DE3727265A1 - Inductive distance pickup - Google Patents

Inductive distance pickup

Info

Publication number
DE3727265A1
DE3727265A1 DE19873727265 DE3727265A DE3727265A1 DE 3727265 A1 DE3727265 A1 DE 3727265A1 DE 19873727265 DE19873727265 DE 19873727265 DE 3727265 A DE3727265 A DE 3727265A DE 3727265 A1 DE3727265 A1 DE 3727265A1
Authority
DE
Germany
Prior art keywords
resonant circuit
parallel resonant
secondary coil
parallel
primary
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.)
Ceased
Application number
DE19873727265
Other languages
German (de)
Inventor
Volker Pretzlaff
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leopold Kostal GmbH and Co KG
Original Assignee
Leopold Kostal GmbH and Co KG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Leopold Kostal GmbH and Co KG filed Critical Leopold Kostal GmbH and Co KG
Priority to DE19873727265 priority Critical patent/DE3727265A1/en
Publication of DE3727265A1 publication Critical patent/DE3727265A1/en
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • G01D5/22—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 differentially influencing two coils
    • G01D5/2291—Linear or rotary variable differential transformers (LVDTs/RVDTs) having a single primary coil and two secondary coils
    • 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
    • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/028—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure
    • G01D3/036—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure on measuring arrangements themselves
    • 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
    • G01D5/204—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 mutual induction between two or more coils
    • G01D5/2046—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 mutual induction between two or more coils by a movable ferromagnetic element, e.g. a core

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)

Abstract

An inductive distance pickup with preferably linearly alterable coupling between a primary coil and a secondary coil. The technical problem is to refine an inductive distance pickup of the type in such a way, that it becomes significantly simpler to operate and a quasi-complete temperature compensation is ensured. The secondary coil (3) has a capacitor (5) connected in parallel to it to form a parallel resonant circuit, to the resonant frequency of which the primary excitation frequency is tuned. The excitation voltage is a square-wave pulse train. <IMAGE>

Description

Die Erfindung betrifft einen induktiven Wegaufnehmer mit vorzugs­ weise linear veränderlicher Kopplung zwischen einer Primärspule und einer Sekundärspule.The invention relates to an inductive displacement sensor with preference wise linearly variable coupling between a primary coil and a secondary coil.

Derartige induktive Wegaufnehmer sind insbesondere als linear veränderliche Differenzialtransformatoren oder Kurzschlußringgeber aus­ gebildet. Bei bekannten Anordnungen wird in die Primärspule eine Si­ nusspannung eingespeist. Diese Sinusspannung wird linear veränderlich auf die Sekundärseite gekoppelt. Die Sekundärspannung wird demodu­ liert. Eine solche Anordnung weist einen Temperaturgang sowohl bei der Erzeugung der primären Sinusspannung als auch in dem Demodulator auf. Infolgedessen ist eine Temperaturkompensation der bekannten An­ ordnung sehr aufwendig.Such inductive displacement transducers are particularly linear variable differential transformers or short-circuit ring encoders educated. In known arrangements, an Si is in the primary coil nut voltage fed. This sine voltage becomes linearly variable coupled to the secondary side. The secondary voltage becomes demodu liert. Such an arrangement has both a temperature response the generation of the primary sine voltage as well as in the demodulator on. As a result, temperature compensation is known order very complex.

Aufgabe der Erfindung ist es, einen induktiven Wegaufnehmer der­ art weiterzubilden, daß derselbe wesentlich einfacher zu betreiben und eine quasi vollständige Temperaturkompensation gewährleistet ist.The object of the invention is to provide an inductive displacement sensor Art to train that the same much easier to operate and virtually complete temperature compensation is guaranteed.

Diese Aufgabe wird nach der Erfindung dadurch gelöst, daß der Se­ kundärspule ein Kondensator zur Bildung eines Parallelschwingkreises parallel geschaltet ist, auf dessen Resonanzfrequenz die primäre Erre­ gerfrequenz abgestimmt ist, und daß die Erregerspannung eine Rechteck­ impulsfolge ist.This object is achieved according to the invention in that the Se secondary coil a capacitor to form a parallel resonant circuit is connected in parallel, on the resonance frequency of the primary excitation gerfrequenz is tuned, and that the excitation voltage is a rectangle is pulse train.

