Vibronic multisensor
A device for determining and/or monitoring a process variable of a medium includes a sensor unit having a mechanically oscillatable unit, a first piezoelectric element, a unit for determining and/or monitoring a temperature of the medium and an electronic system. The device is designed to excite the mechanically oscillatable unit and to receive the mechanical oscillations of the oscillatable unit, to convert them into a first receiving signal, to emit a transmission signal and to receive a second receiving signal, wherein the electronic system is designed to determine the process variable based on the first and/or second receiving signal. The unit for determining and/or monitoring the temperature includes a first and a second temperature sensor arranged at a distance from one another, and the electronic system is designed to determine the temperature of the medium based on a first and/or second temperature receiving signal.
1 . A device for determining a first process variable and a second process variable of a medium, the device comprising:
a sensor unit including a mechanically oscillatable unit, a first piezoelectric element, and a unit for determining a temperature of the medium, and
an electronics unit,
wherein the first process variable is a specifiable fill-level, a density, or a viscosity of the medium,
wherein the second process variable is a sound velocity within the medium,
wherein the device is embodied to excite the mechanically oscillatable unit via an excitation signal to produce mechanical oscillations, to detect the mechanical oscillations of the oscillatable unit, and to convert the detected mechanical oscillations into a first receiving signal,
wherein the device is embodied to transmit a transmission signal and to receive the transmitted transmission signal as a second receiving signal, wherein the transmission signal is an ultrasound signal,
wherein the unit for determining the temperature of the medium includes a first temperature and a second temperature sensor,
wherein the first temperature sensor and the second temperature sensor are arranged at a distance from one another,
wherein the first temperature sensor is arranged and configured to detect a first temperature in a first end region, facing the medium, of the sensor unit,
wherein the second temperature sensor is arranged and configured to detect a second temperature in a second end region, facing away from the medium, of the sensor unit, and
wherein the electronics unit is embodied to determine the first process variable using the first receiving signal and to adjust the first process variable using the first temperature, and
wherein the electronics unit is further embodied to determine the second process variable using the second receiving signal and to adjust the second process variable using the second temperature.
2 . The device according to claim 1 ,
wherein the sensor unit further comprises a second piezoelectric element,
wherein the first and the second piezoelectric element are embodied to excite the mechanically oscillatable unit via the excitation signal to produce the mechanical oscillations, to detect the mechanical oscillations of the oscillatable unit, and to convert the detected mechanical oscillations into the first receiving signal,
wherein the first piezoelectric element is embodied to emit the transmission signal, and
wherein the second piezoelectric element is embodied to receive the second receiving signal.
3 . The device according to claim 2 ,
wherein the mechanically oscillatable unit is a vibrating fork having a first oscillating element and a second oscillating element, and
wherein the first piezoelectric element is at least partially arranged in the first oscillating element, and the second piezoelectric element is at least partially arranged in the second oscillating element.
4 . The device according to claim 3 ,
wherein the unit for determining a temperature includes a rod-shaped housing element that is arranged such that a longitudinal axis of the rod-shaped housing element is parallel to a longitudinal axis of the oscillatable unit,
wherein the first temperature sensor is arranged in the first end region, facing the medium, of the housing element, and
wherein the second temperature sensor is arranged in the second end region, facing away from the medium, of the housing element.