
FUZZY SELF-TUNING
E5AK
A--15
If the step control amount is applied before the maximum temperature
slope (R) is obtained, SRT will not renew any PID constant. If the propor-
tional band obtained from the R and L values that were measured before
the imposition had been completed is larger than the present proportional
band, the PID constants will be renewed because the measured value is in
the direction towards the suitable proportional band value, and the set
point at that time will be the SRT-executed set point.
Temperature
Slope (R)
Stable range
Time
SP
F
Stable Temperature Status
If the temperature is within the stable range for a certain time, it is deemed
that the temperature is stable. This time is called stability judgement time.
Like PID constants, stability judgement time is adjusted with fuzzy self-
tuning according to the characteristics of the object to be controlled. Fuzzy
self-tuning will not be activated if the temperature is stable because the
Temperature Controller deems that temperature control is smooth.
Stable
Stable range
Stable range
Stable
Stability judgement time
Set point
Shorter than the stability judgement time
(Set to 15.0
_
C
before shipping)
F
Balanced Status
If the process value is within the stable range for 60s when there is no out-
put,it is deemed that the temperature is balanced.
F
PID Constant
Refreshing
Conditions