Emerson Micro Motion 2700 Configuration And Use Manual page 104

Troubleshooting
Table 6-3 Output problems and possible remedies (continued)
Symptom
Erratic non-zero flow rate under
no-flow conditions
Erratic non-zero flow rate when flow
is steady
96
Cause
Wiring problem
Incorrectly grounded 9-wire cable
(only in 9-wire remote and remote
core processor with remote
transmitter installations)
Noise in PROFIBUS wiring
Vibration in pipeline at rate close to
sensor frequency
Leaking valve or seal
Inappropriate measurement unit
Inappropriate damping value
Slug flow
Plugged flow tube
Moisture in sensor junction box (only
for 9-wire remote and remote core
processor with remote transmitter
installations)
Mounting stress on sensor
Sensor cross-talk
Improper sensor grounding
Incorrect sensor orientation
Output wiring problem
Inappropriate measurement unit
Inappropriate damping value
Excessive or erratic drive gain
Slug flow
Plugged flow tube
Wiring problem
Possible remedies
Verify all sensor-to-transmitter wiring and
ensure the wires are making good
contact. Refer to the installation manual.
Verify 9-wire cable installation. Refer to
the installation manual.
Verify that the wiring is properly shielded
against noise.
Check the environment and remove the
source of vibration.
Check pipeline.
Check measurement units using a
PROFIBUS host or configuration tool.
Check damping. See Section 6.7.1.
Section 6.10.
Check drive gain and frequency. Purge the
flow tubes.
Open junction box and allow it to dry. Do
not use contact cleaner. When closing,
ensure integrity of gaskets and O-rings,
and grease all O-rings.
Check sensor mounting. Ensure that:
• Sensor is not being used to support
pipe.
• Sensor is not being used to correct
misaligned pipe.
• Sensor is not too heavy for pipe.
Check environment for sensor with similar
(±0.5 Hz) tube frequency.
Check the sensor grounding. Refer to the
installation manual.
Not all orientations work with all process
fluids. See the installation manual for your
sensor.
Verify PROFIBUS wiring.
Check measurement units using a
PROFIBUS host or configuration tool.
Check damping. See Section 6.7.1.
See Sections 6.12.3 and 6.12.4.
See Section 6.10.
Check drive gain and tube frequency.
Purge the flow tubes. Sensor may need to
be replaced.
Verify all sensor-to-transmitter wiring and
ensure the wires are making good
contact. Refer to the installation manual.
Model 2700 Transmitter with PROFIBUS-PA