PID Simulator is a free software for PID tuning for temperature control. It plots a real-time temperature graph for adjustable parameters. You can change the values for parameters like heat loss per second, joules added per second, setpoint, constant values (Kp, Ki, Kd), etc. You can also set PID simulation speed and interval. The graph with temperature value is displayed on the screen.

It is a simple and portable PID simulation software.