Temperature control solution with PLC

In this paper, different solutions for power supply of a resistance used for the liquid heating were analyzed. The authors propose the best solution in terms of reliability, harmonic pollution of power network and precision temperature control. For this were used: the XC-CPU101 PLC, the XV102 HMI (Human Machine Interface) from EATON. The temperature control used a PID controller based on PLC and it was observed by HMI. Desired temperature is set by the user using the HMI and the PID controller, within the PLC, will try to minimize the error value as the difference between desired temperature and measured temperature by adjustment of a control variable.