Emerson Rosemount 3051 User manual

Model 3051
Sensor Module
Replacement
SAFETY MESSAGES
Procedures and instructions in this manual may require special
precautions to ensure the safety of the personnel performing the operations.
Information that raises potential safety issues is indicated by a warning
symbol ( ). Refer to the following safety messages before performing an
operation preceded by this symbol.
Warnings
Explosions can result in death or serious injury.
• Do not remove the instrument cover in explosive environments when the
circuit is alive.
• Both transmitter covers must be fully engaged to meet explosion-proof
requirements.
• Before connecting a communicator in an explosive atmosphere, make
sure the instruments in the loop are installed in accordance with
intrinsically safe or nonincendive field wiring practices.
00809-0400-4001
English
Rev. BA

2
BEFORE YOU DISASSEMBLE THE TRANSMITTER
Maintenance procedures differ for improved and previous style transmitter
housings. Verify the specific physical characteristics of your transmitter
before you begin any maintenance procedures.
DISASSEMBLY PROCEDURES
Do not remove the instrument cover in explosive atmospheres when the
circuit is alive.
Remove the Transmitter from Service
NOTE
Once you have determined a transmitter to be inoperable, remove it from
service.
Be aware of the following:
䡲Isolate and vent the process from the transmitter before removing
the transmitter from service.
䡲Remove all electrical leads and conduit
䡲Detach the process flange by removing the four flange bolts and the
two alignment screws that secure it.
䡲Do not scratch, puncture, or depress the isolating diaphragms.
䡲Clean the isolating diaphragms with a soft rag and a mild cleaning
solution, and rinse with clear water.
䡲Whenever you remove the process flange or flange adapters,
visually inspect the Teflon O-rings. Replace the O-rings if they show
any signs of damage, such as nicks or cuts. If they are undamaged,
you may reuse them.
4.0 in.
(105 mm)
3.2 in.
(80 mm)
IMPROVED PREVIOUS

3
Remove the Electronics Board
1. Remove the housing cover opposite the field terminal side.
2. Loosen the two captive screws that anchor the board. The circuit board
is electrostatically sensitive. To prevent damage to the circuit board, be
sure to observe handling precautions for static-sensitive components.
3. Gently pull the electronics board out of the housing to disconnect
the power connection. With the board free of the housing, only the
sensor module ribbon cable connects the board to the housing.
NOTE
Previous versions of the electronics board use a snap-in power plug and
receptacle. Carefully unsnap the power plug from the receptacle to free the
board from the power cord.
4. Disconnect the sensor module ribbon cable to release the
electronics board from the transmitter.
Step 1
3051-053AB, 054AB, 055AB
Step 2 Step 3
3051-056AB
Step 4

4
Remove the Sensor Module from the Electronics Housing
1. Carefully tuck the cable connector completely inside the internal
shroud.
IMPORTANT
Do not remove the housing until after you tuck the cable connector
completely inside of the internal shroud. The shroud protects the cable from
damage that can occur when you rotate the housing.
2. Loosen the housing rotation set screw with a 5/64-inch hex wrench
and back off one full turn.
IMPORTANT
To prevent damage to the sensor module ribbon cable, disconnect it from the
electronics board before you remove the sensor module from the electrical
housing.
3. Unscrew the housing from the module, making sure the shroud and
sensor cable do not catch on the housing.
IMPORTANT
Make sure the sensor ribbon cable and internal shroud remain completely
free of the housing as you rotate it. Damage can occur to the cable if the
internal shroud and sensor cable rotate with the housing.
Step 1
3051-057AB, 059AB, 060AB
Step 2 Step 3

5
REASSEMBLY PROCEDURES
Attach the Sensor Module to the Electronics Housing
Follow these procedures carefully to ensure proper reassembly:
1. Inspect all cover and housing (non-process-wetted) O-rings and
replace if necessary. Lightly grease with silicone lubricant to ensure
a good seal.
2. Carefully tuck the cable connector completely inside of the internal
shroud. To do this, turn the shroud and cable counterclockwise one
rotation to tighten the cable.
3. Lower the electronics housing onto the module, and guide the internal
shroud and cable through the housing and into the external shroud.
4. Turn the housing clockwise to fasten it to the module.
IMPORTANT
To prevent damage to the cable connector, watch the cable and shroud as
you attach the housing to the module. Make sure the cable connector does
not slip out of the internal shroud and begin to rotate with the housing.
Reinsert the cable connector into the shroud if it escapes before the housing
is fully fastened.
5. Thread the housing completely onto the sensor module. To comply
with explosion-proof requirements, the housing must be no more
than one full turn from flush with the sensor module.
6. Tighten the housing rotation set screw using a 5/64-inch hex wrench.
Step 2
3051-062AB, 060AB, 059AB
Step 3 Step 6

