Endress + Hauser Gmbh + Co. Kg

Endress+hauserse+co. Kg

Stefan Scherr

Bernhard Michalski

Dominik Buser

Roland Grozinger

Ghislain Daufeld

Arnd Kempa

Disclosed is a transmitting device comprising two galvanically isolated sub-circuits. The first sub-circuit comprises: a carrier signal source for outputting a carrier signal; a digital signal source for outputting binary signal levels; and a logic component for performing an AND operation on two input signals. The second sub-circuit comprises: a signal input; a signal output; and a first RC element, the signal input, the signal output and the RC element being connected in parallel to one another with respect to a second reference potential. A first isolating capacitor is connected between the first logic output and the signal input for galvanic isolation. A second isolating capacitor is connected between the first reference potential and the second reference potential for galvanic isolation.

Transmitting device for transmitting digital signals between galvanically isolated circuit parts, and field device having a transmitting device of this type

An apparatus for ascertaining and monitoring a fill level and includes a transmitting/receiving unit and a delay circuit. The delay circuit includes at least a sampling clocking oscillator, which produces a sampling signal having a sampling frequency, a transmission clocking oscillator, which produces a pulse repetition signal having a pulse repetition frequency, and a frequency converter, which produces by means of sequential sampling a difference signal. The apparatus further includes a control/evaluation unit, which determines on the basis of travel time the fill level. Provided on the control/evaluation unit is an external clocking input, which is connected via a clocking line with a first clocking output of the sampling clocking oscillator or with a second clocking output of the transmission clocking oscillator. A stabilized and cost-favorable control circuit for producing an intermediate frequency signal with a highly accurately determinable, transformation factor results.

Propagation time measuring method for determining a distance

A method for determining the fill level (l) on the basis of the travel time (t) of a high-frequency measuring signal (S), which is transformed into a lower frequency, intermediate-frequency measuring signal (S), wherein the transformation factor (K) is obtained from a difference frequency (f) between a pulse repetition frequency (f) and a sampling frequency (f) The pulse repetition frequency (f) or the sampling frequency (f) is altered on the basis of a control with a control variable (c_var) through an appropriate control algorithm, such that a desired value (f) of the difference frequency is controlled to; wherein a gradient (grad) of at least two values is determined, and on the basis of the gradient (grad) and the difference frequency (f), or difference time (t), in the case of a set control variable (c_var), an operating point (OP) of the control is determined, and the control algorithm is adjusted accordingly thereto.

Growing community of inventors

Kandern, Germany

Stefan Scherr