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WO1998053282A1 - Interrupteur de limite de niveau de remplissage a oscillations et procede pour constater et/ou surveiller un niveau d'une substance dans un contenant - Google Patents

Interrupteur de limite de niveau de remplissage a oscillations et procede pour constater et/ou surveiller un niveau d'une substance dans un contenant Download PDF

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Publication number
WO1998053282A1
WO1998053282A1 PCT/DE1998/001348 DE9801348W WO9853282A1 WO 1998053282 A1 WO1998053282 A1 WO 1998053282A1 DE 9801348 W DE9801348 W DE 9801348W WO 9853282 A1 WO9853282 A1 WO 9853282A1
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WIPO (PCT)
Prior art keywords
output signal
frequency
vibrating
vibration
oscillation
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
PCT/DE1998/001348
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German (de)
English (en)
Inventor
Hardi VÖLKEL
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.)
Pepperl and Fuchs SE
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Pepperl and Fuchs SE
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Filing date
Publication date
Application filed by Pepperl and Fuchs SE filed Critical Pepperl and Fuchs SE
Priority to AU83328/98A priority Critical patent/AU8332898A/en
Publication of WO1998053282A1 publication Critical patent/WO1998053282A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • G01F23/28—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 the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/296—Acoustic waves
    • G01F23/2966—Acoustic waves making use of acoustical resonance or standing waves
    • G01F23/2967—Acoustic waves making use of acoustical resonance or standing waves for discrete levels

