PMA KS 98, Manual

Page: 183 / 246

Self-tuning procedure with heating:
(2-point, 3-point stepping, continuous controller)
After reaching ‘Process in rest’, the process is stimulated by means of an output step change and the process response
is used to determine Tu1 and Vmax1 at the step response reversal point, if possible.
Self-tuning procedure with heating and cooling processes:
(3-point / split-range controller)
Self-tuning starts as with a “heating” process. After self-tuning end, the controller settings based on the calculated pa-
rameters are made. This is followed by line-out at the pre-defined set-point, until PiR is reached again. Subsequently,
a step to cooling is made to determine the “cooling” parameters, in order to determine Tu2 and Vmax2 using the step
response. Based on these characteristics, the controller settings for the cooling process are made. When cancelling the
cooling attempt, the parameters for “heating” are also taken over for cooling. No error message (
Ada_Err
) is out-
put.
g
With 3-point stepping controllers, the motor actuator is closed first after starting and opening to
YOptm
will occur only then. This calibration procedure (
Stat: Abgl.
) is not shown in the figures.
g
For maintaining a safe process condition, monitoring for an exceeded set-point is done continuously.
a
During self-tuning, the control’ function is switched off! I.e.: Ypid is within the limits of Ymin and Ymax.
a
With Off controllers, self-tuning is using the function, i.e.Y2 = 0.
Controlled adaptation
For defined applications, adaptation of the control parameter set to the current process condition is purposeful. For this,
the Contr+ is provided with 6 control parameter sets, which can be selected via analog input
ParNo .
9499 040 50611
Controller
183 Self-tuning
r
controller adaptation to the process
t
t
Y
100%
0%
-100%
X
W
60s
60s
PiR
PiR
Start
Adaption
Optimisation
heazing
finished
Optimisation
cooling
finished
Start
+
YOptm
dYopt
Off/Ok PIR_H Step Off/Ok PIR_K Step
Fig.: 10
Self-tuning with
heating and cooling
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