Omron E5CK User Manual page 126

F Imposition
Completion
Condition of Step
Control Amount
F PID Constant
Refreshing
Conditions
Temperature
F Stable Temperature Status
Set point
In order to prevent overshooting, the step controlled amount must be
imposed continuously only while the present deviation is the same as or
greater than the value obtained from the proportional band (P) x 1.27. The
step control will not be applied when the deviation becomes smaller than
this value.
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.
Slope (R)
SP
Completion of SRT
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.
Shorter than the stability judgement time
Stable
Stable range
P x 1.27
Time
Stability judgement time
FUZZY SELF--TUNING
Stable range
Stable range
(Set to 15.0_C
before shipping)
Stable
A--11