Abstract: A radar level gauge system for determining a filling level in a tank. The radar level gauge system comprises a transceiver, a horn antenna having a first opening connected to the transceiver and a second opening facing a surface of the product in the tank, and processing circuitry connected to the transceiver for determining the filling level based on an electromagnetic surface reflection signal. The horn antenna is configured in such a way that an electrical distance from the first opening to the second opening, along a path defined by an intersection between a wall of the horn antenna and a half-plane starting from and extending in parallel with a cone axis of the horn antenna, is different for different orientations of the half-plane with respect to the cone axis. Hereby, disturbance from an antenna reflection signal can be reduced, which provides for improved measurement of high filling levels.

Abstract: A power management circuitry for a radar level gauge including a first voltage converter, having a low-voltage end for receiving a drive voltage from a power interface and a high-voltage end for supplying an intermediate voltage higher than the required operating voltage, a temporary energy store arranged to be charged by the intermediate voltage, a second voltage converter, having a high-voltage end for receiving an input voltage from the energy store, and a low-voltage end for providing the operating voltage lower than the input voltage. By storing energy at a higher voltage, a different type of energy store (e.g. low capacity capacitor) may be used. As a consequence, the cost and start-up time of the energy store is significantly reduced.

Abstract: A radar level gauge system comprising first pulse generating circuitry for generating a transmission signal, second pulse generating circuitry for generating a reference signal; and frequency control circuitry for controlling the second pulse generating circuitry to achieve a predetermined frequency difference between the transmission signal and the reference signal. The radar level gauge system further comprises first frequency selection circuitry configured to provide a higher order harmonic frequency component of the transmission signal to the frequency control circuitry; and second frequency selection circuitry configured to provide a higher order harmonic frequency component of the reference signal to the frequency control circuitry. The frequency control circuitry is configured to control the second pulse generating circuitry based on the higher order harmonic frequency component of the transmission signal and the higher order harmonic frequency component of the reference signal.

Abstract: The invention relates to a method for determining a level of a material interface in a tank, by means of a radar level gauge system comprising a transceiver; a probe for guiding a transmitted electromagnetic signal towards the material interface. The probe comprises a first plurality of reference impedance transitions located above the interface at known physical distances from a reference position, and a second plurality of reference impedance transitions located below the interface at known physical distances from the reference position. The method comprising determining electrical distances to the first and second plurality of reference impedance transitions based on a signal reflected by the reference impedance transition, determining, a first and a second approximation function relating the first and second sets of electrical distance values to the physical distances; and determining the level of the material interface based on the first approximation function and the second approximation function.

Abstract: A method for measurement of a distance to a surface of a product kept in a tank method comprises transmitting a pulse train of distinct carrier wave pulses having a duration greater than 1 microsecond and shorter than 100 milliseconds, the pulse train has an average duty cycle of less than 50 percent, each pulse has a defined center frequency, selected according to a frequency scheme within a predetermined frequency range, greater than 5% of an average center frequency. The method further comprises correlating actual phase properties of received pulses with expected phase properties to provide an updated estimation of the distance. The present invention is based on transmitting a set of carrier wave pulses, each having a distinct frequency selected within a frequency range. The method is therefore referred to as a Frequency Modulated Pulsed Wave (FMPW).

Abstract: The present invention relates to a method of verifying a measurement accuracy of a level gauge system. The method comprises determining a first measurement value indicative of a time-of-flight of a first electromagnetic reflection signal to a reference reflector and back; determining a measurement unit verification measurement value based on a response signal from a verification arrangement; determining a second measurement value indicative of a time-of-flight of a second electromagnetic reflection signal to the reference reflector and back; and determining a verification result based on the first measurement value, the second measurement value and the measurement unit verification measurement value. Through embodiments of the present invention, it will be verified that the measurement unit is functioning correctly and that level gauge system works as it should also after being reconnected to the propagation device.

Abstract: A two-channel directional antenna for use in a radar level gauge. The antenna comprises a partition wall the antenna into a first partition for emitting an electromagnetic transmit signal, and a second partition for receiving an electromagnetic echo signal, the partition wall having an outer potion located downstream in a direction of radiation of the antenna. The partition wall comprises an electromagnetic de-coupling structure, which is arranged to reduce any leakage of electromagnetic energy from the transmit signal into the echo signal. The electromagnetic de-coupling structure according to the present invention ensures that the leakage of transmit signal into the received signal is reduced to a satisfactory level.

