34
7
Reference [About the self-tuning method]
The PID constant is calculated in one of the following two methods.
The method is selected automatically depending on the characteristics of the device to be controlled.
• Step response method
• Limit cycle method
The following figures show the operations at power-on and changing the SV, and under unstable control.
q
Operations at power-on
w
Operations at changing the SV
e
Operation under unstable control
PV
SV
Time
During tuning
PV
SV
Time
During tuning
Step response method
Limit cycle method
PV
SV
Time
During tuning
PV
SV
Time
Step response method
Limit cycle method
During tuning
Changing the SV
Changing the SV
PV
SV
Time
During tuning
Limit cycle method
MV
Unstable control
100%
