asymmetry of the excitation field and the mutual position of the bistable magnetic wire, a difference of 5%, preferably 10%, particularly preferably 25% or more between the values ​​of the magnetic field at the first and second ends is sufficient. This contributes to the magnetization occurring in one jump over the entire wire from one end to the other. If the magnetization occurs in several separate magnetic domains along the length of the wire, the measured response will contain several individual effects, which will significantly impair the interpretability of the measurement. This will prevent the determination of the dependencies of the measurement data and will reduce the applicability of the bistable magnetic wire. The aim of the invention is to achieve an effective and complete true bistable magnetization, in which the magnetic domain structure of the bistable magnetic wire does not consist of a large number of magnetic domains that would cause the magnetization to occur by moving several magnetic domains in a single wire. Although the measurement of a bistable magnetic wire with several magnetic domains along its length can be compared with the measurement of several separate bistable magnetic wires in a single excitation field, the resulting measurement is a sum of individual responses that cannot be reliably distinguished, and therefore the summarized response vector is practically unusable.

[0013] To create a relatively asymmetric magnetic field, several technical possibilities can be used, the appropriate choice of the respective structure also depends on the specific measured quantity or location. In principle, the system according to the invention allows the measurement of temperature, pressure / tension, magnetic field. From these basic quantities, various positional relations as well as a whole range of other physical quantities can be indirectly measured, the presence of bistable magnetic wires can be measured, their mutual position, current parameters can be measured by measuring the magnetic field in conductors, their position in the Earth's magnetic field and linear feed, or bending and torsional stresses or flows of liquids or gases based on the measurement of the elongation in the respective directions.

[0014] By measuring the change in the magnetic field, it is possible to detect changes in position, in rotation of the bistable magnetic wire or the carrier on which it is mounted, and to measure the relative position with respect to other objects carrying the magnetizing element, which can be used to construct position sensors, rotation sensors, end sensors, proximity sensors for magnetic bodies or carriers carrying magnetic bodies, absolute position sensors with respect to the earth's magnetic field, etc.

[0015] Although the antenna of the excitation element may be used for the response measurement, preferably the system is comprised of a separate receiving element, for example in the form of a receiving coil. In this case, the excitation element may be a primary coil and the receiving element is formed by a secondary coil. The secondary coil may be connected to an amplifier and an evaluation unit. The receiving elements may be arranged coaxially with the position of the bistable magnetic wire or may be arranged at different positions from each other so as to be within range of receiving the response.

[0016] A preferred embodiment is that the bistable magnetic wire is in the form of a microwire with a diameter of less than 50 μm, preferably less than 25 μm, particularly preferably less than 15 μm. This is because with a core diameter of less than 15 μm and an appropriate composition of the amorphous metal alloy, the radial magnetic structure disappears, which is associated with the wire drawing process with simultaneous quenching, usually water quenching. For this reason, the bistable magnetic wire behaves as completely bistable and is therefore effectively bistable over the entire length of the wire, with the magnetic domain walls (domain walls) during magnetization extending from the first end to the second end, rather than separately in several individual regions along the length of the wire. It has also been found to be suitable if the length of the bistable magnetic wire is at least 100 times, preferably at least 10,000 times, the diameter of the bistable magnetic wire, which means that it is a small diameter wire that can also be called a microwire.

[0017] A typical structure of a bistable magnetic wire comprises an amorphous metal core and a cover, for example a glass cover, whose outer diameter is no more than three times the diameter of the metal core. The thickness of the glass cover is 1-20 μm. The glass cover, the glass surface layer, protects the metal core from electrical contact with the environment and from aggressive chemical environments, which allows the bistable magnetic wire to be used very universally, for example directly in the windings of electric motors or inside building materials, inside the human body, etc. The bistable magnetic wire can in principle also be used without a circumferential cover and it is also possible to use a cover of a material different from glass.

[0018] As described in older publications by the authors of the invention, magnetic excitation by a triangular signal, usually a symmetrical triangular signal, has proven suitable, which simplifies the evaluation of the measurement signal. For this purpose, the system according to the invention is arranged to be connected to a power element, a control element and an evaluation element. Upon instruction from the control element, the power element transmits to the excitation element a power supply adjusted to obtain a triangular excitation signal. The evaluation element acquires and analyzes the response received from the bistable magnetic wire.