Definitions

  • the invention relates to a vibration level limit switch and a method for determining and / or monitoring a level of a medium in a container according to the preamble of claims 1 and 16, respectively.
  • DE 17 73 815 A1 discloses a device for determining the fill level of a container, which has a probe with an oscillating rod protruding into the container, a device for exciting mechanical vibrations of the oscillating rod and a display device.
  • a second oscillating rod is provided in parallel with the oscillating rod, both rods being set into oscillations in opposite directions.
  • two electromechanical transducers are provided which convert the vibrations of the bars into electrical signals, the amplitude of which depends on the vibration amplitude of the bars.
  • a device for determining and / or monitoring a fill level of a medium in a container which has a mechanical oscillation structure consisting of two oscillating rods, which are excited by a piezoelectric excitation device to mechanical vibrations, the frequency of which is from the environment the vibrating rods depends, in particular on the level of the level.
  • the mechanical oscillation of the vibratory structure is converted back into an electrical signal with a piezoelectric receiving transducer, which is amplified and the frequency of which is evaluated in a transducer circuit.
  • the amplified signal serves as an input signal to the excitation device.
  • the converter circuit is designed in such a way that it converts the output signal of the receive converter into a square-wave signal, the period of which is compared in a time comparison circuit with a predetermined reference duration. If this comparison is negative over a longer period of several periods, an electrical switching element emits an output signal.
  • a vibration level switch with a vibrating device for level detection, which is connected in the feedback branch of a feedback amplifier, and a frequency evaluation circuit, which evaluates the output signal of the feedback amplifier.
  • the output signal of the oscillation device and a weakened output signal of a resonance element connected in parallel to the oscillation device from the output of the feedback amplifier are added and fed to the input of the feedback amplifier in order to avoid safety-related conditions in the case of defective resonators of such a vibration level limit switch.
  • a disadvantage of the known devices for level monitoring is that the mechanical structure with excitation device and separate receiving transducer is complex and expensive. Due to the mechanical structure, the power consumption of such a device is also relatively high, because high signal levels are required to excite a mechanical oscillation with such a high amplitude that the oscillation can still be reliably detected by the reception transducer, since the excitation device and the reception transducer are used for Share the available contact surface to the vibrating structure. This worsens the signal-to-noise ratio.
  • the invention is therefore based on the object of providing a device of the type mentioned at the outset, with which changes in the oscillation frequency or the amplitude of the induced oscillation can be reliably detected when the level changes, while reducing the outlay on the mechanical structure and the operating costs.
  • the object is achieved according to the invention in a vibration level limit switch of the type mentioned, in which the excitation device and the receiving transducer are essentially identical, thus agree in their essential components, in particular the same piezo element or the same piezo elements is / are used for excitation and for the detection of the vibration.
  • An AC voltage thus lies over the piezo element, the signal form of which is determined by the input signal and the response voltage of the oscillation structure, and is generally the sum of the input signal and the response voltage.
  • the input signal of the excitation device is additionally given to a reference element which is connected in parallel with the excitation device, the reference element being designed in such a way that its output signal is proportional to the output signal of the excitation device in the event that an oscillatory structure is not coupled.
  • the difference between the output signal of the excitation device and the output signal of the reference element is amplified in the converter circuit and serves to generate an output signal of the converter or evaluation circuit, which is used as the input signal of the excitation device and the reference element, so that an electrically oscillatable system is created.
  • the frequency or the amplitude of the output signal of the converter circuit is compared in a logic circuit with a predetermined reference frequency or amplitude, a switching element then generating a signal when the actual frequency or amplitude exceeds or exceeds the reference frequency or amplitude for a predetermined time falls below.
  • a method according to the preamble of claim 1 is also specified, in which the following steps are carried out in order to generate a switching signal and to re-excite the oscillatable system: a) the mechanical oscillation of the oscillating structure is detected with the same piezo element that the oscillating structure closes
  • a reference voltage U ref is generated which corresponds to the voltage tapped at the piezo element U er r if the
  • Vibratory structure is proportional; c) the voltages U ref and / or U er r are amplified and / or attenuated that the respective amplitudes are approximately the same if the vibrating structure is not coupled d) in the operating state, the difference between U e rr and U re f is amplified and on the one hand to re-excite the vibrating structure and by comparison with a predetermined amplitude and / or oscillation frequency for determination the level used.
  • the invention has the advantage that the oscillation excitation of the oscillation structure and the detection of the mechanical oscillation is carried out with the same piezo element, that is to say that the excitation device and the reception transducer are integrated in one component.
  • a piezo element is always assumed, but an array of piezo elements can also be used to excite and to detect the vibration.
