A method for determining and/or monitoring a process variable of a medium using a vibronic sensor includes: exciting a mechanically vibratable unit to vibrate in a first vibration mode via a drive/receiving unit using a first excitation signal; receiving and converting the vibrations of the first vibration mode into a first reception signal; generating the first excitation signal based on the first reception signal; determining the process variable from the first reception signal; exciting the vibratable unit to vibrate in a second vibration mode via the drive/receiving unit via a second excitation signal; receiving and converting the vibrations the second vibration mode into a second reception signal, where the second excitation signal is generated based on the second reception signal; and compensating for an influence of a temperature of the medium on the first reception signal using the second reception signal.

Acoustic volume indicators for determining liquid or gas volume within a container comprise a contactor to vibrate a container wall, a detector to receive vibration data from the container wall, a processor to convert vibration data to frequency information and compare the frequency information to characteristic container frequency vs. volume data to obtain the measured volume, and an indicator for displaying the measured volume. The processor may comprise a microprocessor disposed within a housing having lights that each represent a particular volume. The microprocessor is calibrated to provide an output signal to a light that indicates the container volume. The processor may comprise a computer and computer program that converts the data to frequency information, analyzes the frequency information to identify a peak frequency, compares the peak frequency to the characteristic frequency vs. volume data to determine the measured volume, and displays the measured volume on a video monitor.

A bottle having a water volume measuring function comprises a bottle-lid, a bottle-body, and a measure module disposed in the bottle-lid which comprises at least a micro controller unit, a memory unit and a sound wave transceiver unit. The memory unit stores a lookup table with corresponding relationships between a plurality of frequencies and remained water volumes in the bottle-body. The sound wave transceiver unit emits sound waves with sweeping frequencies towards the bottle-body and receives reflected waves. The micro controller unit determines if any frequency of the sound waves is an air-resonance frequency according to the energy level of each of the reflected waves. When a sound wave frequency is determined as an air-resonance frequency, the micro controller unit obtains the corresponding remained water volume by checking with the air-resonance frequency in the lookup table and users can view the remained water volume without opening the bottle-lid.

An Apparatus for determining and/or monitoring at least one process variable of a medium in a container, comprising: a mechanically oscillatable unit a driving/receiving unit for exciting the mechanically oscillatable unit to execute mechanical oscillations by means of an electrical, exciting signal and for receiving and transducing the mechanical oscillations into an electrical, received signal a control unit, which is embodied to produce the exciter signal starting from the received signal and to set a predeterminable phase shift between the exciter signal and the received signal, an electromagnetically oscillatable unit, an active element for producing and/or maintaining electromagnetic oscillations in the electromagnetically oscillatable unit, which active element forms together with the electromagnetically oscillatable unit an oscillator, a coupling unit, which is embodied to tap an output signal from the active element, and an evaluation unit, which evaluation unit is embodied to determine the at least one process variable from the received signal and/or from the output signal.

In some examples, a controller is to receive a measurement of an electrical property of an oscillation control system from a sensor, determine, based on the measurement of the electrical property, a frequency of oscillation of a structure vibrated by the oscillation control system in the system, the vibration of the structure to cause passage of a portion of a material through the structure, and estimate a level of a remaining portion of the material at the structure based on the determined frequency of oscillation of the structure.

In an example, a method comprises fabricating a first validation device for association with a first replaceable print apparatus component. The device may be to form part of circuitry arranged on the first replaceable print apparatus component, and may provide an associated electrically detectable characteristic which varies with the position of at least part of the first validation device. The electrically detectable characteristic may be measured and data indicative of the characteristic may be stored in a first memory. The first replaceable print apparatus component comprising the first device and the first memory may be assembled.

A system and method for determining when a sand separator should be purged to remove solids from the sand separator. The system can include an acoustic sensor which detects the frequency of audible sound coming from the inner chamber of the vessel and generate a signature signal representative of the frequency of audible sound. There is a processor connected to the acoustic sensor and configured to compare the signature signal with a set frequency range of audible sound which in turn generates a signal indicating when he signature frequency and the set frequency are in overlapping relationship.

A device for measuring a mass of a body, the device including a support suitable for supporting the body, a frame and an actuator designed to vibrate the support relative to the frame. The device includes an accelerometer designed to measure values of an acceleration of the support upon vibration of the support, and an electronic control module designed to estimate the mass of the support body from the measured acceleration values.

A system for sensing material within a container includes a container having a reservoir for storing material and an impact member configured to selectively impart an impulse force on the container to cause vibration of the container. A sensor is configured to sense the vibration of the container upon the impact member imparting the impulse force on the container. Processing circuitry in communication with the sensor is configured to determine an estimate of an amount of the material in the container based on the sensed vibration of the container.

Disclosed is a method for determining and/or monitoring at least two different process variables of a medium, wherein a sensor unit is excited to vibrate mechanically by means of an excitation signal, the mechanical vibrations are received from the sensor unit and are converted into a first reception signal, the sensor unit emits a transmission signal and receives a second reception signal, and a first process variable is determined on the basis of the first reception signal and a second process variable is determined on the basis of the second reception signal. Disclosed also is an apparatus configured to carry out a method according to the invention.