摘要:
Apparatus for measuring and/or monitoring a process variable of a medium. The apparatus includes: an oscillatable unit; a driver/receiver unit, which excites the oscillatable unit to oscillate, and/or which receives its oscillations; a control/evaluation unit, which controls the driver/receiver unit, and/or which evaluates the oscillations of the oscillatable unit; and at least one transmitting line and one receiving line between the control/evaluation unit and the driver/receiver unit. At least a third line is provided, which is embodied and arranged in a manner such that it is located between the transmitting line and the receiving line, and is connected with a voltage source, which has an output impedance, which is smaller than the impedance of a condensate bridge.
摘要:
An apparatus and method for determining at least one process variable of a medium in a container or in a pipeline. The apparatus including: at least a first element and a second element, which are necessary components of the apparatus for determining the process variable and which contact at a contact location, which is exposed to a process temperature. The first element comprises a first material, and the second element comprises a second material. The first material and the second material are selected and matched to one another in such a manner that at the contact location between the first material and the second material a thermovoltage dependent on the difference between the process temperature and a reference temperature arises; and a temperature determining unit measures the thermovoltage and determines the process temperature therefrom.
摘要:
A method for determining and/or monitoring a process variable of a medium, wherein a mechanically oscillatable unit is supplied with an exciter signal wherein a received signal coming from the mechanically oscillatable unit is received, and wherein the exciter signal is produced in such a manner, that a phase difference between the exciter signal and the received signal equals a predeterminable phase value. A criterion for judging the determining of the phase difference between the exciter signal and the received signal, or a signal dependent on the exciter signal or on the received signal, is established; in the case, in which the criterion for judging the determining of the phase difference is fulfilled, tuning of the phase difference is closed-loop controlled; and, in the alternative case, tuning of the phase difference is open-loop controlled. An apparatus associated with the method is also disclosed.
摘要:
An apparatus for determining and/or monitoring at least one process variable of a medium, and includes a sensor unit, a feedback electronics and a supplemental electronics. The sensor unit, feedback electronics and supplemental electronics form a first oscillatory circuit, which oscillates with at least one resonance frequency (ω1) and/or with a resonance frequency (ωres) within at least one resonance frequency range. The feedback electronics and the supplemental electronics form a second oscillatory circuit, which oscillates at a resonance frequency (ωcablebreak), which differs from the resonance frequency (ωres, ω1) of the first oscillatory circuit.
摘要:
A device for operating an oscillatable unit of a vibration resonator, including a piezodrive, which is connected with the oscillatable unit, and feedback electronics. The feedback electronics excites the piezodrive to oscillate by means of a periodic exciter signal having rising and falling edges. The response signal of the piezodrive is fed back to the feedback electronics. Present additionally is at least one peak compensation unit, which removes from the response signal at least one interference signal, which results from the charge-reversal process of the piezodrive. Provided in the peak compensation unit, is at least one suppression unit having at least one switch element. The suppression unit is controlled by the exciter signal of the feedback electronics in such a manner that the piezodrive is connected conductively to ground during the rising and/or during the falling edges of the exciter signal.
摘要:
The invention relates to a method and an apparatus for establishing and/or monitoring the filling level of a medium in a container and to the determination of the density of a medium in a container. It is the object of the invention to propose a method and an apparatus which permit reliable determination and/or monitoring of the filling level or the density of a medium. With reference to the apparatus according to the invention, the object is achieved by virtue of the fact that at least a first mode and a second mode of the oscillations of the oscillable unit (2) are evaluated, and the evaluated modes are used to detect a change in mass at the oscillable unit (2).
摘要:
A device for determining a predetermined fill level of a liquid in a container, with a sensor unit, comprising a unit capable of oscillating mechanically, a transmitter unit, and a receiver unit, which is electrically and mechanically coupled to the transmitter unit, and which transduces the oscillation of the unit capable of oscillating into an electrical receiving signal. An electronic unit, comprising a regulating unit, which regulates a phase difference that exists between the electrical transmission signal and electrical receiving signal to a determined value at which the unit capable of oscillating conducts oscillations at a resonant frequency, and which forms an oscillation circuit with the transmitter unit, receiving unit and the unit capable of oscillating. The electronic unit comprises a compensation path with a compensation unit, which for compensating additional signal components in the receiving signal, which results from the mechanical and/or electrical coupling between transmitter unit and receiver unit, at least intermittently produces a compensation signal from the transmission signal and supplies this compensation signal to the receiving signal. The compensation unit produces the compensation signal in a way such that the compensation signal is opposite to the additional signal components in the receiving signal.
摘要:
An apparatus and method for determining at least one process variable of a medium in a container or in a pipeline. The apparatus including: at least a first element and a second element, which are necessary components of the apparatus for determining the process variable and which contact at a contact location, which is exposed to a process temperature. The first element comprises a first material, and the second element comprises a second material. The first material and the second material are selected and matched to one another in such a manner that at the contact location between the first material and the second material a thermovoltage dependent on the difference between the process temperature and a reference temperature arises; and a temperature determining unit measures the thermovoltage and determines the process temperature therefrom.
摘要:
Apparatus for measuring and/or monitoring a process variable of a medium. The apparatus includes: an oscillatable unit; a driver/receiver unit, which excites the oscillatable unit to oscillate, and/or which receives its oscillations; a control/evaluation unit, which controls the driver/receiver unit, and/or which evaluates the oscillations of the oscillatable unit; and at least one transmitting line and one receiving line between the control/evaluation unit and the driver/receiver unit. At least a third line is provided, which is embodied and arranged in a manner such that it is located between the transmitting line and the receiving line, and is connected with a voltage source, which has an output impedance, which is smaller than the impedance of a condensate bridge.
摘要:
A vibration detector for determining and/or monitoring a predetermined fill level in a container. The detector includes an oscillatable unit, a driver/receiver unit and an evaluation unit. The vibration detector can, additionally, be used as a viscosity sensor or as a density sensor. For providing a multivariable sensor, a microprocessor is provided in the oscillation circuit formed of oscillatable unit and feedback electronics. The microprocessor corrects the phase of the feedback electronics over a predetermined frequency bandwidth in such a way that the sum of the phases of the feedback electronics and the microprocessor follows a predetermined function f(v).