Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1996-12-16
2000-01-25
Mullen, Thomas
Communications: electrical
Condition responsive indicating system
Specific condition
3405727, G08B 1314
Patent
active
060182970
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
For remote detection of passive and simple elements different types of magneto-mechanical elements may be used, the magnetic and mechanical properties of which being influenced by an external magnetic field, a so-called bias field.
The elements are forced into states of mechanical self-oscillation, the elements thereby emitting and/or affecting a magnetic field in a detectable way.
DESCRIPTION OF THE PRIOR ART
Elements, which exhibit a comparatively large magneto-mechanical coupling, are suitable. The resonance frequency of these elements changes due to the so-called .DELTA.-E effect with the magnetic flux intensity along the main direction of the element.
WO 93/14478 discloses and describes a method and a device for coding and detection of remotely detectable gauges. A number of magnetic elements of an amorphous material are placed upon each other on a label with a certain angular displacement, the angular position thereby constituting one "bit" or code position. According to the coding method the angles between the amorphous elements in the label are used to define the code position. Accordingly, each element may be arranged to represent any code value within a predetermined number range. The expression "label" mentioned above generally refers to information carriers in the form of several magnetic elements.
The method is based upon the use of at least one reference element, which is used to determine the angular positions of the rest of the elements. Thus, the effective range of actual codes is decreased.
BRIEF SUMMARY OF THE INVENTION
An object with the present invention is to provide a method and a device for coding and detection of magnetic elements, where all of the elements are used as coding elements. Further objects and advantages are obvious from the following description and claim.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described by the following embodiments with reference to the accompanying drawings, on which
FIG. 1 is a schematic perspective view of an arrangement for carrying out the method according to the invention, and
FIG. 2 is a graph illustrating the method for detection according to the invention.
DETAILED DESCRIPTION
In a preferred embodiment two excitation means 12A and 12B are connected to an electronic controller 15 via two driver and amplifier units 16A and 16B. The excitation means 12A and 12B are formed as magnetic coils, which are parallelly and coaxially arranged with respect to each other. By this an interrogation zone 11 is obtained between the excitation coils with a symmetry plane with respect to the excitation field generated by the excitation coils. With equal signal strength from both of the excitation coils the symmetry plane is obtained at half the distance between the coils. Two detection means, preferably magnetic coils, are symmetrically arranged with one means at each side of the symmetry plane. The detection coils 13A and 13B are operatively connected to a central electronic controller 15. In the embodiment shown the detection coils 13A and 13B are connected to amplifier units 17A and 17B, respectively, which in turn are connected to the controller 15.
When the arrangement according to the figure is used, identical excitation signals are generated by the controller 15 in both the excitation coils 12A and 12B. The signals from both the detection coils 13A and 13B are amplified in the amplifiers 17A and 17B, and a signal corresponding to the difference between the recorded signals in the detection coils is determined in the central controller 15. If all the signals are generated fully symmetrically, the detected signal without the presence of any resonance elements will have a zero value, since the same signal is recorded in both the detection coils 13A and 13B.
The symmetry required does not necessarily have to be geometrical. It is also possible to accomplish the desired symmetry electronically. In order to compensate for errors and defects in the manufacture and/or assembly process, displacements and the like, or
REFERENCES:
patent: 4492922 (1985-01-01), Ohkubo
patent: 4647917 (1987-03-01), Anderson, III et al.
patent: 4704602 (1987-11-01), Asbrink
patent: 4710752 (1987-12-01), Cordery
patent: 5005001 (1991-04-01), Cordery
patent: 5049857 (1991-09-01), Plonsky et al.
patent: 5160888 (1992-11-01), Laukien
patent: 5300922 (1994-04-01), Stoffer
patent: 5397986 (1995-03-01), Conway et al.
patent: 5420569 (1995-05-01), Dames et al.
patent: 5551158 (1996-09-01), Tyren et al.
patent: 5576693 (1996-11-01), Tyren et al.
patent: 5621316 (1997-04-01), Dames et al.
Mullen Thomas
RSO Corporation N.V.
LandOfFree
Method and device for coding electronic labels does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for coding electronic labels, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for coding electronic labels will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2318513