Samson foundation 3787, Mounting And Operating Instructions, Page: 12 / 96

with the actuator symbol "actuator stem
extends" or "actuator stem retracts" to
match the actuator version used.
If not, remove the three fastening
screws and the cover plate (18), turn
the seal (17) by 180
°
and reinsert it.
When the
old
connection block is used,
turn the switch plate (19) to align the ac-
tuator symbol with the arrow.
7. Place the connection block with its seal
rings on the positioner and actuator
yoke and screw it tight using the fasten-
ing screw.
For actuators with "actuator stem re-
tracts", additionally attach the ready-
made signal pressure line.
Actuator with 120 cm
2
For the Type 3277-5 Actuator with 120 cm
2
effective diaphragm area, the signal press-
ure is transmitted to the diaphragm cham-
ber via the switchover plate (Fig. 3 bottom).
For a rated travel of 7.5 mm, a brass
throttle (see Accessories table on page 13)
must be pressed into the seal located in the
signal pressure input on the actuator yoke.
For a rated travel of 15 mm, this is only re-
quired when the supply pressure exceeds
4 bar.
6. Remove the screw plug on the rear of
the positioner case and seal the signal
pressure output (Output 38) with the
plug from the accessories.
7. Mount the positioner so that the bore in
the distance plate (15) is aligned with
the seal located in the bore of the actua-
tor yoke.
8. Align the switchover plate with the
corresponding symbol for left attach-
ment and screw the plate to the actua-
tor yoke.
Important!
If, in addition to the positioner, a solenoid
valve or a similar device is attached to the
120 cm
2
actuator, the rear M3 screw must
not be removed. In this case, the signal
pressure has to be fed from the signal press-
ure output to the actuator via the required
connecting plate (see Table 2). The swit-
chover plate is no longer required.
Note!
For faster control valves with a transit time
less than 0.6 seconds, replace the filter in
the signal pressure output (output 38) with a
screw-in throttle (see Accessories table), if
necessary.
Filling the diaphragm chamber with air
If the Type 3277 Actuator’s diaphragm
chamber must be filled with air exhausted
from the positioner, the diaphragm cham-
ber (for version with "actuator stem ex-
tends") can be connected to the connection
block using a tube (see Table 3). To do
this, first remove the screw plug from the
connection block.
For the Type 3277-5 Actuator with "actua-
tor stem retracts", the air exhausted from
the positioner is constantly supplied to the
diaphragm chamber through an internal
bore.
12
EB 8383-1 EN
Attachment to the control valve