45
[How to cancel PID auto-tuning]
Available only during PID auto-tuning Perform
[PID auto-tuning Perform]
Press the
key while
holding down
the
key.
.
PID parameter setting mode is selected
+
and AT Perform/Cancel item is indicated.
[PID parameter setting mode]
AT
Perform/Cancel selection
Press the
key.
Press the
key.
PID auto-tuning is cancelled and the controller
reverts to the program control run mode.
[Program control run mode]
8. Control and Alarm action
8.1 P, I, D, ARW action
(1) Proportional band (P)
Proportional action is the action which the control output varies in proportion to the
deviation between the setting value and the processing temperature.
If the proportional band is narrowed, even if the output changes by a slight variation
of the processing temperature, better control results can be obtained as the offset
decreases.
However, if the proportional band is narrowed too much, even slight disturbances
may cause variation in the processing temperature, control action changes to
ON/OFF action and the so called hunting phenomenon occurs.
Therefore, when the processing temperature comes to the balanced position near
the setting value and a constant temperature is maintained, the most suitable value
is selected by gradually narrowing the proportional band while observing the control
results.
(2) Integral time (I)
Integral action is used to eliminate offset. When the integral time is shortened, the
returning speed to the setting point is accelerated. However, the cycle of oscillation
is also accelerated and the control becomes unstable.
PTN
PV
Actual temp.
STEP
SV
Step SV
PTN
PV
STEP
SV
PTN
PV
STEP
SV
PTN
PV
Actual temp.
STEP
SV
Step SV
