Accuracy refers to the consistency between the measured values of the object being measuredDegree and its proximity to its' true value '.In practical applications,The accuracy of humidity sensors can be affected by various factors, causing them to deviate from their original values. Therefore, high accuracy is not a "one-time solution", it will change.

Rotronic humidity sensors are widely used in various industries, such as pharmaceuticals, semiconductors, HVAC, data centers, meteorology, agriculture, etc. They can gain the trust of customers solely based on their excellent "ability" - precise measurement. But over time, sensors will be affected by different factors, leading to measurement driftLet's explore together how to maintain the high accuracy of the Rohatyn humidity sensor in applications.

Understand humidity sensors

Rozhnik humidity sensor uses capacitive measurement method to determine humidity in the airSensor components are composed of different layers, and different layers will be developed according to the main application.

outer layerIt is made of Teflon material with 5-micron small holes, used as a protective layer to prevent pollution. Important information about this sensor, such as production year, intermediate batch number, and sensor type, will be printed on it. The last four digits represent the capacitance in units of 0.1PF. When replacing a sensor, it is necessary to ensure that the replaced sensor has the highest possible capacitance, otherwise measurement errors may occur.

There are two electrodes under the PTFE protective layer, with polymer HT-1 or IN-1 (hygroscopic dielectric layer) inserted between them. The amount of water vapor absorbed by them varies depending on the environmental humidity, which changes the capacitance of the capacitor (humidity sensor) and can be used to determine humidity.

Factors affecting the accuracy of humidity sensors

The temperature range and calibration of the work are inaccurateQualitative, long-term drift, and environmental pollutants play a crucial role in determining the true long-term performance (measurement accuracy) of equipment.

1. Accuracy variation within temperature range

The accuracy specifications on the parameter table are only valid within a specific temperature range. For example, the accuracy within the range of 23 ° C or 20 ° C ± 5 ° C is ± 0.8% RH, and if the instrument is used outside the parameter range, its accuracy may decrease. This is because the relative humidity probe is sensitive to temperature, and its performance is affected by changes in environmental temperature. So, during use, it is important to pay attention to whether the temperature deviates from the calibration temperature, otherwise it may cause a decrease in the accuracy of the humidity sensor.

Rohatyn's humidity sensor has an automatic temperature compensation function to maintain accurate measurements over a wide range of temperature conditions. The sensor is equipped with AirChip 3000 electronic components and stores a set of 31 tables in memory, corresponding to temperature values ranging from -100 ° C to+200 ° C. Each table contains compensation data with a step change of 1% RH between 0% RH and 100% RH. By combining high-precision temperature measurement, low power consumption, low self heating design, and advanced electronic components, the Rohatyn HygroClip sensor can achieve accurate relative humidity and temperature measurement over a wide temperature range.

2. Potential challenge - Long term drift

fromDue to factors such as electronic component aging, mechanical wear, and accumulation of pollutants (dust, particles, or chemical vapors), sensor readings change over time and drift. Humidity sensors are similar to "air respirators", so they are more susceptible to environmental influences.