B.8.8 Controller Amplifications - Festo CPX Series Manual

B. Basic controlling principles

B.8.8 Controller amplifications

Festo P.BE−CPX−CMA X−CONTROL−EN en 0908NH
The possible controller amplifications in the context of force
control depend on the design of the pneumatic system. An
unnecessarily long tubing connection has a negative effect,
the system may then tend to hum. Exchanging the valve may
also result in differences in the control behaviour.
The controller amplifications are calculated based on the
parameters that describe the pneumatic system. Due to toler
ances, the default controller amplifications do not produce
the same control quality with all systems. Three parameters
are available for optimisation:
Amplification gain
Dynamic amplification
Signal filter factor
The gain factor is used to increase the control amplification.
It makes the controller respond to deviations more strongly
and faster. If this factor is increased too much, the valve
starts to hum. This occurs especially with a static force set
point and with standstill control. This humming can be re
duced by varying the signal filter factor or reducing the ampli
fication.
Dynamic amplification is only effective in the area of the force
ramp, in other words as long as the force setpoint value is
changing. This parameter is suitable for improving the truth
to path in the area of the ramp, when amplification cannot be
further optimised.
The signal filter factor can be used to influence the noise of
the pressure signals. When increasing the factor, the filter
becomes faster and consequently the noise louder. At the
same time the phase shift decreases.
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