Method and device for calibrating a humidity sensor and sensor arrangement having humidity sensor capable of calibration
AssigneeTesto AG
InventorsMartin Rombach, Markus Langenbacher
Life of this patent
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Abstract
For calibrating a humidity sensor, the latter is used to measure the relative humidity (U1, U2) at each of two known gas pressure values (P1, P2), likewise to be measured if necessary. At the same time, other ambient conditions are kept constant. A correction value for correction of the measured values of the humidity sensor to be subtracted from the latter is then obtained from the formula: k=((P1/P2)*U2−U1)/(P1/P2−1). The humidity sensor is thus capable of calibration without measurement of the actual humidity value.
Claims15
A method of calibrating a humidity sensor, comprising:
- measuring a first pressure using a calibrated pressure sensor;
- measuring a first humidity value;
- measuring a second pressure using the calibrated pressure sensor;
- measuring a second humidity value;
- determining a correction value according to the first and second pressures and the first and second humidity values, and at otherwise like conditions;
- and
- maintaining the correction value to be applied to humidity measurements of the humidity sensor.
A method of calibrating a humidity sensor, in which a humidity value is in each instance detected by the humidity sensor under first ambient conditions and under second ambient conditions different from the first, and in which a correction value for the humidity sensor is determined from the parameters of the ambient conditions and the measured humidity values,
- wherein, at a first pressure and at a second pressure different from the first that are determined using a calibrated pressure sensor, and at otherwise like conditions, a humidity value is detected in each instance, at least the ratio of the first pressure value and the second pressure value being known;
- and the correction value for the humidity sensor is determined from the ratio of the pressure values and the measured humidity values.
A humidity sensor, comprising:
- a memory containing a correction value that is determined according to calibrated first and second pressure measurements and first and second humidity value measurements measured respectively at the first and second pressures and at otherwise like conditions;
- and
- a microprocessor that applies the correction value to the first and second humidity value measurements of the humidity sensor.
A device for calibrating a humidity sensor, comprising:
- a calibrated pressure sensor;
- a first data memory that stores measured values of the humidity sensor;
- and
- a microprocessor that determines a correction value of the humidity sensor from the ratio of two pressure values measured by the calibrated pressure sensor and two humidity values detected at the particular pressure values under otherwise like conditions.
A sensor arrangement, comprising:
- a humidity sensor;
- a memory in which a correction value to be subtracted from a measured humidity value is stored;
- and
- a microprocessor coupled to the memory, the microprocessor subtracting the correction value from the detected measured value of the humidity and delivering the result to a display, wherein the correction value is determined using known and calibrated first and second pressures and a first measured humidity value measured at the first pressure and a second measured humidity value measured at the second pressures and under otherwise like conditions.
Dependencies are inferred from the claim text.