Connecting The Supply Air; Signal Pressure Connection; Signal Pressure Gauges; Supply Pressure - Samson TROVIS 3730-3 Mounting And Operating Instructions

5.14 Connecting the supply air

NOTICE
!
Risk of malfunction due to incorrect sequence
of mounting, installation and start-up.
Keep the following sequence.
1. Remove the protective caps from the
pneumatic connections.
2. Mount the positioner on the valve.
3. Connect the supply air.
4. Connect the electrical power.
5. Perform settings.
The pneumatic connections in the connecting
plate, pressure gauge mounting block and
connection block are optionally designed as
a bore with ¼ NPT or G ¼ thread. Custom-
ary fittings for metal or copper tubing or
plastic hoses can be used.
Î Read instructions in section 5.13.
5.14.1 Signal pressure connec-
tion
The signal pressure connection depends on
how the positioner is mounted onto the actu-
ator:
Type 3277 Actuator
Î The signal pressure connection is fixed.
Attachment according to IEC 60534-6
(NAMUR)
Î For "actuator stem retracts" fail-safe ac-
tion: connect the signal pressure to the
connection on top of the actuator.
EB 8484-3 EN
Î For "actuator stem extends" fail-safe ac-
tion: connect the signal pressure to the
connection on the bottom of the actuator.
Rotary actuators (heavy-duty version)
Î For rotary actuators, the manufacturer's
specifications for connection apply.

5.14.2 Signal pressure gauges

Tip
To monitor the supply air and signal pres-
sure, we recommend mounting pressure
gauges (see accessories in section 3.5).
Mounting the pressure gauges:
Î See section 5.4 and Fig. 9.

5.14.3 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.
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):
Mounting and start-up
75