Siemens SIPART DR21, Manual

Page: 116 / 242

3 Functional description of the structure switches
3.10 Other functions of the standard controller
Manual
116
SIPART DR21
C73000-B7476-C143-08
E
A t
t
Figure 3-32 Effect of the adaptive non-linear filter
The factory setting of tF is 1 s. In controllers with D-part -- it should be set as great as possible
because of the input noise amplified by vv
S
kp and in the adaptation.
3.10.2 Response threshold AH
The response threshold AH (dead zone element) is in the control difference connected after the
adaptive filter.
-
AH
AH
x
d
output
x
d
input
Figure 3-33 Effect of the dead zone element
The dead zone element lends the controller a progressive behavior, at small control differences
the gain is low or even 0, at larger control differences the specified Kp is reached. It should be
taken into account that the remaining control difference can adopt the value of the set response
threshold AH.
The factory setting of AH is 0 % and can be set up to 10 % in the parameterization mode onPA.
In S-controllers the minimum necessary setting of AH is given by the minimum
Δ
x=ks
·
Δ
y (see
chapter 6.3, page 183) and can be increased for further settling of the controlled system. In
K-controllers a small threshold value is advisable for settling the control circuit and reducing
wear on the actuator.