Rosemount Tank Radar Ab

Saab Rosemount Tank Radar Ab

Saab Marine Electronics Ab

Leif Nilsson

Håkan Nyberg

Håkan Delin

Mikael Eriksson

Olov Edvardsson

Håkan Fredriksson

Mikael Kleman

Magnus Ohlsson

Niklas Penndal

Håkan Samor

Tobias Lilja

Thomas Lundin

Hans Arkesten

A field device comprising measurement circuitry; loop current circuitry; voltage measurement circuitry; and a controller configured to: acquire a first value of a process variable; determine if the voltage received by the field device is sufficient to support a first loop current; control, when the voltage is insufficient to support the first loop current, the loop current to an alarm current lower than a predefined alarm threshold current; acquire a second value of the process variable and a present voltage received by the field device; determine a second loop current; determine, based on the present voltage and an estimation of a loop impedance, whether or not the present voltage is sufficient for supporting the second loop current; and control, when it is determined that the present voltage received by the field device from the current loop is sufficient, the loop current from the alarm current to the second loop current.

Alarm handling in loop-powered field device

Radar level gauge system comprising: a communication module configured to be connected to an external communication device; a measurement module configured to generate, transmit and receive a measurement signal; a control connection configured to connect the communication module to the measurement module, the control connection being configured to be in a high-impedance mode at least during a measurement by the measurement module; a power supply configured to provide power to the measurement module; an energy storage coupled to the power supply; a measurement connection connecting the communication module to the energy storage, wherein the energy storage is arranged to be charged by the measurement connection and configured to provide power to the power supply for performing a measurement by the measurement module; and a switch arranged between the communication module and the energy storage, the switch being controllable to break the measurement connection between the communication module and the energy storage during a measurement by the measurement module.

Radar level gauge system and method for controlling the radar level gauge system

A guided wave radar level gauge comprising a housing providing explosion proof protection and having an intrinsically safe output, a transmission line probe connected to the IS output. The housing encloses radar level gauge circuitry which is incompatible with intrinsic safety requirements, a microwave unit connected to the IS output, an electrical barrier connected between the RLG circuitry and the microwave unit, the electrical barrier having a barrier ground potential which is independent from the grounded housing wall, and a set of blocking capacitors connected between the microwave unit and the IS output.

Guided wave radar level gauge with explosion proof housing and floating barrier

A pulsed radar level gauge comprising a pulse generator configured to generate a transmit signal (S) in the form of a pulse train, a propagation device connected to direct the transmit signal (S) into a tank and return a microwave return signal (S), a receiver, sampling circuitry configured to provide a time expanded tank signal, and processing circuitry for determining said filling level based on the time expanded tank signal. The gauge further comprises impedance increasing circuitry arranged to ensure that an input impedance of the receiver is at least 2 k&#x3a9; and a delay line arranged between said receiver and said propagation device, the delay line configured to introduce a delay greater than said pulse duration, such that said time expanded signal includes a transmitted pulse.

Pulsed radar level gauge with feedback of transmit pulse

A guided wave radar level gauge comprising an explosion proof housing with an intrinsically safe (IS) output, a resistor having a first terminal connected to the IS output and a second terminal connected to the housing ground potential, and a transmission line probe connected to the IS output. The housing encloses radar level gauge (RLG) circuitry and a microwave unit having a floating ground potential, and a set of blocking capacitors connected between the microwave unit and the IS output. The microwave unit includes a differential receiver, having a first terminal connected to the IS output via the set of blocking capacitors, and a second terminal connected to the housing ground potential via the set of blocking capacitors, a voltage between the first and second terminals forming an input signal to the differential receiver.