  • excitation device and receiving transducer in one component has the result that the available contact area, limited by the mechanical design of the device, for transmitting the mechanical oscillation of the piezo element to the oscillating structure and for transmitting the oscillation of the oscillating structure to the piezo element both for the Excitation as well as for reception can be fully exploited.
  • the excitation takes place by applying a time-varying electrical voltage as an input signal to the excitation device.
  • the piezo element deforms with the frequency of the input signal and excites the vibrating structure to vibrate at the same frequency.
  • the frequency of the input signal advantageously already matches the natural frequency of the vibrating structure when the vibrating structure is first excited by a pulse generator. Then the amplitude of the excited mechanical vibration is greatest with the same excitation power and the detection of the vibration is less prone to errors. After the pulse generator has been decoupled, the feedback of the output signal of the converter circuit to the excitation device basically ensures that the oscillating structure is always excited with its natural frequency.
  • This natural frequency depends on the design of the vibratory structure, in particular on the length and mass of the vibrating rods and the Spring stiffness of the attachment point of the vibrating rods. It is modified by the medium surrounding the vibrating rods and is therefore influenced by the immersion depth or the fill level and by the type of medium, in particular by the mass carried by the movement of the vibrating rods.
  • the natural frequency is therefore a suitable measurement variable for determining the fill level of liquid media, in which mass is carried along by the movement of the oscillating rods if the damping does not largely prevent oscillation.
  • the amplitude of the forced oscillation of the vibratory structure also contains information about the level of the fill level.
  • media with strong damping such as viscous liquids or granular solids
  • the amplitude of the vibration changes greatly with the level and can therefore be evaluated for a reliable level analysis.
  • the device To evaluate the response signal of the vibrating structure, this must first be separated from the response signal of the excitation device or the reception transducer combined therewith, preferably realized by a piezo element connected in series with a resistor.
  • the device according to the invention provides for a reference element to be connected in parallel with the combined excitation and reception element.
  • the reference element supplies an output signal which is proportional, preferably the same, to the output signal of the combined excitation and reception element in the case of a decoupled oscillation structure, that is to say without the superimposed response signal of the oscillation structure.
  • the vibration frequencies must match.
  • the response signal is then determined within the converter circuit by forming a difference, preferably using a differential amplifier, the output signals of the combined excitation and reception element and the reference element.
  • the amplitudes of the signals do not match in the case of a decoupled oscillation structure, they are preferably matched to one another by means of an amplifier or attenuator.
  • the output signal of the converter circuit has the same frequency as the response signal of the oscillation structure, the pulse shape is determined by the design of the converter circuit, especially by reinforcing them.
  • the output signal of the converter circuit serves as an input signal for the excitation device and for the reference element.
  • the converter circuit can be designed differently depending on whether the amplitude or the frequency of the response signal of the converter circuit is to be evaluated as a relevant variable.
  • the highest possible loop gain of the oscillatory electromechanical system consisting of the oscillation structure, which is excited with its feedback and amplified output signal is advantageous.
  • the vibration should not be brought to a standstill by damping the vibrating structure.
  • a high loop gain is preferably realized by overdriving an amplifier within the converter circuit or by means of a NuU pengangs comparator, so that the output signal of the converter circuit is an almost rectangular signal. Such a signal is suitable for controlling the excitation device and replaces the pulse generator. Linear amplification of the response signal with a sinusoidal output signal is also possible as long as the amplitude of the output signal is still sufficient to maintain an undamped oscillation of the oscillation structure.
  • the frequency or period of the output signal can be evaluated using known frequency evaluation methods.
  • a logic circuit consisting of at least four monostable flip-flops is advantageous, two flip-flops generating a time window with a predetermined width and adjustable delay to the negative edge of the comparator, a third A flip-flop generates a pulse if the positive edge of the comparator lies within the time window, and a fourth flip-flop extends the duration of this pulse.
  • the delay is preferably set such that the positive edge of the comparator lies in the middle of the time window when the oscillating structure oscillates in air. This compares the period with a predetermined reference time interval, which corresponds, for example, to the frequency at the level to be detected. An electrical switching element switches with a delay when the pulse of the fourth flip-flop is present.
  • the excitation device is operated with an output signal from the converter circuit which is proportional to the amplitude of the forced oscillation of the oscillating structure. If the vibration structure is strongly damped by the medium, the vibration amplitude decreases due to the weakening feedback when a predetermined fill level is reached, and the vibration may break off. The falling below or exceeding a predetermined amplitude is determined by means of a comparator and indicated with a delay due to the switching of an electrical switching element.
  • Figure 1 shows a vibration level switch with two parallel vibrating rods
  • FIG. 2 is a block diagram showing the functional principle
  • FIG. 3 shows a block diagram of a vibration level limit switch with frequency evaluation.
  • FIG. 4 shows the course over time of various pulses
