DE3542030A1 - Evaluating electronics for differential capacitors - Google Patents

Evaluating electronics for differential capacitors

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Publication number
DE3542030A1
DE3542030A1 DE19853542030 DE3542030A DE3542030A1 DE 3542030 A1 DE3542030 A1 DE 3542030A1 DE 19853542030 DE19853542030 DE 19853542030 DE 3542030 A DE3542030 A DE 3542030A DE 3542030 A1 DE3542030 A1 DE 3542030A1
Authority
DE
Germany
Prior art keywords
voltage
capacitors
comparator
comparators
differential capacitors
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Withdrawn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
DE19853542030
Other languages
German (de)
Inventor
R. Prof. Dr.-Ing. Haberland
Kai 6750 Kaiserslautern Storjohann
Bertold Dipl.-Ing. Vogt
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.)
Individual
Original Assignee
Individual
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
Priority claimed from DE19853516162 external-priority patent/DE3516162A1/en
Application filed by Individual filed Critical Individual
Priority to DE19853542030 priority Critical patent/DE3542030A1/en
Publication of DE3542030A1 publication Critical patent/DE3542030A1/en
Withdrawn legal-status Critical Current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
    • G01D5/24—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 capacitance
    • G01D5/241—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 capacitance by relative movement of capacitor electrodes
    • G01D5/2417—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 capacitance by relative movement of capacitor electrodes by varying separation
    • 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
    • G01D5/24—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 capacitance
    • G01D5/241—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 capacitance by relative movement of capacitor electrodes
    • G01D5/2412—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 capacitance by relative movement of capacitor electrodes by varying overlap

Abstract

As already described in detail in Patent P 35161620, the stability of the measurement value of evaluating electronics for differential capacitors with a pulse-width-modulated squarewave output voltage, in which the individual capacitors are alternately charged, depends both on a stable squarewave voltage amplitude and on the equality and on the drift characteristics of the charging resistors and comparators. The instability caused by the comparators can be avoided in this invention by using only one comparator, the capacitor voltage Uc to be compared with a reference voltage Uref being picked up between charging resistor and change-over switch.

Description

ß e s c h r e i b u n aß e s c h r e i b u n a

Auswerteelektronik für Differentialkondensatoren Die Erfindung betrifft eire Xuswerteelektronik für Differentialkondensatoren mit einer pulsbreiten modulierten Ausgangsspannung, bei der die einzelnen Kondensatoren wechselseitig geladen werden und der jeweils nicht geladene Kondensator auf definiertem Potential (meist Masse) liegt.Evaluation electronics for differential capacitors The invention relates to eire Xuswerteelektronik for differential capacitors with a pulse width modulated Output voltage at which the individual capacitors are charged alternately and the uncharged capacitor at a defined potential (mostly ground) lies.

Wie bereits im Patent P 35 16 1620 beschrieben, hängt die Stabilität der Ausgangsspannung neben einer stabilen Rechteckspannungsamplitude U1 bzw. -U1 hauptsächlich von der Gleichheit und dem Driftverhalten der Ladewiderstände ab.As already described in patent P 35 16 1620, the stability depends the output voltage in addition to a stable square-wave voltage amplitude U1 or -U1 mainly on the equality and the drift behavior of the charging resistors.

Weiterhin hat aber auch das Verhalten der beiden Komparatoren einen Einfluß auf die Stabilität der Schaltung, wobei aufgrund von Bauteiletoleranzen nicht davon ausgegangen werden kann, daß diese Bauelemente gleiche Eigenschaften hinsichtlich Gleichheit und Gleichlauf mit Temperatur und Zeit besitzen.Furthermore, the behavior of the two comparators also has one Influence on the stability of the circuit, due to component tolerances it cannot be assumed that these components have the same properties in terms of equality and synchronization with temperature and time.

Der Erfindung liegt die Aufgabe zugrunde, diese Instabilitäten aufgrund unterschiedlicher Komparatoren zu beseitigen.The invention is based on the object of these instabilities to eliminate different comparators.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß nur noch ein Komparator eingesetzt wird (Fig. 1), wobei die mit der Referenzspannung Uref zu vergleichende Kondensatorspannung U c zwischen Ladewiderstand RL und Umschalter 9 abgegriffen wird.This object is achieved in that only one Comparator is used (Fig. 1), with the reference voltage Uref to comparative capacitor voltage U c between charging resistor RL and changeover switch 9 is tapped.

