Samson 3730-2, Mounting And Operating Instructions

Page: 56 / 128

56 EB 8384-2 EN
Connections
Actuator stem extends FA (AIR TO OPEN)
Fail-close (for globe and angle valves):
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 diaphragm area [cm²]
F = Upper bench range value of the actuator [bar]
If there are no specifications, calculate as
follows:
Required supply pressure = Upper bench
range value + 1 bar
5.1.3 Signal pressure (output)
The signal pressure at the output (38) of the
positioner can be restricted to 1.4 bar,
2.4 bar or 3.7 bar in Code 16.
The limitation is not activated [No] by de-
fault.
5.2 Electrical connections
Risk of electric shock and/or the formation
of an explosive atmosphere.
For electrical installation, observe the rele-
vant electrotechnical regulations and the ac -
cident prevention regulations that apply in
the country of use. In Germany, these are
the VDE regulations and the accident pre -
vention regulations of the employers’ liability
insurance.
The following regulations apply to installa-
tion in hazardous areas: EN 60079-
14: 2008 (VDE 0165, Part 1)
Explosive At-
mospheres – Electrical Installations Design,
Selection and Erection.
Incorrect electrical connection will render the
explosion protection unsafe.
Adhere to the terminal assignment.
Do not undo the enameled screws in or on
the housing.
Do not exceed the maximum permissible val-
ues specified in the EC type examination cer-
tificates when interconnecting intrinsically
safe electrical equipment (U
i
or U
0
, l
i
or I
0
, P
i
or P
0
, C
i
or C
0
and L
i
or L
0
).
Selecting cables and wires
Observe clause 12 of EN 60079-14: 2008
(VDE 0165, Part 1) for installation of the in -
trinsically safe circuits.
DANGER
!
WARNING
!