4-26
Chapter 4. Functions
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AT (Auto-tuning)
The settings related to AT can be set for each control loop.
Item (bank)
Display
Description
Initial value
MV low limit during AT
(CONTROL bank)
MENU > Control
MV low limit during AT
-10.000 to +110.00 %
0.0000
MV high limit during AT
(CONTROL bank)
MENU > Control
MV high limit during AT
-10.000 to +110.00 %
100.00
•
The MV (manipulated variable) can be limited during AT by means of the "MV
low limit during AT" and "MV high limit during AT."
•
If the MV low limit during AT is greater than the MV high limit during AT, the
low limit and the high limit are automatically interchanged.
•
If ON/OFF control is set, AT does not start, and the above setting is invalid.
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SP lag
SP lag suppresses the amount of MV change when the SP is changed.
This can be set for each control loop.
Item (bank)
Display
Description
Initial value
SP lag factor
(CONTROL bank)
MENU > Control
SP lag factor
0.0 to 1000.0
0.0000
z
z
SP lag function
•
If the factor is set to 0.0, the SP lag factor has no effect.
•
If the setting is 0.0001 or more, the larger the factor, the smaller the amount
of MV change when the SP is changed, and the more strongly overshoot is
suppressed.
•
If ON/OFF control is set, the SP lag setting is invalid.
z
z
SP lag formula
OUT = OUT_1 + (IN − OUT_1) / (T / Ts + 1)
IN:
Input to the SP lag
OUT: SP lag filter calculation output
OUT_1: SP lag filter calculation output (previous)
T:
SP lag factor (time constant (s))
Ts:
Sampling cycle (based on the controller setting)
z
z
Initialization of SP lag
The SP lag filter calculation output is initialized to the PV under the condition
given below.
•
When the control loop mode changes from READY to RUN or from MANUAL
to AUTO.
