2640A/2645A NetDAQ

Users Manual

2645A 2-Wire Resistance Measurement Specifications

A-25.

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

A-26.

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.

Table A-33. 2645A 4-Wire RTD Temperature Coefficient

Specification

Temperature Coefficient

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.

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-34. 2645A 4-Wire RTD Specifications

Temperature

Resolution

Slow

Fast

 

 

 

 

 

Accuracy, 3σ ± ºC

 

 

 

 

 

 

 

 

 

 

90 Day, 18ºC to

 

1 Year,

1 Year, -10ºC to

 

18ºC to

 

28ºC

 

 

 

28ºC

 

60ºC

 

 

 

 

 

 

 

 

 

 

 

 

 

Slow

 

Fast

 

Slow

Slow

 

Fast

 

 

 

 

 

 

 

 

-200ºC*

0.03ºC

0.06ºC

0.16ºC

0.25ºC

0.25ºC

0.62ºC

 

 

 

 

 

 

 

0ºC*

0.03ºC

0.06ºC

0.20ºC

0.31ºC

0.31ºC

0.85ºC

 

 

 

 

 

 

 

100ºC

0.03ºC

0.06ºC

0.23ºC

0.34ºC

0.34ºC

0.95ºC

 

 

 

 

 

 

 

300ºC

0.03ºC

0.06ºC

0.30ºC

0.41ºC

0.41ºC

1.18ºC

 

 

 

 

 

 

 

600ºC

0.03ºC

0.06ºC

0.53ºC

0.63ºC

0.63ºC

1.62ºC

 

 

 

 

 

 

 

*The Custom-385 range is not recommended for use below -80ºC. See Appendix D.

1.10ºC

1.30ºC

1.40ºC

1.70ºC

2.12ºC

A-22

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Fluke 2645A 2-Wire Resistance Measurement Specifications, 2645A 4-Wire RTD per ITS-1990 Measurement Specifications

2645A, 2640A specifications

The Fluke 2640A and 2645A are advanced bench multimeters that represent a significant leap in measurement technology, designed primarily for electrical engineers and technicians who require precision and reliability in their readings. These multimeters are built to cater to complex applications in manufacturing, research, and development.

One of the standout features of the Fluke 2640A and 2645A is their high accuracy. With specifications that can reach up to 0.0035% DC Voltage accuracy, users can trust that their measurements will be consistent and precise. This is especially critical in fields like automated test equipment (ATE) where exact measurements can be crucial for product quality and safety.

Both models incorporate a large, easy-to-read display, making it convenient for users to view measurement results clearly from a distance. They also feature a wide measurement range, capable of handling a variety of tasks, from basic voltage and current measurements to more complex tasks such as resistance and temperature measurements with appropriate sensors.

The multimeters also stand out with their advanced data logging capabilities. The Fluke 2645A, for instance, can store up to 10,000 readings, allowing for extensive data collection and analysis without the need for constant monitoring. This is beneficial for long-term studies or processes that require continual oversight.

Connectivity is another key characteristic. Both the 2640A and 2645A support USB and RS-232 interfaces, which enable easy integration with computers and other devices for seamless data transfer. This feature is important for engineers who rely on software for data analysis and visualization.

Another notable technology included in these models is the Fluke Connect app compatibility, which allows users to remotely monitor measurements from their smartphones or tablets. This capability provides added flexibility, enabling technicians to work hands-free while still keeping an eye on process measurements.

Additionally, the Fluke 2645A comes with a graphical display option, allowing users to visualize measurement trends over time. This graphical representation can be invaluable for diagnosing issues or observing patterns in data.

In conclusion, the Fluke 2640A and 2645A multimeters offer exceptional performance with their high accuracy, extensive data logging, connectivity options, and advanced visualization capabilities. These features make them indispensable tools for professionals in a variety of fields, ensuring that they can achieve reliable results in their measurement endeavors.