Troubleshooting
Table
Symptom | Cause | Suggested remedy |
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|
|
Inaccurate density reading | Problem with process fluid | • Use standard procedures to check |
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| quality of process fluid. |
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|
|
| Bad density calibration factors | • Verify characterization. See |
|
| Section 6.2. |
|
|
|
| Wiring problem | • Check the sensor circuitry. See |
|
| Section 11.20. |
|
|
|
| Bad flowmeter grounding | • See Section 11.7.2. |
|
|
|
| Slug flow | • See Section 11.14. |
|
|
|
| Sensor | • 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 | • Check for corrosion, erosion, or tube |
| changed | damage. See Section 11.15. |
|
|
|
Temperature reading significantly | RTD failure | • Check for alarm conditions and follow |
different from process temperature |
| troubleshooting procedure for |
|
| indicated alarm. |
|
| • Verify “Use external temperature” |
|
| configuration and disable if |
|
| appropriate. See Section 9.3. |
|
|
|
Temperature reading slightly different | Sensor leaking heat | • Insulate the sensor. |
from process temperature |
|
|
|
|
|
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. See |
|
| Section 11.3. |
|
|
|
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 11.19.4. |
|
|
|
Unusually high drive gain | Several possible causes | • See Section 11.19.3. |
|
|
|
11.14Checking 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.
Compensation
Measurement Performance
Troubleshooting
Defaults
Configuration and Use Manual | 121 |
