Samson 3766 - Connections; Pneumatic Connections

34 EB 8355-1 EN
Connections
4 Connections
4.1 Pneumatic connections
The pneumatic connections are optionally
designedasaborewith¼NPTorG¼
thread.Customaryttingsformetalorcop-
per tubing or plastic hoses can be used.
The supply air must be dry and free from oil
and dust. The maintenance instructions for
upstream pressure reducing stations must be
observed.
Blow through all air pipes and hoses thor-
oughly before connecting them.
If the positioner is attached directly to the
Type3277Actuator,theconnectionofthe
positioner's output pressure to the actuator is
xed.Forattachmentaccordingto
IEC60534-6(NAMUR),thesignalpressure
can be routed to either the top or bottom di-
aphragm chamber of the actuator, depend-
ing on the actuator's fail-safe action "actua-
tor stem extends" or "actuator stem retracts".
Exhaust air
Modelswithindex3766-x...x.03 and higher
are equipped with a hinged cover without its
own exhaust air port. The exhaust air con-
nections for these models are included in the
accessories.
The vent plug is located on the plastic cover
of the actuator for direct attachment, where-
as for NAMUR attachment, it is located on
the adapter housing. The vent plug is located
on the intermediate piece or reversing ampli-
erforattachmenttorotaryactuators.
If you intend to replace older models with in-
dex 3766-x...x.02 or lower, the mounting
parts may need to be replaced as well.
4.1.1 Pressure gauges
To precisely tune the positioner, we recom-
mend installing pressure gauges for the sup-
ply air and signal pressure.
The required parts are listed as accessories
inTable4,Table5andTable7.
4.1.2 Supply pressure
The required supply air pressure depends on
the bench range and the actuator's operat-
ing direction (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,
atleast1.4bar.
NOTICE
!
NOTICE
!