Eine Rechteckimpulsfolge läßt sich in einfacher Weise temperatur­ stabil erzeugen, so daß primärseitig immer ein temperaturunabhängiges Erregerssignal zur Verfügung steht. Dieses Erregersignal stößt mit den Impulsflanken der übertragenen Impulsgruppen den Parallelschwingkreis zu Schwingungen an, deren Größe von der linearabhängigen Kopplung ab­ hängt. Da der Parallelschwingkreis in Resonanz betrieben wird, erge­ ben sich hohe Sekundärspannungen. Diese Sekundärspannungen werden in einem Diskriminator ausgewertet.A rectangular pulse train can be temperature easily generate stable, so that always a temperature-independent on the primary side Excitation signal is available. This excitation signal hits the Pulse edges of the transmitted pulse groups the parallel resonant circuit to vibrations, the size of which depends on the linearly dependent coupling hangs. Since the parallel resonant circuit is operated in resonance, erge there are high secondary voltages. These secondary voltages are in  evaluated by a discriminator.

In Weiterbildung der Erfindung ist vorgesehen, daß der Kondensa­ tor des Parallelschwingkreises einen entgegengesetzten Temperaturko­ effizienten wie die Sekundärspule hat, so daß die Resonanzfrequenz des Parallelschwingkreises im wesentlichen temperaturunabhängig ist. Hierdurch erzielt man in einfacher und vollständiger Weise eine Tempe­ aturkompensation auch auf der Sekundärseite.In a development of the invention it is provided that the condenser gate of the parallel resonant circuit an opposite Temperaturko efficient as the secondary coil has, so the resonance frequency of the parallel resonant circuit is essentially independent of temperature. In this way, a temperature is achieved in a simple and complete manner Ature compensation also on the secondary side.

Eine Ausführungsform der Erfindung wird im folgenden unter Bezug­ nahme auf die Zeichnung erläutert, die einen induktiven Wegaufnehmer anhand eines linear veränderlichen Differenzialtransfor­ mators erläutert.An embodiment of the invention is hereinafter referred to took explained on the drawing, which is an inductive Displacement transducer using a linearly variable differential transform mators explained.

In der Figur ist ein linear veränderlicher Differenzialtransfor­ mator dargestellt.In the figure is a linearly variable differential transform mator shown.

Derselbe umfaßt eine Primärspule 1, ein magnetisches Koppelele­ ment 2 und zwei Sekundärspulen 3. Das Koppelelement 2 verändert die Kopplung, so daß dadurch eine Wegmessung möglich ist.The same includes a primary coil 1 , a magnetic Koppelele element 2 and two secondary coils 3rd The coupling element 2 changes the coupling, so that a distance measurement is possible.

An die Primärspule ist erfindungsgemäß ein Impulsgenerator 4 zur Erzeugung einer Rechteckimpulsfolge angeschlossen, der mit seiner Im­ pulsfrequenz den Sekundärschwingkreis nahe seiner Resonanzfrequenz er­ regt. Eine bevorzugte Impulsfrequenz liegt im Bereich von etwa 10 kHz.According to the invention, a pulse generator 4 is connected to the primary coil for generating a square-wave pulse train which, with its pulse frequency, excites the secondary resonant circuit near its resonance frequency. A preferred pulse frequency is in the range of about 10 kHz.

An die Sekundärspulen 3 ist ein Kondensator 5 angekoppelt, so daß auf der Sekundärseite ein Parallelschwingkreis gebildet ist, auf dessen Resonanzfrequenz die Impulsfrequenz des Impulsgenerators 4 ab­ gestimmt ist. Der Parallelschwingkreis ist an einen Diskriminator 6 angeschlossen, der die Spannung der sekundärseitigen Schwingung aus­ wertet und so ein Wegsignal auslöst.A capacitor 5 is coupled to the secondary coils 3 , so that a parallel resonant circuit is formed on the secondary side, on the resonance frequency of which the pulse frequency of the pulse generator 4 is tuned. The parallel resonant circuit is connected to a discriminator 6 , which evaluates the voltage of the secondary-side vibration and thus triggers a path signal.

