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PID controller
For defining simple control processes with unknown elements, set Tn to 3600 or 0 and Tv to
0 and start adjusting Kp.
For adjusting Kp, begin with a small value (1 … 10) and gradually increase it until the actual
value periodically oscillates. Now, decrease Kp until the actual value becomes stable (the
actual value will not reach the nominal value as long as Tn has not been adjusted).
To establish an approximate value for Tn (volume time constant), divide the volume of the
vacuum system by the pumping speed of the vacuum pump. Enter that value and gradually
decrease it. The actual value will slowly approximate the nominal value. If Tn is set too low,
the actual value will oscillate.
Now, modify the nominal value or introduce a disturbance and observe the actual value. If it
overshoots, increase Tn. If it approximates the nominal value only very slowly, decrease Tn.
If required, enter a value for Tv. As a rule of thumb, enter the value of Tn divided by 4.5.
Adjust only one component setting at a time and observe the effect of that adjustment.
Check the PID settings by observing (and recording) the step response of the actual value
to a modification of the nominal value or to a disturbance.
The «Pressure» display shows the actual value
(pressure reading) and the nominal value (setpoint).
Press
to get to the «Controller type» display.
The «Controller type» display shows the currently
selected controller type. Press.
to edit the controller type setting.
to return to the «Pressure» display.
CONTROL
PARAM SOURCE CONTROL
Pressure [ ]
Act :
mbar
Nom : 1.33E+01 mbar
>1.00E+03
SAVE
SAVE
Controller type [ ]
Type : PID
Kp :
1.0
Tn : 0.3 s
Tv : 0.0 s