Determining Pid Constants (At, St, Manual Setup); At (Auto-Tuning) - Omron E5 Getting Started Manual

Determining PID Constants (AT, ST, Manual Setup)

Setting the Hysteresis
Operating Procedure
Operation Level
PV
C
25
200
Adjustment Level
Adjustment
1.adj
Level Display
C Hysteresis
hys
(Heating)
1.0
C
hys
2.0
3-8

Determining PID Constants (AT, ST, Manual Setup)

3-8-1

AT (Auto-tuning)

a t
42
Set the hysteresis to 2.0
1. Press the O Key to move from the operation level to the adjustment level.
2. The Adjustment Level Display parameter will be displayed in the adjust-
ment level.
3. Select the Hysteresis (Heating) parameter by pressing the M Key.
4. Press the U and D Keys to set the hysteresis (2.0 in this example). Ei-
ther press the M Key or wait for at least two seconds after setting the hys-
teresis value to confirm the setting.
5. To return to the operation level, press the O Key.
• 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 can-
cel).
• Only 100% AT can be executed for heating and cooling control.
• 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
°
C.
Section 3-8