Rosemount Tank Radar Ab

Tomas Wennerberg

Olov Edvardsson

Mikael Eriksson

Lars-Ove Larsson

Christian Skaug

Michael Larsson

Pär Abrahamsson

Tobias Lilja

Thense Korsbo

Mikael Inglund

Marcus Grahn

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.

Proof test of radar level gauge system

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.

Method and device for providing an indication of the reliability of a process parameter value to a host system

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.

User interface for radar level gauge analysis

The present invention relates to a radar level gauge comprising a reference reflector arranged at a known reference reflector level in a tank. The radar level gauge is controllable between a filling level measuring state and a proof test state. In the proof test state, the radar level gauge is configured to determine a first verification level based on a reference reflector echo resulting from reflection of an electromagnetic transmit signal at the reference reflector; determine a second verification level based on a surface echo resulting from reflection of an electromagnetic transmit signal at the surface of the product; and provide the first verification level and the second verification level to allow determination of a proof test result based on at least the first verification level, the known reference reflector level and the second verification level.

Radar level gauge and methods of testing radar level gauge and system

A method of monitoring operation of a radar level gauge system installed at a tank and arranged to determine a filling level of a product contained in the tank. The method comprises the steps of: providing a first propagation property discontinuity at a first distance from a reference position at a top of the tank; generating and transmitting an electromagnetic signal; propagating the transmitted electromagnetic signal towards the product contained in the tank; receiving a reflected electromagnetic signal comprising a plurality of echoes resulting from reflections at propagation property discontinuities encountered by the transmitted electromagnetic signal, including a first reference echo resulting from reflection at the first propagation property discontinuity and a surface echo resulting from reflection at a surface of the product contained in the tank; identifying the surface echo; determining the filling level based on the surface echo; evaluating a first portion of the reflected electromagnetic signal exhibiting a time-of-flight corresponding to the first distance from the reference position; determining, based on the evaluation, whether or not the first reference echo is detectable in the first portion of the reflected electromagnetic signal. If it is determined that the first reference echo is detectable in the first portion of the reflected electromagnetic signal, a first signal indicative of the filling level is provided; and if it is determined that the first reference echo is non-detectable in the first portion of the reflected electromagnetic signal, a second signal different from the first signal is provided.

Radar level gauge system with operation monitoring functionality

A pulsed radar level gauge, comprising a transmitter for generating and transmitting a signal in the form of a pulse train, means for receiving pulses reflected in said tank, and to form an analogue tank signal based on these reflections, an analogue to digital converter for sampling and digitizing said tank signal and forming a digital time domain reflectometry (TDR) signal, and means for varying the output power of said transmitter during the transmission of said pulse train, in order to adjust an amplitude of said analogue tank signal to match the dynamics of said A/D-converter. A gain function applied on the receiver side is thus replaced by varying the output power on the transmitter side. This allows the signal-to-noise ratio to be improved, as the noise will not be amplified together with the signal.

Radar level gauge with variable transmission power

A method and a system for radar-based gauging of a filling level of a filling material is disclosed, wherein the tank has at least one interfering structure. The method comprises: transmitting at a first time moment a microwave signal towards the surface of the filling material; receiving microwave signals as reflected against the surface of the filling material and as reflected against said at least one interfering structure; calculating based on propagation times of the transmitted and reflected microwave signals at least two distances to reflective surfaces in the tank; and repeating at a second time moment the transmitting, the detecting and the calculating, wherein said first time moment is timely separated from said second time moment. Based on the several repeated measurements, the distance to the surface of the filling material is determined as the calculated distance that exhibits the greatest change between said first and second time moments. Based on this time difference analysis, it is possible to discinguish moving surfaces very easy and acurate. The method is specifically advantageous in overfill or high level alarm systems.

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Kallered, Sweden

Tomas Wennerberg