Abstract: A radar level gauge system comprising: a transceiver arrangement; a first probe to guide a first transmit signal through a surrounding medium towards a product in the tank, and to return a first surface echo signal, the first probe being configured to guide the first transmit signal with a first propagation velocity exhibiting a first dependence on a dielectric constant of the surrounding medium; a second probe to guide a second transmit signal through the surrounding medium towards the product, and to return a second surface echo signal, the second probe being configured to guide the second transmit signal with a second propagation velocity exhibiting a second dependence, different from the first dependence, on the dielectric constant of the surrounding medium; and processing circuitry for determining the filling level based on the first surface echo signal, the second surface echo signal, and a known relation between the first dependence and the second dependence.

Abstract: A radar level gauge system, comprising a transceiver; an antenna; a feed-through connecting the transceiver and the antenna; and processing circuitry coupled to the transceiver.

Abstract: A method of determining a filling level of a product in a tank, comprising generating and transmitting a transmit signal; propagating the transmit signal towards a surface of the product along a signal propagation path comprising a first portion having known signal propagation properties adjacent to the transceiver and a second portion adjacent to the first portion; receiving a reflection signal resulting from reflections at impedance transitions encountered by the transmit signal, including the surface of the product; determining a first measurement relation based on a timing relation between the transmit signal and the reflection signal; determining a second measurement relation based on the first measurement relation and the known signal propagation properties; and determining the filling level based on the second measurement relation.

Abstract: A radar level gauge system comprising: a transceiver; a tank feed-through; a power divider to divide a transmit signal into a first transmit signal and a second transmit signal; a first probe member configured to guide the first transmit signal and to return a first reflection signal, said first probe member providing a first relatively large average attenuation; a second probe member configured to guide said second transmit signal and to return a second reflection signal, said second probe member providing a second relatively small average attenuation; measurement signal forming circuitry for forming a measurement signal comprising a first set of echo indicators indicating reflection of said first transmit signal, and a second set of echo indicators indicating reflection of said second transmit signal; and level determining circuitry for determining a first level based on said first set of echo indicators, and a second, deeper, level based on said second set of echo indicators.

Abstract: A radar level gauge system controllable between a measurement state and a signal processing state. In the measurement state a first timing signal circuit is enabled, a microwave signal source generates a transmit signal with a time-varying frequency being related to first timing signals from the first timing signal generating circuitry, and a sampler samples a mixer signal at sampling times related to the first timing signals. in the signal processing state, the first timing signal circuit is disabled, and a signal processor determines the filling level based on the sampled values of the mixer signal using second timing signals from a second timing signal generating circuit.

Abstract: A pulsed radar level gauge for determining the filling level of a product contained in a tank, comprising a frequency generator for generating a Tx frequency signal and a Rx frequency signal. The frequency generator includes one single oscillating crystal for providing an oscillator frequency fosc and frequency modifying circuitry. The frequency modifying circuitry comprises a path including a PLL configured to receive said oscillator frequency fosc as input frequency and deliver a regulated output frequency being equal to the oscillator frequency fosc multiplied M/N, and a frequency divider connected to receive the regulated output frequency and deliver an output frequency equal to the regulated output frequency divided by an integer factor P. A PLL combined with an integer frequency divider is used to generate at least one of the Tx and Rx frequencies based on an oscillator frequency provided by one single oscillator.

Abstract: A radar level gauge comprising a physical communication interface bi-directional communication of data structured according to either a first digital communication protocol or a second digital communication protocol, first communication circuitry for communicating measurement data from the field device, second communication circuitry for enabling configuration of the field device, protocol identification circuitry connected to the communication interface for intercepting data and configured to parse intercepted data to identify the digital communication protocol, and control circuitry for directing the intercepted data to one of the first and second communication circuitries based on the identified protocol.

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 radar level gauge system for a tank having a tubular mounting structure. The radar level gauge system comprises a transceiver; a single conductor probe extending through the tubular mounting structure; an electrically conductive shielding structure radially spaced apart from the single conductor probe and extending along the single conductor probe inside the mounting structure; a connecting member extending radially from the shielding structure to electrically couple the shielding structure to the tank; and processing circuitry connected to the transceiver for determining the filling level.

Abstract: A field device for determining a process parameter value, comprising a measurement device for determining a process parameter value; circuitry for determining the reliability of the process parameter value; and signaling circuitry for providing the process parameter value and an indication of the reliability of the process parameter value to a host system via a current loop. The signaling circuitry is configurable between a first state in which the indication of the reliability is provided as a digital signal and the process parameter value is provided as an analog DC-value, and a second state in which the indication of the reliability is provided as a predetermined analog DC-value. Hereby, the number of unplanned process interruptions may be reduced when the host system is capable of receiving digital signals.

Abstract: The present invention relates to a 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 field device comprises a measurement device for determining the process variable; a current control device electrically connected in series with the measurement device and controllable by the measurement device to provide the measurement signal to the two-wire current loop; and voltage regulation circuitry electrically connected in series with the current control device and the measurement device for controlling a voltage across the current control device towards a desired voltage by varying a voltage across the voltage regulation circuitry.

