Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 600

Limit cycle method
■Operation method and processing details
1.
Display the [Execute Auto Tuning (Limit Cycle method)] window of the PX Developer monitor tool.
[Control Panel]  [Details] button on the faceplate  [Auto Tuning] button  [Select Auto Tuning Operations] window 
Select [Executes Auto Tuning by Limit Cycle method].  [Next] button
2.
Set the following items and start auto tuning.
The control type is determined by selecting either of "Improves the disturbance response" or "Suppresses the overshoot when
the setting value is changed", and whether to check "Using the Derivative Action (rapid response)".
: Selected, : Not selected
Control type
Constant-value PI control
Constant-value PID control
Follow-up PI control
Follow-up PID control
Set the following items on the detail setting window of the limit cycle method which is displayed by clicking the [Details] button.
• Output high limit (AT2MVH)
• Output low limit (AT2MVL)
• Hysteresis (AT2HS)
• Time-out period (AT1TOUT1) (seconds)
3.
The high and low limit values of the manipulated value are repeatedly output.
Even if the value set to AT2MVH/AT2MVL exceeds MH/ML, the manipulated value is output within the range of MH to ML.
4.
The manipulated value returns to its original value automatically after auto tuning is completed.
Values for proportional gain (Kp), integral time (Ti), and derivative time (Td) which are calculated by auto tuning are set
automatically.
• PID constants are automatically overwritten after auto tuning.
• Auto tuning stops automatically when an alarm occurs.
• MV output values return to the values at start when auto tuning is completed or interrupted.
APPX
598
Appendix 3 Related Functions of Process
Improves the disturbance
response




Suppresses the overshoot when
the setting value is changed




Using the Derivative Action
(rapid response)



