USB 3.0 Interface and the USB3 Vision Standard

The USB 3.0 interface has recently been renamed "USB 3.1 Gen 1." The two terms are essentially interchangeable, as there is virtually no technical difference between them. However, they do differ from the latest generation, USB 3.1 Gen 2—also known as "USB SuperSpeed+"—which offers an even higher maximum bandwidth than its predecessor. At present, USB 3.1 Gen 2 is not yet widely adopted, appearing primarily in development and testing projects, with relatively few devices currently supporting it.

How, then, should users determine which interface best suits their specific needs? Every interface on the market has its own distinct strengths; therefore, it is essential to select the technology that aligns with the requirements of the application. While USB 3.0 is highly impressive in terms of bandwidth and plug-and-play compatibility, GigE offers superior performance regarding cable length (up to 100 meters) and provides better support for multi-camera systems.

Much like the GigE interface, which is defined as part of the GigE Vision standard, the USB 3.0 interface is also governed by an industrial machine vision standard: the USB3 Vision standard. This standard was officially approved in January 2013. Managed directly by the AIA (Automated Imaging Association), this serves as the official standard for USB 3.0 interfaces within the machine vision industry. As a founding member of the association, Basler played a pivotal role in the standard's creation.

The purpose of this standard is to establish unified rules for USB 3.0 communication and configuration architecture. Such a standard is essential to prevent the proliferation of incompatible accessories and proprietary solutions from various manufacturers—a situation that would otherwise become a confusing nightmare for end users.

Prior to the introduction of the USB 3.0 Vision standard, there was no established standard for USB devices in the machine vision industry. While camera manufacturers had previously developed their own proprietary solutions based on the consumer-market USB 2.0 interface, these often failed to provide the stability, durability, and overall system robustness required for industrial applications. History has demonstrated that the logical implementation of an interface—along with its associated standards—is critical to the successful adoption and widespread establishment of any interface technology within the industrial machine vision market.

The USB 3.0 Vision standard incorporates the strengths of GenICam, which serves as the universal programming interface for all modern industrial camera standards. Together, USB 3.0 Vision and GenICam provide users with high stability and low latency for both image data transmission and camera control. Utilizing USB 3.0 Vision-certified cameras, software, and accessories offers significant advantages, including the flexibility to use a diverse range of cameras and the ease of replacing individual components. Furthermore, the standard establishes communication protocols that govern how various hardware and software components interact within a system.

The USB 3.0 Vision standard also addresses mechanical design—for instance, by requiring that cable connectors be designed to allow for secure, screw-locked connections. This enhances the robustness of the interface and ensures the interchangeability of components.

Specifically tailored to the requirements of machine vision technology, the USB 3.0 Vision standard defines its own transport layer. This includes a control transport layer for managing device-to-host communication, an event transport layer for transmitting asynchronous events, and a stream transport layer designed to ensure reliable, high-speed, and cost-effective data transmission.