Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 597

Step response method
■Operation method and processing details
Perform the following procedure after the manipulated value is held and the process variable is stabilized.
1.
Display the auto tuning 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 Step Response method].  [Next] button
2.
Set the following items and click the [Start] button.
• Step manipulated variable (AT1STEPMV)
• Sampling period (AT1ST) (seconds)
(PV data collection period during tuning)
• Time-out period (AT1TOUT1) (seconds)
• Time-out period after maximum slope (AT1TOUT2) (seconds)
3.
The step manipulated variable is output from the current manipulated value in step form.
4.
The manipulated value returns to its original value automatically after auto tuning is completed. P, I, and D constants
generated from auto tuning are automatically saved in the tag data.
• PID constants are automatically overwritten after auto tuning. Save the previous PID constants in advance
as necessary.
• Auto tuning stops automatically when an alarm occurs.
Appendix 3 Related Functions of Process
A
APPX
595