4
Operation
4.1 Combining positioner and
actuator
The arrangement of the actuator, input sig-
nal, operating direction and mounting loca-
tion is schematically represented in Figs. 6
to 9.
Each subsequent change such as reversal of
the operating direction or field reversing the
actuator version from direct "Actuator stem
extends" to reverse "Actuator stem retracts"
or vice versa also involves changing the
mounting location of the positioner.
4.1.1 Determining/reversing the
operating direction
When the input signal (reference variable w)
increases, the signal pressure p
st
can either
be increasing (direct operating direction <<)
or decreasing (reverse operating direction
<>).
The same applies to a decreasing input sig-
nal; the output pressure either decreases (di-
rect operating direction <<) or increases (re-
verse operating direction <>).
Symbols are located on the flapper plate
(10.2) which identify the respective operat-
ing directions (direct << or reverse <>).
EB 8359-1 EN
11
Operation
Actuator: Stem extends (FA)
Actuator: Stem retracts (FE)
1
20
pst
w
Fig. 6 · Operating direction << Left attachment
1
20
pst
w
Fig. 7 · Operating direction <> Right attachment
pst
w
Fig. 8 · Operating direction << Right attachment
pst
w
Fig. 9 · Operating direction <> Left attachment
Lever (1) on top of plate (20)
Plate (20) on top of lever (1)
