Installation; Mounting The Positioner - Emerson Fisher 3710 Instruction Manual

Instruction Manual
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Installation

To change an existing 3710 positioner into a 3720 positioner, install a 3722 electro‐pneumatic converter (figure 3).
The 3722 electro‐pneumatic converter mounts over the input and supply connections of the 3710 positioner.
Figure 3. Fisher 3722 Electro‐Pneumatic Converter
1/2‐NPT CONDUIT CONNECTION
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1. Be sure all safety procedures have been followed. Remove the input and supply connections from the existing 3710
base plate and clean the ports.
2. Locate the two O‐rings (key 85, figure 32) and properly lubricate (key 82) them. Place one O‐ring in the recessed
area surrounding the input port on the positioner base plate. Place the other O‐ring around the supply port.
3. Locate the two socket head mounting screws (key 84). Properly orient the converter and secure it to the positioner
base plate with the mounting screws. Be sure the O‐rings remain in place while securing the converter to the
positioner base plate.
4. Connect supply pressure to the converter supply port.

Mounting the Positioner

Typically, a positioner is ordered with an actuator. At the factory, the positioner is mounted on the actuator and
calibrated. However, a positioner can be ordered separately and mounted on an existing actuator.
To field‐mount a positioner to an existing actuator, an actuator cover plate with mounting holes and purge tube
knockout may be required. Check the existing actuator cover plate. It must have three positioner mounting holes and,
for specific actuators, a purge tube knockout. See table 4.
SUPPLY CONNECTION
EXTERNAL GROUNDING
SCREW
3710 and 3720 Positioners
September 2017
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