Network Considerations

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Network Primer

∙A Repeater is a device used to physically isolate and extend the length of a network segment, but it does not divide the network into subnets.

∙A hub is a device that allows communication among multiple 10BaseT network hosts and allows these hosts to communicate with other Ethernet wiring. Some hubs also perform Router functions.

∙A Bridge is used on Ethernet networks to isolate two portions of the network at the Frame level (see “Basic Network Packet and Frame Contents” in this appendix). This is done to minimize transmission collisions, but the two portions isolated by a Bridge remain on the same subnet. A Bridge also acts as a Repeater.

∙A Router is used to isolate two portions of the network into subnets, as described in “IP Addresses and Segmented Networks” in this appendix. A Router also acts as a Bridge. Make sure your Router will route IP packets if you want to place the PC and NetDAQ instruments in different subnets.

∙A Gateway is used to connect two networks with different architecture and protocols. For example, a Gateway could be used to connect an Ethernet to an X.25 net running on public telephone wiring. Gateways also perform Router, Bridge, and Repeater functions.

The operation of NetDAQ software and instruments should be unaffected by a properly designed network using any of these network devices. However, you must use extra care when setting up PCs and NetDAQ instruments in a network containing multiple subnets (net containing one or more routers and/or gateways). The IP addresses assigned to the PC and instruments must be carefully selected in this case. See “IP Addresses and Segmented Networks” for more information on IP address assignment.

When a Bridge, Router, or Gateway is used in a network containing NetDAQ instruments and hosts, be sure to reboot the host PC whenever an instrument is moved from one section of the net to another. This is required to allow the network hardware devices to initialize bridging and routing tables.

Also, when NetDAQ is used in a different subnet from the PC, the Routers and Gateways used to connect the subnets must be able to route IP packets. The default gateway addresses on the NetDAQ and PC must be set properly.

Basic Network Packet and Frame Contents

I-7.

Network messages consist of short (mostly less than 1K byte) hunks of data, surrounded by header and error detection information used by the protocols. The message, together with the protocol information, is called a "Packet." When physical network information (clock synchronization, error detection, etc.) is wrapped around the packet, it is called a "Frame." The interface hardware adds and

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Fluke 2640A, 2645A user manual Basic Network Packet and Frame Contents
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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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