Siemens RWF 50.2, Installation, Use And Maintenance Instructions

Page: 52 / 72

9.2 Checking the controller parameters
Optimum adjustment of the controller to the controlled system can be checked by
recording a startup sequence with the control loop closed. The following diagrams
indicate possible incorrect adjustments, and their correction.
The response to a setpoint change is shown here for a 3rd order controlled system for
a PID controller. The method used for adjusting the controller parameters can,
however, also be applied to other controlled systems. A suitable value for
dt
is
rt
/
4
.
Pb
too small
Pb
too large
t
x
w
7865d17/1099
Figure 27:
Pb
too small
t
x
w
7865d15/1099
Figure 28:
Pb
too large
rt
,
dt
too small
rt
,
dt
too large
t
x
w
7865d16/1099
Figure 29:
rt
,
dt
too small
t
x
w
7865d14/1099
Figure 30:
rt
,
dt
too large
Optimum adjustment
t
x
w
7865d18/1099
Figure 31: Optimum adjustment
Example
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