A perfusion system includes a fluid reservoir configured to hold a portion of fluid, the portion of fluid having a volume, the fluid reservoir having a total capacity that is greater than the volume; an imaging device, the imaging device configured to obtain image data corresponding to the fluid reservoir; and a controller. The controller is configured to receive the image data from the imaging device; determine the volume based on the image data; and facilitate control, in response to at least one of a user input and the determined volume of the portion of fluid, of an operating parameter corresponding to the fluid reservoir to facilitate changing or maintaining the volume of the portion of the fluid.

A watercraft is provided that includes a support platform having a bottom surface. The watercraft includes a hydrofoil disposed on a strut extending from the bottom surface of the support platform. The watercraft includes a propulsion system coupled to the bottom surface of the board such that a thrust generated by the propulsion system moves the board through a body of water. The watercraft includes a position sensor, a speed sensor, and an altitude controller. The position sensor is configured to output position data of the watercraft relative to a surface of water. The speed sensor is configured to output speed data of the watercraft. The altitude controller is configured to adjust the thrust generated by the propulsion system based at least in part on a ride height derived from the position data and a speed derived from the speed data to achieve a target ride height.

A fluid level sensing apparatus is disclosed having an electrode assembly, signal generating circuit, and signal processing circuit. The electrode assembly includes a first electrode disposed along an outer surface of the electrode assembly and a second electrode disposed along the outer surface of the electrode assembly, the second electrode separate from the first electrode. The signal generating circuit is configured to output a repeating pulse signal to the first electrode. The signal processing circuit is electrically coupled to the second electrode and configured to receive the signal conducted through the fluid from the first electrode to the second electrode when the electrode assembly is at least partially submersed in the fluid. The signal processing circuit is configured to output a voltage corresponding to a length of the electrode assembly that is submersed in the fluid based at least in part on the signal received by the signal processing circuit.

A measuring apparatus for detecting a fill level or limit level of a filling material in a container, wherein the measuring apparatus is designed to be situated on the container and comprises a sensor for determining the fill or limit level, a power supply unit which is electrically connected to the sensor and is designed and configured to supply the sensor with electrical power, an activation unit which is connected at least to the power supply unit for signal communication and an associated method of use.

A level measuring device for level and/or limit determination and for measuring an impedance of a filling material is provided. The level measuring device comprises a measuring probe, arranged for measuring the impedance of the filling material. Further comprising a signal generation unit, arranged for generating a first frequency signal with variable frequency, wherein the measuring probe is supplied with the first frequency signal and outputs a measuring signal. Further, a measurement converter arranged to convert the measurement signal into a mixed signal, wherein the mixed signal has a phase difference with respect to the first frequency signal. Furthermore, the level measuring device comprises a phase difference measuring unit, which is arranged to determine an amplitude-phase characteristic of the filling material measured by the measuring probe, by means of the phase and amplitude difference between the first frequency signal and the mixed signal.

Apparatus (1) for determining and/or monitoring at least one process variable, comprising: a primary side (I) and a secondary side (II), which are galvanically isolated from one another, wherein the secondary side (II) has a sensor element sensitive for the process variable (2) and an electronics unit (9) of the secondary side and provides a measurement signal representing the process variable, and wherein the primary side (I) has an electronics unit (8) of the primary side for evaluating the measurement signal and for producing an output signal. The apparatus (1) is distinguished by features including that the electronics unit (9) of the secondary side has a modulation unit (14), which produces a modulated measurement signal by at least at times modulating at least one other piece of information onto the measurement signal representing the process variable, and that the electronics unit (9) of the secondary side transmits the modulated measurement signal via a galvanically isolated interface to the primary side (I).

A method for checking the functional ability of an FMCW-based fill-level measuring device, which serves for measuring the fill level of a fill substance located in a container, as well as to a fill-level measuring device suitable for performing this method. For checking the functional ability, a microwave signal is produced, whose frequency change differs from the frequency change of the measurement signal used during regular measurement operation. By comparing the frequency of the difference signal resulting from the microwave signal with a predetermined reference frequency, it is ascertained, whether the fill-level measuring device is functionally able. Thus, the fill-level measuring device detects, independently, whether it is functionally able, or whether an error is present, caused principally by device-internal disturbance signals. This offers, especially, a clear advantage as regards meeting safety standards for the field device.

The invention provides a level switch having a near field communications facility which allows at least some functions of the switch to be powered and the communication of data between the switch and a reader. Application and calibration information are examples of data that can be read to and from the switch, both in the factory and in the field.

In accordance with at least one embodiment, a method for detecting a liquid level includes providing a container (402) having a cavity, and disposing a sensor (102) in the cavity of the container (402), such that a ground pattern (310) on a first surface of the sensor (102) is positioned to contact a liquid in the cavity. A first electrode (104) and a second electrode (106) are located on a second surface of the sensor (102). The sensor (102) is coupled to a sensor input and a sensor driver. A cable coupling the sensor (102) to a touch sensor (116) comprises a shield line (112, 114) that is coupled to ground.

A method for operating a measuring device having at least one measured value sensor for recording and forwarding measured values of a primary measured variable. To ensure a particularly high reliability and measuring accuracy, the recording of the measured value and/or the forwarding of the measured value is carried out in dependence on the operating state of the measuring device, recording of the measured value and/or the forwarding of the measured value being interrupted during a disturbance. The measuring device is wherein the measured value sensor is designed in such a manner that the recording of the measured value and/or the forwarding of the measured value is carried out in dependence on the operating state of the measuring device, wherein the recording of the measured value or the forwarding of the measured value is interrupted during a disturbance.