[0019] The asymmetry of the excitation field can be achieved by placing the excitation element, which induces a substantially symmetrical magnetic field, asymmetrically relative to the bistable magnetic wire. As shown in FIG. 3, the positional asymmetry ensures that the first end of the bistable magnetic wire is in a higher magnetic field than the second end, so that the bistable magnetic wire is always magnetized with the movement of one of the domain walls in the higher magnetic field. The positional asymmetry can be achieved by setting up a spatial relationship. At the same time, the coil of the excitation element and the bistable magnetic wire can be placed coaxially, so that they can have the same or parallel oriented longitudinal axes.

[0020] The asymmetry of the excitation field can be ensured, for example, by a construction of the excitation element with non-uniform coil windings with different thread pitches or different thread numbers at the first or second end. Such a construction of the excitation element results in different magnetic field magnitudes at both ends of the excitation element or at a certain distance from both ends. In such a case, the first and second ends of the bistable magnetic wire will have different magnetic field magnitudes, even if the mutual positions of the excitation element and the bistable magnetic wire are spatially symmetrical.

[0021] The definition describing the mutual position of the excitation element and the bistable magnetic wire according to the first claim also includes a symmetric mutual position, in case an asymmetric magnetic field is generated by the excitation element. The definition of the first claim expresses a mutual position that can be achieved by several means or by different combinations of technical means and relative spatial arrangements. The asymmetry of the magnetic field, which is important for achieving the effect according to the invention, is always understood in the relative relationship of the magnitude of the magnetic field at the first end and the second end. The asymmetry of the excitation field can also be achieved by adding a shielding element or by placing another secondary coil on the primary coil of the excitation element. In such cases, the mutual position of the excitation element and the bistable magnetic wire may appear spatially symmetrical, but the asymmetry of the magnetic field at the first end and the second end becomes important.

[0022] In all versions of magnetic field asymmetry, the magnetizing element can be positioned either coaxially with the position of the bistable magnetic wire or next to it. In most applications, it is assumed that the longitudinal axis of the magnetic field generated by the magnetizing element is essentially parallel to the longitudinal axis of the bistable magnetic wire, but in principle, angularly different positions are also possible, for example the longitudinal axis of the magnetizing element is offset from the longitudinal axis of the bistable magnetic wire by up to 30 degrees.

[0023] The drawbacks mentioned in the prior art are eliminated by a method for physical quantity measurement and / or position measurement with a bistable magnetic wire, in which a variable magnetic field is transmitted by an excitation element and at least one bistable magnetic wire is placed within the range of the excitation magnetic field, which is magnetized when this magnetic field changes by a single Barkhausen front jump from a first end to a second end or vice versa, and the response of the bistable magnetic wire is then sensed by a sensing element. According to the invention, it is important that the excitation element and the bistable magnetic wire are maintained in a mutual position in which the magnitude of the magnetic field excited by the excitation element at the first end is different from the magnitude of the magnetic field excited by the excitation element at the second end. Defining the difference in the magnitude of the magnetic fields at both ends is to be explained by the fact that this difference applies in a stationary state, in which the changing position of the bistable magnetic wire is not measured, even if the bistable magnetic wire can move relative to the excitation element (for example, when measuring the pressure of a rotating tire). This means that at the moment of magnetization, both ends of the bistable magnetic wire are in magnetic fields of different magnitudes. When measuring the changing position of a bistable magnetic wire, for example when measuring a linear position, it again applies that at the moment of magnetization, the two ends of the bistable magnetic wire are in magnetic fields of different magnitude and, at the same time, there is a difference in the magnetic field due to the movement to be measured.

[0024] At the same time, it is preferred that the magnetic field has a triangular shape, particularly preferably a symmetrical triangular shape, and that the times of local maxima and minima of the response of the bistable magnetic wire are evaluated, which are essentially the times of magnetization of the bistable magnetic wire. The sum of these times is a parameter that represents the measured quantity and / or the position dependence, while other unmeasured factors and noise are suppressed. This improves the interpretability of the measurement data and also speeds up the evaluation. It is also preferred that the difference of these times is calculated, this parameter representing parasitic magnetic fields that interfere with the measurements of conventional magnetic sensors. The process according to the invention suppresses the influence of parasitic magnetic fields.