  • Figure 1 shows schematically the mechanical components of a vibration level switch for level monitoring with two parallel vibrating rods 2 as vibrations.
  • the device is usually attached to a container, the vibrating rods projecting into the interior of the container and being completely or partially covered with medium. If the level exceeds or falls below a certain level, the device should emit a switching signal.
  • An essential component of the excitation device 3 is a single piezo element 5 which is insulated with an insulating layer 8 and glued to the bottom 9 of the vibratory structure. The piezo element is connected at its contact surfaces 6 and 7 by means of electrodes to an input signal generator.
  • the piezoelectric effect is exploited: an electrical voltage is applied to the contact surfaces 6, 7 of the piezoelectric element 5. This changes the diameter of a circular disk-shaped piezo element or the dimensions of a piezo plate. When using an alternating voltage, the dimensions are alternately increased and decreased. This also changes the dimensions of the bottom 9 of the vibratory structure.
  • the vibrating rods attached to the side of the base facing away from the piezo element vibrate at the frequency of the AC voltage applied to the piezo element for excitation.
  • the vibrating rods 2 vibrate at their natural frequency when the vibration is started.
  • This natural frequency is u. a. depending on the length and mass of the vibrating rods, the spring stiffness of the floor and the medium that is moved when the vibrating rods vibrate.
  • the frequency of the vibration thus contains information about the level and can be evaluated accordingly. Due to the level-related damping, the amplitude of the vibration is also suitable for evaluation and level analysis.
  • the dimensions of the floor change due to the vibration. This also changes the dimensions of the piezo element glued to the floor, which also functions here as a reception transducer 4.
  • the piezoelectric effect is used to convert the mechanical deformation into an electrical signal: by changing the dimensions of the piezo element, an electrical voltage is generated at the contact surfaces 6, 7. This voltage is sinusoidal, since the vibrating rods vibrate in good approximation only at their fundamental frequency even when excited with non-sinusoidal pulse shapes and higher harmonics do not excite this fundamental frequency.
  • Figure 2 shows schematically a block diagram to illustrate the functional principle of the device according to the invention.
  • Excitation device 11 and receive converter 12 are integrated in one component.
  • the vibrational structure 10 mechanically connected to this is schematically indicated.
  • the excitation device is operated with an input signal which is either generated by a pulse generator 18 or which is an output signal of a converter circuit 14 which is fed back via a feedback line 15.
  • the vibrating structure When starting up the device, the vibrating structure must first be set in vibration.
  • the pulse generator can be used, which preferably excites the oscillation structure with its natural frequency, since the amplitude of the forced oscillation is then greatest.
  • this natural frequency changes with the level and is usually the size that is evaluated for level analysis. Permanent excitation with a fixed frequency is therefore not advisable. Rather, it must be ensured that the vibrating structure is always excited resonantly, since only then does the response signal of the vibrating structure carry the information about the natural frequency and thus the level.
  • the resonant excitation is ensured by a feedback of the output signal of the converter circuit to the input of the excitation device.
  • the converter circuit is designed so that it generates a signal with the frequency of the response signal. After the mechanical vibration has been started, the pulse generator is disconnected.
  • the output signal of the combined excitation and reception transducer represents a superimposition of the pure output signal of the excitation device without a coupled oscillation structure and the response signal of the oscillation structure.
  • the vibratory structure is the quantity that carries the information about the vibration behavior of the vibrating rods and thus about the fill level.
  • the reference element 13 which is connected in parallel to the combined excitation and reception converter. It is operated with the same input signal as this.
  • the reference element is designed in such a way that it delivers an output signal which corresponds as closely as possible to the output signal which the excitation device can produce without coupling to an oscillatory structure, i.e. without the superimposition of their response signal, or would be proportional to this signal.
  • FIG. 3 A specific example of the implementation of such a reference element is shown in FIG. 3, the input and output signals measured in this way being explained in FIG.
  • the output signals from the receive converter 12 and reference element 13 are linked and modified in the converter circuit 14. Since the output signal of the receive transducer is composed of the undisturbed output signal without coupling the oscillation structure and its response signal, the difference between the output signals of elements 12 and 13 is evaluated in the transducer circuit. This difference corresponds to the response signal sought.
  • the response signal is amplified and modified in the converter circuit.
  • Figure 3 shows i.a. an example of the converter circuit if the frequency is the quantity of interest. It preferably generates a square-wave signal, the frequency of the response signal being maintained. Such a signal is suitable as an input signal for the excitation device and reference element, as a result of which the electromechanical resonant circuit is closed when it is fed back to the input of these elements. The pulse generator can then be disconnected. If the attenuation-dependent amplitude of the response signal is evaluated, e.g. for the detection of the fill level of very viscous liquids or granular solids, the converter circuit is primarily linearly amplified and this output signal is given to the input of the excitation device and the reference element.
  • the output signal is evaluated in a logic circuit 16.
