GB2067295A - Proximity detector - Google Patents
Proximity detector Download PDFInfo
- Publication number
- GB2067295A GB2067295A GB8100406A GB8100406A GB2067295A GB 2067295 A GB2067295 A GB 2067295A GB 8100406 A GB8100406 A GB 8100406A GB 8100406 A GB8100406 A GB 8100406A GB 2067295 A GB2067295 A GB 2067295A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coil
- detector
- oscillator
- output
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/965—Switches controlled by moving an element forming part of the switch
- H03K17/97—Switches controlled by moving an element forming part of the switch using a magnetic movable element
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P7/00—Arrangements of distributors, circuit-makers or -breakers, e.g. of distributor and circuit-breaker combinations or pick-up devices
- F02P7/06—Arrangements of distributors, circuit-makers or -breakers, e.g. of distributor and circuit-breaker combinations or pick-up devices of circuit-makers or -breakers, or pick-up devices adapted to sense particular points of the timing cycle
- F02P7/061—Arrangements of distributors, circuit-makers or -breakers, e.g. of distributor and circuit-breaker combinations or pick-up devices of circuit-makers or -breakers, or pick-up devices adapted to sense particular points of the timing cycle pick-up devices without mechanical contacts
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
- G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
- G01D5/202—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils by movable a non-ferromagnetic conductive element
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/42—Devices characterised by the use of electric or magnetic means
- G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
- G01P3/48—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
- G01P3/481—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Electronic Switches (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
A proximity detector has an LC circuit in which the inductance coil 14 is to detect the presence or absence of a passing conducting part 10. The coil is powered by a variable gain oscillator 16 having a voltage output which varies according to variation of its gain control input E. An amplitude detector 18 gives a variable output which is a function of the amplitude of the oscillations in the coil, which are damped when part 10 is present. This is compared with a reference voltage from source 22 by amplifier 20 providing an output signal Vs to E to maintain the output voltage of oscillator 16 across coil 14 substantially constant. Signal Vs is of square wave form and provides an indication and measure of the proximity of each tooth (part 10) in succession to the coil. The detector may be part of an ignition system of an internal combustion engine. <IMAGE>
Description
SPECIFICATION
Proximity detector
The present invention relates to proximity detectors and more particularly those which operate with an electrical coil supplied with an alternating current and which are capable of detecting the passage, in the vicinity of this coil, of a part consisting of conducting material, by virtue of the damping of oscillations in the coil (under the effect of the increase in eddy currents upon the approach of the conducting part).
Proximity detectors of this type are known, using an oscillator having a tuned LC circuit (inductance-capacitance) whereof the coil constitutes the inductance. In the absence of a conducting part in the vicinity of the coil, the tuned circuit has a high coefficient of over-voltage and the oscillator oscillates readily. In the presence of a conducting part, the eddy currents caused in this part create considerable damping, i.e. a considerable reduction in the coefficient of over-voltage of the tuned circuit. This results in a high load for the oscillator, which is no longer able to oscillate. Thus, the presence or absence of a conducting metal part in the vicinity of the coil respectively results in the absence or presence of oscillations of the oscillator.
The drawback of detectors of this currently existing type (known by the name of detectors having blocked oscillations) is twofold:
- firstly, if one is not certain of the distance which one wishes to detect between the conducting mass and the coil, it is necessary to use an oscillator which is capable of stopping oscillating both for the greatest and smallest distance at which the part may pass and this is for possible extreme temperature conditions (since the coefficient of over-voltage of the coil, which is essential for the calculations of the oscillator, depends largely on the temperature and airgap to be detected);; - on the other hand, it is not possible to effect a discrimination between two metal parts passing at different distances from the coil, whereas in certain cases it is necessary or desirable to effect such a discrimination and one is thus compelled to use two differently adjusted detectors.
It has been attempted to effect this discrimination by feeding back to the oscillator its rectified voltage. The voltage of the oscillator thus remains approximately constant and this rectified voltage constitutes an approximate measurement of the distance of the metal part.
