Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 1393

Auto tuning procedure
The following shows the auto tuning procedure.
Record the PID constants as required because the
PID constants are overwritten at completion of auto tuning,
Set the loop tag and operation constant required for auto tuning.
Change the control mode (MODE) of the tuning target loop to MAN.
Check that the process of the tuning target loop is stable.
(Adjust the MV as required so that the process is stabilized.)
Disconnect the S.2PID/S.PID instruction of the tuning target loop and connect the
S.AT1 instruction to where the S.2PID/S.PID instruction was located.
Set the auto tuning start signal (e1) to 1 (Start).
Set the auto tuning start signal (e1) to 0 (End).
(The auto tuning completion status (BB16) is set to 0 (Not completed).)
Check the PID constants stored in the loop tag.
Disconnect the S.AT1 instruction of the tuning target loop and connect the
S.2PID/S.PID instruction to where the S.AT1 instruction was located.
Make fine adjustment during normal operation.
Start
(Auto tuning)
The auto tuning completion status (BB16) is set to 1 (Completed) at completion of auto tuning.
End
11 PROCESS CONTROL INSTRUCTIONS
11.7 Auto Tuning
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