4.3 Setting the positioner at the
valve
4
Connect the control signal input to a
compressed air source of max. 1.5 bar
using a remote adjuster and a pressure
gauge.
4
Connect the supply air to the supply in-
put (supply 9).
4.3.1 Setting the air delivery
(volume restriction Q) and
proportional band XP
1. Close the volume restriction (14) as far
as the required speed of response al-
lows.
You can check the speed of response by
pressing the range spring (6) as far as it
will go.
2. Set the input signal to approximately
50 % of its range. Then, turn the zero
adjustment screw (4) until the valve is at
approximately 50 % valve travel.
On setting the Xp restriction, observe the re-
lationship with the supply air pressure as in-
dicated in Fig. 13. The preset value of Xp
should read approximately 3 %.
3. Check the plug stem's tendency to oscil-
lation by pressing the range spring (6)
briefly as far as it will go.
Xp should be set to a value as small as
possible, however, without causing no-
ticeable overshoot.
Note:
Always determine the Xp setting prior to ad-
justing the starting point. Subsequent modifi-
cation displaces the zero point!
The zero can also be shifted by altering the
adjusted supply air pressure.
If necessary, check the zero adjustment un-
der operating conditions of the plant and,
readjust, if need be.
14
EB 8359-1 EN
Operation
Zul. Supply Alim.
Xp
[%]
5
4
3
2
1
0
6 bar 3 bar 1.4 bar
90˚
0˚
180˚ 270˚
270˚
90˚
180˚
0˚
360˚
Fig. 13 · Setting the XP restriction