Abstract: The present invention relates to a method of determining a filling level of a product contained in a tank by propagating a first transmitted electromagnetic signal in a first frequency range and a second transmitted electromagnetic signal in a second frequency range different from the first frequency range along a transmission line probe towards a surface of the product in the tank, receiving a first reflected electromagnetic signal in the first frequency range and a second reflected electromagnetic signal in the second frequency range, and determining the filling level based on a time-of-flight of the first reflected electromagnetic signal and a difference in time-of-flight of the first reflected electromagnetic signal and the second reflected electromagnetic signal.

Abstract: The invention relates to a test arrangement comprising a waveguide, a first signal reflecting device and a second signal reflecting device. The first signal reflecting device is configured to reflect an electromagnetic signal traveling along the waveguide from the second signal reflecting device back towards the second reflecting device and to allow, at least during a time period, an electromagnetic signal traveling along the waveguide from the second signal reflecting device towards the first signal reflecting device to pass the first signal reflecting device. Hereby, a selected number of passages through a waveguide can be used to simulate passage through a much longer waveguide, and that this allows for use of a high-quality waveguide which would otherwise be too bulky, too heavy or too expensive to use depending on field of application.

Abstract: A device for using electromagnetic pulses to determine a distance to a surface includes a pulse generator, a real time sampler and a calibration unit having a signal generator for generating a calibration signal with a predefined frequency. In a calibration mode the real time sampler receives the calibration signal, and an average sample time delay of the sampler is determined based on the sampled calibration signal and the known calibration frequency. In a measurement mode, the real time sampler receives a reflection signal and the distance is determined based on a sampled reflection signal and the average sample time delay. Knowledge of the average delay of the sampler makes it possible to exactly determine the distance (in time and thus space) between two points in the sampled signal.

Abstract: The present invention relates to a method of controlling a pulsed radar level gauge system, comprising the steps of: acquiring a signal indicative of a present operating temperature; determining an initial frequency control parameter for control of at least one of transmission signal generating circuitry and reference signal generating circuitry based on the present operating temperature and a plurality of data sets each comprising data indicative of a previous operating temperature and a previously determined frequency control parameter for the previous operating temperature; and controlling, starting from the initial frequency control parameter, at least one of the transmission signal generating circuitry and the reference signal generating circuitry to achieve the known frequency difference between the first pulse repetition frequency and the second pulse repetition frequency at the present operating temperature.

Abstract: The present invention relates to a method comprising providing an activation signal from a wireless communication unit to a measurement unit to switch the measurement unit from its inactive state to its active state; providing a measurement request signal to the measurement unit to request measurement of a filling level of a product in a tank; and thereafter switching the wireless communication unit from its active state to its inactive state. The measurement unit measures the filling level and provides a measurement ready signal to the wireless communication unit; the wireless communication unit is switched from its inactive state to its active state in response to the measurement ready signal received from the measurement unit; the wireless communication unit retrieves the value indicative of the filling level from the measurement unit; and wirelessly transmits the value indicative of the filling level to the remote device.

Abstract: A radar level gauge for determining a filling level of a product contained in a tank. The gauge has a sealing arrangement comprising a hollow housing, a conductor-; and a dielectric sleeve arranged inside the housing and surrounding the conductor. At least one gap is formed between the dielectric sleeve and an' adjacent, electrically conducting surface, the gap having a first end which is open to an interior of the tank, so that in use, tank atmosphere may enter and condensate in the gap. The sealing arrangement further comprises an electrically conducting coating provided on a surface of the dielectric sleeve facing the gap, and in electrical contact with said adjacent, electrically conducting surface, so that an impedance between the electrically conducting coating and the adjacent electrically conducting surface is sufficiently low at an operating frequency of the gauge to reduce an influence of any medium present in the gap.