[0025] An important feature of both the system and the method according to the invention is the fact that in the evaluation of the response signal, local maxima and minima are searched for and, after their recognition, the method operates on the times T1, T2 at which these maxima and minima were measured. Moreover, the method does not operate on the basis of the values ​​of the measured amplitude, as was common in the prior art, but on the value of time, which is an easily and clearly identifiable parameter in the received signal. This makes the evaluation fast, accurate and less susceptible to various secondary effects. For example, the exact position, shape and size of the excitation and sensing elements are not important.

[0026] In the development of the subject of the invention, it has been shown that the bistable magnetic wire has different reactivity for each measurand depending on the frequency of the excitation magnetic field. In a preferred arrangement, the method according to the invention therefore comprises a step of exciting the magnetic field with different or varying frequencies depending on the type of measurand or position. A universal excitation generator as well as an excitation element are optionally adapted to this or different excitation elements are used for different applications. Due to this finding, one structure of the bistable magnetic wire can also be used with different frequencies. The value of the stable frequency for one application may be different from the stable frequency used in another application or these frequencies may be variable in different ranges for a particular type of measurement.

[0027] An important advantage of the present invention is the repeatability of the measurements, which is associated with an increased level of interpretation of the raw data obtained. A rapid response to changes in the measured physical quantity was also demonstrated. Due to the small dimensions, low cost and energetically passive nature of the bistable magnetic wire, the system according to the present invention can be used for a wide range of technical applications. [Brief description of the drawings]

[0028] The present invention will now be described in more detail with the aid of Figures 1 to 10. The particular sizes of the wires and excitation elements shown, and the values ​​of the measured quantities, are merely illustrative and should not be interpreted as narrowing the claimed protection of the present invention. [Figure 1] FIG. 1 is a block schematic diagram showing the structure of a bistable magnetic wire. [Diagram 2] Fig. 2 shows the bending stress measurement results of a steel bracket, with the classical bistable magnetic wire of the prior art on the left and the bistable magnetic wire according to the present invention on the right. Fig. 2 clarifies the technical problems solved in the prior art solutions. [Diagram 3] FIG. 3 shows a schematic diagram of the position asymmetry of the excitation element relative to the bistable magnetic wire. [Figure 4] FIG. 4 is a schematic diagram of an asymmetrically wound coil of an excitation element. [Diagram 5] FIG. 5 shows the tension measurement system for the test tear samples. [Figure 6] FIG. 6 shows a schematic diagram of a system for measuring the temperature on the surface of a battery cell. [Figure 7] FIG. 7 then shows the dependence of the temperature course on the sum of the time T1+T2. [Figure 8] FIG. 8 is an oscilloscope screen showing the peak time values ​​aT1-T2 through cT1-cT2 when measuring temperature using three bistable magnetic wires. [Figure 9] FIG. 9 shows the coaxial position of the bistable magnetic wire relative to the excitation and sensing elements when measuring the linear position of the piston. [Figure 10] FIG. 10 shows the magnetization of a bistable magnetic wire between two states when excited with a triangular signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Example 1

[0030] In this example according to Fig. 3 and Fig. 5, a bistable magnetic wire 1 is used to measure tension or pressure on a steel part. The tear pattern has a calibrated central area and two clamping ends. A microwire with a metal core with a diameter of about 15 μm and a glass cover with a total diameter of about 45 μm and a length of about 3 cm is glued to the surface of the central area. In this example, the bistable magnetic wire 1 is oriented in the direction of the tensile force, so that the elongation of the steel material is transferred to the deformation of the bistable magnetic wire 1. A slight deviation in the mounting angle position does not significantly affect the measurement accuracy. The bistable magnetic wire 1 is aligned substantially in a straight line at the same time, and the first end 11 and the second end 12 are in mutually opposite positions, so that the bistable magnetic wire 1 is not wound on a core as known from prior art applications.

