Omron E5EK DEVICENET User Manual page 45

J Auto-tuning
(A.T.)
F 40%AT
Deviation at start of AT
execution ≧ 10% full-scale
Set point
Start of AT
execution
F 100%AT
• AT (auto-tuning) cannot be executed while operation is canceled or
during ON/OFF control.
• When you execute auto-tuning, the optimum PID parameters for the
current set point at execution are automatically set by forcibly chang-
ing the manipulated variable to calculate the characteristics (called
the "limit cycle method") of the control target. During auto-tuning,
the AT LED flashes.
• 40%AT or 100%AT can be selected by the limit cycle of MV change
width. Specify [
cancel" parameter (level 1 mode).
• During heating and cooling control, only 100%AT can be executed.
(So, [ ] (40%AT) will not be displayed.)
• To cancel AT execution, specify [
In order to set the limit cycle of MV change width to 40%, select 40%AT
to execute auto-tuning with fluctuations in the process value kept to a
minimum. However, note that auto-tuning takes longer time to execute
compared with 100%AT.
The timing by which limit cycles are generated varies according to
whether or not the deviation (DV) at the start of AT execution is 10%
full-scale or less.
Limit cycle of MV change
width 40%
Deviation 10%
full-scale
Time
End of AT
In order to set the limit cycle of MV change width to 100%, select 100%
AT to shorten the AT execution time without worrying about fluctua-
tions in the process value.
Set point
Start of AT
execution
3.7 Adjusting Control Operation
] or [ ], respectively, in the "AT execute/
] ("AT cancel").
Deviation at start of AT
execution < 10% full-scale
Set point
Deviation 10%
full-scale
Start of AT
execution
Limit cycle of MV
change width 100%
End of AT
Limit cycle of MV change
width 40%
Time
End of AT
Time
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