The Dynamic Behaviour of Capacitive Humidity Sensors
https://doi.org/10.21122/2220-9506-2020-11-1-53-59
Abstract
The sensor design features and the sensing material properties which can influence the response time of the polymer-based capacitive humidity sensors are shortly discussed. The ways of specifying the dynamic properties of capacitive humidity sensors in technical data sheets by the leading companies on the market are briefly characterized and discussed.
The schematic view and operation of the experimental setup for determining of the dynamic parameters of capacitive humidity sensors at different temperatures of humid air are described. The dynamic behaviour of polymer-based capacitive humidity sensors was registered as the measurement profiles for both positive and negative step changes in humidity level. The response and recovery times, as well as the time constants for the exponential approximation fits of the step responses, were determined either graphically or analytically, based on the collected data.
The changes of these parameters under atmospheric pressure within the temperature range from – 30 °C to + 20 °C were analysed. The exemplary transient measurement profiles are shown, together with the illustrations of the graphical method for determining the response and recovery times. Also, the plots of the relationship between response and recovery times as well as time constants, and temperature, are presented. Some explanations of the obtained results are suggested.
About the Author
J. Majewski
Lublin University of Technology
Poland
Poland
Address for correspondence: J. Majewski – Lublin University of Technology, Nadbystrzycka str., 38A, Lublin 20-618, Poland e-mail: j.majewski@pollub.pl
References
1. Lee Ch.-V., Lee G.-B. Humidity Sensors: A Review, Sensor Letters, 2005, vol. 3, pp. 1‒14. DOI: 10.1166/sl.2005.001
2. Boudaden J., Steinmaßl M., Endres H.-E., Drost A., Eisele I., Kutter C., Müller-Buschbaum P. Polyimide-Based Capacitive Humidity Sensor. Sensors, 2018, vol. 18, pp. 1506‒1521. DOI: 10.3390/s18051516
3. Hübert T., Tiebe C., Detjens M., Majewski J. On-site calibration system for trace humidity sensors. Measurement, 2016, vol. 91, pp. 251‒257. DOI: 10.1016/j.measurement.2016.05.013
4. Wildmann M., Kaufmann F., Bange J. An inverse modelling approach for frequency response correction of capacitive humidity sensors in ABL research with small remotely piloted aircraft (RPA). Atmospheric Measurement Techniques, 2014, iss. 7, pp. 3059‒3069. DOI: 10.5194/amt-7-3059-2014
5. Detjens M., Hübert T., Tiebe C., Banach U. Coulometric trace humidity measurement in technical gases. Review of Scientific Measurements, 2018, vol. 89, 085004, pp. 1‒8. DOI: 10.1063/1.5008463
6. Sensirion,theSensorCompany:SensorSpecification Statement, Version 1.1 – June 2018. URL: https://www.sensirion.com/fileadmin/user_upload/customDrs/sensirion/Dokumente/2_Humidity_Sensors/Sensirion_Humidity_Sensors_Specification_Statement.pdf.
7. Sensirion, the Sensor Company: Testing Guide, Version 1.3 – December 2018. URL: https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/2_Humidity_Sensors/Sensirion_Humidity_Sensors_Testing_Guide.pdf.
8. Innovative Sensor Technology IST AG: K5-W Capacitive Humidity Sensor, DHK5-W_E2.2.1, Datasheet. URL: https://www.ist-ag.com/sites/default/files/DHK5-W_E.pdf
9. HIH-4602-L Series Humidity Sensors, Honeywell, Datasheet, December 2008. URL: https://sensing. honeywell.com/honeywell-sensing-hih4602l-seriesproduct-sheet-009043-1-en.pdf
10. HCT01 Humidity/Temperature Sensor, E+E ELEKTRONIK, Datasheet, Version 2019-05. URL: http://downloads.epluse.com/fileadmin/data/product/hct01/datasheet_HCT01.pdf
11. Humidity Sensor HygroMer IN-1, Rotronic AG, Datasheet, 59013-E/2015-02. URL: https://www.rotronic.com/en/productattachments/index/download?id=997
12. Datasheet SHT7x (SHT71,SHT75) Humidity and Temperature Sensor, Sensirion AG, Version 5 December 2011. URL: https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/0_Datasheets/Humidity/Sensirion_Humidity_Sensors_SHT7x_Datasheet.pdf
13. Lorek A. Humidity measurement with capacitive humidity sensors between ‒70 °C and 25 °C in low vacuum. Journal of Sensors and Sensor Systems, 2014, vol. 3, pp. 177‒185. DOI: 10.5194/jsss-3-177-2014
14. Zhou W.-H., Wang L.-Ch., Wang L.-B. Numerical Study of Structural Parameter Effects on the Dynamic Characteristics of a Polyimide Film MicroCapacitive Humidity Sensors. IEEE Sensors Journal, 2016, vol. 16, no. 15, August 1, pp. 5979‒5986. DOI: 10.1109/JSEN.2016.2579644
15. Lorek A., Majewski J. Humidity Measurement in Carbon Dioxide with Capacitive Humidity Sensors at Low Temperature and Pressure. Sensors, 2018, vol. 18, pp. 2615‒2626. DOI: 10.3390/s18082615
Review
For citations:
Majewski J. The Dynamic Behaviour of Capacitive Humidity Sensors. Devices and Methods of Measurements. 2020;11(1):53-59. https://doi.org/10.21122/2220-9506-2020-11-1-53-59
Views:
2058
Email this article 