Electrical Connections For Type 4070 Electro-Pneumatic Positioners; Operating Information; Front Cover And Indicator Cover - Fisher 4070 Instruction Manual

Type 4060 & 4070
A7228 / IL
Figure 6. I/P Unit Storage Seal Location
to prevent pressure buildup inside the case and to pro-
vide a drain hole for any moisture that might collect
inside the case. If a remote vent is required, the vent
line must be as short as possible with a minimum
number of bends and elbows.
The vent port (OUT) or the end of a remote vent pipe
must be protected against the entrance of all foreign
matter that could plug the vent. Check the vent period-
ically to be certain it is not plugged.
Electrical Connections for Type 4070
Electro-Pneumatic Positioners
WARNING
For intrinsically safe installations, refer
to the factory drawings or to instruc-
tions provided by the barrier manufac-
turer for proper wiring and installation.
Do not make connections to port I. It is automatically
sealed off and protected.
Remove the storage seal, shown in figure 6, from the
end of the unit to expose the conduit entry. Use the
1/2-inch NPT conduit connection or PG 13.5 (M20)
cable gland for installation of field wiring.
Refer to figure 7 when connecting field wiring from the
control device to the I/P unit. Connect the positive wire
from the control device to the I/P unit positive (+) ter-
minal, and the negative wire from the control device to
the I/P unit negative (–) terminal. Do not overtighten
6
CONTROL
DEVICE
A3875-1 / IL
Figure 7. Typical Field Wiring Diagram
the terminal screws. Maximum torque is 4 lbf in. (0.45
N m). Connect the I/P unit grounding terminal to an
earth ground.
To monitor the I/P unit output, install a gauge in gauge
port P. Gauge port P is sealed with a plug. To install a
gauge, unscrew the plug and install a gauge.

Operating Information

Front Cover and Indicator Cover

The positioner front cover is shown in figure 8. It is
secured to the unit with four captive screws and
sealed with an O-ring. The front cover O-ring can be
looped over notches in the front cover to allow for
drainage.
There are eight locations on the front cover where the
O-ring can be looped. This O-ring system is common
to the pneumatic unit and I/P unit. This unique sealing
system allows for complete sealing or draining of the
units by changing the position of the front cover O-
ring.
The indicator cover is O-ring sealed and secured by a
bayonet coupling. The indicator cover also secures the
identification cover to the front cover.
To remove the indicator cover, turn it slightly counter-
clockwise until it loosens. The identification cover and
indicator cover O-ring are now removable. When
installing the indicator cover and identification cover,
make sure that the indicator cover O-ring is properly
engaged.
I/P UNIT