2640A Four-Wire Resistance Measurement Specifications; 2640A Two-Wire Resistance Measurement Specifications - Fluke 2640A Service Manual

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2640A Four-Wire Resistance Measurement Specifications

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.
Temperature Coefficient
Table 1-20. 2640A Four-Wire Resistance Range and Resolution Specifications
Range
300Ω 1 mΩ
3 kΩ 10 mΩ
30 kΩ 100 mΩ
300 kΩ 1Ω
3 MΩ 10Ω
Range
300Ω .015%+20 mΩ
3 kΩ .02%+.3Ω
30 kΩ .03%+3Ω
300 kΩ .1%+40Ω
3 MΩ [1]
.25%+800Ω
[1] The 3 MΩ 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 MΩ range meets its accuracy specifications.
However, if the instrument is "soaked" at 50°C, 90% relative humidity, the 3 MΩ 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

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
(nominal +1%/ºC).
1-16
Table 1-19. 2640A Four-Wire Resistance Temperature Coefficient
Specification
Resolution
Applied
Slow Fast
3mΩ 1 mA
100 µA
30 mΩ
10 µA
300 mΩ
10 µA
3Ω
1 µA
30Ω
Table 1-21. 2640A Four-Wire Resistance Accuracy Specifications
18°C to 28°C
90 Day
Slow Fast
.02%+80 mΩ
.02%+.8Ω
.04%+10Ω
.2%+100Ω
.5%+10 kΩ
Add 1/10th the 90 day specification per °C
above 28°C or below 18°C.
Current Full Scale
Voltage
300 mV
300 mV
300 mV
3.0V
3.0V
Accuracy, 3σ + (% input + V)
1 Year
Slow Fast
.02%+50 mΩ .02%+120 mΩ
.02%+.5Ω .02%+1.2Ω
.03%+5Ω .04%+15Ω
.1%+60Ω .2%+150Ω
.25%+1 kΩ .5%+1.5 kΩ
Characteristic
Maximum Voltage
Applied by Instrument
3.5V
3.5V
3.5V
3.5V
3.5V
-10°C to 60°C
1 Year
Slow
.084%+126 mΩ .084%+336 mΩ
.084%+1.26Ω .084%+3.36Ω
.126%+12.6Ω .168%+42Ω
.42%+168Ω .84%+420Ω
1.05%+3.36 kΩ 2.1%+4.2 kΩ
1-23.
Fast
1-24.