West Control Solutions KS98-1 - Manual (Page 43)

reserve:
To permit self-tuning, the distance between setpoint and process value must be higher than 10% of the setpoint range
before self-tuning start.
With inverse controllers, the must be higher than the process value. With direct controllers, it must be smaller.
The determines a limit which is not exceeded during self-tuning.
Self-tuning start
Select function Stat: OFF/OK and con-
firm it with M. Stat:OFF/OK blinks and
is switched over to Stat: Start by pres-
sing I.
Pressing key M starts the self-tuning attempt.
The can be changed also subsequently. After
successful self-tuning, the controller changes to
automatic operation and controls the with the
new parameters.
When ‘Process at rest’ ( PiR) is detected and a
sufficient reserve is provided, the correcting va-
riable is changed by output step (increased with indirect controller, decreased with direct controller).
!
The size of the output step change is set to 100% as standard. In critical processes, this value (parameter dYopt) may
have to be reduced to prevent damage to the process. The parameter is adjustable in the engineering, or via the para -
meter dialogue of the main menu, if the engineering is known . In case of doubt, contact the programming engineer.
When self-tuning is finished with an error ( Ada_Err or 0err on the controller page), the initial correcting varia-
ble is output until self-tuning is finished by pressing key H.
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 parameters are made.
This is followed by line-out at the pre-defined ,
until
PiR is reached again.
Subsequently, a step to cooling is made to de-
termine the “cooling” parameters. When can-
celling the cooling attempt, the parameters for
“heating” are also taken over for cooling. No
error message (
Ada_Err) is output.
a
Whilst self-tuning is active, the control function is switched off!
9499-040-82711 Operating pages
Controller I-43
t
t
Y
100%
0%
X, W
W
X
60s
PiR
Start H
I
+
+
+
Start
Adaption
Optimisation
finished
> 10% W0/W100
dYopt
Off/Ok PIR_H Step Off/Ok
Fig.: 26 Self-tuning with heating and cooling
t
t
Y
100%
0%
-100%
X
W
60s
60s
PiR
PiR
Start
Adaption
Optimization
heating
ready
Optimization
cooling
ready
Start
+
YOptm
dYopt
Off/Ok PIR_H Step Off/Ok PIR_K Step
Fig.29: