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134 Micro Motion
®
Model 2400S Transmitters for PROFIBUS-DP
Troubleshooting
11.14 Checking slug flow
A slug flow alarm is posted whenever the measured process density is outside the configured slug
flow limits (i.e., density is higher or lower than the configured normal range). Slug flow is typically
caused by gas in a liquid process or liquid in a gas process. See Section 8.7 for a discussion of slug
flow functionality.
Inaccurate density reading Problem with process fluid • Use standard procedures to check
quality of process fluid.
Bad density calibration factors • Verify characterization. See
Section 6.2.
Wiring problem • Check the sensor circuitry. See
Section 11.21.
Bad flowmeter grounding • See Section 11.7.3.
Slug flow • See Section 11.14.
Sensor cross-talk • Check environment for sensor with
similar (±0.5 Hz) tube frequency.
Plugged flow tube • Check drive gain and tube frequency.
Purge the flow tubes.
Incorrect sensor orientation • Sensor orientation must be
appropriate to process fluid. See the
installation manual for your sensor.
RTD failure • Check for alarm conditions and follow
troubleshooting procedure for
indicated alarm.
Physical characteristics of sensor have
changed
• Check for corrosion, erosion, or tube
damage. See Section 11.15.
Temperature reading significantly
different from process temperature
RTD failure • Check for alarm conditions and follow
troubleshooting procedure for
indicated alarm.
• Verify “Use external temperature”
configuration and disable if
appropriate. See Section 9.3.
Temperature reading slightly different
from process temperature
Sensor leaking heat • Insulate the sensor.
Unusually high density reading Plugged flow tube • Check drive gain and tube frequency.
Purge the flow tubes.
Incorrect K2 value • Verify characterization. See
Section 6.2.
Unusually low density reading Slug flow • See Section 11.14.
Incorrect K2 value • Verify characterization. See
Section 6.2.
Unusually high tube frequency Sensor erosion • Contact Micro Motion.
Unusually low tube frequency Plugged flow tube, corrosion, or erosion • Purge the flow tubes.
• Perform meter verification. See
Section 11.15.
Unusually low pickoff voltages Several possible causes • See Section 11.20.4
.
Unusually high drive gain Several possible causes • See Section 11.20.3.
Table 11-3 Process variables problems and remedies continued
Symptom Cause Suggested remedy