Preparing for Operation 2

Instrument Preparation

Shielded Wiring

2-10.

Use shielded wires and sensors (such as thermocouples) in environments where electrical noise is present, and connect the wire shield to the chassis ground terminal. Also refer to Appendix B "Noise, Shielding and Crosstalk Considerations."

Crosstalk Considerations

2-11.

Crosstalk between measurement lines causes one signal to interfere with another, introducing measurement errors. To reduce the effects of crosstalk, check the following:

∙Separate Wiring Keep any input wiring carrying ac voltage signals physically separate from the input wiring of sensitive channels. Also keep input wiring separated from, or shielded from, ac power mains wiring.

∙Adjacent Channels Avoid connecting input with ac voltage signals next to sensitive channel inputs. Leave unconnected channels between the inputs when possible.

∙Sensitive Channels Avoid connecting inputs with ac voltage signals adjacent to four-terminal input channels.

∙High Impedance Inputs Avoid high-source impedances on sensitive channels, or minimize the capacitance of the sensitive channel to earth (chassis) ground for high impedance inputs.

∙Precision Resistance Measurements Avoid connecting any ac voltage

inputs when making peak-accuracy high resistance measurements (resistance greater than 10 kΩ).

See Appendix B "Noise, Shielding and Crosstalk Considerations" for a complete discussion of crosstalk and measurement errors.

Digital I/O Connections

2-12.

PCaution

To avoid damage to the instrument, do not apply any voltages greater than 30V maximum between the DIGITAL I/O connector terminals and earth ground.

The 10-terminal DIGITAL I/O connector (Figure 2-5) on the rear panel of the instrument provides connection to the Digital I/O and Totalizer functions.

Complete the following procedure to make a connection to these functions:

1.Remove the DIGITAL I/O connector from the packing material or instrument rear panel.

2-11

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Fluke 2640A, 2645A user manual Shielded Wiring, Crosstalk Considerations, Digital I/O Connections
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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.
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