  • the frequency or amplitude of the output signal is compared with a predetermined reference frequency or amplitude, which, for example. the Vibration frequency or the amplitude at the level whose exceeding or falling below should be displayed. If this comparison turns out to be positive, the logic circuit sends an electrical pulse to an electrical switching element 17, which switches with a delay and indicates that a certain fill level has been exceeded or fallen below.
  • Figure 3 shows an example of the electronic components of a device according to the invention, which are linked according to the principle shown in Figure 2.
  • the basic time course of the electrical pulses is shown in FIG. 4.
  • a single piezo element 20 is connected in series with a resistor
  • the rectangular generator generates a rectangular AC voltage U; n with a fixed frequency, which is the natural frequency of the vibrating structure f 0 in any
  • the signal of the square wave generator 19 is replaced by the output signal of the converter circuit 14 ', which is also rectangular in shape and oscillates at the instantaneous, actual natural frequency f of the oscillation structure.
  • the piezo element 20 has a capacitance C, which is dependent on its dimensions and the dielectric constant.
  • C capacitance
  • the piezo element initially behaves like a capacitor when a voltage is applied.
  • the voltage across the piezo element is a charge-discharge curve, as shown in FIG. 4 with Ure f.
  • Vibration device in any condition, e.g. when swinging in air, is. This ensures that the voltage across the piezo element can follow the applied input voltage within the duration of the stretching pulse.
  • the oscillation of the oscillation device generates a sinusoidal alternating voltage at the contact surfaces of the piezo element, which additively overlaps the charging-discharging voltage.
  • This sum voltage lies on the contact surfaces of the piezo element and is designated U err in FIG.
  • the pure charge-discharge voltage that is to say the output signal of the excitation device in the event that a vibration device is not coupled, is shown in FIG. 4 and is denoted by U ref . It is the output signal of the reference element.
  • the reference element is formed by a capacitor 22 in connection with a further resistor 23 connected in series therewith, which are also connected to the rectangular generator 19 or fed back to the output of the converter circuit 14 '.
  • the time constant of the two components is the same as in the series connection of piezo element 20 and resistor 21 described above. For example, both the capacitance and the resistance value of the components are chosen to be the same.
  • the voltage U ref across the capacitor is the typical charge-discharge curve for one with a square wave signal, here U; n , driven capacitor.
  • the charge-discharge voltage U ref of the capacitor 22 is subtracted from the total voltage U er r at the contact surfaces of the piezo element 20.
  • the difference between the output signals of the combined excitation / reception converter and the reference element is formed.
  • the result U d i ff corresponds to the sinusoidal AC voltage which is generated by the oscillation of the oscillation device on the contact surfaces of the piezo element 20.
  • the output of the differential amplifier 24 is connected to a NuU pengangs comparator 26, which generates a rectangular signal with the frequency of the response signal and a fixed amplitude.
  • An overdriven amplifier 24 has a similar effect. Both produce a high loop gain in the electromechanical oscillating circuit from excitation and reception transducers, oscillation structures and amplifiers.
  • the converter circuit 14 'shown here therefore has a suitable low-pass filter 25 between the amplifier and the comparator.
  • the low pass continues to filter out higher harmonics of the fundamental frequency, so that the excitation of the mechanical vibratory structure always takes place with its basic natural frequency.
  • the circuit shown is suitable for the cases in which the frequency of the vibration device is to be evaluated in order to obtain information about the fill level. This is a particularly suitable measuring method for the detection of the fill level of liquids, since the natural frequency of the oscillation depends strongly on the fill level due to the mass carried by the vibrating rods, but the amplitude of the oscillation is hardly damped.
  • An electrical switching element 32 switches depending on whether the frequency of the vibration device either exceeds or falls below a fixed frequency.
  • a logic circuit 16 'consisting of four monostable flip-flops 27, 28, 29, 30 is used for this.
  • the first two monostable flip-flops 27, 28 generate a time window which has a fixed width and an adjustable delay to the negative edge of the comparator output, that is to say to the negative edge of Uj n from FIG. 4.
  • the delay is set in such a way that that the positive edge of the comparator output lies in the middle of the time window when the vibrating device vibrates in air or in another defined state.
  • the third monostable flip-flop 29 generates a pulse if the positive edge of the comparator output is within the time window in the operating situation.
  • the fourth monostable flip-flop 30 extends the time of this pulse.
  • the electrical switching element 32 switches with a further delay, which is generated by a component 31.
  • the evaluation of the amplitude of the oscillation is suitable if the covering of the oscillatory structure with solids or with highly viscous liquids is to be detected. If the vibrating rods are covered with a solid, the oscillation amplitude of the rods is strongly damped. The overall loop gain of the oscillatory system is thereby greatly reduced. The loop gain is no longer sufficient to excite the vibrating rods at their natural frequency. The vibration breaks off or occurs at a different frequency. The amplitude of the vibration is very low in both cases.
  • An electric one Switching element switches depending on how large the amplitude of the output of the differential amplifier, which in this case - possibly together with a low-pass filter - forms the converter circuit. For this purpose, a comparator with a permanently set switching threshold is used as the logic circuit.
  • the invention is commercially applicable in all areas in which fill levels of various materials, such as liquids in containers or bulk goods on stockpiles or in containers, are to be monitored.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)