However, such a method of construction is not completely satisfactory. In fact, this direct feedback makes the device very sensitive to external parameters, such as temperature, which causes considerable fluctuations in the output signal and also, a device of this type operates solely for a short distance of the metal part and does not make it possible to effect the discrimination between two metal parts in a relatively considerable range of variation.
Previously known devices are thus not suitable
in applications for producing electronic ignition
systems, in which the surrounding conditions and
in particular the temperature variations, the
sudden high voltage necessary for ignition and the
vibrations of the engine, piay an important part.
In order to improve detectors of this type there
is provided according to the invention a proximity
detector comprising an oscillator charged by a
tuned LC circuit having an electrical coil able to
induce eddy currents in a conducting part passing
in the vicinity of the coil, thus creating damping of
the oscillating electrical signals which travel
through the coil, the oscillator having a variable
gain and comprising a gain control input, looping
between an output of the oscillator and said input
being provided in order to keep the amplitude of the oscillations at the terminals of the coil at a substantially constant value, a detector of the amplitude of the electrical oscillations at the terminals of the coil being provided, the detector being connected to the terminals of the coil, the output of the amplitude detector and the output of a source of reference voltage being connected respectively to the inputs of a differential amplifier, the output of the differential amplifier having voltage varying in proportion to the damping of the oscillations, and the output of said differential amplifier being connected to the gain control input of the oscillator which constitutes the output of the detector and supplies a signal representative of the remoteness of the conducting mass.
Thus, the oscillator is looped between its output (taken from the terminals of the inductance) and its gain control input in a manner such that the amplitude of the electrical voltage at the terminals of the coil is always restored to a substantially constant value which is the reference amplitude (apart from a variation value which is the differential voltage at the input of the differential amplifier and which is lower the higher the gain of the amplifier).
In this looped system, the gain of the oscillator is increased if the voltage at the terminals of the coil is too low with respect to the reference amplitude, in the reverse case, it is reduced. The gain control voltage of the oscillator is thus representative of the proximity of the part consisting of conducting material: the closer the part to the coil, the higher the damping and the more it is necessary to increase the gain of the oscillator in order to restore the oscillations to a constant reference amplitude.
The presence of a mass and its greater or lesser proximity are measured directly from the amplitude of the voltage at the gain control input of the oscillator.
One thus obtains a proximity detector which is able either to detect the passage of a conducting part with wide tolerances as regards the distance at which the part passes with respect to the coil and as regards other variable parameters, such as temperature, the no load coefficient of over voltage of the LC circuit etc.. . or to detect and differentiate between the passage of parts at different distances from the coil. In the latter case,
it is possible to provide threshold circuits for
detecting signals corresponding to a given
proximity or a given interval of proximity.
The invention will now be further described by
way of example with reference to the
accompanying drawings in which: Fig. 1 is a block diagram of a proximity detector
formed according to the invention;
Fig. 2 is a time diagram of the output voltage of
the detector in Fig. 1;
Fig. 3a shows a variation of the use of the
detector of Fig. 1, and
Fig. 3b shows the corresponding output signal;
and
Fig. 4 is a detailed circuit diagram of a proximity
detector formed according to the invention.
Figure 1 is a simplified diagram of a detector
intended for detecting the passage of teeth 10
consisting of electrically conducting material,
projecting radially outwards on the periphery of a
rotating disc 12.
To this end, the detector comprises an electrical
coil 14 located in the vicinity of the path of
rotation of the teeth 10. The coil 14 is supplied
with alternating current by an oscillator 1 6 and
the passage of a conducting mass (teeth 10) in the
vicinity of the coil has the effect of damping the
oscillations in the coil all the more the closer the
conducting mass passes with respect to the coil
and the higher the frequency.
In the present invention, the oscillator 1 6 is a variable gain oscillator. It comprises a gain control
input E able to receive a direct voltage and the higher the voltage at the input E, the greater the
gain of the oscillator.
