Instruction Manual
D101728X012
3710 and 3720 Positioners
September 2017
40
Figure 28. Input Module Diaphragm and Diaphragm
Housing
W5915
Figure 29. Assembly of Input Module
A6043
Assembling the Input Module and Summing Beam Assembly
1. Position the summing beam on the input module housing. Place the flexure over the alignment pins extending
from the summing beam and input module. Secure the flexure by placing the two flexure retainers over the
alignment pins extending through the flexure. Install the two machine screws (key 20) that hold the flexure
retainers.
CAUTION
Avoid damage to the diaphragm (key 30B) when installing the machine screw (key 30E) that holds the diaphragm
connector to the summing beam assembly. Use a wrench or other tool to hold the diaphragm connector while installing
the machine screw.
2. Install the machine screw (key 30E) that connects the summing beam assembly to the diaphragm connector,
taking care not to twist the diaphragm connector and diaphragm (key 30B). Use a wrench or other tool to hold the
diaphragm connector while installing the machine screw.
3. Inspect the one O‐ring (key 31) in the positioner base plate. Replace it, if necessary. Properly lubricate (key 63) the
O‐ring.
Note
See figure 30. Before securing the input module and summing beam assembly, make sure the end of the summing beam does not
come in contact with the spool shaft. Instead, the end of the summing beam should engage the spool head.