West Control Solutions Pro-8 - Manual (Page 16)

3.5 Self-tuning
For determination of optimum process parameters, self-tuning is possible.
After starting by the operator, the controller makes an adaptation attempt, where-
by the process characteristics are used to calculate the parameters for fast line-out
to the set-point without overshoot.
The following parameters are optimized when self-tuning:
Parameter set 1:
Pb1
Proportional band 1 (heating) in engineering units [e.g. °C]
ti1
Integral time 1 (heating) in [s] r only, unless set to OFF
td1
Derivative time 1 (heating) in [s] r only, unless set to OFF
t1
Minimum cycle time 1 (heating) in [s]. This parameter is optimized only, unless
parameter Cntr/Adt0 was configured for “no self-tuning” using BlueControl ®
Pb2
Proportional band 2 (cooling) in engineering units [e.g. °C]
ti2
Integral time 2 (cooling) in [s] r only, unless set to OFF
td2
Derivative time 2 (cooling) in [s] r only, unless set to OFF
t2
Minimum cycle time 2 (cooling) in [s]. This parameter is optimized only, unless
parameter Cntr/Adt0 was configured for “no self-tuning”using BlueControl ®
Parameterset 2: according to Parameterset 1 (see page 24)
3.5.1 Preparation before self-tuning
w
As a prerequisite of process evaluation, a stable condition is required. For this
reason, the controller waits, until the process has reached a stable condition
after self-tuning start.
The rest condition is considered as reached, when the process value oscillati-
on is smaller than
± 0,5% of (rnG.H - rnG.L). The limits of the control range
must be adjusted for the controller operating range, i.e. rnG.L and rnG.H
must be adjusted to the limits within which control must take place (Configu-
rationrControllerrspan start and end of control range)
ConFrCntrr
rnG.L and rnG.H
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For starting the self-tuning after start-up, a clearance of 10% of ( SP.LO...
SP.Hi) is required. As the values PArA/SEtp/SP.LO and
PArA/SEtp/SP.Hi mustl always be within the control range, no restriction
is applicable if these values are adjusted correctly.
w
Determine which parameter set must be optimized.
-The currently effective parameter set is optimized.
r activate the corresponding parameter set (1 or 2).
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Determine which parameter must be optimized (see the list given above)
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Select the method for self-tuning
See Chapter 3.5.6
- Step attempt after start-up
- Pulse attempt after start-up
- Optimization at the set-point
Operation
Self-tuning 16
Pro-8