Die Impulsgruppen der Rechteckimpulsfolge weisen Impulsflanken auf, die den Parallelschwingkreis anregen. Die Größe der Anregung wird durch die Lage des Koppelelements 2 bestimmt. So kann man in den Diskriminator 6 die Größe der Resonanzschwingung und damit die Lage des Koppelelements 2 auswerten.The pulse groups of the rectangular pulse train have pulse edges that excite the parallel resonant circuit. The size of the excitation is determined by the position of the coupling element 2 . In this way, the size of the resonance oscillation and thus the position of the coupling element 2 can be evaluated in the discriminator 6 .

Der Impulsgenerator 4 arbeitet temperaturunabhängig und stellt temperaturunabhängig eine Rechteckimpulsfolge gleichbleibender Ampli­ tude zur Verfügung. Die Sekundärspulen 3 haben einen Temperaturgang, so daß zunächst die Resonanzfrequenz des Parallelschwingkreises ent­ sprechend einen Temperaturgang aufweist. Es ist ohne weiteres mög­ lich, den Kondensator 5 mit einem entgegengesetzten Temperaturgang auszustatten, so daß der Parallelschwingkreis insgesamt keinen Tempe­ raturgang aufweist. Man erzielt so eine weitgehend temperaturstabile Ausgangsspannung des induktiven Wegaufnehmers.The pulse generator 4 works independently of temperature and provides a rectangular pulse sequence of constant amplitude independent of temperature. The secondary coils 3 have a temperature response, so that first the resonance frequency of the parallel resonant circuit accordingly has a temperature response. It is readily possible Lich to equip the capacitor 5 with an opposite temperature response so that the parallel resonant circuit has no temperature response as a whole. A largely temperature-stable output voltage of the inductive displacement sensor is achieved in this way.

Der Wegaufnehmer nach der Erfindung arbeitet ohne weiteres in einem Zweig ausgehend von der Mittellage des Koppelelements. Wenn man beide Zweige der Lageänderung des Koppelelements auswerten will, so muß man auch die Phase der Resonanzschwingung auswerten, da sich in der neutralen Stellung des Koppelelements die Phase der Resonanz­ schwingung umkehrt.The displacement sensor according to the invention works easily in a branch starting from the central position of the coupling element. If wants to evaluate both branches of the change in position of the coupling element, so one must also evaluate the phase of the resonance oscillation, because in the neutral position of the coupling element, the phase of the resonance vibration reverses.

Die Anordnung nach der Erfindung läßt sich auch in entsprechen­ der Weise bei einem Kurzschlußringgeber anwenden.The arrangement according to the invention can also correspond to apply the way to a short-circuit ring encoder.

Claims (3)

1. Induktiver Wegaufnehmer mit vorzugsweise linear veränderli­ cher Kopplung zwischen einer Primärspule und einer Sekundärspule, da­ durch gekennzeichnet, daß der Sekundärspule (3) ein Kondensator (5) zur Bildung eines Parallelschwingkreises parallel geschaltet ist, auf dessen Resonanzfrequenz die primäre Erregerfrequenz abgestimmt ist, und daß die Erregerspannung eine Rechteckimpulsfolge ist.1. Inductive displacement transducer, preferably with a linearly variable coupling between a primary coil and a secondary coil, characterized in that the secondary coil ( 3 ) has a capacitor ( 5 ) connected in parallel to form a parallel resonant circuit, the resonance frequency of which is matched to the primary excitation frequency, and that the excitation voltage is a rectangular pulse train. 2. Wegaufnehmer nach Anspruch 1, dadurch gekennzeichnet, daß der Parallelschwingkreis an einen Diskriminator (6) zur Ermittlung der In­ tensität der Schwingung angeschlossen ist.2. Position sensor according to claim 1, characterized in that the parallel resonant circuit is connected to a discriminator ( 6 ) for determining the intensity of the vibration. 3. Wegaufnehmer nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Kondensator (5) des Parallelschwingkreises einen entgegenge­ setzten Temperaturkoeffizienten wie die Sekundärspule (3) hat, so daß die Resonanzfrequenz des Parallelschwingkreises im wesentlichen tempe­ raturunabhängig ist.3. Transducer according to claim 1 or 2, characterized in that the capacitor ( 5 ) of the parallel resonant circuit has an oppositely set temperature coefficient as the secondary coil ( 3 ), so that the resonance frequency of the parallel resonant circuit is essentially temperature-independent.
DE19873727265 1987-08-15 1987-08-15 Inductive distance pickup Ceased DE3727265A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19873727265 DE3727265A1 (en) 1987-08-15 1987-08-15 Inductive distance pickup