6
Attach the Electronics Board
1. Remove the cable connector from its position inside of the internal
shroud, and attach it to the electronics board.
2. Insert the electronics board into the housing, making sure that the
posts from the electronics housing properly engage the receptacles
on the electronics board.
NOTE
If you are reassembling a previous version of the electronics board, or if you
are placing a shrouded version of the electronics board in a previous version
of the housing, attach the snap-in power connection to the receptacle on the
board with the black and red wires routed toward the center of the board and
below the white reed switch holder.
3. Tighten the captive mounting screws.
4. Replace the electronics housing cover. The transmitter covers must
engaged metal-to-metal to ensure a proper seal and to meet
explosion-proof requirements.
NOTE
Electronics board revision 5.3.163 or later (all shrouded designs) have
increased functionality that allows verification testing of alarm current levels.
If you repair or replace the transmitter electronics board, sensor module, or
LCD meter, verify the transmitter alarm level before you return the
transmitter to service. Refer to the Model 3051 Product Manual, Rosemount
doc. no. 00809-0100-4001 for more information.
Step 1
3051-053AB, 054AB, 055AB
Step 3 Step 4

7
Reassemble the Process Sensor Body
1. Visually inspect the Teflon sensor module O-rings. If the O-rings are
undamaged, you may reuse them. If the O-rings show signs of
damage, such as nicks or cuts, or if there is any doubt about their
ability to seal properly, replace them with new O-rings.
IMPORTANT
If replacing the O-rings, take care not to scratch or deface the
O-ring grooves or the surface of the isolating diaphragm while you remove
the damaged O-rings.
2. Install the process flange on the sensor module. To hold the process
flange in place, install the two hex head alignment screws. These
screws are not pressure retaining and need only be finger tight. Do
not overtighten; this will affect the module/flange alignment.
3. Where applicable, install the appropriate flange bolts:
䡲For installations requiring a 1/4–18 NPT mounting, install the four 1.75-
inch process flange bolts. First finger-tighten, then tighten the bolts
incrementally in a cross pattern until they are tightened to the appropriate
torque values. When fully tightened, the bolts should extend through the
top of the module housing. Refer to The Model 3051 Product Manual
(Rosemount pub. no. 00809-0100-4001) for complete bolt installation
information and torque values.
䡲For installations requiring a 1/2–14 NPT mounting, hold the flange
adapters and flange adapter O-rings in place while finger-tightening
the four 2.88-inch process flange/adapter bolts (use two 2.88-inch
bolts and two 1.75-inch bolts for gage pressure configurations).
Tighten the bolts incrementally in a cross pattern until they are
tightened to the appropriate torque values. When fully tightened, the
bolts should extend through the top of the module housing. Refer to The
Model 3051 Product Manual (Rosemount pub. no. 00809-0100-4001) for
complete bolt installation information and torque values.
䡲For installations with a three-valve manifold (differential pressure
applications only), align the process flange with the three-valve
manifold, and finger-tighten the four 2.25-inch manifold flange bolts
following the procedure outlined above. Tighten the bolts
incrementally in a cross pattern until they are tightened to the
appropriate torque values. When fully tightened, the bolts should extend
through the top of the module housing. Refer to The Model 3051 Product
Manual (Rosemount pub. no. 00809-0100-4001) for complete bolt
installation information and torque values. Install flange adapters on the
process end of the three-valve manifold using the 1.75-inch flange
bolts supplied with the transmitter.

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8200 Market Boulevard
Chanhassen, MN 55317 USA
Tel [phone]
Telex 4310012
Fax [phone]
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© Rosemount Inc. 1997. All rights reserved.
http://www.rosemount.com
4. If you replaced the Teflon sensor module O-rings, torque the flange bolts
after installation to compensate for cold flow.
5. Install the drain/vent valve:
a. Apply sealing tape to the threads on the seat. Starting at the base of
the valve with the threaded end pointing toward the installer, apply two
clockwise turns of the sealing tape.
b. Take care to place the opening on the valve so that process fluid will drain
toward the ground and away from personnel when the valve is opened.
c. Tighten the drain/vent valve to 70 in-lb (0.5 N-m).
NOTE
After replacing O-rings on Range 1 transmitters and re-installing the process
flange, expose the transmitter to a temperature of 185 °F (85 °C) for two hours.
Then re-tighten the flange bolts in a cross pattern, and again expose the
transmitter to a temperature of 185 °F (85 °C) for two hours before calibration.
¢00809-0400-4001m¤
00809-0400-4001, Rev. BA