2640a 2-wire resistance measurement specifications, A-13 – Fluke NetDAQ 2645A User 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)