17.38 Check for two-phase flow (slug flow)
Two-phase flow can cause rapid changes in the drive gain. This can cause a variety of measurement issues.
Procedure
1. Check for two-phase flow alerts (e.g., A105).
If the transmitter is not generating two-phase flow alerts, verify that two-phase flow limits have been
set. If limits are set, two-phase flow is not the source of your problem.
2. Check the process for cavitation, flashing, or leaks.
3. Monitor the density of your process fluid output under normal process conditions.
4. Check the settings of
Two-Phase Flow Low Limit
,
Two-Phase Flow High Limit
, and
Two-Phase Flow
Timeout
.
Tip
You can reduce the occurrence of two-phase flow alerts by setting
Two-Phase Flow Low Limit
to a
lower value,
Two-Phase Flow High Limit
to a higher value, or
Two-Phase Flow Timeout
to a higher
value.
17.39 Temperature measurement problems
Table 17-6: Temperature measurement problems and recommended actions
Problem
Possible causes
Recommended actions
Temperature reading
significantly different
from process
temperature
•
RTD failure
•
Wiring problem
•
Incorrect calibration factors
•
Line temperature in bypass does not match
temperature in main line
•
For sensors with a junction box, check for
moisture in the junction box.
•
Check the sensor coils for electrical shorts.
If you find problems, replace the sensor.
•
Ensure that all of the calibration
parameters have been entered correctly.
See the sensor tag or the calibration sheet
for your meter.
•
Refer to status alerts (especially RTD failure
alerts).
•
Disable external temperature
compensation.
•
Verify temperature calibration.
•
Check the wiring between the sensor and
the transmitter.
Troubleshooting
Configuration and Use Manual
March 2019
MMI-20025166
304
Micro Motion Model 5700 Transmitters with Configurable Outputs
