Replacing The Module Final Assembly - Emerson Fisher 846 Instruction Manual

Instruction Manual
Form 5739
February 2002
A6649/IL
Figure 6-2. Alignment Key Above Module Cover Indicating Boss
compartment cover. Unscrew the module cover.
When the module cover threads clear the housing,
slowly pull on the cover, and the module final
assembly will gradually come out of the housing.
The module and the housing are
designed for minimal clearance;
therefore, patience may be required
while pulling on the cover. Time must
be allowed for release of the vacuum
effect between the housing and
module. If the module becomes tilted
and cannot be removed, reinsert it
completely into the housing and fully
engage the module cover threads.
Then proceed again with removal,
ensuring that you pull slowly in a
straight line.
Support both the module cover and the module final
assembly as it comes out of the housing. This is to
prevent dropping them, should they become
detached accidentally.
CAUTION
Do not grip the module cover threads.
The threads are sharp and may cause
minor injury. Wear gloves when
removing the module cover.
2. Prepare to remove the module final assembly
from the module cover. Align the module feet with
the two interior cover slots. To accomplish this,
identify the indicating boss on the module cover,
shown in figure 6-2.
MODULE
ALIGNMENT
KEY
INDICATING
BOSS
Note
A6650/IL
Figure 6-3. Removing the Module Final Assembly from the
Module Cover
Grasp the module cover with one hand and the
module final assembly with the other hand. Rotate
the module final assembly so that the module
alignment key is directly above the indicating boss
on the module cover. Figure 6-2 shows the module
alignment key and the indicating boss. The module
feet are now aligned with the cover slots.
3. Remove the module final assembly from the
module cover. To accomplish this, hold the cover
steady, and push the module final assembly in the
direction of the module cover indicating boss. At the
same time, lift the opposite foot of the module final
assembly out of the cover slot, as shown in figure
6-3.

Replacing the Module Final Assembly

Use the following procedure to attach the module
cover and replace the module final assembly:
1. Ensure that the electronic circuit board and the
pilot actuator assembly provide the desired action
(direct or reverse). See the Electronic Circuit
Board and Pilot/actuator Assembly Action
descriptions later in this section.
2. Ensure that the slip ring is in place around the
feet of the module final assembly. The module cover
O-ring should be lightly lubricated with silicone
grease and placed in the O-ring gland. The stroke
port screen should be clean and in place.
WARNING
Personal injury and property damage
could result from fire or explosion. Do
not operate the transducer with the
CENELEC flameproof options at a
supply pressure in excess of 1.4 bar
(20 psi). Doing so invalidates the
Maintenance
6–3