Product Focus New VXI Products Increase Options, Reduce Costs

Have you hesitated to select a VXI implementation for an instrumentation or data acquisition application because it may not fit your specific needs or would cost too much? Well, today this quandary isn’t nearly so difficult. Hewlett-Packard’s new VXI products have expanded the range of choices so that you can have an optimum solution with a smaller price tag.

A new set of mainframes, offering two power options and standard or extended monitoring facilities, provides a foundation for your application. Speed and controller costs also are not a problem: Your system can be controlled by a PC with data being transferred at a rate as fast as 400 Mb/s using an IEEE 1394 FireWire bus PC-to-VXI interface (see sidebar).

Flexible source/measurement-to-UUT signal switching can be accomplished via a new relay multiplexer module. A VXI B-sized Mezzanine Module (M-Module) carrier provides a VXI interface for up to four industry-standard M-modules.

New and Enhanced Mainframes

Four new members of the HP E8400A family of C-size mainframes are VXI plug-and-play-compliant and feature a new, higher-performance fan (impeller) design for improved cooling with less noise. They contain front-panel monitoring lights that report power supply, fan, backplane communications, and system status. An auxiliary front connector lets you easily access diagnostic information.

The HP E8401A, with 550 W of usable power, is the lowest priced mainframe in the family. The HP E8403A has all the features of the HP E8401A plus 1,000 W of usable power.

The HP E8402A (550 W) and the HP E8404A (1,000 W) come with new, enhanced VXI mainframe monitoring features. A menu-driven, full-color LCD shows data regarding temperatures, voltages, currents, power, and fan speeds. The display also shows system messages, warnings, usage history, and maintenance-timer and RS-232 settings. Users have a choice of numeric, strip-chart, and histogram readouts.

Two enhanced B-size VXI mainframes, the HP E1300B and the HP E1301B, now include dual fans, which extend the life expectancy of VXI cards. These higher-performance mainframes support more demanding B-size modules, such as multimeters and cards with M-Modules.

IEEE 1394-to-VXI Interface

The new HP E8491A Interface facilitates data transfer between a PC and the VXIbus at a maximum speed of 400 Mb/s. Data transfer takes place over the new IEEE 1394 communications bus, known as FireWire. According to industry forecasts, approximately 50% of all PCs shipped in the year 2000 will be equipped with a FireWire connection.

The HP E8491A Interface consists of a single-slot, C-size VXI module; a 4.5-meter cable, and an IEEE 1394 PC interface card. It supports multiple mainframes communicating with one PC and comes with an I/O software library for Microsoft® Windows® 95 and Windows NT®. It is easy to reconfigure IEEE 1394-based systems since new devices are recognized automatically.

Density Multiplexer

The new HP E8462A 256-channel relay multiplexer, a single-slot, C-size VXI card, uses nonlatching armature relays which switch up to 250 V and power up to 125 W. The architecture allows you to program it in various topologies, such as 256×1, 128×1, 64×1, and 32×1.

Mixtures of these topologies can be used on a single card and two-, three-, and four-wire configurations. Optional terminal blocks come with HP QUIC, a feature that saves time and effort when inserting and disconnecting the terminal block from the module and the module from the mainframe.

B-Size M-Module Carrier

With the new HP E2250A M-Module Carrier, you can use industry-standard M-Modules in a VXI B-size environment. Up to four M-Modules can be placed on the HP E2250A card and interfaced with the VXIbus. The carrier supports more than 150 industry-standard M-Modules. HP E8401A: $3,695; HP E8402A: $6,395; HP E8403A: $6,395; HP E8404A: $7,495; HP E1300B: $2,495; HP E1301: $3,195; HP E8491A: $2,495; HP E2250A: $1,195; HP E8462A: $2,995. Hewlett-Packard, (800) 452-4844, ext. 5706. Circle 194

(HPE8400A, E8491A)


IEEE 1394 Standard for High-Speed Data Transfer

The IEEE 1394 Standard, known as the FireWire bus, is a new interface alternative for high-speed data transfer between VXI instruments and PCs. IEEE 1394 transfers data at rates of up to 50 times faster than GPIB—at about the same cost.

The FireWire bus, originally created by Apple Computer, was born out of the need for a low-cost, consumer-oriented connection between digital-video recorders and PCs. The reduction in cost is achieved largely through serial data transfer, which uses simplified electronics and cables.

High-speed operation is accomplished, in part, by using small signals that are transmitted differentially over twisted-pair wire with controlled-impedance characteristics. Data is sent over one of the twisted-pair sets, while the other set is used for the clock.

FireWire bus transmitters and receivers, available as standard chip sets, handle addressing, initialization, arbitration, and protocol. The plug-and-play capability of the IEEE 1394 bus is achieved in the chip set. Node addresses, for example, are assigned to devices on the bus upon power-up.

The IEEE 1394 cable medium allows up to 16 physical connections or cable hops, each up to 4.5 meters long. This gives a system using IEEE 1394 a total cable distance of 72 meters.

Copyright 1998 Nelson Publishing Inc.


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