[0031] An important feature of this embodiment is to create an asymmetry of the excitation field by using the position asymmetry. The excitation element 2 is placed next to the bistable magnetic wire 1, the longitudinal axis of the excitation element 2 is substantially parallel to the longitudinal axis of the bistable magnetic wire 1, and the center of the coil of the excitation element 2 is displaced by the value X recorded in Fig. 6 relative to the center of the bistable magnetic wire 1. In order to reduce the distance between the excitation element 2 and the bistable magnetic wire 1, the longitudinal axes of the excitation element 2 and the longitudinal axis of the bistable magnetic wire 1 are placed in a position where they intersect with one common plane passing through them, this common plane being substantially perpendicular to the surface of the steel part. In principle, however, this measuring system is not affected by inaccuracies in the positioning of the individual elements. All that matters is that the elongation of the material to be measured is reliably transmitted to the bistable magnetic wire 1.

[0032] The positional asymmetry of the excitation element 2 results in the desired difference in the magnetic fields at the first end 11 and the second end 12 which, combined with the properties of the bistable magnetic wire 1, results in magnetization with a single Barkhausen jump from the first end 11 to the second end 12. The excitation element 2 generates a magnetic field of a triangular signal, the response of the bistable magnetic wire 1 is captured by the sensing element 3 which is connected to a control unit 4 where the response is evaluated.

[0033] The static and dynamic measurements are carried out on a tear machine. The signals obtained at the sensing element 3 are generally monotonic and highly repeatable.

[0034] Example 2

[0035] For temperature measurement of a cylindrical battery cell according to Figures 6 and 7, a heat-sensitive bistable magnetic wire 1 is placed on the cell surface. The system also consists of a planar coil of the excitation element 2 and a small coil of the sensing element 3. Measurements were performed in the temperature range from -20 to +100 °C.

[0036] The analog signal of two peaks (minimum and maximum) from the bistable magnetic wire 2 is monitored on an oscilloscope. The position times of the signal peaks T1 (maximum) and T2 (minimum) are processed and converted into digital signals in the control unit 4, which are then displayed on the PC. The measured and evaluated signals show an almost linear dependence between temperature and the magnetic response of the bistable magnetic wire 1, which is defined by the sum of the values ​​T1+T2. The parameters of the detected dependence are then used to adjust the parameters of the software that displays the actual temperature. In the case of a monotonic dependence, a calibration polynomial can be defined, which is used to assign the raw data to the actual temperature. The sampling frequency is 2 samples / s and the sensitivity is 0.4 °C (K), which corresponds to 288 points of change at 120 °C intervals.

[0037] With one excitation element 2 and one sensing element 3, it is possible to build a system for measuring the temperature of several battery cells. As can be seen in Figure 9, it is possible to clearly distinguish the time positions of the signal peaks of three bistable magnetic wires 1 arranged individually on three cylindrical battery cells. The peaks are labeled as aT1-aT2 to cT1-cT2. The signals thus received can be clearly detected, decomposed and converted into the temperatures of the individual battery cells.

[0038] Example 3

[0039] A single bistable magnetic wire 1 connected to a moving piston is used for high-precision linear position measurement. The bistable magnetic wire 1 in this embodiment has the composition Fe 77.5 S 7.5 B 15 It has positive magnetostriction, a length of 30 mm, a metal core diameter of 39 μm, and a diameter including the glass layer of 71 μm.

[0040] In this embodiment according to Fig. 9, the excitation element 2 and the sensing element 3 are formed by coils, loosely surrounding the sliding piston. The longitudinal axes of the excitation element 2, the sensing element 3 and the piston are identical. The bistable magnetic wire 1 is attached to the surface of the piston, so it only has an approximately coaxial position with the excitation element 2 and the sensing element 3, but this does not affect the accuracy of the position measurement.

