DE4019290A1 - Contactless sensing arrangement for media - has capacitance proximity switch with LF clock generator driving switch in supply line - Google Patents

Contactless sensing arrangement for media - has capacitance proximity switch with LF clock generator driving switch in supply line

Info

Publication number
DE4019290A1
DE4019290A1 DE19904019290 DE4019290A DE4019290A1 DE 4019290 A1 DE4019290 A1 DE 4019290A1 DE 19904019290 DE19904019290 DE 19904019290 DE 4019290 A DE4019290 A DE 4019290A DE 4019290 A1 DE4019290 A1 DE 4019290A1
Authority
DE
Germany
Prior art keywords
clock generator
switch
media
supply line
output stage
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.)
Withdrawn
Application number
DE19904019290
Other languages
German (de)
Inventor
Wolfgang Reinwardt
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.)
Polygraph Leipzig Kombinat Veb
Original Assignee
Polygraph Leipzig Kombinat Veb
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 Polygraph Leipzig Kombinat Veb filed Critical Polygraph Leipzig Kombinat Veb
Publication of DE4019290A1 publication Critical patent/DE4019290A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
    • G01F23/266—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors measuring circuits therefor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
    • G01B7/023—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring distance between sensor and object
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
    • G01F23/265—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors for discrete levels

Abstract

An arrangement for contactless sensing of media contains a capacitive proximity switch consisting of a probe head acting as a capacitor plate, an oscillator circuit, an amplifier forming a trigger and an output stage. The output stage's input is connected to a power supply. Its output is connected to a display and operation unit. A switch (10) connected to a low frequency clock generator (11) is connected in the line (8) between the power supply and the output stage. ADVANTAGE - Achieves compensation of effects of hysteresis at reduced circuit costs.

Description

Anwendungsgebiet der ErfindungField of application of the invention

Die Erfindung betrifft eine Einrichtung zum berührungslosen Abtasten von Medien mit einem kapazitiven Näherungsschalter.The invention relates to a device for non-contact scanning of media with a capacitive Proximity switch.

Charakteristik des bekannten Standes der TechnikCharacteristic of the known prior art

Kapazitive Näherungsschalter zur berührungslosen Abtastung von Medien bestehen bekanntermaßen aus einem als Kondensatorplatte wirkenden Sondenkopf, einer Oszillatorschaltung, einer als Trigger ausgebildeten Verstärkerschaltung und einer eingangsseitig mit einer Stromversorgung und ausgangsseitig mit einer Anzeige- und Betätigungseinheit verbundenen Ausgangsstufe. Die durch die Hysterese der Oszillatorschaltung bedingten Ungenauigkeiten in der Bestimmung des Pegelstandes des Mediums werden durch eine 2fache Kapazitätsmessung mittels Wechselstrombrückenschaltung kompensiert (DD 2 26 073). Nachteilig ist dabei, daß die negativen Auswirkungen der Hysterese auf das Meßergebnis durch sehr hohen Schaltungsaufwand mit erhöhter Fehleranfälligkeit ausgeglichen werden.Capacitive proximity switches for contactless scanning of media is known to consist of an as Capacitor plate acting probe head, one Oscillator circuit, one designed as a trigger  Amplifier circuit and one on the input side with a Power supply and output side with a display and Actuator connected Output stage. The hysteresis of the Inaccuracies in the oscillator circuit The level of the medium is determined by a Double capacity measurement using AC bridge circuit compensated (DD 2 26 073). The disadvantage here is that the negative effects of Hysteresis on the measurement result due to very high Circuit effort with increased susceptibility to errors be balanced.

Ziel der ErfindungAim of the invention

Ziel der Erfindung ist eine Verringerung des schaltungstechnischen Aufwandes bei kapazitiven Näherungsschaltern zur Kompensation der negativen Auswirkungen der Hysterese.The aim of the invention is to reduce the circuitry complexity with capacitive Proximity switches to compensate for the negative Effects of the hysteresis.

Darlegung des Wesens der ErfindungState the nature of the invention

Aufgabe der Erfindung ist die Schaffung einer Einrichtung zum berührungslosen Abtasten von Medien, mit kapazitiven Näherungsschaltern bei der die Hysterese unberücksichtigt bleibt.The object of the invention is to create a device for contactless scanning of media, with capacitive Proximity switches without taking the hysteresis into account remains.