It is arranged that the oscillator is looped to
itself so that if the voltage at the terminals of the coil 14 decreases excessively, the gain is increased and if the voltage increases, the gain is decreased, the voltage at the terminals of the coil finally remaining constant due to a suitable variation of the gain of the oscillator whatever the damping of the coil 14.
The absence or presence of a conducting mass and even more precisely its greater or lesser proximity with respect to the coil are detected by examining the voltage which it is necessary to apply to the gain control input of the oscillator 1 6 in order to keep the voltage at the terminals of the coil 14 at a predetermined value.
The output of the proximity detector according to the invention is thus provided on the gain control input E of the oscillator 16, whereas in the prior art (where the oscillator has a fixed gain) the output is taken from the terminals of the coil 14 itself.
In order to obtain a constant amplitude at the terminals of the coil, despite the damping variations created by the approach or withdrawal of a conducting mass, an amplitude detector 1 8 is provided having an input connected to the terminals of the coil 14 and an output connected to one input of a differential amplifier 20, whereof the other input is connected to a reference voltage source 22.The output of the amplifier 20 is connected to the gain control input E of the oscillator 1 6. The amplifier 20 has a high gain so that the differential voltage between these inputs is always low and consequently the gain of the oscillator 1 6 is permanently controlled so that the output voltage of the amplitude detector 18 is always virtually equal to the voltage of the reference source 22 (except fot the variation voltage at the input terminals of the amplifier).
According to the preceding explanations, it will be understood that the output voltage of the detector Vs taken from the output of the amplifier 20, i.e. from the gain control input E of the oscillator 1 6, increases if the voltage at the terminals of the coil 14 decreases, i.e. if the damping of the latter increases owing to the approach of a conducting mass. On the contrary, the output voltage Vs decreases if the voltage at the terminals of the coil increases due to a reduction of the damping, i.e. to the withdrawal of a conducting mass.
Figure 2 shows the output voltage Vs of the detector which is obtained with the system of figure 1 for a disc 12 rotating uniformly and teeth
10 uniformly spaced on the periphery of the disc
12. One obtains uniform square-waves, whereof the peaks correspond to the passage of successive teeth in front of the coil 14.
It will be noted that with this method of operation, a square wave voltage Vs is obtained at the output of the detector for a very wide range of proximities between the teeth 10 and the coil 14, there being no necessity for the distance between the coil 14 and the path of the teeth 10 to be strictly fixed in order to allow a detection of the passage of each tooth. In simple terms, if the teeth pass at too great a distance, the square waves Vs will be of relatively low amplitude, whereas if the teeth pass very close to the coil 14, the square waves will have a greater amplitude.
The present invention makes it possible not only to obtain a signal which is significant for a wide range of distances between the coil and the path of the teeth 10, but also to discriminate between teeth of different height, i.e. passing at a different distance from the coil 14.
In effect, in the example illustrated in figure 3a, a disc is provided comprising teeth 10' alternating with teeth 10" of different height, so that the teeth 10' pass at a distance dl from the coil, whereas the teeth 1 O" pass at a distance d2 from the coil.
The damping caused by the teeth 10" is greater than the damping caused by the teeth 10' and consequently, in order to restore the electrical signal at the terminals of the coil 14 to the constant reference value determined by the source 22, it is necessary to provide a higher gain of the oscillator at the time of passage of the teeth 10" than at the time of passage of the teeth 10'.
In figure 3b, this results in a signal form Vs of alternating square waves of different amplitudes,
Al being the amplitude of the square waves corresponding to the passage of a tooth 10' and
A2 being the voltage amplitude corresponding to the passage of a tooth 10". Due to a detection of the level of the square waves, it is possible to
effect a discrimination between the teeth 10' and
10", or more generally between parts passing at different distances from the coil 14.
Details of an embodiment of the detector comprising a controlled oscillator according to the invention are shown in figure 4.