[0041] The asymmetry of the magnetic field in this embodiment is achieved by a positional asymmetry, so that in each position of the piston, the centre of the bistable magnetic wire 1 is located outside the centre of the excitation element 2. Furthermore, in this example, both ends 11, 12 are also located outside the centre of the excitation element 2 in each position. In this way, the position of the excitation element 2 is set such that in the end positions of the piston, one end of the bistable magnetic wire 1 extends into the coil of the excitation element 2, but does not reach the centre of the excitation element 2. The piston with the bistable magnetic wire 1 then extends further from inside the coil of the excitation element 2.

[0042] Unlike conventional position sensors, where the position is defined by the magnetic permeability and the amplitude of the signal on a sensing coil, the system according to the present embodiment detects the magnetization of the bistable magnetic wire 1, which is proportional to the position.

[0043] A reliable induction method is used to detect the magnetization. The excitation magnetic field has a triangular shape and the switching time is measured. Here, T1 and T2 represent the magnetization time between two stable magnetic states (positive and negative switching) according to Fig. 10. The switching time corresponds to the time when the maximum voltage is induced. Maximum and minimum values ​​of the received signal are clearly identifiable and the background does not affect the interpretation possibilities. Correctly amplified and filtered detected signals are connected to the digital inputs of a single-chip computer with a time resolution within 10 ns. A simple electronic circuit of the control unit 4 is sufficient to achieve very high accuracy and measurement speed. The digital unit of the microcontroller generates a PWM signal of the desired frequency (135 Hz in this example). After filtering and converting the received signal, the time T1+T2 is summed up by a timer.

[0044] The advantages of the system according to this embodiment are the sharp maximum of the signal induced during magnetization, the high sensitivity at the level of 10 μm, the independence of the system from the ambient temperature, and the measurement error due to temperature sensitivity of less than 0.19%.

[0045] Example 4

[0046] In this embodiment according to Fig. 4, the coil of the excitation element 2 is wound non-uniformly with an increased number of threads at one end. At the same time, the bistable magnetic wire 1 is arranged in such a way that at a given time of non-zero excitation, the magnitude (amplitude) of the magnetic field excited by the excitation element 2 at the first end 11 differs from the magnitude (amplitude) of the magnetic field excited by the excitation element 2 at the second end 12 by at least 5%. [Industrial Applicability]

[0047] The industrial applicability is obvious: according to the invention it is possible to repeatedly manufacture and use the spatial and structural arrangement of the magnetizing elements and the bistable magnetic wires industrially for the measurement of physical quantities and / or for the measurement of position, in particular for the measurement of temperature, pressure, tension, magnetic field, current, position, earth magnetic field, torsion, linear position or angular position. [Explanation of symbols]

[0048] 1 - Bistable magnetic wire 11 - First end 12 - second end 2 - Excitation element 3 - Sensing elements 4 - Control Unit T1 - Maximum signal response time T2 - Minimum signal response time

Claims

1. A system for measuring physical quantities and / or positions using a bistable magnetic wire, comprising an excitation element (2) for generating a magnetic field within a range in which a bistable magnetic wire (1) is arranged, and a sensing element (3) for receiving a response from the bistable magnetic wire (1), the bistable magnetic wire (1) having a first end (11) and a second end (12) arranged opposite the first end (11), the magnetization of which is adjusted by a single Barkhausen jump from the first end (11) to the second end (12) or vice versa, A system for measuring physical quantities and / or positions using a bistable magnetic wire, characterized in that the excitation element (2) and the bistable magnetic wire (1) are arranged at a mutual position such that the amplitude of the magnetic field excited by the excitation element (2) at a first end (11) is different from the amplitude of the magnetic field excited by the excitation element (2) at a second end (12).

2. A system for measuring physical quantities and / or positions using a bistable magnetic wire as claimed in claim 1, characterized in that the difference in amplitude of the magnetic field at the first end (11) and the second end (12) is at least 5%, preferably at least 10%.

3. A system for measuring physical quantities and / or positions using a bistable magnetic wire as claimed in claim 1 or 2, characterized in that it is adapted to measure temperature and / or pressure and / or tension and / or magnetic field and / or linear position.

4. 4. A system for measuring physical quantities and / or positions using a bistable magnetic wire as claimed in claim 1, characterized in that the coil of the receiving element (3) is separate from the coil of the exciting element (2).