Erfindungsgemäß wird die Aufgabe dadurch gelöst, daß bei einer Einrichtung zum berührungslosen Abtasten von Medien mit einem kapazitiven Näherungsschalter, bestehend aus einem als Kondensatorplatte wirkenden Sondenkopf, einer Oszillatorschaltung, einer als Trigger ausgebildeten Verstärkerschaltung und einer eingangsseitig über eine Versorgungsleitung mit einer Stromversorgung und ausgangsseitig mit einer Anzeige- und Betätigungseinheit verbundenen Ausgangsstufe in der Versorgungsleitung ein mit einem Taktgenerator verbundener Schalter angeordnet ist. Dabei ist der Taktgenerator als niederfrequente Signale liefernder Taktgenerator ausgebildet.According to the invention the object is achieved in that in a device for contactless scanning of Media with a capacitive proximity switch from a probe head acting as a capacitor plate, one Oscillator circuit, one designed as a trigger Amplifier circuit and one on the input side via a Supply line with a power supply and on the output side with a display and actuation unit connected output stage in the supply line  arranged with a clock generator connected switch is. The clock generator is a low frequency Clock generator providing signals.

AusführungsbeispielEmbodiment

Nachfolgend wird die Erfindung an einem Ausführungsbeispiel näher erläutert. Die Zeichnung zeigt die erfindungsgemäße Einrichtung.The invention is based on a Embodiment explained in more detail. The drawing shows the device according to the invention.

Die erfindungsgemäße Einrichtung ist oberhalb eines in einem Vorratsbehälter 1 befindlichen Mediums 2 angeordnet. Die Einrichtung besteht aus einem als Kondensatorplatte ausgebildeten Sondenkopf 3, einer dem Sondenkopf nachgeordneten Oszilltorschaltung 4, einer der Oszillatorschaltung 4 nachgeordneten, als Trigger ausgebildeten Verstärkerschaltung 5 und einer der Verstärkerschaltung 5 nachgeordneten Ausgangsstufe 6. Die Ausgangsstufe 6 ist ausgangsseitig mit einer Anzeige- und Betätigungseinheit 7 verbunden. In der Anzeige- und Betätigungseinheit 7 wird der Pegelstand des Mediums angezeigt und Schritte zum Anheben oder Absenken des Pegelstandes eingeleitet. Eingangsseitig ist die Ausgangsstufe über eine Versorgungsleitung 8 mit einer Stromversorgung 9 verbunden. In der Versorgungsleitung 8 ist ein Schalter 10 angeordnet, der mit einem Taktgenerator 11 verbunden ist. Der Taktgenerator 11 liefert niederfrequente Taktsignale zur taktweisen Betätigung des Schalters 10.The device according to the invention is arranged above a medium 2 located in a storage container 1 . The device consists of a plate formed as a capacitor probe head 3, a probe head the downstream Oszilltorschaltung 4, one of the oscillator circuit 4 downstream, designed as a trigger amplifier circuit 5 and the amplifier circuit 5 downstream output stage. 6 The output stage 6 is connected on the output side to a display and actuation unit 7 . The level of the medium is displayed in the display and actuation unit 7 and steps for raising or lowering the level are initiated. On the input side, the output stage is connected to a power supply 9 via a supply line 8 . A switch 10 is arranged in the supply line 8 and is connected to a clock generator 11 . The clock generator 11 supplies low-frequency clock signals for the cyclical actuation of the switch 10 .

Nachfolgend wird die Wirkungsweise der erfindungsgemäßen Einrichtung beschrieben.The mode of operation of the invention is described below Establishment described.

Durch die Annäherung des Mediums an den Sondenkopf (Abstand a) wird diese aktiviert, d. h. die Oszillatorschaltung 4 fängt an zu schwingen. Dieser Anschwingzustand bewirkt in der Anzeige- und Betätigungseinheit 7 eine Anzeige bzw. eine Betätigung zur Beeinflussung des Pegelstandes des Mediums. As the medium approaches the probe head (distance a), it is activated, ie the oscillator circuit 4 begins to oscillate. This start-up state causes a display or an actuation in the display and actuation unit 7 to influence the level of the medium.

Die Oszillatorschaltung schwingt infolge der Hysterese derselben weiter und der Schwingzustand wird erst bei einem Abstand b beendet.The oscillator circuit oscillates due to the hysteresis the same continues and the vibrational state is only at a distance b ended.

Durch die periodische Unterbrechung der Stromversorgung, der Taktgenerator betätigt den Schalter 10, wird der Schwingzustand der Oszillatorschaltung 4 nach dem Anschwingen beendet, d. h. ein Schwingen im Hysteresezustand unterbleibt.Due to the periodic interruption of the power supply, the clock generator actuates the switch 10 , the oscillation state of the oscillator circuit 4 is ended after the oscillation, ie oscillation in the hysteresis state does not take place.

