Density measurement problems and recommended actions
(continued)
Table 10-2:
Problem
Possible causes
Recommended actions
Density reading too
low
•
Leaks in the pipework or fittings
•
Incorrect calibration factors
•
Inaccurate temperature measurement
•
Erosion or corrosion on the sensor tubes
•
Two-phase flow
•
Verify the calibration factors.
•
Verify the temperature reading from the
RTD (on-board temperature sensor).
•
Verify the temperature reading from the
external temperature device, if applicable.
•
Check for two-phase flow. See
.
10.8
Temperature measurement problems
Important
Temperature measurement is ISO 17025–calibrated and accredited. Do not perform a temperature
calibration or change the temperature slope. Either of these actions will invalidate the accreditation.
You may change the temperature offset.
Temperature measurement problems and recommended actions
Table 10-3:
Problem
Possible causes
Recommended actions
Temperature reading
significantly different
from process temper-
ature
•
RTD failure
•
Incorrect compensation factors
•
Line temperature in bypass does not
match temperature in main line
•
Verify that the temperature compensation
factors match the value on the sensor tag
or calibration sheet.
•
If Alert A004, A016, or A017 is active, per-
form the actions recommended for that
alert.
Temperature reading
slightly different from
process temperature
•
Sensor temperature not yet equalized
•
Sensor leaking heat
•
If the error is within the temperature speci-
fication for the sensor, there is no prob-
lem. If the temperature measurement is
outside the specification, contact
Micro Motion.
•
The temperature of the fluid may be
changing rapidly. Allow sufficient time for
the sensor to equalize with the process flu-
id.
•
Check the reading of Tube-Case Tempera-
ture Difference.
•
If Alert A004, A016, or A017 is active, per-
form the actions recommended for that
alert.
•
The electrical connection between the RTD
and the sensor may be damaged. This may
require replacing the sensor.
Troubleshooting
150
Micro Motion
®
Compact Density Meters (CDM)
Summary of Contents for CDM100M
Page 8: ...Getting Started 2 Micro Motion Compact Density Meters CDM ...
Page 12: ...Before you begin 6 Micro Motion Compact Density Meters CDM ...
Page 20: ...Configuration and commissioning 14 Micro Motion Compact Density Meters CDM ...
Page 26: ...Introduction to configuration and commissioning 20 Micro Motion Compact Density Meters CDM ...
Page 110: ...Integrate the meter with the control system 104 Micro Motion Compact Density Meters CDM ...
Page 116: ...Operations maintenance and troubleshooting 110 Micro Motion Compact Density Meters CDM ...
Page 124: ...Transmitter operation 118 Micro Motion Compact Density Meters CDM ...
Page 194: ...Using the transmitter display 188 Micro Motion Compact Density Meters CDM ...
Page 208: ...Using ProLink III with the transmitter 202 Micro Motion Compact Density Meters CDM ...