Determining Pid Constants (At, St, Manual Setup); At (Auto-Tuning) - Omron E5CZ User Manual

Determining PID Constants (AT, ST, Manual Setup)

3-8

Determining PID Constants (AT, ST, Manual Setup)

3-8-1

AT (Auto-tuning)

a t
AT Operations
• 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.
• To execute AT, specify on (AT execute), and to cancel AT, specify off
(AT cancel).
• AT cannot be executed when control has stopped or during ON/OFF con-
trol.
• The results of AT are reflected in the "proportional band" (P), "integral
time" (I), and "derivative time" (D) parameters in the adjustment level.
Adjustment Level
Proportional band
C
p
(0
Integral time
i
233
Derivative time
d
40
AT is started when the "AT execute/cancel" parameter is set to ON. 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
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
Only the "communications writing," "RUN/STOP," and "AT execution/cancel"
parameters can be changed during AT execution. Other parameters cannot
be changed.
at at
off
AT execution in progress
25 C 25
100 100
AT execution in progress
Section 3-8
No. 1 display
on
No. 2 display
43