Damit wird erreicht, daß eine Messung des Pegelstandes nur beim Abstand a erfolgt. Dadurch wird das Meßergebnis ohne großen Aufwand verbessert.This ensures that a measurement of the water level only at distance a. As a result, the measurement result is without great effort improved.

Aufstellung der verwendeten BezugszeichenList of the reference numerals used

1 Vorratsbehälter
2 Medium
3 Sondenkopf
4 Oszillatorschaltung
5 Verstärkerschaltung
6 Ausgangsstufe
7 Anzeige- und Betätigungseinheit
8 Versorgungsleitung
9 Stromversorgung
10 Schalter
11 Taktgenerator 1 storage container
2 medium
3 probe head
4 oscillator circuit
5 amplifier circuit
6 output stage
7 display and actuation unit
8 supply line
9 Power supply
10 switches
11 clock generator

Claims (2)

1. Einrichtung zum berührungslosen Abtasten von Medien mit einem kapazitiven Näherungsschalter, bestehend aus einem als Kondensatorplatte wirkenden Sondenkopf, einer Oszillatorschaltung, einer als Trigger ausgebildeten Verstärkerschaltung und einer eingangsseitig über eine Versorgungsleitung mit einer Stromversorgung und ausgangsseitig mit einer Anzeige- und Betätigungseinheit verbundenen Ausgangsstufe, dadurch gekennzeichnet, daß in der Versorgungsleitung (8) ein mit einem Taktgenerator (11) verbundener Schalter (10) angeordnet ist.1.Device for contactless scanning of media with a capacitive proximity switch, consisting of a probe head acting as a capacitor plate, an oscillator circuit, an amplifier circuit designed as a trigger, and an output stage connected to a power supply on the input side and to a display and actuation unit on the output side, thereby characterized in that a switch ( 10 ) connected to a clock generator ( 11 ) is arranged in the supply line ( 8 ). 2. Einrichtung zum berührungslosen Abtasten von Medien nach Anspruch 1, dadurch gekennzeichnet, daß der Taktgenerator (11) als niederfrequente Signale liefernder Taktgenerator ausgebildet ist.2. Device for contactless scanning of media according to claim 1, characterized in that the clock generator ( 11 ) is designed as a low-frequency signal supplying clock generator.
DE19904019290 1989-07-20 1990-06-16 Contactless sensing arrangement for media - has capacitance proximity switch with LF clock generator driving switch in supply line Withdrawn DE4019290A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DD33099089A DD286425A5 (en) 1989-07-20 1989-07-20 DEVICE FOR TOUCH-FREE SCANNING OF MEDIA

Publications (1)

Publication Number Publication Date
DE4019290A1 true DE4019290A1 (en) 1991-01-31

Family

ID=5611007

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19904019290 Withdrawn DE4019290A1 (en) 1989-07-20 1990-06-16 Contactless sensing arrangement for media - has capacitance proximity switch with LF clock generator driving switch in supply line

Country Status (2)

Country Link
DD (1) DD286425A5 (en)
DE (1) DE4019290A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4214300C1 (en) * 1992-04-30 1993-06-17 Wsp Ingenieurgesellschaft Fuer Waermetechnik, Stroemungstechnik Und Prozesstechnik Mbh, 5100 Aachen, De Hysteresis reduction method for inductive or capacitive proximity switch - disconnects operating voltage when detected object lies within response range of switch sensor to prevent hysteresis
WO2017125281A1 (en) * 2016-01-20 2017-07-27 BSH Hausgeräte GmbH Method for determining the filling level of a removable container

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108225480B (en) * 2018-01-16 2020-08-25 重庆邮电大学 Non-contact liquid volume measurement method based on linear capacitance liquid level sensor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4214300C1 (en) * 1992-04-30 1993-06-17 Wsp Ingenieurgesellschaft Fuer Waermetechnik, Stroemungstechnik Und Prozesstechnik Mbh, 5100 Aachen, De Hysteresis reduction method for inductive or capacitive proximity switch - disconnects operating voltage when detected object lies within response range of switch sensor to prevent hysteresis
WO2017125281A1 (en) * 2016-01-20 2017-07-27 BSH Hausgeräte GmbH Method for determining the filling level of a removable container

Also Published As

Publication number Publication date
DD286425A5 (en) 1991-01-24

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