5. A system for measuring physical quantities and / or positions using a bistable magnetic wire as described in any one of claims 1 to 4, characterized in that the bistable magnetic wire (1) has a diameter of less than 50 μm, preferably less than 25 μm, particularly preferably less than 15 μm.

6. 6. A system for measuring physical quantities and / or positions using a bistable magnetic wire as claimed in any one of claims 1 to 5, characterized in that the bistable magnetic wire (1) is covered with a layer of insulating material, preferably a layer of glass.

7. 7. System for measuring physical quantities and / or positions with a bistable magnetic wire according to claim 6, characterized in that the glass has a thickness of up to 20 μm.

8. A system for measuring physical quantities and / or positions using a bistable magnetic wire as described in any one of claims 1 to 7, characterized in that the length of the bistable magnetic wire (1) is at least 1000 times, preferably at least 10000 times, the diameter of the metal core of the bistable magnetic wire (1).

9. 9. A system for measuring physical quantities and / or positions using a bistable magnetic wire as claimed in any one of claims 1 to 8, characterized in that the excitation element (2) is arranged asymmetrically with respect to the position of the bistable magnetic wire (1).

10. 10. A system for measuring physical quantities and / or position using a bistable magnetic wire as claimed in any one of claims 1 to 9, characterized in that the excitation element (2) has an asymmetric structure with different magnetic field amplitudes at its ends.

11. 11. The system for measuring physical quantities and / or position using a bistable magnetic wire as claimed in claim 10, characterized in that the excitation element (2) is formed by a coil having different winding densities at its first end (11) and its second end (12).

12. A system for measuring physical quantities and / or positions using a bistable magnetic wire as described in any one of claims 1 to 11, characterized in that the longitudinal axis of the excitation element (2) is the same as or parallel to the longitudinal axis of the bistable magnetic wire (1), or the longitudinal axis of the excitation element (2) is offset from the longitudinal axis of the bistable magnetic wire (1) by no more than 30 degrees.

13. A method for measuring a physical quantity and / or a position using a bistable magnetic wire, comprising: transmitting a variable magnetic field by an excitation element (2); placing at least one bistable magnetic wire (1) within the range of the excited magnetic field and magnetizing it when the magnetic field changes by a single Barkhausen front jump from a first end (11) to a second end (12) or vice versa; and detecting a response of the bistable magnetic wire (1) thereafter by a detection element (3), A method for measuring a physical quantity and / or a position using a bistable magnetic wire, characterized in that an excitation element (2) and a bistable magnetic wire (1) are maintained at mutual positions where the amplitude of the magnetic field excited by the excitation element (2) at the first end (11) and the amplitude of the magnetic field excited by the excitation element (2) at the second end (12) are different.

14. 14. A method for measuring a physical quantity and / or a position using a bistable magnetic wire as described in claim 13, characterized in that the excitation magnetic field has a waveform with a triangular magnitude, preferably a symmetrical triangular shape, and the time T1 of the local maximum and the time T2 of the local minimum of the response of the bistable magnetic wire (1) are evaluated.

15. A method for measuring a physical quantity and / or a position using a bistable magnetic wire as described in claim 13 or 14, characterized in that the excitation magnetic field has a frequency within a region in which the bistable magnetic wire (1) has at least one local maximum of sensitivity to a specific type of measurand or position.

16. A method for measuring a physical quantity and / or a position using a bistable magnetic wire as described in any one of claims 13 to 15, characterized in that when evaluating the signal received as a response from the bistable magnetic wire (1), the sum of the time T1 of the local maximum value and the time T2 of the local minimum value of the signal is evaluated, preferably without taking into account the absolute amplitude of the signal.

17. A method for measuring a physical quantity and / or a position using a bistable magnetic wire as described in claim 16, characterized in that when evaluating the signal received as a response from the bistable magnetic wire (1), the difference between the time T2 of the local minimum and the time T1 of the local maximum of the signal is taken into account.

18. 18. A method for measuring a physical quantity and / or a position using a bistable magnetic wire according to any one of claims 13 to 17, characterized in that the response of the bistable magnetic wire (1) intercepted in the sensing element (3) is evaluated in a control unit (4).

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