WIKA CF1H User Manual
Page 52
Operating Instructions Temperature Indicating Controller CF1H
V 1.2
•
01/2007
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8. Control actions
8.1 Fuzzy self-tuning
Fuzzy self-tuning is a function to perform a fine adjustment of PID values automatically. The stable
control can be carried out even if the conditions of the process are changed due to things like change
in types and rates of production.
(1) When the control is rising, the controller performs the control by the PID
values tuned in advance.
(2) When the control result is disordered by the disturbance or a change in the process, the controller
checks the converging status, and performs a fine adjustment of PID values if necessary.
(a) If the convergence is performed smoothly, the PID values are not changed.
(b) If the convergent speed is slow, the controller corrects the PID values
to accelerate the convergence.
(c) When overshoot is generated during the convergence, the controller corrects
the PID values so as not to generate the overshoot.
(d) When hunting is generated, the controller checks the waveform and performs
a fine adjustment of PID values.
(3) The controller can be used without Fuzzy self-tuning by designating the internal switch.
(4) When using the controller for the first time, performing the PID auto-tuning
or setting the proper PID values by key operation is recommended.
The instrument is always in self-tuning status itself, and when deviation is created, it starts the tuning.
Even if in Fuzzy self-tuning status, when very large hunting is caused and the control is not stabilized,
it starts auto-tuning automatically.
When the auto-tuning performance is designated by the key operation, tuning is initiated, and when the
control is stabilized, the auto-tuning is released and returns to self-tuning status.
When lock mode [
] or [
] is designated, Fuzzy self-tuning
or Auto-tuning PID action cannot work.
With the control system in which load fluctuation periodically occurs,
the Fuzzy self-tuning may fall into malfunction.
In such a case, use the controller with the PID auto-tuning mode.