User guide

B. Basic controlling principles
B−25
Festo P.BE−CPX−CMA X−CONTROL−EN en 0908NH
B.7 Optimisation of the controller
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.
B.7.1 Description of the controller factors for position control
Further instructions on optimising the positioning behaviour
can be found in section B.7.2.
Amplification gain 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 Factor
The drive tends towards instability (tendency to vi
brate during positioning, up to continuous vibration
around the setpoint position).
Reduce
Bad positioning accuracy or high contouring error as
well as long positioning time.
Increase
The positioning process is carried out quickly and
accurately.
Optimal