Samson 4765 - Pneumatic Connections

16 EB 8359-1 EN
Mounting and start-up
5.4 Pneumatic connections
The pneumatic connections are optionally
designed as a bore with NPT or ISO288/1-
G thread.
Customary ttings for metal or copper tubing
or plastic hoses can be used.
Risk of malfunction due to failure to comply
with air quality requirements.
− Only use supply air that is dry and free of
oil and dust.
− Read the maintenance instructions for up-
stream pressure reducing stations.
− Blow through all air pipes and hoses thor-
oughly before connecting them.
5.4.1 Pressure gauges
To monitor the positioner, we recommend in-
stalling pressure gauges for the supply air
and signal pressure. The required parts are
listed on page10.
5.4.2 Supply pressure
The required supply air pressure depends on
the bench range and the actuator's direction
of action (fail-safe action).
The bench range is written on the nameplate
either as the bench range or signal pressure
range. The operating direction is marked FA
or FE or by a symbol.
Actuator stem extends (FA)
Fail-close
(for globe and angle valves)
Required supply pressure =
Upper bench range value + 0.2 bar,
minimum 1.4 bar
Actuator stem retracts (FE)
Fail-open
(for globe and angle valves)
For tight-closing valves, the maximum signal
pressure pst
max
is roughly estimated as fol-
lows:
pst
max
= F +
d² · π · ∆p
[bar]
4 · A
d = Seat diameter [cm]
∆p = Differential pressure across the valve
[bar]
A = Actuator area [cm²]
F = Upper bench range value of
actuator [bar]
If there are no specications, calculate as
follows:
Required supply pressure =
Upper bench range value + 1bar
The positioner output pressure is routed to
the top or bottom diaphragm case of the
actuator as shown in Fig.5 to Fig.8.
NOTICE
!