Emerson Micro Motion LNG Series, Configuration And Use Manual

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10.5 Temperature measurement problems
Temperature measurement problems and recommended actions Table 10-4:
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
• RTD cable length configuration is not cor-
rect
• Check junction box for moisture or verdi-
gris.
• 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.
• Verify that the RTD cable length configura-
tion matches the actual cable length for
each sensor
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.
• The electrical connection between the RTD
and the sensor may be damaged. This may
require replacing the sensor.
10.6 Check power supply wiring
If the power supply wiring is damaged or improperly connected, the transmitter may not
receive enough power to operate properly.
Prerequisites
You will need the installation manual for your transmitter.
Procedure
1. Use a voltmeter to test the voltage at the transmitter’s power supply terminals.
• If the voltage is within the specified range, you do not have a power supply
problem.
• If the voltage is low, ensure that the power supply is adequate at the source, the
power cable is sized correctly, there is no damage to the power cable, and an
appropriate fuse is installed.
Troubleshooting
78 Micro Motion ® LNG Series Meters