The coil 14 is connected in parallel to a capacitor C1 in order to constitute a resonant circuit LC serving to keep an oscillator in oscillation, at a frequency determined by the resonance frequency of the circuit, said oscillator comprising two transistors Q2 and Q4, whereof the collectors are each connected to a terminal of the LC circuit, the collector of one of the transistors Q2 being connected to a terminal of the LC circuit by the intermediary of two diodes
CR2 and CR3 in series. The terminal of the LC circuit connected to the collector of one of the transistors is also connected through the intermediary of a resistor (respectively R6, R3) to the base of the other transistor in order to constitute the oscillating circuit.The bases of the transistors 02 and Q4 also receive positive continuous polarisation through the intermediary of resistors R2 and R5.
Charging of the oscillator and thus its gain may be adjusted by means of a transistor Q3 provided with an emitter resistor R4 and connected in series with the two other transistors Q2 and Q4 and the base of the transistor Q3 constitutes the gain control input E of the oscillator which is connected to the output of the differential amplifier 20 through the intermediary of the resistors in series R7 and R10, in conjunction with
R8 and Q5 which constitute a certain temperature compensation.
On its inverting input, the amplifier 20 receives a direct voltage, established by means of a Zener diode CR6 and a divider bridge R30, R12, R13, R14, the resistor R13 being a variable resistor making it possible to adjust the reference voltage applied in this way to the inverting input of the amplifier.
The divider bridge is formed not only by the resistors R30 and R12 to R14, but also from a stabilized voltage defined, between + and by a resistor R1 and a Zener diode CR1. The cathode of the latter is connected through a resistor R28, on the one hand to a diode CR5 connected to the negative pole, on the other hand to a resistor R23, also connected to the common point of R13 and
R14. The non-inverting input charged buy a resistor R 1 5 is connected to a detector of the amplitude of the oscillations at the terminals of the LC circuit and this detector is constituted by a charge capacitor C2 and a charge resistor R 1 connected in series to each other and in series to a rectifying diode CR4.The voltage which is applied to the terminals of this series connection is essentially that which is taken from the terminals of the coil 14, a transistor Q6 connected with a common collector and provided with an emitter resistor R9 simply being provided for preventing unnecessary charging of the oscillator by the amplitude
detector. The non-inverting input of the differential amplifier 20 is connected to a terminal of the charge capacitor C2 of the amplitude detector and the voltage which appears on this input corresponds to the peak voltage of the oscillations at the terminals of the coil 14. The feedback to the amplifier 20 at its non-inverting input is formed by a parallel cell R29-C3.
A particular embodiment of the detector comprising a controlled gain oscillator according to the invention has thus been described. Naturally other embodiments could be provided without diverging from the scope of the invention.
This detector may be used particularly for constructing electronic ignition systems for explosion engines where position detectors are required for controlling the rotation of the drive shaft and consequently controlling the ignition of the explosive mixture in the cylinders of the engine.
Claims (6)
1. A proximity detector comprising an oscillator charged by a tuned LC circuit having an electrical coil able to induce eddy current in a conducting part passing in the vicinity of the coil, thus creating damping of the oscillating electrical signals which travel through the coil, the oscillator having a variable gain and comprising a gain control input, looping between an output of the oscillator and said input being provided in order to keep the amplitude of the oscillations at the terminals of the coil at a substantially constant value, a detector of the amplitude of the electrical oscillations at the terminals of the coil being provided, the detector being connected to the terminals of the coil, the output of the amplitude detector and the output of a source of reference voltage being connected respectively to the inputs of a differential amplifier, the output of the differential amplifier having voltage varying in proportion to the damping of the oscillations, and the output of said differential amplifier being connected to the gain control input of the oscillator which constitutes the output of the detector and supplies a signal representative of the remoteness of the conducting mass.
2. A proximity detector as claimed in claim 1, in which the amplitude detector comprises a filtering circuit supplying a voltage equal to the peak value of the alternating voltage at the terminals of the coil.
3. A proximity detector as claimed in Claim 1 or
Claim 2, in which the oscillator is supplied by a variable current source controlled by the output of the differential amplifier.
