Rosemount 248 - Page 51

Reference Manual
00809-0100-4825, Rev BB
August 2005
A-5
Rosemount 248
Transmitter Accuracy and Ambient Temperature Effects
NOTE
The accuracy and ambient temperature effect is the greater of the fixed and
percent of span values (see example below).
Table A-2. Rosemount 248 Transmitter Input Options, Accuracy, and Ambient Temperature Effects
Transmitter Accuracy Example
When using a Pt 100 (a = 0.00385) sensor input with a 0 to 100 °C span:
Accuracy would be ±0.2 °C.
Transmitter Temperature Effects Example
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.
When using a Pt 100 (α = 0.00385) sensor input with a 0-100 °C span at 30
°C ambient temperature-Temperature Effects: 0.006 °C x (30 - 20) = 0.06 °C
Total Transmitter Error
Worst Case Transmitter Error: Accuracy + Temperature Effects = 0.2 °C +
0.06 °C = 0.26 °C
Total Probable Transmitter Error:
Sensor Transmitter Input Ranges Accuracy
Temperature Effects per 1.0 °C (1.8 °C)
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.
°C °F Fixed % of Span Fixed % of Span
2-, 3-, 4-wire RTDs
Pt 100
(2)
(α = 0.00385)
(2) IEC 751, 1995
–200 to 850 –328 to 1562 0.2 °C (0.36 °F) ±0.1 0.006 °C (0.011 °F) ±0.004
Pt 100
(3)
(α = 0.003916)
(3) JIS 1604, 1981
–200 to 645 –328 to 1193 0.2 °C (0.36 °F) ±0.1 0.006 °C (0.011 °F) ±0.004
Pt 200
(2)
–200 to 850 –328 to 1562 1.17 °C (2.11 °F) ±0.1 0.018 °C (0.032 °F) ±0.004
Pt 500
(2)
–200 to 850 –328 to 1562 0.47 °C (0.85 °F) ±0.1 0.018 °C (0.032 °F) ±0.004
Pt 1000
(2)
–200 to 300 –328 to 572 0.23 °C (0.41 °F) ±0.1 0.010 °C (0.018 °F) ±0.004
Ni 120
(4)
(4) Edison Curve No. 7
–70 to 300 –94 to 572 0.16 °C (0.29 °F) ±0.1 0.004 °C (0.007 °F) ±0.004
Cu 10
(5)
(5) Edison Copper Winding No. 15
–50 to 250 –58 to 482 2 °C (3.60 °F) ±0.1 0.06 °C (0.108 °F) ±0.004
Thermocouples
(6)
(6) Total accuracy for thermocouple measurement: sum of accuracy +0.5 °C.
Type B
(7)
(7) NIST Monograph 175, IEC 584
100 to 1820 212 to 3308 1.5 °C (2.70 °F) ±0.1 0.056 °C (0.101 °F) ±0.004
Type E
(7)
–50 to 1000 –58 to 1832 0.4 °C (0.72 °F) ±0.1 0.016 °C (0.029 °F) ±0.004
Type J
(7)
–180 to 760 –292 to 1400 0.5 °C (0.90 °F) ±0.1 0.016 °C (0.029 °F) ±0.004
Type K
(7)
–180 to 1372 –292 to 2502 0.5 °C (0.90 °F) ±0.1 0.02 °C (0.036 °F) ±0.004
Type N
(7)
–200 to 1300 –328 to 2372 0.8 °C (1.44 °F) ±0.1 0.02 °C (0.036 °F) ±0.004
Type R
(7)
0 to 1768 32 to 3214 1.2 °C (2.16 °F) ±0.1 0.06 °C (0.108 °F) ±0.004
Type S
(7)
0 to 1768 32 to 3214 1 °C (1.80 °F) ±0.1 0.06 °C (0.108 °F) ±0.004
Type T
(7)
–200 to 400 –328 to 752 0.5 °C (0.90 °F) ±0.1 0.02 °C (0.036 °F) ±0.004
DIN Type L
(8)
(8) DIN 43710
–200 to 900 –328 to 1652 0.7 °C (1.26 °F) ±0.1 0.022 °C (0.040 °F) ±0.004
DIN Type U
(8)
–200 to 600 –328 to 1112 0.7 °C (1.26 °F) ±0.1 0.026 °C (0.047 °F) ±0.004
Type W5Re/W26Re
(9)
(9) ASTME 988-96
0 to 2000 32 to 3632 1.4 °C (2.52 °F) ±0.1 0.064 °C (0.115°F) ±0.004
Millivolt Input –10 to 100 mV 0.03 mV ±0.1 0.001 mV ±0.004
2-, 3-, 4-wire Ohm Input 0 to 2000 ohms 0.7 ohm ±0.1 0.028 ohm ±0.004
0.2
2
0.06
2
+ 0.21°C=