Application of thermistor effect intelligent ozone sensors
T. Habdank-Wojewódzki, Tadeusz Pisarkiewicz, Przemyslaw Potempa, Seweryn Habdank-Wojewodzki · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1999
When constructing ozone sensor one should consider dynamics of circuit inputs and of circuit itself. That dynamics is related to heat capacity conductivity of sensors substrate and case. Physical parameters are described as an implicit functions but we can use simplified model to resolve input space. During measurement stochastic parameters like humidity, medium temperature, medium flow velocity should be observed, due to their influence on heat conductivity and convection. When PID controller with two state output was used to stabilize temperature, regardless of constant input parameters at system output appeared binary noise. That phenomenon is related to temperature sensitivity of semiconductor layer which is higher than sensitivity of PID controller. That sensitivity causes amplification of controller output signal changes. Solution of that problem are physical models based estimators.