Guided wave radar level gauge having an explosion proof housing with an intrinsically safe output

A radar level gauge comprising a housing enclosing a compartment providing explosion proof protection, RLG circuitry located inside compartment, which circuitry is incompatible with intrinsic safety requirements, and a signal propagation device located outside the compartment. The housing has an explosion proof first signal passage providing a transmission line for the microwave transmit signal, and an explosion proof second signal passage in providing a two-wire interface for electrically conductively connecting the radar level gauge to an intrinsically safe system located externally of the radar level gauge. Further, the RLG includes an electrical barrier connected between the RLG circuitry and the two-wire interface, the electrical barrier preventing energy and/or thermal energy in the RLG circuitry from compromising the intrinsic safety of an intrinsically safe system connected to the two-wire interface.

Explosion proof radar level gauge

The present invention relates to a field device adapted to determine a process parameter value related to a tank, the field device comprising a terminal block with: a first interface configured to connect to two wires of a loop; a first electrical conductor and a second electrical conductor for connecting the first interface with field device electronics, the second electrical conductor having a voltage drop generating element; a first power supply conductor connected to said second electrical conductor upstream of the voltage drop generating element and a second power supply conductor connected to said second electrical conductor downstream of the voltage drop generating element; and a second, auxiliary interface adapted for wired connection to an external device and configured at least for communication with said external device, wherein the second auxiliary interface comprises a communications connector which is galvanically isolated from the field device electronics.

Field device with second auxiliary interface

A radar level gauge system, for determining a filling level of a product in a tank. The radar level gauge system includes a transmission line probe arranged inside the tank; a tank feed-through for mechanically attaching the transmission line probe to a tank wall of the tank through a non-conductive mechanical connection between the transmission line probe and the tank wall, and for providing a conductive electrical connection to the transmission line probe from outside the tank; and a measurement electronics unit arranged outside the tank. The measurement electronics unit includes: a transceiver; an electrical filter circuit having an input coupled to the transceiver and an output coupled to the transmission line probe via the tank feed-through, the electrical filter circuit exhibiting a series capacitance for non-conductively coupling the transceiver to the transmission line probe via the tank feed-through; and processing circuitry for determining the filling level.

Radar level gauge system with feeding comprising an electrical filter

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.

Pulsed level gauge system with temperature-based control of pulse repetition frequency

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.

Pulsed radar level gauging with efficient start-up

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. If the acquired signal indicates that the time between the previous filling level determination and the present filling level determination is longer than the predefined time, the frequency control circuitry iteratively regulates at least one of the transmit signal generating circuitry and the reference signal generating circuitry towards achieving a desired pulse repetition frequency difference between the pulse repetition frequency of the transmit signal and the pulse repetition frequency of the reference signal.

Pulsed level gauge system and method

A method of determining a filling level of a product contained in a tank using a level gauge system, comprising the steps of: transmitting a first signal towards a surface of the product; receiving a first echo signal; determining a present echo characteristic value based on the first echo signal; and comparing the present echo characteristic value and a stored echo characteristic value. If a difference between the present echo characteristic value and the stored echo characteristic value is greater than a predefined value, the method further comprises transmitting at least a second transmit signal towards the surface; receiving at least a second echo signal; and determining the filling level based on the at least second electromagnetic echo signal.

Intermittent filling level determination with dynamically determined number of measurements

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.

Battery-powered level gauge system adapted for wireless communication

The method comprises the steps of generating a transmission signal; propagating the transmission signal towards the product; receiving a reflected signal; providing a reference signal exhibiting a time-varying phase difference in relation to the transmission signal; forming a measurement signal; and determining the filling level based on the measurement signal. The method further comprises the steps of: determining a reduced time period comprising a time when the time-varying phase difference corresponds to an anticipated filling level, the reduced time period being shorter than the measurement sweep time period; controlling the level gauge system to change from a low-power state to a high-power state at a start of the reduced time period; and controlling the level gauge system to change back from the high-power state to the low-power state at an end of the reduced time period.

Pulsed level gauge system with adaptive transceiver control

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.

Growing community of inventors

Linköping, Sweden

Leif Nilsson