Logix 3400MD Digital Positioner FCD LGENIM3404-00 – 9/09
38
24. Verify that the three O-rings are in the counterbores on the
machined platform where the spool valve block is to be placed
(Figure 22).
25. Carefully slide the spool into the connecting clip on the top of the
driver module assembly.
26. Carefully slide the block over the spool, using the machined surface
of the housing base as a register (Figure 14). Slide the block toward
the driver module until the two retaining holes line up with the
threaded holes in the base.
27. Install two spool-valve screws and tighten securely with a Phillips
screwdriver (see Figure 14).
28. Slide the spool valve cover assembly over the spool valve until the
tang engages into the housing slot. Install spool valve cover screw
and tighten securely (see Figure 13).
29. Install the plastic board cover. Insert the three retaining screw
through the plastic cover into the threaded boss and tighten evenly,
using a Phillips screwdriver. Do not overtighten (see Figure 16).
30. Reconnect power and air supply to the positioner and perform a
stroke calibration.
31. Reinstall all covers.
8.2 Regulator
The regulator reduces the pressure of the incoming supply air to a level
that the driver module can use.
Replacing Regulator
To replace the regulator, refer to Figures 12 and 16 and proceed as
outlined below. The following tools are required:
• Phillips screwdriver
• 1/4” nutdriver
0
WARNING:
Observe precautions for handling electrostatically
sensitive devices.
1. Make sure valve is bypassed or in a safe condition.
2. Disconnect the power and air supply to the unit.
3. Remove the main cover.
4. Remove the plastic board cover by removing the three retaining
screws (see Figure 16).
5. Remove the retaining screw from the main PCB assembly.
6. Remove the five wire connections from the main PCB assembly and
lift the main PCB out of the housing.
7. Remove the four screws from the regulator base. Verify that as
regulator is removed, the O-ring and filter remain in the counter-
bore.
8. Remove tubing and barbed fitting from the regulator base.
9. Install barbed fitting and tubing to the new regulator.
10. Verify O-ring and filter are in the counterbore. Install new regulator
using 8-32 x 1/2” screws.
NOTE:
Do not mix the regulator with those from older Logix
positioners. Older models contain regulators with different settings
that will not work in the Logix 3400MD
model. The regulator
pressure setting is printed on the top of the regulator. The Logix
3400MD
regulator is set to 17.4 psig.
11. Reinstall the five wire connections.
12. Install the main PCB into the housing. Insert the retaining screw
through the board into the threaded boss and tighten evenly, using
a Phillips screwdriver. Do not overtighten.
13. Install the plastic board cover. Insert the three retaining screws
through the plastic cover into the threaded boss and tighten evenly,
using a Phillips screwdriver. Do not overtighten (see Figure 16).
14. Reinstall all covers.
8.3 Checking or Setting Internal
Regulator Pressure
To check or set the internal regulator pressure, refer to Figure 17 and
proceed as outlined below. The tools and equipment used in the next
procedure are from indicated vendors. The following tools are required:
• Calibrated pressure gauge (0 to 30 psi)
•
1
⁄
16
” flexible tubing
• Barbed Tee (Clippard Minimatic part number T22-2 or equivalent)
•
3
⁄
32
” Allen wrench
•
3
⁄
8
” open-end wrench
0
WARNING:
Observe precautions for handling electrostatically
sensitive devices.
Figure 17: Driver Module Regulator Pressure Check
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