Samson TROVIS SAFE 3730-6, Монтаж и эксплуатация, Страница: 84 / 184

84 EB 8384-6S EN
Mounting and start-up
a bore with ¼ NPT or G ¼ thread. Custom -
ary fittings for metal or copper tubing or
plastic hoses can be used.
Signal pressure connection
The signal pressure connection depends on
how the positioner is mounted onto the actu-
ator:
−
Type 3277 Actuator
The signal pressure connection is fixed.
−
Attachment according to IEC 60534-6
(NAMUR)
For "actuator stem retracts" fail-safe ac-
tion: connect the signal pressure to the
connection on top of the actuator.
For "actuator stem extends" fail-safe ac-
tion: connect the signal pressure to the
connection on the bottom of the actuator.
−
Rotary actuators
For rotary actuators, the manufacturer's
specifications for connection apply.
5.15.2 Output signal display
To monitor the supply air and signal pres -
sure, we recommend mounting pressure
gauges
(see accessories in section 3.8).
Mounting the pressure gauges:
Î
See section 5.4 and section Fig. 8
5.15.3 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 depending on the actuator. The direc-
tion of action is marked FA or FE or by a sym-
bol.
PLOW is indicated under Code 0 if the sup-
ply pressure is lower than the upper bench
range value determined during plotting of
the valve signature.
Actuator stem extends FA (AIR TO OPEN)
Fail-close (for globe and angle valves):
Î
Required supply pressure = Upper bench
range value + 0.2 bar, at least 1.4 bar.
Actuator stem retracts FE (AIR TO CLOSE)
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 the
actuator [bar]
Tip
Note