B.7 Optimisation Of The Controller - Festo CPX Series Manual

B. Basic controlling principles
B.7 Optimisation of the controller
B.7.1 Description of the controller factors for position control
Amplification gain
Festo P.BE−CPX−CMA X−CONTROL−EN en 0908NH
From the basic parameters the CMAX ascertains various con
troller parameters. These determine the dynamics (speed) as
well as transition behaviour (cushioning) of the controller. The
aim is to guarantee fast, overswing−free positioning with little
contouring error (dynamic deviation).
The controller factors are standardised to 1.0 by the CMAX.
If the factors are increased (>1), the parameters will be in
creased accordingly; if the factors are reduced (<1), the para
meters will be reduced accordingly.
The controller data ascertained by the CMAX are usually the
optimum values. The (real) pneumatic axes used, however,
do not always correspond to the axes used as a basis for the
control process (ideal axes). In order that possible deviations
can be taken into consideration, you can influence the control
parameters by entering factors.
Further instructions on optimising the positioning behaviour
can be found in section B.7.2.
With the amplification gain you can influence the sensitivity
with which the positioning control circuit reacts to modifica
tions of the variables" (position, speed, acceleration).
Behaviour of the axis
The drive tends towards instability (tendency to vi
brate during positioning, up to continuous vibration
around the setpoint position).
Bad positioning accuracy or high contouring error as
well as long positioning time.
The positioning process is carried out quickly and
accurately.
Factor
Reduce
Increase
Optimal
B−25