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Grounding
Step 5 Grounding
The sensor can be grounded via the piping if the joints in the pipeline are ground-bonded. If the sensor is not
grounded via the piping, connect a ground wire to the internal or external grounding screw, which is located
on the core processor housing or junction box.
Improper grounding can cause measurement error. Ground the flowmeter to earth, or follow ground
network requirements for the facility.
If national standards are not in effect, follow these guidelines to ground the sensor:
• Use copper wire, 14 AWG (2,0 mm²) or larger wire size for grounding.
• Keep all ground leads as short as possible, less than 1 ohm impedance.
• Connect ground leads directly to earth, or follow plant standards.
Purge Fittings
If the sensor has purge fittings, they should remain sealed at all times. After a purge plug has been removed,
the sensor case should be purged with argon or nitrogen and resealed.
Purging the case protects internal components. The sensor is purged of all oxygen and sealed at the factory. If
the purge plugs are never removed, it is not necessary to purge or re-seal the sensor. For more information,
contact Micro Motion Customer Service.
Removing a purge plug
If a purge plug is removed from the sensor case, it will be necessary to repurge the case.
Removing a purge plug compromises the secondary containment of the sensor and could expose the
user to process fluid. Take all necessary precautions when removing purge plugs.
Improper pressurization of the sensor case could result in personal injury. Removing a purge plug will
require the sensor case to be repurged with a dry inert gas. Follow all instructions provided in the case
purging procedure.
Case purging procedure
Read all instructions before performing the case purging procedure. It is not necessary to perform this
procedure unless a purge plug has been removed.
1. Shut down the process, or set control devices for manual operation.
Performing the purge procedure while the flowmeter is operating could affect measurement accuracy,
resulting in inaccurate flow signals. Before performing the case purging procedure, shut down the
process, or set control devices for manual operation.
2. Remove both purge plugs from the sensor case. If purge lines are being used, open the valve in the
purge lines.
3. Prepare the purge plugs for reinstallation by wrapping them with 3–5 turns of Teflon
®
tape.