How does my graph look?


Hello! What do you think about this chart? The setup is an old freezer. The room should be around 20º at this time of the year. Should the freezer temperature be oscilating less?

These are the current settings:
Beer to Fridge:
Kp = 8
Ti = 15000
Td = 1200
beer set point = 10
input delay = 159
Kp = 10
Ti = 1800
Td = 200



Your Td is likely the cause of the fast fluctuations in fridge temperature, because it reacts to small one bit changes in beer temp. I would reduce it to 120 and set the derivative filtering to max.