Samson 3730-0, Монтаж и эксплуатация

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40 EB 8384-0 EN
Start-up and settings
7 Start-up and settings
7.1 Default switch positions
After the positioner has been mounted on the
valve, all switches
S1 to S10 must be set to
OFF .
7.2 Fail-safe position
The switch position of switch S1 depends on
the fail-safe position of the valve:
− AIR TO OPEN · When the actuator is
vented, the valve is completely closed. As
the signal pressure increases at the posi
-
tioner output (38), the valve opens.
−
AIR TO CLOSE · When the actuator is
vented, the valve is completely opened.
As the signal pressure increases at the
positioner output, the valve closes.
To determine the switch position, read the as -
sociated switch position S1 = ON or OFF
from the cover plate at the actuator symbols.
The symbols are read properly when the
symbol shows the actuator on top of the
valve; symbols upside down do not apply.
AIR TO OPEN:
Pneumatic connections point
to the right S1 = ON . Pneumatic connections
point to the left S1 = OFF .
AIR TO CLOSE: Pneumatic connections point
to the right S1 = OFF . Pneumatic connections
point to the left S1 = ON .
AIR TO OPEN always applies for double-act -
ing actuators. Proceed as described in sec -
tion 4.3 to connect the reversing amplifier.
7.3 Volume restriction Q
MAX BACK
MIN SIDE
MIN BACK
MAX SIDE
Q
Fig. 12: Volume restriction Q
MAX BACK/MIN SIDE setting
The volume restriction Q serves to adapt the
air output capacity to the size of the actuator:
− Actuators with a transit time < 1 s , e.g.
linear actuators with an effective area
smaller than 240 cm², require a restrict
-
ed air flow rate (MIN).
−
Actuators with a transit time ≥ 1 s do not
require the air flow rate to be restricted
(MAX).
The position of volume restriction Q also de -
pends on how the signal pressure is routed
at the actuator in SAMSON actuators :
−
The SIDE position applies for actuators
with a loading pressure connection at the
side, e.g. Type 3271-5.
− The BACK position applies for actuators
with a loading pressure connection at the
back, e.g. Type 3277-5.
The SIDE restriction position always applies
for
non-SAMSON actuators .
Table 8: Position of the volume restriction*
Transit time
< 1 s ≥ 1 s
Signal pressure
Connection at the side MIN SIDE MAX SIDE
Connection at the back MIN BACK MAX BACK
* Intermediate settings are not permitted.