# US 11,112,293 B2 · Impedance level sensor

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- Number: US 11,112,293 B2
- Document ID: US11112293B2
- Status: Granted
- Kind: B2
- Application number: 16/410,759
- Filed: 2019-05-13
- Published: 2019-11-21
- Granted: 2021-09-07
- Earliest claimed: 2018-05-17
- Assignees: VEGA Grieshaber KG
- Applicants: Vega Grieshaber KG
- Inventors: Christian Weinzierle; Juergen Haas
- Web page: https://patentgrep.com/patent/US11112293B2

## CPC

- G01F 23/265: {for discrete levels}
- G01F 23/266: {measuring circuits therefor}
- G01F 23/268: {mounting arrangements of probes}
- G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME

## Abstract

Impedance level sensor with a probe, which is influenced by a medium surrounding the probe in a measuring capacity, with the probe comprising a measuring electrode and a reference electrode isolated from the measuring electrode, between which the measuring capacity forms, a measuring oscillation circuit, in which the probe is arranged as a capacity-determining element, an electronic unit with a signal generator to excite the measuring oscillation circuit, an evaluation and control unit for generating a measuring signal, which is connected to the electronic unit, characterized in that the electronic unit comprises a current meter for detecting a current at the input of the signal generator.

## Claims

### Claim 1

An impedance point level sensor, comprising:
a probe, which can be influenced by a medium surrounding the probe in a measuring capacity, with the probe comprising a measuring electrode and a reference electrode isolated from the measuring electrode, with the measuring capacity forming therebetween,
a measuring oscillation circuit, in which the probe is arranged as a capacity-determining element,
an electronics unit with a signal generator for analyzing the measuring oscillation circuit and exciting the measuring resonant circuit with a frequency sweep, and
an evaluation and control unit for generating a measuring signal, connected to the electronics unit,
wherein the electronics unit comprises a current meter for detecting a current at an input of the signal generator.

### Claim 2 (depends on 1)

The impedance point level sensor according to claim 1, wherein the current meter is embodied as a current sensor.

### Claim 3 (depends on 2)

The impedance point level sensor according to claim 2, wherein the current sensor is embodied as a current resistor.

### Claim 4 (depends on 1)

The impedance point level sensor according to claim 1, wherein the current meter is embodied as a magnetic field sensor.

### Claim 5

A method for operating an impedance point level sensor with
a probe, which can be influenced by a medium surrounding the probe in a measuring capacity, with the probe comprising a measuring electrode and a reference electrode isolated from the measuring electrode, between which the measuring capacity forms,
a measuring oscillation circuit, in which the probe is arranged as a capacity-determining element,
an electronics unit with a signal generator to excite the measuring oscillation circuit and, excite the measuring resonant circuit with a frequency sweep, and
an evaluation and control unit for generating a measuring signal, which is connected to the electronics unit, in which the measuring oscillation circuit is excited via the signal generator with a plurality of different frequencies,
wherein the resonance point of the measuring oscillation circuit occurs by determining a current at an input of the signal generator.

### Claim 6 (depends on 5)

The method for operating an impedance point level sensor according to claim 5, wherein the current occurs by a voltage measurement at a current resistor.