4. A proximity detector as claimed in any one preceding claim, in which means are provided for detecting the amplitude of the voltage applied to the gain control input of the oscillator.
5. A proximity detector as claimed in any one preceding claim, in which amplitude discrimination means are provided at the output of the detector, for facilitating the differentiated detection of the passage of parts at different proximities from the coil.
6. A proximity detector, substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8000602A FR2473700A1 (en) | 1980-01-11 | 1980-01-11 | PROXIMITY SENSOR |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2067295A true GB2067295A (en) | 1981-07-22 |
| GB2067295B GB2067295B (en) | 1983-12-14 |
Family
ID=9237456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8100406A Expired GB2067295B (en) | 1980-01-11 | 1981-01-08 | Proximity detector |
Country Status (6)
| Country | Link |
|---|---|
| AR (1) | AR226089A1 (en) |
| DE (1) | DE3100432A1 (en) |
| ES (1) | ES498551A0 (en) |
| FR (1) | FR2473700A1 (en) |
| GB (1) | GB2067295B (en) |
| IT (1) | IT1167809B (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0076982A1 (en) * | 1981-10-01 | 1983-04-20 | Mitsubishi Denki Kabushiki Kaisha | Ignition system for internal combustion engines |
| EP0077483A1 (en) * | 1981-10-01 | 1983-04-27 | Mitsubishi Denki Kabushiki Kaisha | Ignition circuit for internal combustion engines |
| FR2538895A1 (en) * | 1982-12-30 | 1984-07-06 | Owens Illinois Inc | POSITION DETECTING APPARATUS FOR A GLAZED ARTICLE FORMING MACHINE |
| GB2156524A (en) * | 1984-03-22 | 1985-10-09 | Cambridge Electronic Ind | Tachogenerators |
| EP0250864A3 (en) * | 1986-05-28 | 1988-12-28 | Still Gmbh | Inductive sensor arrangement |
| GB2222257A (en) * | 1988-07-19 | 1990-02-28 | Glacier Metal Co Ltd | Displacement sensor |
| GB2231342A (en) * | 1989-04-19 | 1990-11-14 | Truetzschler & Co | Safety system for openable parts of protective covers in textile machines |
| EP0467753A1 (en) * | 1990-07-20 | 1992-01-22 | Schlumberger Industries | Device for detecting the movement of a rotating element such as the turbine in a water meter |
| EP0489350A1 (en) * | 1990-12-03 | 1992-06-10 | VOGT electronic Aktiengesellschaft | Apparatus for static and/or dynamic length and/or angle measurement |
| WO1996041134A3 (en) * | 1995-06-07 | 1997-02-06 | Peter U Wolff | Method and apparatus for sensing proximity or position of an object using near-field or magnetic effects |
| WO2001069168A1 (en) * | 2000-03-14 | 2001-09-20 | Isis Innovation Limited | Position and electromagnetic field sensor |
| US7394243B2 (en) * | 2001-03-15 | 2008-07-01 | Omron Corporation | Proximity sensor |
| WO2011152946A1 (en) * | 2010-06-03 | 2011-12-08 | Allegro Microsystems, Inc. | Motion sensor, method, and computer-readable storage medium providing a motion sensor that can rapidly calibrate gains |
| US8446146B2 (en) | 2010-06-03 | 2013-05-21 | Allegro Microsystems, Inc. | Motion sensor, method, and computer-readable storage medium providing a motion sensor with a validated output signal from the motion sensor |
| US8450996B2 (en) | 2010-06-03 | 2013-05-28 | Allegro Microsystems, Llc | Motion sensor, method, and computer-readable storage medium providing a motion sensor with a magnetic field sensing element for generating a magnetic field signal and a state processor to identify a plurality of states corresponding to ranges of values of the magnetic field signal having a reduced amount of state chatter |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59141001A (en) * | 1983-02-01 | 1984-08-13 | Mitsubishi Electric Corp | Detecting method for effective end position of metallic pipe |
