WIKA CS4S - Manual (Page 27)

Operating Instructions Temperature Indicating Controller CS4S
V1.1
•
10/2006 - 27 -
8. PID auto-tuning of this controller
In order to set each value of P, I, D and ARW automatically, fluctuation is applied to the controlled object to
get an optimal value. One of 3 types of fluctuation below is automatically selected.
(1) When the difference between the setting value and processing temperature is large as the
temperature rises.
When AT bias is set to 20 °C (°F), fluctuation is applied at the temperature 20°C lower than the setting
value.
(1) Calculating PID constant
(2) PID constant calculated
(3) Controlled by the PID constant
set by auto-tuning.
(4) AT bias value
(2) When the control is stable or when control temperature is within ±20 °C (°F) of setting value.
Fluctuation is applied at the setting value.
(1) Calculating PID constant
(2) PID constant calculated
(3) Controlled by the PID constant
set by auto-tuning.
(3) When the control temperature is 20 °C (°F) or higher than the setting value.
When AT bias is set to 20°C (°F), fluctuation is applied at the temperature 20°C (°F) higher than the setting
value.
(1) Calculating PID constant
(2) PID constant calculated
(3) Controlled by the PID constant
set by auto-tuning.
(4) AT bias value
(1) (2) (3)
(4)
AT starting point
Setting
value
Temperature
Time
AT starting point
(1) (2) (3)
Temperature
Setting value
Time
AT starting point
(1) (2) (3)
(4)
Temperature
Setting
value
Time
Temperature 20 °C (°F) higher
than the setting value
Temperature 20 °C (°F) lower
than the setting value