VXI Technology announces the launch of the EX1048, a 48-channel precision thermocouple instrument based upon the LXI (LAN Extensions for Instrumentation) standard. The EX1048 combines all of the features necessary to address the most demanding temperature measurement applications in an easy to use configuration.

This high-density, scalable instrument is compact and standalone, and can connect directly to your Ethernet network, greatly reducing setup and installation time. Multiple devices are easily integrated and synchronized through the built-in dedicated LXI Trigger Bus interface, as well as with other synchronization features inherent in LXI based instrumentation.

Individual sampling rates of 1000 Sa/s/channel are coupled through independent signal conditioning paths and programmable filters, to provide the ultimate in flexibility and performance. Complete internal end-to-end self-calibration is simple and quick, affording the user the convenience of performing it as often as necessary. Measurement integrity is further enhanced through open thermocouple detection that provides the user with a continual indication of the channel status.

"This product is ideally suited for applications requiring precision temperature measurement, whether in the laboratory or across the facility on the shop floor," commented Tom Sarfi of VXI Technology.

For more information about these and other products, simply visit www.vxitech.com, or call VXI Technology, Inc., 2031 Main Street, Irvine, CA 92614. Tel. 949.955.1VXI or 949-955-1894. Fax 949.955.3041. eeProductCenter's Alex Mendelsohn Says ...

In autumn of 2004 we reported the news that VXI Technology (Irvine, Calif.) and Agilent Technologies (Palo Alto, Calif.) had partnered to introduce the LXI (LAN extensions for instrumentation) standard. Combining the attributes of rack-and-stack instruments and modular test capabilities rolled into compact packages, Agilent and VXI Technology helped define LXI as a next-generation LAN-based modular test platform.

In its broad definition, LXI would use standard I/O and would be based on the popular IEEE-802.3 networking standards, using TCP/IP (Internet Protocol) sockets, VXI-11 instrument discovery, and IVI-COM drivers. It would also make use of standard 1U-sized and 2U-sized rack packaging.

A First At Rev. 0.9

Keep in mind, however, that the LXI Consortium has published 0.9 of its spec, and the EX1048 is a preliminary product. According to VXI Technology marketing director Jon Semancik, who also sits on the Consortium's board of directors, a finalized Rev 1.0 LXI spec will not appear until March of 2005.

VXI Tech's new EX1048 thermocouple instrument, is arguably one of the first (if not the first) VXI instrument to hit the scene. Priced starting at less than $4000, the EX1048 should fill the bill for temperature measurement in industrial and scientific applications.

The EX1048 works with all standard thermocouple types, including J, K, T, E, S, B, R, and N types, providing 0.01°C temperature resolution. Speaking of specs, the EX1048 also has a voltage input range that extends from ±66-mV, and affords a microvolt of resolution. Its voltage accuracy (with self calibration; more on its cal functions in a moment) is within ±0.05% (plus 10 µV); it's within ±0.1% (plus 30 µV) without calibration.

Click to see thermocouple accuracy table

Finally, all of this instrument's inputs are over-voltage protected, which is a sanity-saving feature in noisy industrial settings. Each input can thwart ±35-V, which can also prove a life saver if an errant (high) sensor voltage is inadvertently applied.

Ethernet Plug-and-Play

Kudos to VXI Technology for making this product easy to use. As a 1U-sized module (measuring 1.75 x 17.5 x 14.4-in.), it can be connected to any 10/100-Base-T Ethernet network for straightforward instrument installation and set-up over a wide physical area. In use, all you need do is plug-in a standard Ethernet network cable and start taking data.

Its integrated Web server lets you verify communications and instrument functions. Beyond that, industry-standard VXI Plug-and-play drivers provide an API (application programming interface) that can shorten integration and program development.

Multiple Instruments

Multiple VXIbus devices can also be integrated and synchronized. VXI supplies a dedicated so-called Trigger Bus for that purpose. As such, the EX1048 can be readily used in distributed applications, where sensors may be physically separated by large distances.

On the analog input side, as the company's press release notes, the EX1048 can sample as fast as 1000-samples/s on each of its 48 high-Z (40-Mohm) differential-input channels, thanks to each analog input provided with independent signal conditioning paths. This architecture ensures data integrity regardless of sample speed or possible input overloads.

These individual inputs are also equipped with software-selectable 4-Hz and 1-kHz filters. The 4 Hz filter gives you at least 100 dB of CMRR (common-mode rejection ratio), measured at DC. At line frequencies (50/60-Hz) CMRR is typically 140 dB (120 dB min). Similarly, the 1 kHz filter gives you at least 100 dB at DC, and typically 100 dB at line frequencies (80-dB min.)

End-to-End Calibration

The EX1048 also performs self-calibration, and you can invoke the cal routines whenever you deem it necessary to do so. What's more, internal end-to-end programmable calibration is provided for each signal path. An on-board calibration source provides reference signals that are applied prior to analog filtering and gain circuits to compensate for the effects of drift, component aging, and temperature.

The EX1048 system also warns you if there are any defective or open thermocouples connected to it. Like the channel-independent signal conditioning, each of the unit's channels also packs its own thermocouple detection circuitry.

Of course, every thermocouple system uses cold junction compensation. For its part, the EX1048 combines multiple thermistors, a significant thermal mass, and careful parts placement to ensure accuracy and repeatability.

Need more information about this hot and cool product? Contact VXI Technology marketing director Jon Semancik at 949-955-1894, or visit VXI's dedicated Web pages for this instrument.