Abstract

L'invention concerne un interrupteur de limite de niveau de remplissage à oscillations et un procédé pour constater et/ou surveiller un niveau d'une substance dans un contenant. Un élément mécanique oscillant (1, 10) est excité au moyen d'une unité d'excitation piézoélectrique (3, 11) de façon à produire des oscillations qui sont détectées au moyen d'un convertisseur de réception (4, 12) pratiquement identique à l'unité d'excitation (3, 11). Le signal de réponse de l'élément oscillant est détecté dans un circuit convertisseur (14, 14') par comparaison du signal de sortie du convertisseur de réception (4, 12) avec le signal de sortie d'un élément de référence (13). Le signal de réponse est amplifié et, le cas échéant, converti en impulsions rectangulaires, et réinjecté avec le signal d'entrée de l'unité d'excitation (3, 11) et de l'élément de référence (13), de sorte que l'oscillation de l'élément oscillant (1, 10) soit stabilisée en permanence sur sa fréquence propre à un moment donné. Selon le mode d'utilisation de l'invention, cette fréquence propre est comparée avec une fréquence prédéterminée correspondant à un niveau déterminé, ou l'amplitude du signal de réponse est évaluée. L'avantage de l'invention réside en particulier dans le fait que sa conception mécanique est simplifiée et sa consommation électrique réduite.
PCT/DE1998/001348 1997-05-16 1998-05-14 Interrupteur de limite de niveau de remplissage a oscillations et procede pour constater et/ou surveiller un niveau d'une substance dans un contenant Ceased WO1998053282A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU83328/98A AU8332898A (en) 1997-05-16 1998-05-14 Vibration filling level limit switch and method for determining and/or monitoring the filling level of a medium in a container

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19720519.4 1997-05-16
DE1997120519 DE19720519C2 (de) 1997-05-16 1997-05-16 Vorrichtung zur Feststellung und/oder Überwachung eines Füllstandes eines Mediums in einem Behälter

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Publication Number Publication Date
WO1998053282A1 true WO1998053282A1 (fr) 1998-11-26

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AU (1) AU8332898A (fr)
DE (1) DE19720519C2 (fr)
WO (1) WO1998053282A1 (fr)

Cited By (3)

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CN104024811A (zh) * 2011-12-28 2014-09-03 恩德莱斯和豪瑟尔两合公司 用于确定和/或监视至少一个过程变量的设备
US9989398B2 (en) 2010-08-20 2018-06-05 Endress + Hauser Gmbh + Co. Kg Device for determining and/or monitoring at least one predetermined fill level
US10429229B2 (en) * 2014-09-18 2019-10-01 Maschinenfabrik Reinhausen Gmbh Electrical device with a housing holding insulation oil and a sensor and method of monitoring the device

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DE10056353A1 (de) * 2000-11-14 2002-05-23 Grieshaber Vega Kg Verfahren und Anordnung zur Füllstandsmessung
JP2004530121A (ja) * 2001-03-28 2004-09-30 エンドレス ウント ハウザー ゲーエムベーハー ウント コンパニー コマンディートゲゼルシャフト 容器内の所定の充填レベルを決定及び／又は監視する装置
EP1373840B1 (fr) 2001-03-28 2009-09-23 Endress + Hauser GmbH + Co. Dispositif pour la determination ou la surveillance d'un niveau de remplissage predefini dans un contenant
DE10153936A1 (de) * 2001-03-28 2002-11-14 Endress & Hauser Gmbh & Co Kg Vorrichtung zur Feststellung und/oder Überwachung eines vorbestimmten Füllstandes in einem Behälter
DE10203461A1 (de) * 2002-01-28 2003-08-14 Grieshaber Vega Kg Schwingungsgrenzstandsensor
DE10331428B4 (de) * 2003-07-10 2005-07-28 Endress + Hauser Gmbh + Co. Kg Feldgerät zur Bestimmung und/oder Überwachung einer Prozessgröße
DE102008039549A1 (de) 2008-08-25 2010-03-04 OCé PRINTING SYSTEMS GMBH Sensoranordnung zur Überwachung des Füllstandes eines ein Füllgut aufweisenden Behälters mit Hilfe eines Schwingkörpers
DE102008050266A1 (de) 2008-10-07 2010-04-08 Endress + Hauser Gmbh + Co. Kg Vorrichtung zur Bestimmung und/oder Überwachung einer Prozessgröße eines Mediums
DE102010030791A1 (de) 2010-07-01 2012-01-05 Endress + Hauser Gmbh + Co. Kg Vorrichtung zur Bestimmung und/oder Überwachung einer Prozessgröße eines Mediums
EP2592397B1 (fr) * 2011-11-09 2015-08-05 VEGA Grieshaber KG Interrupteur de fin de course du type vibrant
DE102011090014A1 (de) 2011-12-28 2013-07-04 Endress + Hauser Gmbh + Co. Kg Vorrichtung zur Bestimmung und/oder Überwachung mindestens einer Prozessgröße
DE102020127077A1 (de) * 2020-10-14 2022-04-14 Endress+Hauser SE+Co. KG Verfahren zum Betreiben eines vibronischen Sensors

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DE19720519C2 (de) 2000-03-30
AU8332898A (en) 1998-12-11

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