Abstract: A field device comprising a first loop terminal and a second loop terminal; a measurement unit; a loop current control device for controlling the loop current to encode a process variable determined by the measurement unit, the loop current control device being provided in the electric circuit between the first loop terminal and an a first node of the electric circuit; an asymmetrically conducting device provided in the electric circuit between the first node of the electric circuit and a second node of the electric circuit; an energy storage device in the electric circuit between the second node of the electric circuit and the second loop terminal; and a controllable shunt regulator provided in the electric circuit between the first node of the electric circuit and the second loop terminal, wherein the measurement unit is in the electric circuit between the second node and the second loop terminal.

Abstract: 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.

Abstract: 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.

Abstract: A pulsed radar level gauge comprising a pulse generator configured to generate a transmit signal (ST) in the form of a pulse train, a propagation device connected to direct the transmit signal (ST) into a tank and return a microwave return signal (SR), 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? 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.

Abstract: 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.

Abstract: Packaging for liquid food, where the packaging has an outer casing (2) of cardboard, an inner bag (8) of plastic foil which consists of e.g.

Abstract: A microwave transmission arrangement, comprising a microwave circuit board including a patch; microwave transceiver circuitry coupled to the patch; an electrically conductive hollow waveguide arranged to guide microwave signals between a first end and a second end; and a separator sheet sandwiched between the microwave circuit board and the first end of the hollow waveguide, the separator sheet being configured to allow passage of microwaves between the patch and the hollow waveguide through the separator sheet. The separator sheet is included in an encapsulation separating an encapsulated interior of the microwave transmission arrangement from an exterior outside the encapsulation, the patch, and the microwave transceiver circuitry being in the encapsulated interior, and the hollow waveguide being in the exterior outside the encapsulation.

Abstract: A method of determining a filling level of a product in a tank, comprising, for each transmit pulse repetition frequency in a sequence of different transmit pulse repetition frequencies: generating and transmitting an electromagnetic transmit signal in the form of a pulse train of transmit pulses, the pulse train exhibiting the transmit pulse repetition frequency; propagating the transmit signal towards a surface of the product in the tank; returning an electromagnetic reflection signal resulting from reflection of the transmit signal at the surface back towards the transceiver; receiving the reflection signal; determining a measure indicative of signal disturbance of the reflection signal; evaluating the measure indicative of signal disturbance of the reflection signal in view of a predefined signal disturbance criterion; and determining the filling level based on at least one of the reflection signals fulfilling the signal disturbance criterion.

Abstract: 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 stor

Abstract: 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.

Abstract: A pulsed radar level gauge comprising a pulse generator configured to generate a transmit signal (ST) in the form of a pulse train, a propagation device connected to direct the transmit signal (ST) into a tank and return a microwave return signal (SR), 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? 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

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: 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.

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.