| DE3935594C2 (en) * | 1989-10-26 | 1997-04-30 | Hella Kg Hueck & Co | Circuit arrangement for measuring and evaluating the speed of a DC motor or the adjustment path of a DC motor drive in a motor vehicle |
| DE4303222A1 (en) * | 1993-02-04 | 1994-08-11 | Krupp Foerdertechnik Gmbh | Laying vehicle for layable bridges |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3387776A (en) * | 1964-08-07 | 1968-06-11 | Rank Organisation Ltd | Gauging device including feedback means applying a signal comparison means to control the level of a detected signal |
| DE1951137B2 (en) * | 1969-10-10 | 1973-03-01 | lfm electronic gerate GmbH & Co KG, 4300 Essen | ELECTRONIC, CONTACTLESS SWITCHING DEVICE |
| DE1952679A1 (en) * | 1969-10-20 | 1971-04-29 | Lochstampfer Horst Dipl Ing | Electronic proximity initiator |
| GB1448877A (en) * | 1973-09-04 | 1976-09-08 | Weber G | Electronic switching device for sensing a body and for converting such sensing into an electrical signal |
| FR2287676A1 (en) * | 1974-10-10 | 1976-05-07 | Itt | Magnetic proximity detector for metal parts - has oscillator with control input and resonant circuit emitting signal |
| GB1561641A (en) * | 1976-08-05 | 1980-02-27 | Redland Automation Ltd | Presence detector apparatus |
| US4255789A (en) * | 1978-02-27 | 1981-03-10 | The Bendix Corporation | Microprocessor-based electronic engine control system |
| DE2831598C2 (en) * | 1978-07-19 | 1986-01-02 | Robert Bosch Gmbh, 7000 Stuttgart | Device for distance and speed measurement |
-
1980
- 1980-01-11 FR FR8000602A patent/FR2473700A1/en active Granted
- 1980-12-23 ES ES498551A patent/ES498551A0/en active Granted
-
1981
- 1981-01-07 AR AR283895A patent/AR226089A1/en active
- 1981-01-08 IT IT09309/81A patent/IT1167809B/en active
- 1981-01-08 GB GB8100406A patent/GB2067295B/en not_active Expired
- 1981-01-09 DE DE19813100432 patent/DE3100432A1/en active Granted
Cited By (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0076982A1 (en) * | 1981-10-01 | 1983-04-20 | Mitsubishi Denki Kabushiki Kaisha | Ignition system for internal combustion engines |
| EP0077483A1 (en) * | 1981-10-01 | 1983-04-27 | Mitsubishi Denki Kabushiki Kaisha | Ignition circuit for internal combustion engines |
| FR2538895A1 (en) * | 1982-12-30 | 1984-07-06 | Owens Illinois Inc | POSITION DETECTING APPARATUS FOR A GLAZED ARTICLE FORMING MACHINE |
| GB2156524A (en) * | 1984-03-22 | 1985-10-09 | Cambridge Electronic Ind | Tachogenerators |
| EP0250864A3 (en) * | 1986-05-28 | 1988-12-28 | Still Gmbh | Inductive sensor arrangement |
| GB2222257A (en) * | 1988-07-19 | 1990-02-28 | Glacier Metal Co Ltd | Displacement sensor |
| GB2231342B (en) * | 1989-04-19 | 1993-06-16 | Truetzschler Gmbh & Co Kg | Safety system for openable parts of protective covers in textile machines |
| US5050271A (en) * | 1989-04-19 | 1991-09-24 | Trutzschler Gmbh & Co. Kg | Rotation and standstill responsive locking device for an access door of a textile machine |
| GB2231342A (en) * | 1989-04-19 | 1990-11-14 | Truetzschler & Co | Safety system for openable parts of protective covers in textile machines |
| EP0467753A1 (en) * | 1990-07-20 | 1992-01-22 | Schlumberger Industries | Device for detecting the movement of a rotating element such as the turbine in a water meter |
| FR2664973A1 (en) * | 1990-07-20 | 1992-01-24 | Schlumberger Ind Sa | DEVICE FOR DETECTING THE ROTATION OF A ROTATING ELEMENT SUCH AS THE TURBINE OF A WATER METER. |
