
82
Using ProLink
®
Software with Micro Motion
®
Transmitters
Configure Menu: Characterize
continued
Temperature factor for RFT9739
8.6 Temperature factor for
RFT9739
Temperature characterization (calibrating the flowmeter for temperature)
is not recommended.
For an RFT9739, the temperature calibration factor describes the slope
and offset of the equation used for calculating the output level that
represents the temperature of the sensor flow tubes. In a Micro Motion
flow sensor, a platinum resistance temperature detector (RTD) with a
resistance of 100 ohms at 0
°
C measures the flow tube temperature. The
specified temperature accuracy is ±1
°
C ± 0.5% of the reading in
°
C.
The temperature calibration factor represents A and B in the following
equation, which expresses a straight-line correction of the linear output
indicating flow tube temperature:
Where:
A=Slope
B = Offset
Since the transmitter ordinarily does not correct the measured
temperature, T
corrected
= T
measured
. The linear output therefore has a slope
of one and an offset of zero. The default temperature calibration factor is:
1.00000T0000.0
Example:
Vaporization of the process liquid sometimes causes slug flow in a
liquid flow stream in which the density of the liquid should remain
above 0.9000 grams per cubic centimeter (g/cc).
To detect density below the specified density of the process liquid due
to vaporization, set the low slug flow limit at a density above 0.9000
g/cc. Such a setting will cause the transmitter to indicate slug flow
when the process density goes below the specified limit for the liquid.
CAUTION
Temperature characterization will cause
measurement error.
Temperature characterization affects the RFT9739
flow and density and will require completely
recalibrating the flowmeter for flow, density, and
viscosity measurement.
Temperature characterization of the RFT9739 is not
recommended.
T
corrected
AT
measured
⋅
B
+=
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