Abstract: A method for analyzing a level gauge, comprising storing in a storage device a consecutive sequence of data triplets including a time stamp, a filling level measurement, and an echo curve information, plotting a trend line including filling level as a function of time, graphically indicating a pointer in the trend line, displaying an echo curve corresponding to a point in time initially represented by the pointer, receiving user input indicating a set of points along a section of the trend line selected for analysis, and for each point in the set of points, moving the pointer to this point and replacing contents of the second graphical element, such that an echo curve displayed in the second graphical element always corresponds to a point in time represented by a current position of the pointer. The invention enables a user to analyze operation of the level gauge during a time period corresponding to the selected trend line section.

Abstract: A level gauge for detecting process variables related to a distance to a surface of a content in a tank, includes a first and second functionally independent circuitry arrangements comprising transceiver circuitry and processing circuitry. The gauge further comprises a power divider providing isolation between signals having the same propagation mode, a single wire transmission line probe, and a matching arrangement providing an electrically matched connection between the electrical connection of a process seal and the single wire transmission line probe. A combination of a power divider with a matching arrangement allows multiple channels on one single wire transmission line probe.

Abstract: Method for determining product surface distance in a tank comprising: i) generating a transmission signal as a first pulse train; ii) generating a reference signal having a second pulse train by time delaying said first pulse train; wherein each pulse in said first and second pulse trains have essentially identical waveforms and pulse repetition frequency; iii) guiding said transmission signal towards the product surface; iv) receiving a reflected signal; v) forming a correlation value based on a time correlation between the reference signal and the reflected signal; vi) carrying out steps i) to v) in sequence for at least three different pulse repetition frequencies, until at least three pairs of correlation values and associated pulse repetition frequencies have been stored; vii) determining said distance based on said at least three pairs of correlation values and associated pulse repetition frequencies, and said fixed time delay.

Abstract: A method for powering a radar level gauge, comprising an initial frequency stabilization procedure, ensuring a stable separation frequency between a first and a second clock frequencies, during which frequency stabilization procedure said radar level gauge is not powered to provide a level output, and a subsequent measurement cycle, performed only when a stable separation frequency has been established, during which said radar level gauge is powered to provide a level output. The present invention allows a radar level gauge system to save power by not providing power to and operating the radar level gauge circuit during such times when the frequency separation would not enable the radar level gauge to provide proper level measurements.

Abstract: A method for providing narrow-band interference unaffected measurement of a distance to a surface of a product kept in a tank, comprising mixing a return signal with a transmit signal to provide an intermediate frequency signal, and determining the distance, based on the intermediate frequency signal. The step of determining the distance further comprises dividing the intermediate frequency signal into a plurality of frequency portions, wherein each frequency portion corresponds to a frequency interval of the transmit signal, identifying disturbed frequency portions as frequency portions affected by narrow-band interference, and determining the distance based on frequency portions being unaffected by narrow-band interference. By dividing the IF-signal into frequency portions corresponding to frequency intervals of the transmit signal, frequency intervals where narrow-band interferences are present may be detected.

Abstract: A radar level gauge arrangement for determining the fill level of a filling material in a tank is disclosed, which arrangement is mounted on a hatch of a tank and/or on a support which is adapted to be mounted on a hatch of a tank. The arrangement comprises a transmitter for transmitting measuring signals at least along a first axis for determining the fill level of the tank; a receiver for receiving echo signals corresponding to the distance to the surface; a first processing circuitry for receiving the echo signals and to determine a fill level of the tank based on the echo signal; an inclinometer attached to the support and adapted to generate an inclination output corresponding to the inclination relative the surface normal; a second processing circuitry for generating, based on the inclination output, an angular output when there is an angular difference between the first axis and the surface normal.

Abstract: The present invention relates to a guided wave radar level gauge for determining a filling level of a product contained in a tank, said guided wave radar level gauge i.a. comprising a probe comprising a plurality of elongate probe sections each being pivotably connected to an adjacent probe section by means of a joint, said joint allowing probe sections to pivot between an operating state where said probe sections are substantially aligned along a straight line, and a transporting state. The present invention also relates to a probe, and to a method for arranging a guided wave radar level gauge in a tank.

Abstract: The present invention relates to a radar level gauge system comprising a first receiver branch for converting a reflection signal to a first digital measurement signal, and a second receiver branch configured to convert the reflection signal to a second digital measurement signal. The first receiver branch modulates an amplitude of the first measurement signal according to a first gain function, and the second receiver branch modulates an amplitude of the second measurement signal according to a second gain function different from the first gain function. The radar level gauge system further comprises processing circuitry configured to determine the filling level based on the first measurement signal and the second measurement signal.

Abstract: The present invention relates to a pulsed level gauge system comprising frequency control circuitry. If an acquired signal indicates that the time between the previous filling level determination and the present filling level determination is shorter than a predefined time, the frequency control circuitry controls at least one of a transmit signal generating circuitry and a reference signal generating circuitry comprised in the pulsed level gauge system using previous frequency control settings stored in memory.