Notes on Controller Settings
4–135
IP244
C79000–B8576–C860–02
4.5 Setting the Controller Characteristics (Tuning)
The setting range of the most common controllers for temperature and pressure are listed below.
Once you have selected the suitable controller, the controller characteristics must be adapted to
the controller system.
Controller setting ranges for the most important controlled variables in process
engineering
Controller
Controlled variable
X
P
T
n
T
v
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!
!
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If the controlled system parameters T
u
and T
g
and the rate of rise v
max
are known, the required
controller parameters X
p
, T
n
und T
v
can be approximately predicted.
Rule of thumb for parameter settings
Controller structure Setting
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For controllers with a PID and PD/PID structure, the setting of the integral action time and the
derivative action time are connected.
!
$&"
% &)! ! ! % "$ "%& "!&$" %+%& %
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With PD controllers, the derivative action time T
v
is not critical.With PI or PID controllers, however,
oscillations occur if the integral action time T
n
is selected more than 50% too low.
Too high an integral action slows down the correction of disturbances. No-one can expect that
control loops function perfectly after the first parameter assignment. Generally, re-adjustments are
necessary if the system is difficult to control, i.e. T
u
/T
g
> 0.3.
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