Abstract: A level gauge using microwaves to determine a distance to a surface of a product in a tank, wherein a measurement signal comprises a first frequency sweep, and a second frequency sweep, and a mixer is arranged to mix the measurement signal with an echo signal to form a first IF signal based on the first frequency sweep, and a second IF signal based on the second frequency sweep. Processing circuitry is adapted to sample the first IF signal and the second IF signal, to form a combined sample vector including samples from each tank signal, and to determine the distance based on the combined sample vector. By combining the samples from two (or more) different sweeps, the number of samples and the bandwidth can both be increased, thus maintaining the range L. However, as the samples are obtained from two separate sweeps, the sweep time for each individual sweep does not need to be increased, and the average power consumption can be maintained.

Abstract: A loop-powered field device for determining a process variable and providing a measurement signal indicative of the process variable to a remote location via a two-wire current loop, the loop-powered field device comprising: a measurement device for determining the process variable; and loop interface circuitry for providing the measurement signal to the two-wire current loop and for providing power from the two-wire current loop to the measurement device.

Abstract: A process measurement instrument adapted for wireless communication, comprising a measurement unit (7) arranged to determine a measurement value of a process variable, a memory (21) arranged to store a current measurement value of the process variable, a wireless communication unit (8), arranged to access the current measurement value and communicate the current measurement value over a wireless communication channel according to a protocol with intermittently active communication, and arbitration logic (22), in communication with the measurement unit and the wireless communication unit, and arranged to ensure that active periods of the measurement unit occur when the wireless communication is inactive. The measurement unit and communication unit are thus able to share information via the common memory, e.g. by sequential read/write access. This avoids the need for simultaneous activity.

Abstract: A radar level gauge for determining the filling level of a product in a tank, comprising a transceiver for transmitting and receiving microwaves, processing circuitry connected to the transceiver and adapted to determine the filling level, an antenna connected to said transceiver and arranged to emit and receive microwaves through an opening of the tank, and a microwave transmissive sealing member adapted to cover said opening and to provide pressure sealing of the tank. The sealing member comprises a metal grid layer providing structural strength, which metal grid layer has sealed openings formed to allow transmission of microwaves. The tank opening is thus divided into a number of smaller openings by the metal grid, thereby improving the mechanical strength of the sealing member. At the same time, the sealing member is designed to maintain its pressure sealing properties, e.g. by suitable dielectric filling of the openings.

Abstract: A radar level gauge system, for determining a filling level of a product contained in a tank, the radar level gauge system comprising: a transceiver for generating, transmitting and receiving electromagnetic signals; a propagating device electrically connected to the transceiver and arranged to propagate a transmitted electromagnetic signal towards a surface of the product contained in the tank, and to return echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signal, including a surface echo signal resulting from reflection at the surface, back to the transceiver; processing circuitry connected to the transceiver and configured to determine the filling level based on the surface echo signal; and a bottom reflector arranged at a bottom of the tank.

Abstract: The present invention relates to a gauging system, comprising a gauge configured to sense a process variable and to provide process data representative of the process variable, a processing unit connected to the gauge, the processing unit comprising power supply circuitry configured to receive power from a remote external power source and to provide regulated power, and first circuitry configured to receive process data from the gauge and to superimpose the process data onto the regulated power forming a power signal, and a wireless communication unit electrically connected to the processing unit by means of a two-wire control loop, the wireless communication unit comprising second circuitry configured to receive the power signal and to separate the process data from the regulated power, an antenna, and radio frequency (RF) communication circuitry being powered by means of the regulated power from the second circuitry, configured to receive process data from the second circuitry, and to transmit RF signals re

Abstract: The present invention relates to a method for determining a distance between a wireless transceiver and a wireless receiver arranged to communicate with each other in a wireless communication network, the wireless receiver having an active and an inactive reception state, the method comprising transmitting, with the wireless receiver in the active reception state, a first transmission signal, receiving a first reflection signal, the first reflection signal being a reflection of the first transmission signal and influenced by the active reception state of the wireless receiver, transmitting, with the wireless receiver in the inactive reception state, a second transmission signal, receiving a second reflected signal, the second reflection signal being a reflection of the second transmission signal and influenced by the inactive reception state of the wireless receiver, and determining a distance between the wireless transceiver and the wireless receiver based on the second reflection signal.