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Control loop with controller and control paths:
Control parameter
Kp – proportional amplification. For controller P component.
Tn – reset time. For controller I component.
Tv – derivative time. For controller D component.
Typical formula for a standard PID controller:
∫
y
K
x
x d t
T
=
*
+
*
+
*
p
d
T
d
v
d x
d t
1
n
d
Characteristic control system values
KS – process gain. dX/dY of a system step response.
Tu – delay time
Tg – compensation time
Tt – dead time
W – inflection point
KI – integral gain
TI – integral time
Control paths
To find a suitable controller, you must know the characteristics of the con-
trol paths to be influenced.
A control path is that part of a system between the final control element for
the control quantity (the process quantity to be controlled) and the control
quantity's measuring point. The final control element and the measuring
element are also part of the control path.
Control paths can be fundamentally divided into two categories:
l
Control paths with compensation: When a control or interference variable
changes, the control variable searches for a new final value (steady state).
Example: Flow, temperature, etc.
141
Delphin Technology AG
Januar 2018
Expert
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