This paper presents a sensor system with temperature control of platinum microheater using a combined control strategy of open-loop and closed-loop control. The method proposed in this paper modifies the proportional integral control for faster response under sampling time constraint of large sampling interval, as a large sampling interval between two control commands slow the response. The initial quick temperature rising open-loop response of microheater contributes to faster rise time, and then, it is switched to closed-loop control when the quick initial rise has taken place, hence termed open-loop to closed-loop switched proportional integral (OLCLS PI) control. The settling time obtained by OLCLS PI and PI are 3 and 14 s, respectively, for 2% accuracy, thereby providing faster response than PI. The work is studied with elaborate modeling and simulation using MATLAB, and a practical implementation on embedded platform is presented using an in-house developed MOX-based gas sensor, which utilizes a platinum microheater.
- Fast settling
- integrated gas sensor
- open loop to closed loop switched proportional integral (OLCLS PI) control
- platinum microheater
- proportional integral temperature controller
- settling time