The USB 3.0 Speed Bump

April 23, 2009
USB 3.0, the latest version of the USB connectivity standard, holds promise for industrial applications such as vision systems and high-performance data acquisition.

The latest version of USB, completed last year, increases bandwidth up to 5 Gbits/s, moving 25 Gbytes in only 70 seconds. While most industrial applications won’t need that much speed for I/O applications, observers feel that USB 3.0 will eventually play a role in applications that move lots of data.

Though the first CPUs supporting the standard won’t move into high volume until later this year, industrial designers are already speculating how engineers may use it in manufacturing. At those speeds, the standard—also called SuperSpeed USB—is expected to see use in applications like vision and high-performance data acquisition.

Makers of data-acquisition systems are looking at the standard for demanding applications. And, suppliers like Tektronix and LeCroy are rolling out test equipment that will help designers finalize their USB 3.0 designs.

There are other industrial applications as well. “Areas such as wireless communication, audio, and fast read/write applications such as recognition will all be pushing the 3.0 technology,” says Susan Wooley, president of Micro/Sys. However, she noted that embedded users are rarely early adopters of consumer standards, so it will be quite some time before SuperSpeed makes its way into industrial apps.

In machine vision, there’s a chance that USB 3.0 could compete with 1394. It doesn’t offer isochronous capabilities, but it has enough bandwidth to become a link for cameras.

“USB 3.0’s speed could make it a bigger player,” says Jeff Fryman, director of standards development for the Automated Imaging Association (AIA).

However, some observers note that USB cables can’t stretch more than three meters. That will be a roadblock for applications including vision, where cameras and other devices are often more than 10 feet from controllers.

But many industrial applications don’t need long cables. For them, USB 3.0 offers benefits beyond speed. It reduces power consumption by eliminating the polled architecture used until now. SuperSpeed nodes also tell the host when they have traffic, eliminating the power consumption often associated with frequent polling.

Adaptive equalization should help users set up systems. In addition, the amount of power available for devices is nearly doubled. USB 3.0 provides a maximum draw of 900 mA, up from 500 mA for USB 2.0, sometimes called HighSpeed USB.

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