Endress+hauserse+co. Kg

Markus Vogel

Alexey Malinovskiy

Stefan Gorenflo

Jens Merle

Ghislain Daufeld

Dietmar Spanke

Harald Faber

Johannes Baureithel

Anton Kochetkov

In an FMCW-based fill-level measurement device, the fill-level value can be compensated with regard to component tolerances. A diagnosis unit of the fill-level measurement device compares the clock rate of the signal-generating PLL with the sampling rate of the analog/digital converter and determines a first compensation factor. With the aid of the first compensation factor, the determined fill-level value can be compensated with regard to these sampling or clock rates without any external high-precision reference source having to be used for this purpose.

Fill-level measurement device

Disclosed is a method for detecting an event-based state, such as foam formation or a working stirring mechanism in a container during a radar-based measurement of a fill level of a filler located in a container. The method includes: generating an analysis curve and detecting a specified characteristic value of the analysis curve within at least one specified sub-region of the measurement region. The characteristic value can be the amplitude of a local maximum or the area under the analysis curve for example. A change or a dispersion of the characteristic value is ascertained over proceeding measurement cycles. The fill level measuring device detects the event-based state if the change or the dispersion exceeds a corresponding threshold. Thus, the occurrence of different events in the container can be imparted to a system controller automatically and without additional measurement instruments.

Detection of event-based states during a fill level measurement

The present disclosure relates to a method for compressing an evaluation curve, which is recorded during a radar-based fill level measurement of a filling material located in a container, and to a corresponding fill level measurement device for carrying out the method. Corresponding to the compression method according to the present disclosure, the present disclosure comprises a corresponding method for decompressing the compressed evaluation curve. The compression method is characterized in that the compression occurs using linear prediction, by corresponding estimation coefficients and an error curve being created. This makes use of the finding according to the present disclosure that evaluation curves can be compressed for diagnostic purposes, in particular in the case of FMCW-based fill level measurement, efficiently and without data loss using the model of linear prediction.

Method for data compression during fill level measurement

Disclosed is a method for a radar-based fill level measurement according to the pulse transit time method. Also disclosed a fill level measuring device for carrying out said method. On the basis of an evaluation signal, the relation between the clock rate and the sampling rate, and a predefined target relation, an evaluation curve is generated. The fill level is thereby determined on the basis of said evaluation curve. The evaluation curve is generated by means of temporal expansion or compression of the evaluation signal, wherein the compression or the expansion is carried out as a function of a ratio between the measured relation and the target relation. Any deviation of the sampling rate from the setpoint value of the sampling rate, for example due to faulty control, is compensated. Thus, the potentially attainable accuracy of the fill level measurement is increased due to the invention.

Fill level measuring device

A method for checking the functional ability of an FMCW-based fill-level measuring device, which serves for measuring the fill level of a fill substance located in a container, as well as to a fill-level measuring device suitable for performing this method. For checking the functional ability, a microwave signal is produced, whose frequency change differs from the frequency change of the measurement signal used during regular measurement operation. By comparing the frequency of the difference signal resulting from the microwave signal with a predetermined reference frequency, it is ascertained, whether the fill-level measuring device is functionally able. Thus, the fill-level measuring device detects, independently, whether it is functionally able, or whether an error is present, caused principally by device-internal disturbance signals. This offers, especially, a clear advantage as regards meeting safety standards for the field device.

Method for checking the functional ability of a radar-based fill-level measuring device

A method for determining an inner diameter of a sounding tube, which, for measuring the fill level of a fill substance located in a process space of a container, extends in the process space, or is placed alongside the container and connected with the process space. The method can be implemented in the case of a fill-level measuring device working according to the FMCW-principle. Besides the intermediate frequency of the difference signal, also its phase shift is ascertained, wherein the exact tube inner diameter can be determined based on the phase shift. An advantage of the method is that the fill-level measuring device with the help of the then exactly known tube diameter can be recalibrated and accordingly the fill level determined more exactly. The exact tube inner diameter does not have to have been previously known.

Method for determining an inner diameter of a sounding tube by a fill-level measuring device

A method for measuring fill level and a measuring device for performing the method, wherein, in measuring cycles following one after the other, signal pulses of predetermined frequency sent by means of a transmitting and receiving system with a predetermined repetition frequency into a container, and their signal components reflected back in the container in the direction of the transmitting and receiving system after a travel time dependent on their traveled path, are received as received signal. A fill level is measured taking into consideration a phase relationship between the transmitted and received signals related physically with the fill level to be measured. In each measuring cycle, based on the received signal, an auxiliary signal is derived reflecting amplitude and phase information in the received signal as a function of travel time, based on the auxiliary signal, a travel time of a signal fraction reflected on a surface of the substance is determined as fundamental travel time are determined, based on the travel times of the zero crossings of the auxiliary signals determined in the current and in a plurality of preceding measuring cycles, a phase appearance-frequency distribution is derived as a function of travel time, which gives appearance-frequencies, with which zero crossings were present on the respective travel times in the associated auxiliary signals, a travel time of a maximum of the frequency distribution lying nearest the fundamental travel time is determined as fill level travel time, and the fill level is determined based on the fill level travel time.

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Schopfheim, Germany

Markus Vogel