Fluke NetDAQ 2640A, Service Manual

Page: 32 / 260

NetDAQ
Service Manual
1-16
2640A Four-Wire Resistance Measurement Specifications 1-23.
Tables 1-19 to 1-21 provide 2640A specifications for the four-wire resistance
measurement function. The four-wire measurements use 2 input channels a decade apart,
e.g., channels 4 and 14.
Table 1-19. 2640A Four-Wire Resistance Temperature Coefficient
Specification Characteristic
Temperature Coefficient Add 1/10th the 90 day specification per
°
C
above 28
°
C or below 18
°
C.
Table 1-20. 2640A Four-Wire Resistance Range and Resolution Specifications
Resolution
Current Full Scale Maximum Voltage
Range Slow Fast
Applied Voltage Applied by Instrument
300
Ω
1 m
Ω
3m
Ω
1 mA 300 mV 3.5V
3 k
Ω
10 m
Ω
30 m
Ω
100
µ
A 300 mV 3.5V
30 k
Ω
100 m
Ω
300 m
Ω
10
µ
A 300 mV 3.5V
300 k
Ω
1
Ω
3
Ω
10
µ
A 3.0V 3.5V
3 M
Ω
10
Ω
30
Ω
1
µ
A 3.0V 3.5V
Table 1-21. 2640A Four-Wire Resistance Accuracy Specifications
Accuracy, 3
σ
+ (% input + V)
18
°
C to 28
°
C -10
°
C to 60
°
C
Range
90 Day 1 Year 1 Year
Slow Fast Slow Fast Slow Fast
300
Ω
.015%+20 m
Ω
.02%+80 m
Ω
.02%+50 m
Ω
.02%+120 m
Ω
.084%+126 m
Ω
.084%+336 m
Ω
3 k
Ω
.02%+.3
Ω
.02%+.8
Ω
.02%+.5
Ω
.02%+1.2
Ω
.084%+1.26
Ω
.084%+3.36
Ω
30 k
Ω
.03%+3
Ω
.04%+10
Ω
.03%+5
Ω
.04%+15
Ω
.126%+12.6
Ω
.168%+42
Ω
300 k
Ω
.1%+40
Ω
.2%+100
Ω
.1%+60
Ω
.2%+150
Ω
.42%+168
Ω
.84%+420
Ω
3 M
Ω [1]
.25%+800
Ω
.5%+10 k
Ω
.25%+1 k
Ω
.5%+1.5 k
Ω
1.05%+3.36 k
Ω
2.1%+4.2 k
Ω
[1] The 3 M
Ω
range is susceptible to the absorption of humidity under extreme conditions. If the instrument is
operated normally within its specified temperature-humidity range, the 3 M
Ω
range meets its accuracy specifications.
However, if the instrument is “soaked” at 50
°
C, 90% relative humidity, the 3 M
Ω
range may require 1 hour of “dry-out”
time at 25
°
C, <40% relative humidity for each hour of soak time in order to achieve its specified accuracy.
2640A Two-Wire Resistance Measurement Specifications 1-24.
The 2640A specifications for the two-wire resistance measurement function is based on
the four-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
(n1%/ºC).