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Drift reduction of gas sensors by temperature modulation and signal-proccessing

Drift-Verringerung für Gassensoren mit Temperaturmodulation und Neuronalen Netzen
: Roth, M.; Hartinger, R.; Schwaiger, M.; Gräber, M.; Endres, H.-E.

Foulloy, L. ; International Federation of Automatic Control -IFAC-, Technical Committee on Components and Instruments:
SICICA '97. 3rd IFAC Symposium on Intelligent Components and Instruments for Control Applications. Preprints
Annecy, 1997
Symposium on Intelligent Components and Instruments for Control Applications (SICICA) <1997, Annecy>
Conference Paper
Fraunhofer IFT; 2000 dem IZM eingegliedert
CO2 sensor; Drift reduction; signal processing; Temperature modulation

Drift effects and cross sensitivities hinder the application of chemical sensor, especially with coatings based on organic or organically modified substances. A temperature modulated mode of sensor operation (AT-mode) is investigated to reduce drift and humidity influence on organic gas-sensitive coatings. The transducers are interdigital capacitance structures with ring heater (IDC). As sensitive material a CO2 sensitive organically modified heteropolysiloxane is used. Heteropolysiloxanes are well known materials for gas-sensing. They also have common weaknesses of organic sensor coatings. Different kinds and patterns of temperature modulation together with adapted signal-processing were used to reduce long time drift effects and diminsh cross-sensitivities. A typical application for CO2 sensors is the field of home automation. The hardware and software realization of the system will be discussed for two systems: First as a subpart of a complex, flexible, intelligent multi-gas sensor system based on the CAN field bus and secondly as stand-alone low cost solution for a CO2 alarm device.