185
Supplementary information
Type 8792, 8793 REV.2
26.2 Properties of PID controllers
A PID controller has a proportional, an integral and a differential portion (P, I and D portion).
26.2.1 P portion
Function:
Kp is the proportional coefficient (amplification factor). It is the ratio of the adjustment range ∆Y and the
proportional range ∆Xd.
Characteristic and step response of the P portion of a PID controller
Characteristic
Step response
Xd
X
Ymax
Ymin
Y0
Kp
⋅
Xd
t
t
Xd
Y
Proportional range ∆Xd
Y
Adjustment
range ∆Y
Figure 71:
Characteristic and step response of the P portion of a PID controller
Properties
In theory a pure P-controller functions instantaneously, i.e. it is quick and therefore dynamically favorable.
It has a constant control difference, i.e. it does not fully correct the effects of malfunctions and is therefore
statically relatively unfavorable.
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