Design and Realization of a Temperature Measurement and Control System Adapted to Gas Nanosensors

In this work, we present the implementation of a temperature measurement and control system, suitable for testing new gas sensors based on metal oxide nanoparticles. The system consists of a software part, and an electronic part. In the software section, an interface was designed using graphic design software. This interface ensures the display, control and recording of the working temperature while ensuring a real-time handshake with the electronics part. The latter consists of a thermocouple type K, a heating resistor, a microcontroller-based board and a power circuit. The microcontroller-based board provides reading, local display and temperature control according to the desired set point value. The implemented control algorithm ensures real-time control parameters change according to the set point and the measuring period. A full bridge rectifier, a photocoupler, an optocoupler and a TRIAC form the power part. This system works as follows: The zero pass can be detected by the full bridge rectifier and the photocoupler, measure the temperature by the thermocouple, calculate the pulse delay with the PID control and create the pulse on the pin connected to the optocoupler that will apply a pulse to the TRIAC. This will control the amount of energy passed to the AC heating resistor. This allows to find a low static maximum error. The strength of this system is the algorithm generates, in real-time, the parameters of PID regulation, control of energy quantity using the zero-detect method, and stability over time.