CH532254A - Differential effect eddy current electronic proximity switch - Google Patents
Differential effect eddy current electronic proximity switchInfo
- Publication number
- CH532254A CH532254A CH1860570A CH1860570A CH532254A CH 532254 A CH532254 A CH 532254A CH 1860570 A CH1860570 A CH 1860570A CH 1860570 A CH1860570 A CH 1860570A CH 532254 A CH532254 A CH 532254A
- Authority
- CH
- Switzerland
- Prior art keywords
- coil
- circuits
- eddy current
- amplifier
- oscillations
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
- G01V3/104—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils
- G01V3/105—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
- G01R17/10—AC or DC measuring bridges
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geophysics (AREA)
- Electronic Switches (AREA)
Description
Détecteur de proximité électronique à courants de Foucault à effet différentiel
La présente invention a pour but l'amélioration de la stabilité en température des détecteurs de proximité à courants de Foucault.
Les détecteurs actuellement construits ont tous une dérive appréciable en température. Cette dérive est due au fait que la ou les bobines et circuits qui entretiennent un champ électromagnétique haute fréquence dans la zone de détection sont toujours électriquement dissymétriques. Ainsi, la variation de résistance, capacitance ou inductance des éléments, due aux variations de température, crée toujours une distorsion se traduisant par la modification de la portée.
L'objet de la présente invention est un détecteur de proximité électronique à courants de Foucault à effet différentiel insensible aux variations de température, comprenant une bobine d'excitation couplée à deux circuits de détection, caractérisé par le fait que la bobine et les circuits de détection sont disposés de façon électriquement symétrique.
De cette façon, les variations de température entraînant des modifications identiques dans les circuits, le niveau du signal de sortie ne sera pas perturbé.
Le dessin annexé représente une application de ce principe. Le schéma est donné à titre d'exemple parmi les solutions possibles.
Sur le dessin, 1 représente un oscillateur haute fréquence, 2, 3 et 4 trois bobines accordées à la même fréquence, 5 un amplificateur et 6 une bascule électronique à seuil.
L'oscillateur 1 entretient dans la bobine d'excitation 2 des oscillations d'amplitude constante. Ces oscillations créent un champ électro-magnétique haute fréquence dans le voisinage de la bobine.
Le champ haute fréquence induit à son tour des oscillations identiques et opposées dans les bobines 3 et 4 des circuits de détection branchés à l'entrée de l'amplificateur 5.
En l'absence de tout objet métallique, le signal reçu par l'amplificateur est donc nul.
Dès l'approche dissymétrique d'un objet métallique, des courants de Foucault sont induits dans celui-ci, ce qui a pour effet de détruire la symétrie du champ haute fréquence d'une part et de désaccorder la bobine la plus proche par modification de son inductance d'autre part.
En conséquence, I'amplitude des oscillations de la bobine la plus proche décroît et une ondulation apparaît à l'entrée de l'amplificateur 5.
Dès que cette ondulation atteint un certain niveau, la bascule à seuil change d'état et émet le signal: présence d'ob jet .
REVENDICATION
Détecteur de proximité électronique à courants Foucault à effet différentiel insensible aux variations de température, comprenant une bobine d'excitation couplée à deux circuits de détection, caractérisé par le fait que la bobine et les circuits de détection sont disposés de façon électriquement symétrique.
**ATTENTION** fin du champ DESC peut contenir debut de CLMS **.
Differential effect eddy current electronic proximity switch
The object of the present invention is to improve the temperature stability of eddy current proximity detectors.
The detectors currently built all have an appreciable temperature drift. This drift is due to the fact that the coil or coils and circuits which maintain a high-frequency electromagnetic field in the detection zone are always electrically asymmetrical. Thus, the variation in resistance, capacitance or inductance of the elements, due to variations in temperature, always creates a distortion resulting in the modification of the range.
The object of the present invention is an electronic proximity detector with eddy currents with differential effect insensitive to temperature variations, comprising an excitation coil coupled to two detection circuits, characterized in that the coil and the circuits of detection are arranged electrically symmetrically.
In this way, since temperature variations lead to identical changes in the circuits, the level of the output signal will not be disturbed.
The accompanying drawing represents an application of this principle. The diagram is given by way of example among the possible solutions.
In the drawing, 1 represents a high frequency oscillator, 2, 3 and 4 three coils tuned to the same frequency, 5 an amplifier and 6 an electronic threshold rocker.
Oscillator 1 maintains constant amplitude oscillations in excitation coil 2. These oscillations create a high frequency electro-magnetic field in the vicinity of the coil.
