Optimizing The Controller Data - Siemens SIPART PS2 6DR50xx Manual

4.7

Optimizing the controller data

13 Pulse length up
14 Pulse length
down
17 Short step zone up
18 Short step zone down
34 Prediction up
35 Prediction down
We recommend that you perform an automatic initialization first and only then adapt the
parameter determined by the positioner to your own special requirements.
TIP: To have a fixed reference value, it is helpful if you specify a fixed value for the dead zone
(DEBA parameter) instead of "Auto" for the optimization of your particular controller.
You select the parameters above from the diagnosis menu in the accustomed manner and
activate the joint adjustment by pressing the increment or decrement button for 5 seconds.
If you now adjust the relevant parameter, the new value is activated immediately. You can test
the effects of the new values on the controller results immediately.
When you quit the diagnosis menu, the parameter adjustment option is deactivated again.
SIPART PS2 Manual
A5E00074631--06
The data for the control quality that was automatically determined
during initialization is optimized for short compensation with low
overshooting. In special cases (e.g. extremely small and therefore
particularly fast actuators or for operation with boosters), you might
want to modify this data specifically for faster compensation or a
greater damping effect. The following six parameters are available for
this purpose:
This is for defining the smallest pulse lengths with which the actuator is
to move for each actuating direction. The optimal value mainly depends
on the volume of the actuator.
Small values result in small actuating increments and frequent activa-
tion of the actuator. Bear in mind that if the values are too small, there
will be no movement. Large values are advantageous for large actuator
volumes. Also bear in mind that large actuating increments for small
actuators also result in large movements.
The short step zone is the range of the control deviation between the
fast step zone and the dead band in which the actuator is activated by
pulses.
In the case of small control deviations, small values already cause
relatively high actuating speeds and can therefore result in over-
shooting. Large values in particular reduce overshooting in the case of
large changes in the nominal value and result in slow actuating speeds
near the compensated status.
This parameter has the same effect as a damping factor and is used to
set the control dynamics.
Small values cause fast compensation with overshooting. Large values
cause slow compensation without overshooting.
Operation
143