Omron e5ck User Manual page 54

CHAPTER 3 BASIC OPERATION
JAuto-tuning
(A.T.)
F 40%AT
Deviation at start of AT
execution y 10% FS
Set point
Start of AT
execution
F 100%AT
3–24
• AT (auto tuning) cannot be executed while operation is reset or during
ON/OFF control.
• When you execute auto tuning, the optimum PID parameters are auto
matically set by forcibly changing the manipulated variable to calculate
the characteristics (called the limit cycle method") of the control target.
During auto tuning, time counting is stopped and the AT" LED flashes.
• 40%AT or 100%AT can be selected by the limit cycle of MV change width.
Specify [ ] or [
rameter (level 1 mode).
• During heating and cooling control, only 100%AT can be executed. (So,
[ ] (40%AT) is not 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 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
execution
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 fluctuations in
the process value.
Set point
Start of AT
execution
], respectively, in the AT execute/cancel" pa
: 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
execution
Limit cycle of MV change
width 40%
Time
End of AT
execution
Time