For our final project, we designed a 4-channel temperature controller using PID control. The system was designed to monitor and regulate the temperature of four individual channels by applying 120V to heating elements using on/off switching.
This switching was indirectly manipulated by the micro-controller using relays. Data was continuously collected from resistive thermal devices (RTD’s) and processed by the micro-controller to set a duty cycle for this output, and thus regulate the temperature at a given set point. The system would then display the current temperature of the channels to user.
Read More Detail :Four Channel Temperature Controller