Samson 5825 Mounting And Operating Instructions - 4.2.2 Potentiometer
3. Use a 4 mm Allen key to turn the adjust-
ers (7.1 or 7.2 in Fig. 2) until contact is
made. The angle of rotation of the cam
disks is limited. Therefore, the top
adjuster (7.1) should preferably be used
for the upper travel range and the bot-
tom adjuster (7.2) for the lower travel
range.
4.2.2 Potentiometer
As the valve passes through its travel range,
the resistance value changes from 0
Ω
to
max. 80 % of its nominal value.
Place a screwdriver on the slotted shaft (11
in Fig. 8) to calibrate the potentiometer.
Calibrating actuator with extended actua-
tor stem at 0
Ω
1. Connect ohmmeter to terminals 61 and
62.
2. Extend actuator stem as far as it will go
to its final position.
3. Turn the potentiometer counterclockwise
as far as it will go. The ohmmeter indi-
cates the initial value of approx. 0
Ω
.
Calibrating actuator with retracted actuator
stem at 0
Ω
1. Connect ohmmeter to terminals 61 and
63.
2. Retract actuator stem as far as it will go
to its final position.
3. Turn the potentiometer clockwise as far
as it will go. The ohmmeter indicates the
initial value of approx. 0
Ω
.
4. Only for actuators with 6 or 12 mm
travel:
Slowly turn the potentiometer
counterclockwise up to the point where
the resistance just changes from 0
Ω
.
4.2.3 Positioner
The actuator is optionally controlled by a
DC current signal or a DC voltage signal as
the reference variable.
This reference variable, a 0 (2) to 10 V or
0 (4) to 20 mA signal, must be assigned to
the valve travel (0 to 100 %).
EB 5824 EN
13
Operation and settings
Fig. 7 · Characteristic increasing >> and
decreasing <>
Actuator stem
retracted
Actuator stem
extended
Travel
Span
Span
Zero
Zero
Reference variable
Input signal