The high frequency field in turn induces identical and opposite oscillations in coils 3 and 4 of the detection circuits connected to the input of amplifier 5.
In the absence of any metallic object, the signal received by the amplifier is therefore zero.
From the asymmetrical approach of a metallic object, eddy currents are induced in it, which has the effect of destroying the symmetry of the high frequency field on the one hand and of detuning the closest coil by modification of its inductance on the other hand.
As a result, the amplitude of the oscillations of the closest coil decreases and a ripple appears at the input of amplifier 5.
As soon as this ripple reaches a certain level, the threshold rocker changes state and emits the signal: presence of an object.
CLAIM
Eddy current electronic proximity detector with differential effect insensitive to temperature variations, comprising an excitation coil coupled to two detection circuits, characterized in that the coil and the detection circuits are arranged electrically symmetrically.
** ATTENTION ** end of DESC field can contain start of CLMS **.
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH1860570A CH532254A (en) | 1970-12-15 | 1970-12-15 | Differential effect eddy current electronic proximity switch |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH1860570A CH532254A (en) | 1970-12-15 | 1970-12-15 | Differential effect eddy current electronic proximity switch |
Publications (1)
Publication Number | Publication Date |
---|---|
CH532254A true CH532254A (en) | 1972-12-31 |
Family
ID=4434120
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH1860570A CH532254A (en) | 1970-12-15 | 1970-12-15 | Differential effect eddy current electronic proximity switch |
Country Status (1)
Country | Link |
---|---|
CH (1) | CH532254A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2493076A1 (en) * | 2011-02-22 | 2012-08-29 | Rockwell Automation Technologies, Inc. | Inductive proximity sensor |
WO2014161689A1 (en) * | 2013-04-04 | 2014-10-09 | Robert Bosch Gmbh | Object locater and method for locating a metallic and/or magnetizable object |
-
1970
- 1970-12-15 CH CH1860570A patent/CH532254A/en not_active IP Right Cessation
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2493076A1 (en) * | 2011-02-22 | 2012-08-29 | Rockwell Automation Technologies, Inc. | Inductive proximity sensor |
WO2014161689A1 (en) * | 2013-04-04 | 2014-10-09 | Robert Bosch Gmbh | Object locater and method for locating a metallic and/or magnetizable object |
CN105051572A (en) * | 2013-04-04 | 2015-11-11 | 罗伯特·博世有限公司 | Object locater and method for locating a metallic and/or magnetizable object |
JP2016519299A (en) * | 2013-04-04 | 2016-06-30 | ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングRobert Bosch Gmbh | Object search device and metal object and / or magnetizable object localization method |
US10054709B2 (en) | 2013-04-04 | 2018-08-21 | Robert Bosch Gmbh | Object locater and method for locating a metallic and/or magnetizable object |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3609580A (en) | Electrical sensing apparatus | |
US6335619B1 (en) | Inductive proximity sensor comprising a resonant oscillatory circuit responding to changes in inductive reaction | |
JPH0329415A (en) | Induction proximity switch | |
GB1032867A (en) | Improvements in or relating to magnetometers | |
US3469204A (en) | Proximity sensitive on-off oscillator switch circuit | |
US3601691A (en) | Metal detector responsive to small metallic objects for differentiating between ferrous and nonferrous objects | |
US4305034A (en) | Magnetic field intensity measuring device with frequency change indication | |
JPS5829468B2 (en) | Kanno impedance system | |
CH532254A (en) | Differential effect eddy current electronic proximity switch | |
US3355658A (en) | Differentiating metal detector for detecting metal objects and distinguishing between detected diamagnetic and non-diamagnetic objects | |
US3541432A (en) | Magnetometer capable of operating with a very low input power | |
US4321539A (en) | Digital BFO metal detecting device with improved sensitivity at near-zero beat frequencies | |
US3983475A (en) | Frequency selective detecting system for detecting alternating magnetic fields | |
US3528004A (en) | Apparatus for detecting the proximity of a metal body | |
JPH0252220A (en) | Signal former | |
US2926311A (en) | Variable frequency signal generator | |
SU135982A1 (en) | Self-generating metal detector | |
RU2564383C1 (en) | Variable magnetic field sensor | |
AU753651B2 (en) | Induction sensor | |
US2013799A (en) | Means for measuring frequencies | |
US6057683A (en) | Induction sensor having conductive concentrator with measuring gap | |
SU81934A1 (en) | Device for measuring magnetic fields | |
JPH0355895Y2 (en) | ||
SU178862A1 (en) | ||
SU113114A1 (en) | Amplifier |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PL | Patent ceased |