Emerson Rosemount 644h, Reference Manual

Page: 56 / 78

Reference Manual
00809-0100-4728, Rev HA
December 2002
Models 644H and 644R
A-6
Ambient Temperature Effect
Transmitters can be installed in locations where the ambient temperature is
between –40 and 85 °C (–40 and 185 °F). In order to maintain excellent
accuracy performance, each transmitter is individually characterized over this
ambient temperature range at the factory.
Temperature Effects Example
When using a Pt 100 (a = 0.00385) sensor input with a 0–100 °C span at
30 °C ambient temperature:
• Digital Temperature Effects: 0.003 °C x (30 - 20) = 0.03 °C
• D/A Effects: [0.001% of 100] x (30 - 20) = 0.01 °C
• Worst Case Error: D D/A + Digital Temperature E D/A
Effects = 0.15 °C + 0.03 °C + 0.03 °C + 0.01 °C = 0.22 °C
• Total Probable Error:
Table A-3. Ambient Temperature Effect
Sensor Options
Temperature Effects per 1.0 °C (1.8 °F) Change
in Ambient Temperature
(1)
(1) Change in ambient is with reference to the calibration temperature of the transmitter 68 °F (20 °C) from factory.
Range D/A Effect
2-, 3-, 4-wire RTDs
Pt 100 (( α = 0.00385) 0.003 °C (0.0054 °F) Entire Sensor Input Range 0.001% of span
Pt 100 (
α
= 0.003916) 0.003 °C (0.0054 °F) Entire Sensor Input Range 0.001% of span
Pt 200 0.004 °C (0.0072 °F) Entire Sensor Input Range 0.001% of span
Pt 500 0.003 °C (0.0054 °F) Entire Sensor Input Range 0.001% of span
Pt 1000 0.003 °C (0.0054 °F) Entire Sensor Input Range 0.001% of span
Ni 120 0.003 °C (0.0054 °F) Entire Sensor Input Range 0.001% of span
Cu 10 0.03 °C (0.054 °F) Entire Sensor Input Range 0.001% of span
Thermocouples
Type B 0.014 °C R ≥ 1000°C 0.001% of span
0.032 °C – (0.0025% of (R – 300)) 300 °C
≤
R < 1000 °C 0.001% of span
0.054 °C – (0.011% of (R – 100)) 100 °C
≤
R< 300 °C 0.001% of span
Type E 0.005 °C +(0.00043% of R) All 0.001% of span
Type J 0.0054 °C +(0.0029%of R) R ≥ 0 °C 0.001% of span
0.0054 °C + (0.0025% of absolute value R) R < 0 °C 0.001% of span
Type K 0.0061 °C +(0.00054% of R) R
≥
0 °C 0.001% of span
0.0061 °C + (0.0025% of absolute value R) R < 0 °C 0.001% of span
Type N 0.0068 °C +(0.00036% of R) All 0.001% of span
Type R, S, W5Re/W26Re 0.016 °C R
≥
200°C 0.001% of span
0.023 °C – (0.0036% of R) R < 200 °C 0.001% of span
Type T 0.0064 °C R ≥ 0 °C 0.001% of span
0.0064 °C +(0.0043% of absolute value R) R < 0 °C 0.001% of span
DIN Type L 0.0054 °C + (0.00029% of R) R
≥
0 °C 0.001% of span
0.0054 °C +(0.0025% of absolute value R) R < 0 °C 0.001% of span
DIN Type U 0.0064 °C R ≥ 0 °C 0.001% of span
0.0064 °C +(0.0043% of absolute value R) R < 0 °C 0.001% of span
Millivolt Input 0.0005 mV Entire Sensor Input Range 0.001% of span
2-, 3-, 4-wire Ohm 0.0084
Ω
Entire Sensor Input Range 0.001% of span
0.15
2
0.03
2
0.03
2
0.01
2
+ + +
0.16
°
C
=