Method for calibration in level measurement
First Claim
1. A method for calibrating a device for measuring a level and a volume of a material in a container wherein the device includes a sensor located above the highest fill level of the material which measures a distance to the surface of the material in the container and an evaluation circuit in which a relationship between the level of the material and the volume of the material in the container is stored, said evaluation circuit computing the level of the material in the container using the distance measured by the sensor and an empty distance corresponding to a distance measured by the sensor when the container is empty, and said evaluation circuit determining the volume of the material in the container using the computed level of the material in the container and the stored relationship between the level of the material and the volume of the material, said calibration method comprising the steps of:
- a) interrupting an on-going filling or emptying of the container;
b) recording an actual volume of the material in the container during the interruption;
c) measuring the distance to the surface of the material in the container with the sensor of the measuring device to be calibrated;
d) entering the actual volume of the material into the evaluation circuit;
e) determining, in the evaluation circuit, the level of the material corresponding to the entered actual volume of the material as a function of the stored relationship between the level of the material and the volume of the material;
f) computing the empty distance by summing the level of the material determined in the evaluation circuit and the distance to the surface of the material measured with the sensor; and
g) storing the computed empty distance in the evaluation circuit for use in computing the level of the material and in determining the volume of the material in the container.
1 Assignment
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Accused Products
Abstract
Measuring the level of a material in a container using a sensor fitted above the highest level occurring and measuring the distance to the surface of the material in the container. An evaluation circuit computes the level from the distance measured by the sensor and the empty distance. The material volume is determined from the relationship between level and material volume memorized in the evaluation circuit. For calibrating a sensor in the case of an unknown empty distance, without having to completely empty the container, the on-going filling or emptying of the container is interrupted and the actual material volume is recorded. Using the sensor to be calibrated a distance measurement is implemented and the actual material volume is entered in the evaluation circuit. The evaluation circuit determines on the basis of the memorized relationship between level and material volume the level corresponding to the entered material volume and computes the empty distance as the sum of the level corresponding to the entered material volume and the distance measured by the sensor. In this way calibration is possible at a single calibration point without having to change the level in the container.
24 Citations
2 Claims
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1. A method for calibrating a device for measuring a level and a volume of a material in a container wherein the device includes a sensor located above the highest fill level of the material which measures a distance to the surface of the material in the container and an evaluation circuit in which a relationship between the level of the material and the volume of the material in the container is stored, said evaluation circuit computing the level of the material in the container using the distance measured by the sensor and an empty distance corresponding to a distance measured by the sensor when the container is empty, and said evaluation circuit determining the volume of the material in the container using the computed level of the material in the container and the stored relationship between the level of the material and the volume of the material, said calibration method comprising the steps of:
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a) interrupting an on-going filling or emptying of the container; b) recording an actual volume of the material in the container during the interruption; c) measuring the distance to the surface of the material in the container with the sensor of the measuring device to be calibrated; d) entering the actual volume of the material into the evaluation circuit; e) determining, in the evaluation circuit, the level of the material corresponding to the entered actual volume of the material as a function of the stored relationship between the level of the material and the volume of the material; f) computing the empty distance by summing the level of the material determined in the evaluation circuit and the distance to the surface of the material measured with the sensor; and g) storing the computed empty distance in the evaluation circuit for use in computing the level of the material and in determining the volume of the material in the container.
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2. A method for calibrating a device for measuring a level and a volume of a material in a container wherein the device includes a sensor located above the highest fill level of the material which measures a distance to the surface of the material in the container and an evaluation circuit in which a relationship between the level of the material and volume of the material in the container is stored, said evaluation circuit computing the level of the material using the distance measured by the sensor and an empty distance corresponding to a distance measured by the sensor when the container is empty, and said evaluation circuit determining the volume of the material in the container using the computed level of the material and the stored relationship between level of the material and volume of the material;
- wherein the relationship between the level of the material and volume of the material in the container is a linear relationship of unknown slope;
said calibration method comprising the steps of;a) interrupting an on-going filling or emptying of the container; b) recording an actual volume of the material and an actual level of the material in the container during the interruption; c) measuring the distance to the surface of the material in the container with the sensor of the measuring device to be calibrated; d) entering the actual volume of the material and the actual level of the material into the evaluation circuit; e) computing, in the evaluation circuit, the slope of the linear relationship between the level of the material and the volume of the material using the actual volume of the material and the actual level of the material; f) computing the empty distance by summing the actual level of the material and the distance to the surface of the material measured with the sensor; and g) storing the computed slope of the linear relationship between the level of the material and the volume of the material and the computed empty distance in the evaluation circuit for use in computing the level of the material and in determining the volume of the material in the container.
- wherein the relationship between the level of the material and volume of the material in the container is a linear relationship of unknown slope;
Specification