USB high-voltage I/O module supplants PCI equivalent

Universal Serial Bus continues its ascendancy for many moderate-speed measurement and data acquisition applications, especially those where plug-and-play in a PC environment is paramount. Look at data acquisition and test-and-measurement supplier Measurement Computing Corp.'s new Measurement Advantage USB-based high-voltage, high-current digital I/O module. It's an alternative to, or replacement for, PCI-based systems used for high-voltage monitoring and control—but its' entirely plug-and-play, thanks to USB.

Dubbed the USB-PDISO8, the new USB module gives you eight isolated 24V ac-dc inputs, and eight 6A Form C (SPDT) relays that have 240Vac/28Vdc contact ratings. The digital I/O provides 500V of isolation. The relays provide the same. What's more, you can configure each isolated input with an optional input filter. The input filters are enabled and disabled by software.

The module includes screw terminals to make connection to the outside world, and it's housed in an all-metal shielded enclosure. With its small footprint, it can be used on the bench or mounted on a DIN rail.

The system will also work on USB 1.1 and USB 2.0 ports, and is supported under Windows 98, Windows SE, Windows ME, Windows 2000 and Windows XP.

Cheaper than PCI
Priced at $299, measurement says its USB-PDISO8 is also about 37 percent less expensive than the equivalent PCI-based alternative, which Measurement Computing makes (it's the PCI-PDISO8).

The USB-PDISO8 also offers a built-in USB expansion port that lets you daisy-chain up to five units together. Optional power cables daisy-chain power from one unit to another.

The USB-PDISO8 compliments the other Measurement Advantage high-voltage digital IO products, namely measurement's USB-ERB08 and USB-ERB24. These let you control and monitor electromechanical relays. A USB-SSR08 and USB-SSR24 let you monitor and control industry-standard solid-state relays.

Altogether, these five products make an argument for replacing PCI systems with USB. For many high-voltage applications they're functionally equivalent but are lower cost, and more easily re-deployed.

Freebie bits
All ship with free software, too. TracerDAQ is Measurement Computing's strip chart recorder, oscilloscope, and data logger application. SoftWIRE is a graphical programming interface for Visual Studio .NET.

But wait. There's more. Universal Library is a language interface that lets you write programs in all popular programming languages. It uses a high-level command syntax. Measurement Computing also supplies UL for LabVIEW a package of drivers, VIs (virtual instruments), and program examples, for using the company's hardware in National Instruments's popular LabVIEW graphical programming environment.

Finally, measurement supplies InstaCal. It's an all-in-one installation, calibration, and test application that simplifies important initial steps involved in turning your PC into a measurement system.

- Alex Mendelsohn
eeProductCenter