A system and a method for fault detection for a liquid level sensing device are provided. The liquid level sensing device comprising a plurality of switches arranged to measure variance in a liquid level. A sensing signal comprising a plurality of measurements indicative of the liquid level is received from the liquid level sensing device. Each measurement is obtained in response to one or more of the plurality of switches being in a given position at a given liquid level. It is determined, based on the sensing signal, whether the liquid level changed according to one or more expected change patterns. A fault signal is output in response to determining that the liquid level changed according to an abnormal change pattern.

A radar-based, fill-level measurement device for measuring a fill-level of a filling material in a container, the high-frequency unit of which can be checked with regard to its functionality, is designed redundantly and thus comprises two, activatable, high-frequency sources for generating the high-frequency signal and two, activatable receivers for sampling the received signal such that a time-prolonged evaluation signal is generated. As a result, a correspondingly designed diagnosis unit can switch between the active high-frequency source and/or between the active receiver, wherein before and after the switching, a defined property of the evaluation signal, such as a signal amplitude, is ascertained. If the defined property of the evaluation signal changes at least by a defined value as a result of the switching, the high-frequency unit is classified as not functional.

An apparatus for determining a vertical position of at least one interface between a first component and at least one second component, the components comprised as different layers in a sample container. The apparatus comprises a first sensing unit and a first light detector configured to generate a first sensing signal, a second sensing unit comprising a second light detector configured to generate a second sensing signal, a driving unit configured to move the sample container, a position sensing unit configured to output a position sensing signal indicative of a vertical position of the sample container, a vertical position determining unit configured to match the first and the second sensing signal such that first and the second sensing signal correspond to identical vertical positions, and to determine the vertical position of the at least one interface in response to the matched sensing signals and the position sensing signal.

A method for validating a capacitance measurement device including, sending a first drive signal from a capacitance measurement device to a capacitor emulator, modifying the first drive signal by an four quadrant analog multiplier, directing the modified signal across a capacitor to produce a return signal, sending the return signal to the capacitance measurement device to validate the capacitor, and validating the return signal against an expected return signal by the capacitance measurement device.

A fuel cell system includes a fuel cell stack, a gas liquid separator, a water level sensor, a drain valve, and a control unit. When a failure detection processing method is performed, a control unit makes a determination of main conditions where the water level sensor determines that water is present, a power generation current value of the fuel cell stack is not more than a predetermined current threshold value, a drain valve for discharging water in the gas liquid separator is open. Then, the control unit counts elapsed time when the main conditions are satisfied, and in the case where the main conditions are kept satisfied for the elapsed time which is larger than a time threshold value, the control unit determines that the water level sensor has a failure.

The present invention relates to a method for monitoring state of a coil having at least two connection wires, which coil is part of an apparatus for determining at least one process variable of a medium in a containment, as well as relating to an apparatus for executing the method. The method, in such case, includes method steps as follows: ascertaining a desired-value of an ohmic total resistance for the coil and the connection wires, supplying the coil with an electrical excitation signal and receiving an electrical, received signal from the coil by means of the two connection wires, ascertaining an actual-value of the ohmic total resistance based at least on the received signal, and comparing the actual-value with the desired-value and ascertaining a state indicator based on the comparison.

The present invention relates to a method of proof-testing a radar level gauge system arranged to determine a filling level of a product in a tank, the method comprising the steps of: transmitting an electromagnetic transmit signal towards a surface of the product in the tank; receiving an electromagnetic reflection signal resulting from reflection of the transmit signal at the surface of the product; forming a measurement representation based on the transmit signal and the reflection signal, the measurement representation comprising surface echo information indicative of the filling level of the product; adding, to the measurement representation, proof test echo information indicative of a predefined proof test level, resulting in a modified measurement representation; processing the modified measurement representation to determine a proof test level based on the modified measurement representation; and providing a signal indicative of a result of the processing.

Disclosed is a method for determining the serviceability of a fill-level measuring device that includes at least one electronic unit. The method can be applied to any type of field device that includes at least one electronic unit supplied by an energy store of the field device. The method includes: measuring the capacitance of the energy store and/or measuring the power withdrawal at the energy store. The field device is classified as not operationally reliable if the capacitance of the energy store is below a defined minimum capacitance and/or if the power withdrawal deviates from a predefined normal consumption. An advantage of the method according to the invention is that, in addition to the functional diagnosis, in particular also a prediction up to the expected elapsing of the remaining operating time can be created by recording the power withdrawal or the capacitance over progressive measurement cycles.

Methods and apparatus are provided for determining an offset detection for a fuel level sensor fault. The method includes receiving an electrical resistance reading from a potentiometer of a fuel level sensor and generating an estimated fuel level based on an established fuel usage table that references the electrical resistance reading. The fuel level sensitivity is calculated based on the change in electrical resistance readings divided by the change in the estimated fuel levels (R/F). The fuel level sensitivity is compared to a predetermined sensitivity curve to determine any necessary offset to the electrical resistance reading. Finally, the fuel usage table is updated with the offset to the electrical resistance reading.

A fire suppressant storage device (20) comprises: a tank (22) having a first port (40), a second port (70), and an interior (32) for storing fire suppressant. A discharge assembly (46) is mounted to the first port and comprises: a discharge valve (48); and a discharge conduit (50). The discharge conduit is at least partially within the interior and has an interior and an exterior. A liquid level measurement assembly is mounted to the second port and comprises: a tube (100) at least partially within the interior and having: an exterior and an interior sealed relative to the surrounding tank interior. A float (120) surrounds the tube and has one or more magnets (130) and having a range of motion. A plurality of magnetic field sensors (152, 154) are along a carrier (150) within the tube interior. The carrier extends from a proximal end to a distal end. The plurality of magnetic field sensors (152, 154) comprise: a first plurality of one dimensional sensors (152); and at least two three-dimensional sensors distally of the first plurality (154)