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Application Number Priority Date Filing Date Title
DE19873727265 DE3727265A1 (en) 1987-08-15 1987-08-15 Inductive distance pickup

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DE3727265A1 true DE3727265A1 (en) 1989-02-23

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3927833A1 (en) * 1989-08-23 1991-02-28 Bosch Gmbh Robert MEASURING CIRCUIT AND APPLICATION THEREOF, IN PARTICULAR WITH INDUCTIVE WAYERS
DE4105642A1 (en) * 1991-02-22 1992-09-03 Rainer Thiessen Temp. compensation for inductive and capacitive transducers for distance measurement - using control signal derived from input parameters to influence evaluation electronics and minimise temp. dependency
DE19635298A1 (en) * 1996-08-30 1998-03-05 Schenck Process Gmbh Measurement coil esp for use in oscillator loop e.g. for machine monitoring
EP0992765A1 (en) * 1998-10-09 2000-04-12 Mahr GmbH Inductive position measurement system
WO2017100024A1 (en) * 2015-12-09 2017-06-15 Probe Holdings, Inc. Inductive differential position sensor with constant current drive
DE102016223940A1 (en) * 2016-12-01 2018-06-07 Autoliv Development Ab Belt buckle for a seat belt device
CN112414289A (en) * 2020-11-09 2021-02-26 安徽感航电子科技有限公司 Design method of high-stability displacement sensor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4100480A (en) * 1976-08-20 1978-07-11 Dataproducts Corporation Position and velocity sensors
DE3603565A1 (en) * 1985-02-12 1986-08-14 Sokkisha Co., Ltd., Tokio/Tokyo MEASURING VALUE WITH MAGNETIC SCALE

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4100480A (en) * 1976-08-20 1978-07-11 Dataproducts Corporation Position and velocity sensors
DE3603565A1 (en) * 1985-02-12 1986-08-14 Sokkisha Co., Ltd., Tokio/Tokyo MEASURING VALUE WITH MAGNETIC SCALE

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3927833A1 (en) * 1989-08-23 1991-02-28 Bosch Gmbh Robert MEASURING CIRCUIT AND APPLICATION THEREOF, IN PARTICULAR WITH INDUCTIVE WAYERS
DE3927833C2 (en) * 1989-08-23 1998-07-02 Bosch Gmbh Robert Measuring circuit and application of the same, especially with inductive displacement sensors
DE4105642A1 (en) * 1991-02-22 1992-09-03 Rainer Thiessen Temp. compensation for inductive and capacitive transducers for distance measurement - using control signal derived from input parameters to influence evaluation electronics and minimise temp. dependency
DE19635298A1 (en) * 1996-08-30 1998-03-05 Schenck Process Gmbh Measurement coil esp for use in oscillator loop e.g. for machine monitoring
EP0992765A1 (en) * 1998-10-09 2000-04-12 Mahr GmbH Inductive position measurement system
WO2017100024A1 (en) * 2015-12-09 2017-06-15 Probe Holdings, Inc. Inductive differential position sensor with constant current drive
GB2560471A (en) * 2015-12-09 2018-09-12 Probe Tech Services Inc Inductive differential position sensor with constant current drive
US10087740B2 (en) 2015-12-09 2018-10-02 Probe Technology Services, Inc. Caliper tool with constant current drive
GB2560471B (en) * 2015-12-09 2021-06-16 Probe Tech Services Inc Inductive differential position sensor with constant current drive
DE102016223940A1 (en) * 2016-12-01 2018-06-07 Autoliv Development Ab Belt buckle for a seat belt device
CN112414289A (en) * 2020-11-09 2021-02-26 安徽感航电子科技有限公司 Design method of high-stability displacement sensor

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