Pid auto-tuning of this controller – WIKA CS4S User Manual

Page 27

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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

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