38
5 - Automatic tuning
275..0
274.8
tune
stop
tune
strt
Operator
mode
press until
To start
select
strt
To stop
select
stop
Step response
SP
Natural frequency
Start of autotune
operation
PV variable
Control output
PV variable
Control output
tuning start
End of the tuning
operating and setting of
the new calculated
terms.
Setpoint change
End of the tuning
operating and setting of
the new calculated
terms.
5
AUTOMATIC
TUNING
Two tuning methods are provided:
• Initial one shoot
Fuzzy-tuning
• Continuous, self learning
Adaptive Tuning
The Fuzzy-Tuning
allows the calcu-
lation of the optimal PID terms para-
meters, monitoring the response of
the process to disturbances.
The controller provides 2 types of
“one shot” tuning algorithm, that
are selected automatically accord-
ing to the process condition when
the operation is started.
Step response
This type is selected when, at the
start of the autotune operation, the
PV is far from the Setpoint of more
than 5% of the span.
This method has the big advantage
of fast calculation, with a reasonable
accuracy in the term calculation.
Natural frequency
This type is selected when the PV is
close to the SP Setpoint.
This method has the advantage of
a better accuracy in the term cal-
culation with a reasonable speed
calculation.
The Fuzzy Tuning determines
automatically the best method to
use to calculate the PID term,
according the process conditions.
The green led
{
blinking goes on
when the Fuzzy Tuning is in
progress. At the end of this opera-
tion, the calculated PID terms para-
meter are stored and used by the
control algorithm and the controller
goes back to the operator mode.
The green led
{
becomes off.
M4UK.ed6 20-05-2005 11:43 Pagina 38
