Reference Manual
00809-0100-4021, Rev FB
August 2011
3-33
Rosemount 3144P
HART
Transmitter-Sensor
Matching
The 3144P accepts Callendar-Van Dusen constants from a calibrated RTD
schedule and generates a special custom curve to match that specific sensor
Resistance vs. Temperature performance. Matching the specific sensor curve
with the transmitter significantly enhances the temperature measurement
accuracy. See the comparison below:
The following input constants, included with specially-ordered Rosemount
temperature sensors, are required:
R
0
= Resistance at Ice Point
Alpha = Sensor Specific Constant
Beta = Sensor Specific Constant
Delta = Sensor Specific Constant
Other sensor may have “A, B, or C” values for constants.
Field Communicator
To input Callendar-Van Dusen constants, perform the following procedure
with the Traditional Fast Key sequence:
1. From the HOME screen, select 1 Device Setup, 3 Configuration, 2
Sensor Config, 1 Change Type/Conn., 1 Sensor 1. Select OK after you
set the control loop to manual.
2. Select Cal VanDusen at the ENTER SENSOR TYPE prompt.
3. Select the appropriate number of wires at the ENTER SENSOR
CONNECTION prompt.
4. Enter the R
o
, Alpha, Beta, and Delta values from the stainless steel tag
attached to the special-order sensor when prompted.
5. Select OK after you return the control loop to automatic control.
To disable the Transmitter-Sensor Matching feature from the HOME
screen select 1 Device Setup, 3 Configuration, 2 Sensor Config, 1 Change
Type/Conn. Choose the appropriate sensor type from the ENTER
SENSOR TYPE prompt.
When using two sensors, repeat Steps 1 – 5 for the second sensor. In Step
1, select Sensor 2 instead of Sensor 1.
NOTE
When the Transmitter-Sensor Matching is disabled, the transmitter reverts to
factory trim input. Make certain the transmitter engineering units default
correctly before placing the transmitter into service.
Callendar Van-Dusen constants can be viewed anytime by
making the following selections:
From the Home screen select 1 Device Setup, 3 Configuration, 2 Sensor
Config, 2 Show Type/Conn.
Traditional Fast Keys 1, 3, 2, 1, 1
Device Dashboard
Fast Keys
2, 2, 1, 10
System Accuracy Comparison at 150 °C Using a PT 100 (=0.00385)
RTD with a Span of 0 to 200 °C
Standard RTD Matched RTD
3144P ±0.10 °C 3144P ±0.10 °C
Standard RTD ±1.05 °C Matched RTD ±0.18 °C
Tota l S ys t e m
(1)
(1) Calculated using root-summed-squared (RSS) statistical method
±1.05 °C Tota l S ys tem
(1)
±0.21 °C
TotalSystemAccuracy TransmitterAccuracy
2
SensorAccuracy
2
+=
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