E5CNH E5AN-H E5EN-H Digital Controllers User's Manual - OMRON

Determining PID Constants (AT, ST, Manual Setup) Section 3-8
3-8 Determining PID Constants (AT, ST, Manual Setup)
3-8-1 AT (Auto-tuning)
60
at
When AT is executed, the optimum PID constants for the set point at that
time are set automatically. A method (called the limit cycle method) for
forcibly changing the manipulated variable and finding the characteristics
of the control object is employed.
Either 40% AT or 100% AT can be selected depending on the width of MV
variation in the limit cycle. In the AT Execute/Cancel parameter, specify
at-2 (100% AT) or at-1 (40% AT). To cancel AT, specify off (AT cancel).
Only 100% AT can be executed for heating and cooling control or for floating
control for position-proportional models.
AT cannot be executed when control has stopped or during ON/OFF control.
The results of AT are reflected in the Proportional Band (P), Integral Time
(I), and Derivative Time (D) parameters for the PID set at the time AT execution
starts. For details on PID sets, refer to PID Sets on page 129.
PID Setting Level
C
PID* Proportional Band
∗.p (0
∗.i
233.0
∗.d
40.0
AT Operations AT is started when either at-2 (100% AT) or at-1 (40% AT) is specified for
the AT Execute/Cancel parameter. During execution, the AT Execute/Cancel
parameter on the No. 1 display flashes. When AT ends, the AT Execute/Cancel
parameter turns OFF, and the No. 1 display stops flashing.
AT Execute/Cancel
PID* Integral Time
PID* Derivative Time
at
off
(∗ : 1 to 8)
at
at-2
If you move to the operation level during AT execution, the No. 2 display
flashes to indicate that AT is being executed.
PV/SP
C
25.0
100.0
100% AT execution in progress
No. 1 display
Only the Communications Writing, RUN/STOP, AT Execution/Cancel, and Program
Start parameters can be changed during AT execution. Other parameters
cannot be changed.
C
25.0
100.0
AT execution in progress
No. 2 display