Hi everyone,
I have encountered some problems when the PID controller(type23) was used for controling the outlet air temperature of cooling coil (type508).
The fluid flow rate of cooling coil is conected with a outlet of flow diverter (type11). Thus, the fluid flow rate of cooling coil is determined by the control signal of the flow diverter. I build this mechanism in order to model a cooling cooling with a bypass in fluid side (3-ways valve flow controlling).
Then, the PID controller is used for keeping the outlet air temperature (Controlled variable) of cooling coil at a setpoint, the control signal is basically the fluid proportion of the flow diverter.
But no matter how to adjust the parameters of PID, the outlet air temperature oscillation cannot be eliminated.
So, I have the following questions :
How to determine the parameters of PID controller, such as Gain constant, Integral time and Derivative time, to avoid Controlled variable oscillation ?
Is there a better way to accurately model this system?
Thanks in advance,
Regards