| US5187989A (en) * | 1990-07-20 | 1993-02-23 | Schlumberger Industries | Apparatus for detecting rotation of a rotary element such as the spinner of a water meter |
| EP0489350A1 (en) * | 1990-12-03 | 1992-06-10 | VOGT electronic Aktiengesellschaft | Apparatus for static and/or dynamic length and/or angle measurement |
| US5670886A (en) * | 1991-05-22 | 1997-09-23 | Wolf Controls Corporation | Method and apparatus for sensing proximity or position of an object using near-field effects |
| WO1996041134A3 (en) * | 1995-06-07 | 1997-02-06 | Peter U Wolff | Method and apparatus for sensing proximity or position of an object using near-field or magnetic effects |
| EP1666834A1 (en) * | 2000-03-14 | 2006-06-07 | Isis Innovation Limited | Position and electromagnetic field sensor |
| US6984994B2 (en) * | 2000-03-14 | 2006-01-10 | Isis Innovation Limited | Position and electromagnetic field sensor |
| WO2001069168A1 (en) * | 2000-03-14 | 2001-09-20 | Isis Innovation Limited | Position and electromagnetic field sensor |
| EP1666835A1 (en) * | 2000-03-14 | 2006-06-07 | Isis Innovation Limited | Position and electromagnetic field sensor |
| US7394243B2 (en) * | 2001-03-15 | 2008-07-01 | Omron Corporation | Proximity sensor |
| WO2011152946A1 (en) * | 2010-06-03 | 2011-12-08 | Allegro Microsystems, Inc. | Motion sensor, method, and computer-readable storage medium providing a motion sensor that can rapidly calibrate gains |
| US8446146B2 (en) | 2010-06-03 | 2013-05-21 | Allegro Microsystems, Inc. | Motion sensor, method, and computer-readable storage medium providing a motion sensor with a validated output signal from the motion sensor |
| US8450996B2 (en) | 2010-06-03 | 2013-05-28 | Allegro Microsystems, Llc | Motion sensor, method, and computer-readable storage medium providing a motion sensor with a magnetic field sensing element for generating a magnetic field signal and a state processor to identify a plurality of states corresponding to ranges of values of the magnetic field signal having a reduced amount of state chatter |
| US8680848B2 (en) | 2010-06-03 | 2014-03-25 | Allegro Microsystems, Llc | Motion sensor, method, and computer-readable storage medium providing a motion sensor that adjusts gains of two circuit channels to bring the gains close to each other |
| US8686720B2 (en) | 2010-06-03 | 2014-04-01 | Allegro Microsystems, Llc | Motion sensor, method, and computer-readable storage medium providing a motion sensor with a validated output signal from the motion sensor |
| US9170128B2 (en) | 2010-06-03 | 2015-10-27 | Allegro Microsystems, Llc | Motion sensor, method, and computer-readable storage medium providing a motion sensor with a vibration processor to set a state of a flag in response to selected ones of a plurality of test results being indicative of a passing conditions |
| US9175981B2 (en) | 2010-06-03 | 2015-11-03 | Allegro Microsystems, Llc | Motion sensor, method, and computer-readable storage medium providing a motion sensor generating a signal having signal states with a reduced amount of state chatter |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3100432A1 (en) | 1982-01-21 |
| IT8109309A0 (en) | 1981-01-08 |
| ES8202143A1 (en) | 1982-01-01 |
| IT1167809B (en) | 1987-05-20 |
| AR226089A1 (en) | 1982-05-31 |
| ES498551A0 (en) | 1982-01-01 |
| FR2473700B1 (en) | 1983-12-23 |
| GB2067295B (en) | 1983-12-14 |
| DE3100432C2 (en) | 1989-06-15 |
| FR2473700A1 (en) | 1981-07-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19990108 |