Trim The Transmitter - Emerson Rosemount Reference Manual

Section 3: HART commissioning
April 2014
Example for Rosemount 3144P Pt 100 ( = 0.00385)
Reference temperature is 20 °F
Process Temperature change is 0-100 °C
Ambient Temperature is 30 °C
1.
2.
a.
b. D/A Accuracy = (0.02%) x (30 – 20) °C = ±0.002 °C
c.
d. D/A Effect = (0.001%/ °C) x (100 °C) x (30-20) °C = 00.01 °C
e. Sensor Accuracy = ± 0.420 °C @ 400 °C for a class A RTD sensor with CVD constants
f.
3.
4.
3.15

Trim the transmitter

The trim functions should not be confused with the rerange functions. Although the rerange
command matches a sensor input to a 4–20 mA output—as in conventional calibration—it does
not affect the transmitter's interpretation of the input.
One or more of the trim functions may be used when calibrating. The trim functions are as
follows:




122
Required Performance: ± 0.35 °C
TPE = 0.102 °C
Digital Accuracy = 0.10 °C
Digital Temperature Effects = (0.0015 °C/ °C) x (30-20) °C = 0.015 °C
 
2
2
TPE =
0.102 + 0.0022 +
Stability per Month: (0.25%/60 months) x (100 °C) = 0.00416 °C
Calibration Frequency:
Sensor Input Trim
Transmitter-Sensor Matching
Output Trim
Output Scaled Trim
0.4202  = 0.102 °C
2
2 2
0.0152 + 0.012 +
0.35 0.102 –
------------------------------- -
= 60 Months (5 Years)
0.00416
Reference Manual
00809-0100-4021, Rev GC
HART® commissioning