Eventuelle Toleranzen des Komparators 3 in Fig. 1 spielen hier überhaupt keine Rolle mehr, da die Kondensatorspannungen der Teilkondensatoren C1 und C2 durch den gleichen Komparator mit der Referenzspannung ref verglichen wird.Any tolerances of the comparator 3 in FIG. 1 play a role here at all no longer matter, since the capacitor voltages of the partial capacitors C1 and C2 through the same comparator is compared with the reference voltage ref.

Die mit der Erfindung erzielten Vorteile bestehen insbesondere darin, daß trotz der Verwendung eines Komparators eine verbesserte Stabilität der Schaltung erreicht wird und zwar sowohl hinsichtlich der Temperatur als auch hinsichtlich des Alterungsverhaltens.The advantages achieved with the invention are in particular: that despite the use of a comparator improved stability the circuit is achieved both in terms of temperature and with regard to aging behavior.

nin Ausführungsbeispiel der Erfindung ist in Fi. 1 dargestellt und wird im folgenden näher beschrieben.nin embodiment of the invention is shown in Fi. 1 and is described in more detail below.

In Fig. 1 ist eine Auswerteelektronik dargestellt, bei der die Kondensatorspannung c direkt hinter dem Ladewidersta von einem Komparator 3 mit der Referenzspannung Uref verglichen wird. Mach jedem Impuls des Komparators ändert das r-Flip Flop seinen Zustand und steuert die Umschalter 9a und 9b an.In Fig. 1, evaluation electronics are shown in which the capacitor voltage c directly behind the charging resistor from a comparator 3 with the reference voltage Uref is compared. Every pulse of the comparator changes the r-flip-flop State and controls the switches 9a and 9b.

- Leerseite -- blank page -

Claims (1)

Patentansprüche: 1. Auswerteelektronik für einen Differentialkondensator mit wechselseitigem Laden der beiden Kondensatoren und pulsbreiten modulierten Ausgangsspannung ist dadurch gekennzeichnet, daß die Kondensatorspannung Uc zwischen Ladewiderstand RL und Umschalter von einem Komparator mit der Referenzspannung Uref verglichen wird.Claims: 1. Evaluation electronics for a differential capacitor with alternating charging of the two capacitors and pulse-width modulated output voltage is characterized in that the capacitor voltage Uc between the charging resistor RL and changeover switch compared with the reference voltage Uref by a comparator will.
DE19853542030 1985-05-06 1985-11-28 Evaluating electronics for differential capacitors Withdrawn DE3542030A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19853542030 DE3542030A1 (en) 1985-05-06 1985-11-28 Evaluating electronics for differential capacitors

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853516162 DE3516162A1 (en) 1985-05-06 1985-05-06 Evaluating electronics for differential capacitors for use in sensors
DE19853542030 DE3542030A1 (en) 1985-05-06 1985-11-28 Evaluating electronics for differential capacitors

Publications (1)

Publication Number Publication Date
DE3542030A1 true DE3542030A1 (en) 1986-10-09

Family

ID=25831994

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19853542030 Withdrawn DE3542030A1 (en) 1985-05-06 1985-11-28 Evaluating electronics for differential capacitors

Country Status (1)

Country Link
DE (1) DE3542030A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0457515A1 (en) * 1990-05-11 1991-11-21 New Sd, Inc. Capacitive position detector
DE4103200A1 (en) * 1991-02-02 1992-08-06 Vdo Schindling Measurement transducer for physical parameters - has two sensors e.g. capacitive, inductive or resistor sensors, and changeover switch selecting on sensor at time for connection to evaluation circuit
DE4205989A1 (en) * 1992-02-27 1993-09-02 Mannesmann Kienzle Gmbh CIRCUIT ARRANGEMENT FOR AN ENCODER

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0457515A1 (en) * 1990-05-11 1991-11-21 New Sd, Inc. Capacitive position detector
US5122755A (en) * 1990-05-11 1992-06-16 New Sd, Inc. Capacitive position detector
DE4103200A1 (en) * 1991-02-02 1992-08-06 Vdo Schindling Measurement transducer for physical parameters - has two sensors e.g. capacitive, inductive or resistor sensors, and changeover switch selecting on sensor at time for connection to evaluation circuit
DE4205989A1 (en) * 1992-02-27 1993-09-02 Mannesmann Kienzle Gmbh CIRCUIT ARRANGEMENT FOR AN ENCODER

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