Fuzzy Self-Tuning - Omron E5AK-AA2-500 Manual

E5 K

FUZZY SELF-TUNING

Fuzzy self-tuning is a function that enables the E5
the most suitable PID constants for the control output.
Features


•
The E5 K determines by itself when to perform fuzzy self-
tuning.
•
During fuzzy self-tuning, the E5
nal that disturbs the temperature or output value.
Fuzzy Self-tuning Function
The fuzzy self-tuning function has three modes.
•
In SRT (step response tuning) mode, the PID constants are
tuned using a step response method at the time the set point
is changed.
•
In DT (disturbance tuning) mode, the PID constants are
amended so that the controlled temperature will be within the
target range set in advance when there is external distur-
bance.
•
In HT (hunting tuning) mode, when hunting occurs, the PID
constants are amended to suppress the hunting.
Startup Conditions of SRT
SRT will start if conditions 1 to 5 are satisfied when the set point


is changed, or the E5 K is turned on.
1. The new set point is different from the set point used at the
time SRT was last executed.
2. The difference between the new set point and the last set
point is larger than the value obtained from the calculation:
present proportional band value (P) x approximately 1.27+4.


Note: When the E5 K is turned on, the difference between the
process value and set point is regarded as Deviation.
3. The temperature is stable before changing the set point, or
the temperature is balanced while the E5
before any output is obtained.
4. The set point is changed in the direction that the controlled
amount increases (i.e., the control amount is in the upper
direction at the time of reverse operation and in the lower
direction at the time of normal operation).
5. No SRT has been executed with the current set point.
In the following cases, SRT will not be executed accurately.


Therefore the E5 K must be tuned in DT or HT mode.
1. The maximum temperature slope (R) is not obtained before
the process value reaches the value obtained from the cal-
culation: present proportional band value (P) x approximately
1.27 (i.e., the maximum temperature slope (R) is not ob-
tained before the SRT is finished). If the proportional band,
obtained before SRT is finished, is larger than the previous
proportional band, however, the PID constants will be re-
newed, so their values will be more accurate.
2. The set point is changed during SRT, and the SRT comple-
tion conditions are satisfied; and, no PID constant will be
renewed.


K to calculate


K does not output any sig-


K is turned on
Note: You must turn ON the power supply to the LOAD
either before or simultaneously with the start of
Temperature Controller operation.
Dead time will be measured from the time the
Temperature Controller starts operating. If a load,
such as a heater, is turned on after the Temperature
Controller is turned on, dead time longer than the
actual value will be measured, and inappropriate PID
constants will be obtained.
If an extremely large amount of dead time is
measured, the control amount will be set to 0% for a
short period of time before being returned to 100%,
and the constants will then be retuned. Retuning is
performed only for large amounts of dead time, so
be sure to follow the precaution given above when
starting operation.
Stable Temperature Status
If the temperature is within the stable range for a specified period,
the temperature is considered stable .
Slope (R)
Temperature
SP
Completion of SRT
Time
Balanced Status
If the process value is within the stable range for 60 s when there
is no output, the the temperature is considered balanced .
E5 K
Stable range
P x 1.27