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Reference Manual
00809-0400-4728, Rev AA
June 2011
Rosemount 644
A-6
Accuracy
Accuracy Example
When using a Pt 100 ( = 0.00385) sensor input:
• Total accuracy = ±0.15 °C.
• No D/A accuracy effects apply
Table A-1. Rosemount 644 Input Options and Accuracy
Sensor
Options
Sensor
Reference
Input
Ranges
Recommended
Min. Span
(1)
Digital
Accuracy
(2)
D/A
Accuracy
(3)
2-, 3-, 4-wire RTDs °C °F °C °F °C °F
Pt 100 ( = 0.00385) IEC 751 –200 to 850 –328 to 1562 10 18 ± 0.15 ± 0.27 ±0.03% of span
Pt 200 ( = 0.00385) IEC 751 –200 to 850 –328 to 1562 10 18 ± 0.15 ± 0.27 ±0.03% of span
Pt 500 ( = 0.00385) IEC 751 –200 to 850 –328 to 1562 10 18 ± 0.19 ± 0.34 ±0.03% of span
Pt 1000 ( = 0.00385) IEC 751 –200 to 300 –328 to 572 10 18 ± 0.19 ± 0.34 ±0.03% of span
Pt 100 ( = 0.003916) JIS 1604 –200 to 645 –328 to 1193 10 18 ± 0.15 ± 0.27 ±0.03% of span
Pt 200 ( = 0.003916) JIS 1604 –200 to 645 –328 to 1193 10 18 ± 0.27 ± 0.49 ±0.03% of span
Ni 120 Edison Curve No. 7 –70 to 300 –94 to 572 10 18 ± 0.15 ± 0.27 ±0.03% of span
Cu 10 Edison Copper Winding No. 15 –50 to 250 –58 to 482 10 18 ±1.40 ± 2.52 ±0.03% of span
Pt 50 ( = 0.00391) GOST 6651-94 –200 to 550 –328 to 1022 10 18 ± 0.30 ± 0.54 ±0.03% of span
Pt 100 ( = 0.00391) GOST 6651-94 –200 to 550 –328 to 1022 10 18 ± 0.15 ± 0.27 ±0.03% of span
Cu 50 ( = 0.00426) GOST 6651-94 –50 to 200 –58 to 392 10 18 ±1.34 ± 2.41 ±0.03% of span
Cu 50 ( = 0.00428) GOST 6651-94 –185 to 200 –301 to 392 10 18 ±1.34 ± 2.41 ±0.03% of span
Cu 100 ( = 0.00426) GOST 6651-94 –50 to 200 –58 to 392 10 18 ±0.67 ± 1.20 ±0.03% of span
Cu 100 ( = 0.00428) GOST 6651-94 –185 to 200 –301 to 392 10 18 ±0.67 ± 1.20 ±0.03% of span
Thermocouples
(4)
Type B
(5)
NIST Monograph 175, IEC 584 100 to 1820 212 to 3308 25 45 ± 0.77 ± 1.39 ±0.03% of span
Type E NIST Monograph 175, IEC 584 –50 to 1000 –58 to 1832 25 45 ± 0.20 ± 0.36 ±0.03% of span
Type J NIST Monograph 175, IEC 584 –180 to 760 –292 to 1400 25 45 ± 0.35 ± 0.63 ±0.03% of span
Type K
(6)
NIST Monograph 175, IEC 584 –180 to 1372 –292 to 2501 25 45 ± 0.50 ± 0.90 ±0.03% of span
Type N NIST Monograph 175, IEC 584 –200 to 1300 –328 to 2372 25 45 ± 0.50 ± 0.90 ±0.03% of span
Type R NIST Monograph 175, IEC 584 0 to 1768 32 to 3214 25 45 ± 0.75 ± 1.35 ±0.03% of span
Type S NIST Monograph 175, IEC 584 0 to 1768 32 to 3214 25 45 ± 0.70 ± 1.26 ±0.03% of span
Type T NIST Monograph 175, IEC 584 –200 to 400 –328 to 752 25 45 ± 0.35 ± 0.63 ±0.03% of span
DIN Type L DIN 43710 –200 to 900 –328 to 1652 25 45 ± 0.35 ± 0.63 ±0.03% of span
DIN Type U DIN 43710 –200 to 900 –328 to 1112 25 45 ± 0.35 ± 0.63 ±0.03% of span
Type W5Re/W26Re ASTM E 988-96 0 to 2000 32 to 3632 25 45 ± 0.70 ± 1.26 ±0.03% of span
GOST Type L GOST R 8.585-2001 –200 to 800 –328 to 1472 25 45 ± 1.00 ± 1.26 ±0.03% of span
Other Input Types
Millivolt Input –10 to 100 mV ±0.015 mV ±0.03% of span
2-, 3-, 4-wire Ohm Input 0 to 2000 ohms ±0.45 ohm ±0.03% of span
(1) No minimum or maximum span restrictions within the input ranges. Recommended minimum span will hold noise within accuracy specification with damping at
zero seconds.
(2) The published digital accuracy applies over the entire sensor input range. Digital output can be accessed by HART or F
OUNDATION fieldbus Communications or
Rosemount control system.
(3) Total Analog accuracy is the sum of digital and D/A accuracies. This is not applicable for F
OUNDATION fieldbus.
(4) Total digital accuracy for thermocouple measurement: sum of digital accuracy +0.5 °C. (cold junction accuracy).
(5) Digital accuracy for NIST Type B T/C is ±3.0 °C (±5.4 °F) from 100 to 300 °C (212 to 572 °F).
(6) Digital accuracy for NIST Type K T/C is ±0.70 °C (±1.26 °F) from –180 to –90 °C (–292 to –130 °F).