3Transmitter-Sensor Matching - Emerson Rosemount Reference Manual

Reference Manual
00809-0100-4021, Rev GC
3.15.3 Transmitter-sensor matching
HART 7 Fast Keys
HART 7 Fast Keys
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:
Standard RTD
3144P
Standard RTD
Total System
(1) Calculated using root-summed-squared (RSS) statistical method.
Problem description: Depending on the process being measured, a certain amount of
accuracy may be needed from the sensor.
Our solution: A more precise compensation for RTD inaccuracies is provided by Transmit-
ter-Sensor Matching using the transmitter's factory programmed Callendar-Van Dusen (CVD)
equation. This equation describes the relationship between resistance and temperature of
platinum resistance thermometers (RTDs). The matching process allows the user to enter the
four sensor specific Callendar-Van Dusen (CVD) constants into the transmitter. The transmitter
uses these sensor-specific constants in solving the CVD equation to match the transmitter to
that specific sensor thus providing outstanding accuracy. See comparison below:
Standard RTD
3144P
Standard RTD
Total System
(1) Calculated using root-summed-squared (RSS) statistical method.
Take away: "Transmitter-Sensor Matching customizes sensor curves to minimize sensor
inaccuracy"
Note
In order to use this diagnostic, the RTD must be set as type Cal VanDusen.
HART® commissioning
Sensor 1 - 2, 2, 1, 11
Sensor 1 - 2, 2, 2, 11
System accuracy comparison at 150 °C using a PT 100 (=0.00385)
RTD with a span of 0 to 200 °C
(1)
System accuracy comparison at 150 °C using a PT 100 (=0.00385)
RTD with a span of 0 to 200 °C
(1)
Matched RTD
±0.08 °C 3144P
±1.05 °C Matched RTD
(1)
±1.05 °C Total System
Matched RTD
±0.08 °C 3144P
±1.05 °C Matched RTD
(1)
±1.05 °C Total System
Section 3: HART commissioning
±0.08 °C
±0.18 °C
±0.21 °C
±0.08 °C
±0.18 °C
±0.21 °C
April 2014
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