Magnetic Sensor Calibration for Value Documents
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Solution Overview
Problem
Magnetic sensors used to check valuable documents often experience measurement deviations despite calibration and adjustment, due to fluctuations in the mechanical fastening of magnetosensitive elements and magnets, which are not fully accounted for by previous calibration methods, leading to inaccuracies in detecting different magnetic materials.
Innovation Solution
The magnetic sensor employs multiple calibration parameters specific to soft and hard magnetic materials, allowing it to correct measurement deviations individually without altering the permanent magnets, by using first and second calibration parameters to compensate for errors in detected magnetic signals from soft and hard magnetic areas respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a magnetic sensor is calibrated using a single calibration parameter, then the calibration process is simple, but measurement deviations remain for different types of magnetic material
Solution Approach 1:
The calibration parameter is segmented into at least two distinct calibration parameters: a first calibration parameter for soft magnetic magnetic material and a second calibration parameter for hard magnetic magnetic material. This segmentation allows the magnetic sensor to be calibrated separately for different types of magnetic material, thereby eliminating measurement deviations that occur when using a single calibration parameter for both types.
2Measurement precision
If the magnetic sensor is adjusted to compensate for measurement deviations, then measurement accuracy improves for one type of magnetic material, but measurement deviations persist for other types
Solution Approach 1:
Different calibration parameters are applied locally depending on the type of magnetic material being detected. The magnetic sensor uses the first calibration parameter when detecting soft magnetic magnetic material and the second calibration parameter when detecting hard magnetic magnetic material. This local quality approach ensures optimal measurement accuracy for each specific type of magnetic material without compromising versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate detection of magnetic signals from both soft and hard magnetic materials, reducing measurement deviations and improving the reliability of magnetic sensor calibration and adjustment, without requiring hardware changes to the sensor.
Implementation Method 1
a magnetic sensor that is designed to check valuable documents
Data Source
Figure 1a~1b
Figure 2a~2c
Figure 3a~3b
AI summary
The invention relates to a magnetic sensor that is designed for checking value documents and a method for calibrating the magnetic sensor. The magnetic sensor has different calibration parameters for hard-magnetic and soft-magnetic regions, by means of which parameters the magnetic sensor can correct the detected magnetic signals of a value document, in order to compensate measuring errors of the magnetic sensor in accordance with the type of the respectively detected magnetic region. For the calibration, the magnetic sensor detects calibration measured values of a calibration medium that is transported past the sensor. The function of the magnetic sensor is checked by means of the calibration measured values. After the calibration the sensor is optionally adjusted by means of the calibration measured values, during which adjustment the calibration parameters for hard- and/or soft-magnetic magnetic regions are determined from the detected calibration measured values of the calibration medium.