Emerson 9739 사용자 설명서
Density measurement problems and recommended actions
(continued)
Table 10-4:
Problem
Possible causes
Recommended actions
Unusually low density
reading
reading
•
Slug flow
•
Incorrect K2 value
•
In low frequency meters this can indi-
cate erosion or corrosion
cate erosion or corrosion
•
Check your process conditions against the
values reported by the flowmeter.
values reported by the flowmeter.
•
Verify that all of the characterization parame-
ters match the data on the sensor tag.
ters match the data on the sensor tag.
•
Check the wiring between the sensor and
transmitter. See
transmitter. See
.
•
Check for tube erosion, especially if the proc-
ess fluid is abrasive.
ess fluid is abrasive.
10.5
Temperature measurement problems
Temperature measurement problems and recommended actions
Table 10-5:
Problem
Possible causes
Recommended actions
Temperature reading
significantly different
from process temper-
ature
significantly different
from process temper-
ature
•
RTD failure
•
Wiring problem
•
Check junction box for moisture or verdi-
gris.
gris.
•
Perform RTD resistance checks and check
for shorts to case (see
for shorts to case (see
).
•
Confirm the temperature calibration factor
matches the value on the sensor tag.
matches the value on the sensor tag.
•
Refer to status alarms (especially RTD fail-
ure alarms).
ure alarms).
•
Disable external temperature compensa-
tion.
tion.
•
Verify temperature calibration.
•
Check the wiring between the sensor and
transmitter. See
transmitter. See
.
Temperature reading
slightly different from
process temperature
slightly different from
process temperature
•
Sensor temperature not yet equalized
•
Sensor leaking heat
•
The RTD has a specification of ±1 °C. If the
error is within this range there is no prob-
lem. If the temperature measurement is
outside the specification for the sensor,
contact Micro Motion.
error is within this range there is no prob-
lem. If the temperature measurement is
outside the specification for the sensor,
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.
changing rapidly. Allow sufficient time for
the sensor to equalize with the process flu-
id.
•
Insulate the sensor if necessary.
•
Perform RTD resistance checks and check
for shorts to case (see
for shorts to case (see
).
•
The RTD may not be making good contact
with the sensor. The sensor may need to
be replaced.
with the sensor. The sensor may need to
be replaced.
Troubleshooting
Configuration and Use Manual
169