Fill-level measurement device

Patent metadata

Field	Value
Publication number	US-12345559-B2
Application number	US-202118252122-A
Country	US
Kind code	B2
Filing date	Sep 23, 2021
Priority date	Nov 11, 2020
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

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.

First claim

The invention claimed is:

1. A frequency modulated continuous wave (FMCW)-based, fill-level measurement device for measuring a compensated fill level value of a filling material in a container, comprising:
a transmission unit via which a high-frequency signal can be transmitted in a direction of the filling material and, after reflection at the filling material surface, can be received as a received signal;
a signal generation unit designed to generate the high-frequency signal according to an FMCW principle and with reference to a defined clock rate;
a receiving unit designed to:
downmix the received signal into a low-frequency base signal in accordance with the FMCW principle; and
sample the base signal at a defined sampling rate;

an evaluation unit designed to:
determine a distance value from the filling material by using the sampled base signal;
compensate the distance value using a first compensation factor and/or a second compensation factor;, and
determine the compensated fill-level value with the aid of the compensated distance value; and

a diagnosis unit designed to:
determine the first compensation factor by comparing the clock rate with the sampling rate;
determine the second compensation factor by comparing the clock rate and/or the sampling rate with a reference frequency and/or the first compensation factor; and
transmit the first compensation factor or the second compensation factor to the evaluation unit.

2. The fill-level measurement device according to claim 1 , further comprising:
a production interface,
wherein for transmitting the first compensation factor, the second compensation factor, the clock rate, the sampling rate, and/or an external reference frequency, the fill-level measurement device can be connected via the production interface.

3. The fill-level measurement device according to claim 1 , wherein the signal generation unit is realized as a phase-locked loop.

4. The fill-level measurement device according to claim 1 , wherein the evaluation unit is designed to determine the distance value via a Fourier transform of the sampled base signal.

5. A method for compensating a fill-level measurement device, the method comprising:
providing the fill-level measurement device, including:
a transmission unit via which a high-frequency signal can be transmitted in a direction of a filling material and, after reflection at the filling material surface, can be received as a received signal;
a signal generation unit designed to generate the high-frequency signal according to an FMCW principle and with reference to a defined clock rate;
a receiving unit designed to:
downmix the received signal into a low-frequency base signal in accordance with the FMCW principle; and
sample the base signal at a defined sampling rate;

an evaluation unit designed to:
determine a distance value from the filling material by using the sampled base signal;
compensate the distance value using a first compensation factor and/or a second compensation factor; and
determine the compensated fill-level value with the aid of the compensated distance value; and

a diagnosis unit designed to:
determine the first compensation factor by comparing the clock rate with the sampling rate;
determine the second compensation factor by comparing the clock rate and/or the sampling rate with a reference frequency and/or the first compensation factor; and
transmit the first compensation factor or the second compensation factor to the evaluation unit;

determining the first compensation factor by comparing the clock rate with the sampling rate, and/or
determining the second compensation factor by comparing the clock rate and/or the sampling rate with the reference frequency.

6. The method according to claim 5 , wherein the clock rate (clk 1 ) and the sampling rate (clk 2 ) are compared with one another according to:

R

2
,
1

=

c
⁢
l
⁢

k
2

c
⁢
l
⁢

k
1

wherein the first compensation factor (k 1 ) is calculated according to:

k
1

=

R

2
,
1

*

c
⁢
l
⁢

k

1
,
soll

c
⁢
l
⁢

k

2
,
soll

and wherein clk 1,soll is the target value of the clock rate (clk 1 ) and clk 2, soll is the target value of the sampling rate (clk 2 ).

7. The method according to claim 6 , wherein the clock rate (clk 1 ) and the sampling rate (clk 2 ) are each compared with the reference frequency (clk ref ) according to:

R

1
,
ref

=

c
⁢
l
⁢

k
1

c
⁢
l
⁢

k
ref

;

R

2
,
ref

=

c
⁢
l
⁢

k
2

c
⁢
l
⁢

k
ref

and wherein the second compensation factor (k 2 ) is calculated according to:

Assignees

• Endress Hauser Se Co Kg

Inventors

• Vogel Markus
• Faber Harald
• Kochetkov Anton

Classifications

• G01S7/4004

  of parts of a radar system · CPC title

• G01S13/343

  using sawtooth modulation · CPC title

• G01S7/03

  Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver · CPC title

• G01F23/284 Primary

  Electromagnetic waves · CPC title

• G01S13/88 Primary

  Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) · CPC title