Method for determining fill level on the basis of travel time of a high-frequency measuring signal
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Abstract
A method for determining the fill level (l) on the basis of the travel time (t) of a high-frequency measuring signal (SHF), which is transformed into a lower frequency, intermediate-frequency measuring signal (SZF), wherein the transformation factor (KT) is obtained from a difference frequency (fSweep) between a pulse repetition frequency (fPRF) and a sampling frequency (fsample) The pulse repetition frequency (fPRF) or the sampling frequency (fsample) is altered on the basis of a control with a control variable (c_var) through an appropriate control algorithm, such that a desired value (fSweepsetpoint) 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 (fSweep), or difference time (tSweep), 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.
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Citations
22 Claims
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1-11. -11. (canceled)
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12. A method for determining the fill level (l) in a container on the basis of the travel time (t) of a high frequency measuring signal (SHF), which, by means of a transformation method with a certain transformation factor (KT), is transformed into a lower frequency, intermediate-frequency signal (SZF), comprising the steps of:
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producing the transformation factor (KT) and obtained from a difference frequency (fSweep), or a difference time (tSweep), of a difference signal (SSweep) between a pulse repetition signal (SPRF) having a pulse repetition frequency (fPRF), and a sampling signal (Ssample) having a sampling frequency (fsample);
altering the pulse repetition frequency (fPRF), and/or the sampling frequency (fsample), on the basis of a control with control variable (c_var), through a corresponding control algorithm, such that the difference frequency (fSweep) is controlled to a desired value (fSweepsetpoint) of the difference frequency, or the difference time (tSweep) is controlled to a desired value (tSweep—
setpoint) of the difference time;
determining a gradient (grad) between at least two values of the difference frequency (fSweep), or between at least two values of the difference time (tSweep), as a function of the control variable (c_var); and
determining, on the basis of the gradient (grad) and the difference frequency (fSweep), or difference time (tSweep), at a set control variable (c_var), an operating point (OP) of the control, and the control algorithm is adjusted accordingly thereto. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification