Fluke NetDAQ 2645A - Manual (Page 223)

Specifications
2640A Specifications
A
A-13
2640A 2-Wire Resistance Measurement Specifications A-16.
The 2640A specifications for the 2-wire resistance measurement function is based
on the 4-wire resistance measurement specification (above) except you add a
nominal 5-Ohm (10-Ohm maximum) positive offset. This value varies for each
channel and with temperature (nominal +1%/ºC).
2640A RTD’s 4-Wire, per ITS-1990 Measurement Specifications A-17.
Tables A-18 and A-19 provide 2640A specifications for the 4-wire Resistance-
Temperature Detector (RTD) measurement function. The 4-wire measurements
use 2 input channels a decade apart, e.g., channels 4 and 14.
Table A-18. 2640A 4-Wire RTD Temperature Coefficient
Specification Characteristic
Temperature Coefficient To calculate RTD accuracy for temperatures
between 28
°
C and 60
°
C, or -10
°
C and 18
°
C,
use a linear interpolation between the two
applicable points. e.g. if the applicable spec at
28
°
C is .2 and the spec at 60
°
C is .75, then the
specification at 40
°
C = (.75-.2)x(40-28)/(60-
28)+.2=.55*(12/32) + .2 = .406.
Accuracy at -20
°
C Multiply the -10
°
C to + 60
°
C accuracy
specification by 2. After 1 hour warm-up. For
accuracy between -10
°
C and -20
°
C, interpolate
linearly.
Table A-19. 2640A 4-Wire RTD Specifications
Accuracy, 3
σ ±
ºC
Temperature
Resolution 90 Day, 18 º C to
28 º C
1 Year,
18 º C to
28 º C
1 Year, -10 º C to
60 º C
Slow Fast Slow Fast Slow Slow Fast
-200 º C (Note1) 0.003 º C 0.007 º C 0.06 º C 0.16 º C 0.09 º C 0.33 º C 0.63 º C
0 º C (Note 1) 0.003 º C 0.007 º C 0.09 º C 0.20 º C 0.13 º C 0.53 º C 0.86 º C
100 º C 0.003 º C 0.007 º C 0.10 º C 0.23 º C 0.16 º C 0.63 º C 0.97 º C
300 º C 0.003 º C 0.007 º C 0.14 º C 0.3 º C 0.21 º C 0.83 º C 1.2 º C
600 º C 0.003 º C 0.007 º C 0.19 º C 0.53 º C 0.30 º C 1.2 º C 1.6 º C
1. The Custom 385 range is not recommended for use below -80 º C. (See Appendix D)