WIKA CF2S - Manual (Page 32)

Operating Instructions Temperature Indicating Controller CF2S
V1.2 • 08/2004 - 32 -
8.3 PID auto-tuning of this controller
In order to decide each value of P, I, D and ARW automatically, this system makes the
controlled object’s temperature fluctuate.
(1) When the difference between setting value and processing temperature
is large when the temperature rises.
Fluctuation is applied at the temperature 1.5% of scaling span less than the setting value.
(2) When the control is stable or when control temperature is within ±1.5%
of scaling span.
Fluctuation is applied at the setting value.
(3) When the control temperature is 1.5% or greater of scaling span higher
than the setting value.
Fluctuation is applied at the temperature 1.5% of scaling span higher than the setting value.
1.5% of scaling span
Controlling action is performed
with the values set by PID
auto-tuning.
Setting value
Time
Temperature
[Figure 8.3-1]
Temperature
Setting value
Time
Controlling action is performed
with the values set by PID
auto-tuning.
[Figure 8.3-3]
1.5% of scaling span
Temperature
Setting value
Starting point of auto-tuning
[Figure 8.3-2] Time
Controlling action is performed
with the values set by PID
auto-tuning.