A-33. 2645A 4-Wire Rtd Temperature Coefficient; A-34. 2645A 4-Wire Rtd Specifications - Fluke NetDAQ 2640A User Manual

2640A/2645A NetDAQ
Users Manual
2645A 2-Wire Resistance Measurement Specifications
The 2645A specifications for the 2-wire resistance measurement function is based
on the 4-wire resistance measurement specification (above) except you add a 700
to 1000 Ohm positive offset. This value varies for each channel and temperature
gradient (nominal +1%/ºC).
2645A 4-Wire RTD per ITS-1990 Measurement Specifications
Tables A-33 and A-34 provide 2645A 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.
Specification
Temperature Coefficient
Accuracy at -20 C
Temperature
-200ºC*
0ºC*
100ºC
300ºC
600ºC
* The Custom-385 range is not recommended for use below -80ºC. See Appendix D.
A-22
Table A-33. 2645A 4-Wire RTD Temperature Coefficient
Table A-34. 2645A 4-Wire RTD Specifications
Resolution
Slow Fast
0.03ºC 0.06ºC 0.16ºC
0.03ºC 0.06ºC 0.20ºC
0.03ºC 0.06ºC 0.23ºC
0.03ºC 0.06ºC 0.30ºC
0.03ºC 0.06ºC 0.53ºC
Characteristic
To calculate RTD accuracy for temperatures
between 28ºC and 60ºC, or -10ºC and 18ºC,
use a linear interpolation between the two
application points. e.g., if the applicable spec at
28ºC is .2 and the spec at 60ºC is .75, then the
specification at 40ºC is (.75-.2)*(40-28)/(60-28)
+ .2 = .55*(12/32)+.2 = .406.
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.
Accuracy, 3
1 Year,
90 Day, 18ºC to
18ºC to
28ºC
28ºC
Slow Fast Slow
0.25ºC 0.25ºC
0.31ºC 0.31ºC
0.34ºC 0.34ºC
0.41ºC 0.41ºC
0.63ºC 0.63ºC
A-25.
A-26.
ºC
1 Year, -10ºC to
60ºC
Slow Fast
0.62ºC 1.10ºC
0.85ºC 1.30ºC
0.95ºC 1.40ºC
1.18ºC 1.70ºC
1.62ºC 2.12ºC